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Transcriptome Analysis Reveals the Molecular Regularity Mechanism Underlying Stem Bulblet Formation in Oriental Lily 'Siberia'; Functional Characterization of the LoLOB18 Gene. Int J Mol Sci 2022; 23:ijms232315246. [PMID: 36499579 PMCID: PMC9738039 DOI: 10.3390/ijms232315246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 11/28/2022] [Accepted: 12/01/2022] [Indexed: 12/09/2022] Open
Abstract
The formation of underground stem bulblets in lilies is a complex biological process which is key in their micropropagation. Generally, it involves a stem-to-bulblet transition; however, the underlying mechanism remains elusive. It is important to understand the regulatory mechanism of bulblet formation for the reproductive efficiency of Lilium. In this study, we investigated the regulatory mechanism of underground stem bulblet formation under different conditions regarding the gravity point angle of the stem, i.e., vertical (control), horizontal, and slanting. The horizontal and slanting group displayed better formation of bulblets in terms of quality and quantity compared with the control group. A transcriptome analysis revealed that sucrose and starch were key energy sources for bulblet formation, auxin and cytokinin likely promoted bulblet formation, and gibberellin inhibited bulblet formation. Based on transcriptome analysis, we identified the LoLOB18 gene, a homolog to AtLOB18, which has been proven to be related to embryogenic development. We established the stem bud growth tissue culture system of Lilium and silenced the LoLOb18 gene using the VIGS system. The results showed that the bulblet induction was reduced with down-regulation of LoLOb18, indicating the involvement of LoLOb18 in stem bulblet formation in lilies. Our research lays a solid foundation for further molecular studies on stem bulblet formation of lilies.
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Transcriptome analysis of genes involved in starch biosynthesis in developing Chinese chestnut (Castanea mollissima Blume) seed kernels. Sci Rep 2021; 11:3570. [PMID: 33574357 PMCID: PMC7878784 DOI: 10.1038/s41598-021-82130-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022] Open
Abstract
Chinese chestnut (Castanea mollissima Blume) seed kernels (CCSK) with high quality and quantity of starch has emerged as a potential raw material for food industry, but the molecular regulatory mechanism of starch accumulation in developing CCSK is still unclear. In this study, we firstly analyzed the fruit development, starch accumulation, and microscopic observation of dynamic accumulation of starch granules of developing CCSK from 10 days after flowering (DAF) to 100 DAF, of which six representative CCSK samples (50–100 DAF) were selected for transcriptome sequencing analysis. Approximately 40 million valid reads were obtained, with an average length of 124.95 bp, which were searched against a reference genome, returning 38,146 unigenes (mean size = 1164.19 bp). Using the DESeq method, 1968, 1573, 1187, 1274, and 1494 differentially expressed unigenes were identified at 60:50, 70:60, 80:70, 90:80 and 100:90 DAF, respectively. The relationship between the unigene transcriptional profiles and starch dynamic patterns in developing CCSK was comparatively analyzed, and the specific unigenes encoding for metabolic enzymes (SUSY2, PGM, PGI, GPT, NTT, AGP3, AGP2, GBSS1, SS1, SBE1, SBE2.1, SBE2.2, ISA1, ISA2, ISA3, and PHO) were characterized to be involved potentially in the biosynthesis of G-1-P, ADPG, and starch. Finally, the temporal transcript profiles of genes encoding key enzymes (susy2, pgi2, gpt1, agp2, agp3, gbss1, ss1, sbe1, sbe2.1, sbe2.2, isa1, isa2, isa3, and pho) were validated by quantitative real-time PCR (qRT-PCR). Our findings could help to reveal the molecular regulatory mechanism of starch accumulation in developing CCSK and may also provide potential candidate genes for increasing starch content in Chinese chestnut or other starchy crops.
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Dai D, Ma Z, Song R. Maize kernel development. MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2021; 41:2. [PMID: 37309525 PMCID: PMC10231577 DOI: 10.1007/s11032-020-01195-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/03/2020] [Indexed: 06/14/2023]
Abstract
Maize (Zea mays) is a leading cereal crop in the world. The maize kernel is the storage organ and the harvest portion of this crop and is closely related to its yield and quality. The development of maize kernel is initiated by the double fertilization event, leading to the formation of a diploid embryo and a triploid endosperm. The embryo and endosperm are then undergone independent developmental programs, resulting in a mature maize kernel which is comprised of a persistent endosperm, a large embryo, and a maternal pericarp. Due to the well-characterized morphogenesis and powerful genetics, maize kernel has long been an excellent model for the study of cereal kernel development. In recent years, with the release of the maize reference genome and the development of new genomic technologies, there has been an explosive expansion of new knowledge for maize kernel development. In this review, we overviewed recent progress in the study of maize kernel development, with an emphasis on genetic mapping of kernel traits, transcriptome analysis during kernel development, functional gene cloning of kernel mutants, and genetic engineering of kernel traits.
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Affiliation(s)
- Dawei Dai
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Beijing Key Laboratory of Crop Genetic Improvement, Joint International Research Laboratory of Crop Molecular Breeding, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193 China
- Shanghai Key Laboratory of Bio-Energy Crops, Plant Science Center, School of Life Sciences, Shanghai University, Shanghai, 200444 China
| | - Zeyang Ma
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Beijing Key Laboratory of Crop Genetic Improvement, Joint International Research Laboratory of Crop Molecular Breeding, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193 China
| | - Rentao Song
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Beijing Key Laboratory of Crop Genetic Improvement, Joint International Research Laboratory of Crop Molecular Breeding, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193 China
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4
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Meng Q, Zhang W, Hu X, Shi X, Chen L, Dai X, Qu H, Xia Y, Liu W, Gu M, Xu G. Two ADP-glucose pyrophosphorylase subunits, OsAGPL1 and OsAGPS1, modulate phosphorus homeostasis in rice. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:1269-1284. [PMID: 32996185 DOI: 10.1111/tpj.14998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 09/03/2020] [Indexed: 06/11/2023]
Abstract
Plant acclimatory responses to phosphate (Pi) starvation stress include the accumulation of carbohydrates, namely sugar and starch. However, whether altered endogenous carbohydrate profile could in turn affect plant Pi starvation responses remains widely unexplored. Here, two genes encoding the large and small subunits of an ADP-glucose pyrophosphorylase (AGP) in rice (Oryza sativa), AGP Large Subunit 1 (AGPL1) and AGP Small Subunit 1 (AGPS1), were functionally characterized with regard to maintenance of phosphorus (P) homeostasis and regulation of Pi starvation signaling. AGPL1 and AGPS1 were both positively responsive to nitrogen (N) or Pi deprivation, and expressed in almost all the tissues except in the meristem and mature zones of root. AGPL1 and AGPS1 physically interacted in chloroplast, and catalyzed the rate-limiting step of starch biosynthesis. Low-N- (LN) and low-Pi (LP)-triggered starch accumulation in leaves was impaired in agpl1, agps1 and apgl1 agps1 mutants compared with the wild-type plants. By contrast, mutation of AGPL1 and/or AGPS1 led to an increase in the content of the major sugar, sucrose, in leaf sheath and root under control and LN conditions. Moreover, the Pi accumulation was enhanced in the mutants under control and LN conditions, but not LP conditions. Notably, the LN-induced suppression of Pi accumulation was compromised attributed to the mutation of AGPL1 and/or AGPS1. Furthermore, the increased Pi accumulation was accompanied by the specific suppression of OsSPX2 and activation of several Pi transporter genes. These results indicate that a balanced level of carbohydrates is vital for maintaining plant P homeostasis.
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Affiliation(s)
- Qi Meng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
| | - Wenqi Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
| | - Xu Hu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
| | - Xinyu Shi
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
| | - Lingling Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
| | - Xiaoli Dai
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
| | - Hongye Qu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, 210095, China
| | - Yuwei Xia
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
| | - Wei Liu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
| | - Mian Gu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, 210095, China
| | - Guohua Xu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing, 210095, China
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, 210095, China
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Li Z, Cao L, Zhao L, Yu L, Chen Y, Yoon KS, Hu Q, Han D. Identification and Biotechnical Potential of a Gcn5-Related N-Acetyltransferase Gene in Enhancing Microalgal Biomass and Starch Production. FRONTIERS IN PLANT SCIENCE 2020; 11:544827. [PMID: 32983212 PMCID: PMC7483765 DOI: 10.3389/fpls.2020.544827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
Microalgae are promising feedstocks for starch production, which are precursors for bioenergy and chemicals manufacturing. Though starch biosynthesis has been intensively studied in the green alga Chlamydomonas reinhardtii, regulatory mechanisms governing starch metabolism in this model species have remained largely unknown to date. We proposed that altering triacylglycerol (TAG) biosynthesis may trigger intrinsic regulatory pathways governing starch metabolism. In accordance with the hypothesis, it was observed in this study that overexpression of the plastidial lysophosphatidic acid acyltransferase gene (i.e. LPAAT1) in C. reinhardtii significantly enhanced TAG biosynthesis under nitrogen (N)-replete conditions, whereas the starch biosynthesis was enhanced in turn under N depletion. By the exploitation of transcriptomics analysis, a putative regulatory gene coding Gcn5-related N-acetyltransferase (GNAT19) was identified, which was up-regulated by 11-12 times in the CrLPAAT1 OE lines. Overexpression of the cloned full-length CrGNAT19 cDNA led to significant increase in the starch content of C. reinhardtii cells grown under both N-replete and N-depleted conditions, which was up to 4 times and 26.7% higher than that of the empty vector control, respectively. Moreover, the biomass yield of the CrGNAT19 OE lines reached 1.5 g L-1 after 2 days under N-depleted conditions, 72% higher than that of the empty vector control (0.87 g L-1). Overall, the yield of starch increased by 118.5% in CrGNAT19 OE lines compared to that of the control. This study revealed the great biotechnical potentials of an unprecedented GNAT19 gene in enhancing microalgal starch and biomass production.
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Affiliation(s)
- Zhongze Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Li Cao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Lihua Yu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yi Chen
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Kang-sup Yoon
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
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Song Y, Luo G, Shen L, Yu K, Yang W, Li X, Sun J, Zhan K, Cui D, Liu D, Zhang A. TubZIP28, a novel bZIP family transcription factor from Triticum urartu, and TabZIP28, its homologue from Triticum aestivum, enhance starch synthesis in wheat. THE NEW PHYTOLOGIST 2020; 226:1384-1398. [PMID: 31955424 DOI: 10.1111/nph.16435] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 01/07/2020] [Indexed: 05/20/2023]
Abstract
Starch in wheat grain provides humans with carbohydrates and influences the quality of wheaten food. However, no transcriptional regulator of starch synthesis has been identified first in common wheat (Triticum aestivum) due to the complex genome. Here, a novel basic leucine zipper (bZIP) family transcription factor TubZIP28 was found to be preferentially expressed in the endosperm throughout grain-filling stages in Triticum urartu, the A genome donor of common wheat. When TubZIP28 was overexpressed in common wheat, the total starch content increased by c. 4%, which contributed to c. 5% increase in the thousand kernel weight. The grain weight per plant of overexpression wheat was also elevated by c. 9%. Both in vitro and in vivo assays showed that TubZIP28 bound to the promoter of cytosolic AGPase and enhanced both the transcription and activity of the latter. Knockout of the homologue TabZIP28 in common wheat resulted in declines of both the transcription and activity of cytosolic AGPase in developing endosperms and c. 4% reduction of the total starch in mature grains. To the best of our knowledge, TubZIP28 and TabZIP28 are transcriptional activators of starch synthesis first identified in wheat, and they could be superior targets to improve the starch content and yield potential of wheat.
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Affiliation(s)
- Yanhong Song
- Agronomy College, National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, 15 Longzihu College District, Zhengzhou, 450046, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology/Innovative Academy of Seed Design, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Guangbin Luo
- State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology/Innovative Academy of Seed Design, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing, 100101, China
- Agronomy Department, University of Florida, Gainesville, FL, 32611, USA
| | - Lisha Shen
- State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology/Innovative Academy of Seed Design, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kang Yu
- State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology/Innovative Academy of Seed Design, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Wenlong Yang
- State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology/Innovative Academy of Seed Design, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing, 100101, China
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xin Li
- State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology/Innovative Academy of Seed Design, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Jiazhu Sun
- State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology/Innovative Academy of Seed Design, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Kehui Zhan
- Agronomy College, National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, 15 Longzihu College District, Zhengzhou, 450046, China
| | - Dangqun Cui
- Agronomy College, National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, 15 Longzihu College District, Zhengzhou, 450046, China
| | - Dongcheng Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology/Innovative Academy of Seed Design, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing, 100101, China
- Agriculture and Biology Research Center, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100024, China
| | - Aimin Zhang
- Agronomy College, National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, 15 Longzihu College District, Zhengzhou, 450046, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology/Innovative Academy of Seed Design, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing, 100101, China
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7
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Nowicka B. Target genes for plant productivity improvement. J Biotechnol 2019; 298:21-34. [PMID: 30978366 DOI: 10.1016/j.jbiotec.2019.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/06/2019] [Accepted: 04/08/2019] [Indexed: 12/26/2022]
Abstract
The use of chemical fertilizers and pesticides, as well as the development of high-yielding varieties enabled substantial increase in crop productivity during the 20th century. However, the increase in yield over the last two decades has been slower. It is thought that further improvement in productivity of the major crop species using traditional cultivation methods is limited. Therefore, the use of genetic engineering seems to be a promising approach. There is ongoing research concerning genes that have an impact on plant growth, development and yield. The proteins and miRNAs encoded by these genes participate in a variety of processes, such as growth regulation, assimilate transport and partitioning as well as macronutrient uptake and metabolism. This paper presents the major directions in research concerning genes that may be targets of genetic engineering aimed to improve plant productivity.
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Affiliation(s)
- Beatrycze Nowicka
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.
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Hwang SK, Singh S, Maharana J, Kalita S, Tuncel A, Rath T, Panda D, Modi MK, Okita TW. Mechanism Underlying Heat Stability of the Rice Endosperm Cytosolic ADP-Glucose Pyrophosphorylase. FRONTIERS IN PLANT SCIENCE 2019; 10:70. [PMID: 30804963 PMCID: PMC6378277 DOI: 10.3389/fpls.2019.00070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/17/2019] [Indexed: 05/22/2023]
Abstract
Rice grains accumulate starch as their major storage reserve whose biosynthesis is sensitive to heat. ADP-glucose pyrophosphorylase (AGPase) is among the starch biosynthetic enzymes severely affected by heat stress during seed maturation. To increase the heat tolerance of the rice enzyme, we engineered two dominant AGPase subunits expressed in developing endosperm, the large (L2) and small (S2b) subunits of the cytosol-specific AGPase. Bacterial expression of the rice S2b with the rice L2, potato tuber LS (pLS), or with the mosaic rice-potato large subunits, L2-pLS and pLS-L2, produced heat-sensitive recombinant enzymes, which retained less than 10% of their enzyme activities after 5 min incubation at 55°C. However, assembly of the rice L2 with the potato tuber SS (pSS) showed significantly increased heat stability comparable to the heat-stable potato pLS/pSS. The S2b assembled with the mosaic L2-pLS subunit showed 3-fold higher sensitivity to 3-PGA than L2/S2b, whereas the counterpart mosaic pLS-L2/S2b showed 225-fold lower sensitivity. Introduction of a QTC motif into S2b created an N-terminal disulfide linkage that was cleaved by dithiothreitol reduction. The QTC enzyme showed moderate heat stability but was not as stable as the potato AGPase. While the QTC AGPase exhibited approximately fourfold increase in 3-PGA sensitivity, its substrate affinities were largely unchanged. Random mutagenesis of S2bQTC produced six mutant lines with elevated production of glycogen in bacteria. All six lines contained a L379F substitution, which conferred enhanced glycogen production in bacteria and increased heat stability. Modeled structure of this mutant enzyme revealed that this highly conserved leucine residue is located in the enzyme's regulatory pocket that provides interaction sites for activators and inhibitors. Our molecular dynamic simulation analysis suggests that introduction of the QTC motif and the L379F mutation improves enzyme heat stability by stabilizing their backbone structures possibly due to the increased number of H-bonds between the small subunits and increased intermolecular interactions between the two SSs and two LSs at elevated temperature.
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Affiliation(s)
- Seon-Kap Hwang
- Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
| | - Salvinder Singh
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, India
| | - Jitendra Maharana
- Distributed Information Centre (DIC), Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, India
| | - Samhita Kalita
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, India
| | - Aytug Tuncel
- Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
| | - Tanmayee Rath
- Distributed Information Centre (DIC), Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, India
| | - Debashish Panda
- Distributed Information Centre (DIC), Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, India
| | - Mahendra Kumar Modi
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, India
| | - Thomas W. Okita
- Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
- *Correspondence: Thomas W. Okita,
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Boehlein SK, Shaw JR, Hannah LC. Enhancement of Heat Stability and Kinetic Parameters of the Maize Endosperm ADP-Glucose Pyrophosphorylase by Mutagenesis of Amino Acids in the Small Subunit With High B Factors. FRONTIERS IN PLANT SCIENCE 2018; 9:1849. [PMID: 30619417 PMCID: PMC6300691 DOI: 10.3389/fpls.2018.01849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/29/2018] [Indexed: 06/09/2023]
Abstract
ADP-glucose pyrophosphorylase (AGPase) is an important enzyme in starch synthesis and previous studies showed that the heat lability of this enzyme is a determinant to starch synthesis in the maize endosperm and, in turn, seed yield. Here, amino acids in the AGPase endosperm small subunit with high B-factors were mutagenized and individual changes enhancing heat stability and/or kinetic parameters in an Escherichia coli expression system were chosen. Individual mutations were combined and analyzed. One triple mutant, here termed Bt2-BF, was chosen for further study. Combinations of this heat stable, 3-PGA-independent small subunit variant with large subunits also heat stable yielded complex patterns of heat stability and kinetic and allosteric properties. Interestingly, two of the three changes reside in a protein motif found only in AGPases that exhibit high sensitivity to 3-PGA. While not the 3-PGA binding site, amino acid substitutions in this region significantly alter 3-PGA activation kinetics.
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Affiliation(s)
- Susan K. Boehlein
- Genetics Institute, University of Florida, Gainesville, FL, United States
- Department of Horticultural Sciences, University of Florida, Gainesville, FL, United States
| | - Janine R. Shaw
- Genetics Institute, University of Florida, Gainesville, FL, United States
- Department of Horticultural Sciences, University of Florida, Gainesville, FL, United States
| | - L. Curtis Hannah
- Genetics Institute, University of Florida, Gainesville, FL, United States
- Department of Horticultural Sciences, University of Florida, Gainesville, FL, United States
- Plant Molecular and Cellular Biology, University of Florida, Gainesville, FL, United States
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Boehlein SK, Shaw JR, Boehlein TJ, Boehlein EC, Hannah LC. Fundamental differences in starch synthesis in the maize leaf, embryo, ovary and endosperm. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:595-606. [PMID: 30062763 DOI: 10.1111/tpj.14053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 07/23/2018] [Indexed: 05/25/2023]
Abstract
Enzymological and starch analyses of various ADP-glucose pyrophosphorylase (AGPase) null mutants point to fundamental differences in the pathways for starch synthesis in the maize leaf, embryo, ovary and endosperm. Leaf starch is synthesized via the AGPase encoded by the small and large subunits shown previously to be expressed at abundant levels in the leaf, whereas more than one AGPase isoform functions in the embryo and in the ovary. Embryo starch content is also dependent on genes functioning in the leaf and in the endosperm. AGPase encoded by shrunken-2 and brittle-2 synthesizes ~75% of endosperm starch. The gene, agpsemzm, previously shown to encode the small subunit expressed in the embryo, and agpllzm, the leaf large subunit gene, are here shown to encode the endosperm, plastid-localized AGPase. Loss of this enzyme does not reduce endosperm starch. Rather, the data suggest that AGPase-independent starch synthesis accounts for ~25% of endosperm starch. Three maize genes encode the small subunit of the AGPase. Data here show that the triple mutant lacking all three small subunits is lethal in early seed development but can be viable in both male and female gametes. Seed and plant viability is restored by any one of the three small subunit genes, including one previously thought to function only in the cytosol of the endosperm. Data herein also show the functionality of a fourth gene encoding the large subunit of this enzyme. Although adenosine diphosphate glucose pyrophosphorylase is shown here to be essential for maize viability, strong evidence for starch synthesis in the endosperm that is independent of this enzyme is also presented. Starch synthesis is distinct in the maize embryo, ovary, leaf and endosperm, and is coordinated among the various tissues.
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Affiliation(s)
- Susan K Boehlein
- Program in Plant Molecular and Cellular Biology, Genetics Institute and the Department of Horticultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - Janine R Shaw
- Program in Plant Molecular and Cellular Biology, Genetics Institute and the Department of Horticultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - Timothy J Boehlein
- Program in Plant Molecular and Cellular Biology, Genetics Institute and the Department of Horticultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - Emily C Boehlein
- Program in Plant Molecular and Cellular Biology, Genetics Institute and the Department of Horticultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - L Curtis Hannah
- Program in Plant Molecular and Cellular Biology, Genetics Institute and the Department of Horticultural Sciences, University of Florida, Gainesville, FL, 32611, USA
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11
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Ben Ali SE, Schamann A, Dobrovolny S, Indra A, Agapito-Tenfen SZ, Hochegger R, Haslberger AG, Brandes C. Genetic and epigenetic characterization of the cry1Ab coding region and its 3′ flanking genomic region in MON810 maize using next-generation sequencing. Eur Food Res Technol 2018. [DOI: 10.1007/s00217-018-3062-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Ferrero DML, Asencion Diez MD, Kuhn ML, Falaschetti CA, Piattoni CV, Iglesias AA, Ballicora MA. On the Roles of Wheat Endosperm ADP-Glucose Pyrophosphorylase Subunits. FRONTIERS IN PLANT SCIENCE 2018; 9:1498. [PMID: 30459778 PMCID: PMC6232684 DOI: 10.3389/fpls.2018.01498] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/25/2018] [Indexed: 05/09/2023]
Abstract
The ADP-glucose pyrophosphorylase from wheat endosperm controls starch synthesis in seeds and has unique regulatory properties compared to others from this family. It comprises two types of subunits, but despite its importance little is known about their roles. Here, we synthesized de novo the wheat endosperm ADP-glucose pyrophosphorylase small (S) and large (L) subunit genes, heterologously expressed them in Escherichia coli, and kinetically characterized the recombinant proteins. To understand their distinct roles, we co-expressed them with well characterized subunits from the potato tuber enzyme to obtain hybrids with one S subunit from one source and an L subunit from the other. After kinetic analyses of these hybrids, we concluded that the unusual insensitivity to activation of the wheat endosperm enzyme is caused by a pre-activation of the L subunit. In addition, the heat stability and sensitivity to phosphate are given by the S subunit.
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Affiliation(s)
- Danisa M. L. Ferrero
- Laboratorio de Enzimología Molecular, Instituto de Agrobiotecnología del Litoral (CONICET – UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Matias D. Asencion Diez
- Laboratorio de Enzimología Molecular, Instituto de Agrobiotecnología del Litoral (CONICET – UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL, United States
| | - Misty L. Kuhn
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL, United States
| | | | - Claudia V. Piattoni
- Laboratorio de Enzimología Molecular, Instituto de Agrobiotecnología del Litoral (CONICET – UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Alberto A. Iglesias
- Laboratorio de Enzimología Molecular, Instituto de Agrobiotecnología del Litoral (CONICET – UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
- *Correspondence: Alberto A. Iglesias, Miguel A. Ballicora,
| | - Miguel A. Ballicora
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL, United States
- *Correspondence: Alberto A. Iglesias, Miguel A. Ballicora,
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13
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Hannah LC, Shaw JR, Clancy MA, Georgelis N, Boehlein SK. A brittle-2 transgene increases maize yield by acting in maternal tissues to increase seed number. PLANT DIRECT 2017; 1:e00029. [PMID: 31245677 PMCID: PMC6508519 DOI: 10.1002/pld3.29] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 11/03/2017] [Accepted: 11/14/2017] [Indexed: 05/24/2023]
Abstract
The enzyme ADP-glucose pyrophosphorylase is essential for starch biosynthesis and is highly regulated. Here, mutations that increased heat stability and interactions with allosteric effectors were incorporated into the small subunit of the isoform known to be expressed at high levels in the maize endosperm. The resulting variants were transformed into maize with expression targeted to the endosperm. Transgenes harboring the changes increased yield some 35%; however, yield enhancement occurred via an increase in seed number rather than by increased seed weight. Interestingly, seed number increase is controlled by the genotype of the plant rather than the genotype of the seed as seeds increase in number whether or not they contain the transgene as long as the maternal parent has the transgene. The transgene is however expressed in the endosperm, and the altered allosteric and stability properties initially seen in Escherichia coli expression experiments are also seen with the endosperm-expressed gene. The extent of seed number increase is positively correlated with the average daily high temperature during the first 4 days postpollination. While these results were unexpected, they echo the phenotypic changes caused by the insertion of an altered large subunit of this enzyme reported previously (Plant Cell, 24, 2012, 2352). These results call into question some of the reported fundamental differences separating starch synthesis in the endosperm vis-à-vis other plant tissues.
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Affiliation(s)
- L. Curtis Hannah
- Program in Plant Molecular and Cellular BiologyDepartment of Horticultural SciencesUniversity of FloridaGainesvilleFLUSA
| | - Janine R. Shaw
- Program in Plant Molecular and Cellular BiologyDepartment of Horticultural SciencesUniversity of FloridaGainesvilleFLUSA
| | - Maureen A. Clancy
- Program in Plant Molecular and Cellular BiologyDepartment of Horticultural SciencesUniversity of FloridaGainesvilleFLUSA
| | - Nikolaos Georgelis
- Program in Plant Molecular and Cellular BiologyDepartment of Horticultural SciencesUniversity of FloridaGainesvilleFLUSA
- Present address:
Simplot Plant SciencesJ.R. Simplot CompanyBoiseIDUSA
| | - Susan K. Boehlein
- Program in Plant Molecular and Cellular BiologyDepartment of Horticultural SciencesUniversity of FloridaGainesvilleFLUSA
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14
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Maize defective kernel mutant generated by insertion of a Ds element in a gene encoding a highly conserved TTI2 cochaperone. Proc Natl Acad Sci U S A 2017; 114:5165-5170. [PMID: 28461460 DOI: 10.1073/pnas.1703498114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have used the newly engineered transposable element Dsg to tag a gene that gives rise to a defective kernel (dek) phenotype. Dsg requires the autonomous element Ac for transposition. Upon excision, it leaves a short DNA footprint that can create in-frame and frameshift insertions in coding sequences. Therefore, we could create alleles of the tagged gene that confirmed causation of the dek phenotype by the Dsg insertion. The mutation, designated dek38-Dsg, is embryonic lethal, has a defective basal endosperm transfer (BETL) layer, and results in a smaller seed with highly underdeveloped endosperm. The maize dek38 gene encodes a TTI2 (Tel2-interacting protein 2) molecular cochaperone. In yeast and mammals, TTI2 associates with two other cochaperones, TEL2 (Telomere maintenance 2) and TTI1 (Tel2-interacting protein 1), to form the triple T complex that regulates DNA damage response. Therefore, we cloned the maize Tel2 and Tti1 homologs and showed that TEL2 can interact with both TTI1 and TTI2 in yeast two-hybrid assays. The three proteins regulate the cellular levels of phosphatidylinositol 3-kinase-related kinases (PIKKs) and localize to the cytoplasm and the nucleus, consistent with known subcellular locations of PIKKs. dek38-Dsg displays reduced pollen transmission, indicating TTI2's importance in male reproductive cell development.
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Yang Y, Gao T, Xu M, Dong J, Li H, Wang P, Li G, Guo T, Kang G, Wang Y. Functional Analysis of a Wheat AGPase Plastidial Small Subunit with a Truncated Transit Peptide. Molecules 2017; 22:molecules22030386. [PMID: 28257051 PMCID: PMC6155376 DOI: 10.3390/molecules22030386] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 02/17/2017] [Accepted: 02/25/2017] [Indexed: 11/16/2022] Open
Abstract
ADP-glucose pyrophosphorylase (AGPase), the key enzyme in starch synthesis, consists of two small subunits and two large subunits with cytosolic and plastidial isoforms. In our previous study, a cDNA sequence encoding the plastidial small subunit (TaAGPS1b) of AGPase in grains of bread wheat (Triticum aestivum L.) was isolated and the protein subunit encoded by this gene was characterized as a truncated transit peptide (about 50% shorter than those of other plant AGPS1bs). In the present study, TaAGPS1b was fused with green fluorescent protein (GFP) in rice protoplast cells, and confocal fluorescence microscopy observations revealed that like other AGPS1b containing the normal transit peptide, TaAGPS1b-GFP was localized in chloroplasts. TaAGPS1b was further overexpressed in a Chinese bread wheat cultivar, and the transgenic wheat lines exhibited a significant increase in endosperm AGPase activities, starch contents, and grain weights. These suggested that TaAGPS1b subunit was targeted into plastids by its truncated transit peptide and it could play an important role in starch synthesis in bread wheat grains.
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Affiliation(s)
- Yang Yang
- The Collaborative Innovation Center of Henan Food Crops, Henan Agricultural University, Zhengzhou 450002, China.
| | - Tian Gao
- The Collaborative Innovation Center of Henan Food Crops, Henan Agricultural University, Zhengzhou 450002, China.
| | - Mengjun Xu
- The National Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, Zhengzhou 450002, China.
| | - Jie Dong
- The National Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, Zhengzhou 450002, China.
| | - Hanxiao Li
- The National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450002, China.
| | - Pengfei Wang
- The Collaborative Innovation Center of Henan Food Crops, Henan Agricultural University, Zhengzhou 450002, China.
| | - Gezi Li
- The National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450002, China.
| | - Tiancai Guo
- The National Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, Zhengzhou 450002, China.
| | - Guozhang Kang
- The National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450002, China.
| | - Yonghua Wang
- The Collaborative Innovation Center of Henan Food Crops, Henan Agricultural University, Zhengzhou 450002, China.
- The National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450002, China.
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16
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Li W, Guo H, Wang Y, Xie Y, Zhao L, Gu J, Zhao S, Zhao B, Wang G, Liu L. Identification of novel alleles induced by EMS-mutagenesis in key genes of kernel hardness and starch biosynthesis in wheat by TILLING. Genes Genomics 2016. [DOI: 10.1007/s13258-016-0504-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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17
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Oiestad AJ, Martin JM, Giroux MJ. Overexpression of ADP-glucose pyrophosphorylase in both leaf and seed tissue synergistically increase biomass and seed number in rice (Oryza sativa ssp. japonica). FUNCTIONAL PLANT BIOLOGY : FPB 2016; 43:1194-1204. [PMID: 32480538 DOI: 10.1071/fp16218] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 08/24/2016] [Indexed: 05/14/2023]
Abstract
Increased expression of leaf or seed ADPglucose pyrophosphorylase activity (AGPase) has been shown to increase plant growth. However, no study has directly compared AGPase overexpression in leaves and/or seeds. In the present study, transgenic rice overexpressing AGPase in leaves or in seeds were crossed, resulting in four F2:3 homozygous genotypes with AGPase overexpression in leaves, seeds, both leaves and seeds, or neither tissue. The impact of AGPase overexpression in these genotypic groups was examined at the metabolic, transcriptomic, and plant growth levels. Leaf-specific AGPase overexpression increased flag leaf starch up to five times that of the wild type (WT) whereas overexpression of AGPase in both leaves and seeds conferred the greatest productivity advantages. Relative to the WT, AGPase overexpression in both leaves and seeds increased plant biomass and panicle number by 61% and 51%, respectively while leaf-specific AGPase overexpression alone only increased plant biomass and panicle number by 24 and 32% respectively. Extraction and analysis of RNA and leaf-specific metabolites demonstrated that carbon metabolism was broadly increased by AGPase overexpression in seeds and leaves. These findings indicate that stimulation of whole-plant growth and productivity can be best achieved by upregulation of starch biosynthesis in both leaves and seeds.
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Affiliation(s)
- Alanna J Oiestad
- 119 Plant Bioscience Building, Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA
| | - John M Martin
- 119 Plant Bioscience Building, Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA
| | - Michael J Giroux
- 119 Plant Bioscience Building, Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA
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18
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Seferoglu AB, Gul S, Dikbas UM, Baris I, Koper K, Caliskan M, Cevahir G, Kavakli IH. Glu-370 in the large subunit influences the substrate binding, allosteric, and heat stability properties of potato ADP-glucose pyrophosphorylase. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 252:125-132. [PMID: 27717448 DOI: 10.1016/j.plantsci.2016.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
ADP-glucose pyrophosphorylase (AGPase) is a key allosteric enzyme in plant starch biosynthesis. Plant AGPase is a heterotetrameric enzyme that consists of large (LS) and small subunits (SS), which are encoded by two different genes. In this study, we showed that the conversion of Glu to Gly at position 370 in the LS of AGPase alters the heterotetrameric stability along with the binding properties of substrate and effectors of the enzyme. Kinetic analyses revealed that the affinity of the LSE370GSSWT AGPase for glucose-1-phosphate is 3-fold less than for wild type (WT) AGPase. Additionally, the LSE370GSSWT AGPase requires 3-fold more 3-phosphogyceric acid to be activated. Finally, the LSE370GSSWTAGPase is less heat stable compared with the WT AGPase. Computational analysis of the mutant Gly-370 in the 3D modeled LS AGPase showed that this residue changes charge distribution of the surface and thus affect stability of the LS AGPase and overall heat stability of the heterotetrameric AGPase. In summary, our results show that LSE370 intricately modulate the heat stability and enzymatic activity of potato the AGPase.
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Affiliation(s)
- Ayse Bengisu Seferoglu
- Koc University, Department of Chemical and Biological Engineering, Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
| | - Seref Gul
- Koc University, Department of Chemical and Biological Engineering, Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
| | - Ugur Meric Dikbas
- Koc University, Department of Molecular Biology and Genetics, Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
| | - Ibrahim Baris
- Koc University, Department of Molecular Biology and Genetics, Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
| | - Kaan Koper
- Koc University, Department of Chemical and Biological Engineering, Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
| | - Mahmut Caliskan
- Istanbul University, Department of Biology, 34134 Suleymaniye, Istanbul, Turkey
| | - Gul Cevahir
- Istanbul University, Department of Biology, 34134 Suleymaniye, Istanbul, Turkey
| | - Ibrahim Halil Kavakli
- Koc University, Department of Chemical and Biological Engineering, Rumelifeneri Yolu, Sariyer, Istanbul, Turkey; Koc University, Department of Molecular Biology and Genetics, Rumelifeneri Yolu, Sariyer, Istanbul, Turkey.
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19
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Abstract
Starch-rich crops form the basis of our nutrition, but plants have still to yield all their secrets as to how they make this vital substance. Great progress has been made by studying both crop and model systems, and we approach the point of knowing the enzymatic machinery responsible for creating the massive, insoluble starch granules found in plant tissues. Here, we summarize our current understanding of these biosynthetic enzymes, highlighting recent progress in elucidating their specific functions. Yet, in many ways we have only scratched the surface: much uncertainty remains about how these components function together and are controlled. We flag-up recent observations suggesting a significant degree of flexibility during the synthesis of starch and that previously unsuspected non-enzymatic proteins may have a role. We conclude that starch research is not yet a mature subject and that novel experimental and theoretical approaches will be important to advance the field.
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Affiliation(s)
- Barbara Pfister
- Department of Biology, ETH Zurich, 8092, Zurich, Switzerland
| | - Samuel C Zeeman
- Department of Biology, ETH Zurich, 8092, Zurich, Switzerland.
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20
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Zhang XW, Li SY, Zhang LL, Yang Q, Jiang QT, Ma J, Qi PF, Li W, Chen GY, Lan XJ, Deng M, Lu ZX, Liu C, Wei YM, Zheng YL. Structure and expression analysis of genes encoding ADP-glucose pyrophosphorylase large subunit in wheat and its relatives. Genome 2016; 59:501-7. [PMID: 27299732 DOI: 10.1139/gen-2016-0007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ADP-glucose pyrophosphorylase (AGP), which consists of two large subunits (AGP-L) and two small subunits (AGP-S), controls the rate-limiting step in the starch biosynthetic pathway. In this study, a full-length open reading frame (ORF) of AGP-L gene (named as Agp2) in wheat and a series of Agp2 gene sequences in wheat relatives were isolated. The coding region of Agp2 contained 15 exons and 14 introns including a full-length ORF of 1566 nucleotides, and the deduced protein contained 522 amino acids (57.8 kDa). Generally, the phylogenetic tree of Agp2 indicated that sequences from A- and D-genome donor species were most similar to each other and sequences from B-genome donor species contained more variation. Starch accumulation and Agp2 expression in wheat grains reached their peak at 21 and 15 days post anthesis (DPA), respectively.
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Affiliation(s)
- Xiao-Wei Zhang
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Si-Yu Li
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Ling-Ling Zhang
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Qiang Yang
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Qian-Tao Jiang
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Jian Ma
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Peng-Fei Qi
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Wei Li
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Guo-Yue Chen
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Xiu-Jin Lan
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Mei Deng
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Zhen-Xiang Lu
- b Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada
| | - Chunji Liu
- c CSIRO Agriculture Flagship, 306 Carmody Road, St Lucia, Brisbane, QLD 4067, Australia
| | - Yu-Ming Wei
- a Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - You-Liang Zheng
- d Key Laboratory of Southwestern Crop Germplasm Utilization, Ministry of Agriculture, Sichuan Agricultural University, Ya'an, Sichuan 625014, China
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21
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Liu F, Zhao Q, Mano N, Ahmed Z, Nitschke F, Cai Y, Chapman KD, Steup M, Tetlow IJ, Emes MJ. Modification of starch metabolism in transgenic Arabidopsis thaliana increases plant biomass and triples oilseed production. PLANT BIOTECHNOLOGY JOURNAL 2016; 14:976-985. [PMID: 26285603 DOI: 10.1111/pbi.12453] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/25/2015] [Accepted: 06/27/2015] [Indexed: 06/04/2023]
Abstract
We have identified a novel means to achieve substantially increased vegetative biomass and oilseed production in the model plant Arabidopsis thaliana. Endogenous isoforms of starch branching enzyme (SBE) were substituted by either one of the endosperm-expressed maize (Zea mays L.) branching isozymes, ZmSBEI or ZmSBEIIb. Transformants were compared with the starch-free background and with the wild-type plants. Each of the maize-derived SBEs restored starch biosynthesis but both morphology and structure of starch particles were altered. Altered starch metabolism in the transformants is associated with enhanced biomass formation and more-than-trebled oilseed production while maintaining seed oil quality. Enhanced oilseed production is primarily due to an increased number of siliques per plant whereas oil content and seed number per silique are essentially unchanged or even modestly decreased. Introduction of cereal starch branching isozymes into oilseed plants represents a potentially useful strategy to increase biomass and oilseed production in related crops and manipulate the structure and properties of leaf starch.
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Affiliation(s)
- Fushan Liu
- Department of Molecular and Cellular Biology, Summerlee Science Complex, University of Guelph, Guelph, ON, Canada
| | - Qianru Zhao
- Department of Molecular and Cellular Biology, Summerlee Science Complex, University of Guelph, Guelph, ON, Canada
| | - Noel Mano
- Department of Molecular and Cellular Biology, Summerlee Science Complex, University of Guelph, Guelph, ON, Canada
| | - Zaheer Ahmed
- Department of Molecular and Cellular Biology, Summerlee Science Complex, University of Guelph, Guelph, ON, Canada
| | - Felix Nitschke
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Yinqqi Cai
- Department of Biological Sciences, Center for Plant Lipid Research, University of North Texas, Denton, TX, USA
| | - Kent D Chapman
- Department of Biological Sciences, Center for Plant Lipid Research, University of North Texas, Denton, TX, USA
| | - Martin Steup
- Department of Molecular and Cellular Biology, Summerlee Science Complex, University of Guelph, Guelph, ON, Canada
| | - Ian J Tetlow
- Department of Molecular and Cellular Biology, Summerlee Science Complex, University of Guelph, Guelph, ON, Canada
| | - Michael J Emes
- Department of Molecular and Cellular Biology, Summerlee Science Complex, University of Guelph, Guelph, ON, Canada
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22
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Mukherjee S, Liu A, Deol KK, Kulichikhin K, Stasolla C, Brûlé-Babel A, Ayele BT. Transcriptional coordination and abscisic acid mediated regulation of sucrose transport and sucrose-to-starch metabolism related genes during grain filling in wheat (Triticum aestivum L.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 240:143-60. [PMID: 26475195 DOI: 10.1016/j.plantsci.2015.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 07/31/2015] [Accepted: 09/08/2015] [Indexed: 05/22/2023]
Abstract
Combining physiological, molecular and biochemical approaches, this study investigated the transcriptional coordination and abscisic acid (ABA) mediated regulation of genes involved in sucrose import and its conversion to starch during grain filling in wheat. Sucrose import appears to be mediated by seed localized TaSUT1, mainly TaSUT1D, while sucrose cleavage by TaSuSy2. Temporal overlapping of the transcriptional activation of AGPL1 and AGPS1a that encode AGPase with that of the above genes suggests their significance in the synthesis of ADP-glucose; TaAGPL1A and TaAGPL1D contributing the majority of AGPL1 transcripts. ABA induced repressions of TaSUT1, TaSuSy2, TaAGPL1 and TaAGPS1a imply that ABA negatively regulates sucrose import into the endosperm and its subsequent metabolism to ADP-glucose, the substrate for starch synthesis. The formations of amyloses and amylopectin from ADP-glucose appear to be mediated by specific members of GBSS, and SS, SBE and DBE gene families, and the ABA-induced transcriptional change in most of these genes implies that ABA regulates amylose and amylopectin synthesis. The findings provide insights into the molecular mechanisms underlying the coordination and ABA mediated regulation of sucrose transport into the developing endosperm and its subsequent metabolism to starch during grain filling in wheat.
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Affiliation(s)
- Shalini Mukherjee
- Department of Plant Science, 222 Agriculture Building, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Aihua Liu
- Department of Plant Science, 222 Agriculture Building, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Kirandeep K Deol
- Department of Plant Science, 222 Agriculture Building, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Konstanin Kulichikhin
- Department of Plant Science, 222 Agriculture Building, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Claudio Stasolla
- Department of Plant Science, 222 Agriculture Building, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Anita Brûlé-Babel
- Department of Plant Science, 222 Agriculture Building, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Belay T Ayele
- Department of Plant Science, 222 Agriculture Building, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
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23
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Saripalli G, Gupta PK. AGPase: its role in crop productivity with emphasis on heat tolerance in cereals. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2015; 128:1893-916. [PMID: 26152573 DOI: 10.1007/s00122-015-2565-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/16/2015] [Indexed: 05/11/2023]
Abstract
AGPase, a key enzyme of starch biosynthetic pathway, has a significant role in crop productivity. Thermotolerant variants of AGPase in cereals may be used for developing cultivars, which may enhance productivity under heat stress. Improvement of crop productivity has always been the major goal of plant breeders to meet the global demand for food. However, crop productivity itself is influenced in a large measure by a number of abiotic stresses including heat, which causes major losses in crop productivity. In cereals, crop productivity in terms of grain yield mainly depends upon the seed starch content so that starch biosynthesis and the enzymes involved in this process have been a major area of investigation for plant physiologists and plant breeders alike. Considerable work has been done on AGPase and its role in crop productivity, particularly under heat stress, because this enzyme is one of the major enzymes, which catalyses the rate-limiting first committed key enzymatic step of starch biosynthesis. Keeping the above in view, this review focuses on the basic features of AGPase including its structure, regulatory mechanisms involving allosteric regulators, its sub-cellular localization and its genetics. Major emphasis, however, has been laid on the genetics of AGPases and its manipulation for developing high yielding cultivars that will have comparable productivity under heat stress. Some important thermotolerant variants of AGPase, which mainly involve specific amino acid substitutions, have been highlighted, and the prospects of using these thermotolerant variants of AGPase in developing cultivars for heat prone areas have been discussed. The review also includes a brief account on transgenics for AGPase, which have been developed for basic studies and crop improvement.
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Affiliation(s)
- Gautam Saripalli
- Molecular Biology Laboratory, Department of Genetics and Plant Breeding, Ch.Charan Singh University, Meerut, 250004, India
| | - Pushpendra Kumar Gupta
- Molecular Biology Laboratory, Department of Genetics and Plant Breeding, Ch.Charan Singh University, Meerut, 250004, India.
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24
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Saripalli G, Gupta PK. AGPase: its role in crop productivity with emphasis on heat tolerance in cereals. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2015. [PMID: 26152573 DOI: 10.1007/s00122-015-2565-2562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
AGPase, a key enzyme of starch biosynthetic pathway, has a significant role in crop productivity. Thermotolerant variants of AGPase in cereals may be used for developing cultivars, which may enhance productivity under heat stress. Improvement of crop productivity has always been the major goal of plant breeders to meet the global demand for food. However, crop productivity itself is influenced in a large measure by a number of abiotic stresses including heat, which causes major losses in crop productivity. In cereals, crop productivity in terms of grain yield mainly depends upon the seed starch content so that starch biosynthesis and the enzymes involved in this process have been a major area of investigation for plant physiologists and plant breeders alike. Considerable work has been done on AGPase and its role in crop productivity, particularly under heat stress, because this enzyme is one of the major enzymes, which catalyses the rate-limiting first committed key enzymatic step of starch biosynthesis. Keeping the above in view, this review focuses on the basic features of AGPase including its structure, regulatory mechanisms involving allosteric regulators, its sub-cellular localization and its genetics. Major emphasis, however, has been laid on the genetics of AGPases and its manipulation for developing high yielding cultivars that will have comparable productivity under heat stress. Some important thermotolerant variants of AGPase, which mainly involve specific amino acid substitutions, have been highlighted, and the prospects of using these thermotolerant variants of AGPase in developing cultivars for heat prone areas have been discussed. The review also includes a brief account on transgenics for AGPase, which have been developed for basic studies and crop improvement.
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Affiliation(s)
- Gautam Saripalli
- Molecular Biology Laboratory, Department of Genetics and Plant Breeding, Ch.Charan Singh University, Meerut, 250004, India
| | - Pushpendra Kumar Gupta
- Molecular Biology Laboratory, Department of Genetics and Plant Breeding, Ch.Charan Singh University, Meerut, 250004, India.
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25
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Saripalli G, Gupta PK. AGPase: its role in crop productivity with emphasis on heat tolerance in cereals. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2015; 128:1893-1916. [PMID: 26152573 DOI: 10.1007/s00122-015-25652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/16/2015] [Indexed: 05/26/2023]
Abstract
AGPase, a key enzyme of starch biosynthetic pathway, has a significant role in crop productivity. Thermotolerant variants of AGPase in cereals may be used for developing cultivars, which may enhance productivity under heat stress. Improvement of crop productivity has always been the major goal of plant breeders to meet the global demand for food. However, crop productivity itself is influenced in a large measure by a number of abiotic stresses including heat, which causes major losses in crop productivity. In cereals, crop productivity in terms of grain yield mainly depends upon the seed starch content so that starch biosynthesis and the enzymes involved in this process have been a major area of investigation for plant physiologists and plant breeders alike. Considerable work has been done on AGPase and its role in crop productivity, particularly under heat stress, because this enzyme is one of the major enzymes, which catalyses the rate-limiting first committed key enzymatic step of starch biosynthesis. Keeping the above in view, this review focuses on the basic features of AGPase including its structure, regulatory mechanisms involving allosteric regulators, its sub-cellular localization and its genetics. Major emphasis, however, has been laid on the genetics of AGPases and its manipulation for developing high yielding cultivars that will have comparable productivity under heat stress. Some important thermotolerant variants of AGPase, which mainly involve specific amino acid substitutions, have been highlighted, and the prospects of using these thermotolerant variants of AGPase in developing cultivars for heat prone areas have been discussed. The review also includes a brief account on transgenics for AGPase, which have been developed for basic studies and crop improvement.
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Affiliation(s)
- Gautam Saripalli
- Molecular Biology Laboratory, Department of Genetics and Plant Breeding, Ch.Charan Singh University, Meerut, 250004, India
| | - Pushpendra Kumar Gupta
- Molecular Biology Laboratory, Department of Genetics and Plant Breeding, Ch.Charan Singh University, Meerut, 250004, India.
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26
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Simas-Rodrigues C, Villela HDM, Martins AP, Marques LG, Colepicolo P, Tonon AP. Microalgae for economic applications: advantages and perspectives for bioethanol. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4097-108. [PMID: 25873683 DOI: 10.1093/jxb/erv130] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Renewable energy has attracted significant interest in recent years as a result of sustainability, environmental impact, and socio-economic considerations. Given existing technological knowledge and based on projections relating to biofuels derived from microalgae, microalgal feedstock is considered to be one of the most important renewable energy sources potentially available for industrial production. Therefore, this review examines microalgal bioethanol technology, which converts biomass from microalgae to fuel, the chemical processes involved, and possible ways of increasing the bioethanol yield, such as abiotic factors and genetic manipulation of fermenting organisms.
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Affiliation(s)
- Cíntia Simas-Rodrigues
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Helena D M Villela
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Aline P Martins
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Luiza G Marques
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Pio Colepicolo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Angela P Tonon
- Los Alamos National Laboratory, Bioscience Division, PO Box M888, Los Alamos, NM 87545, USA
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Comparative Genetics of Seed Size Traits in Divergent Cereal Lineages Represented by Sorghum (Panicoidae) and Rice (Oryzoidae). G3-GENES GENOMES GENETICS 2015; 5:1117-28. [PMID: 25834216 PMCID: PMC4478542 DOI: 10.1534/g3.115.017590] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Seed size is closely related to fitness of wild plants, and its modification has been a key recurring element in domestication of seed/grain crops. In sorghum, a genomic and morphological model for panicoid cereals, a rich history of research into the genetics of seed size is reflected by a total of 13 likelihood intervals determined by conventional QTL (linkage) mapping in 11 nonoverlapping regions of the genome. To complement QTL data and investigate whether the discovery of seed size QTL is approaching “saturation,” we compared QTL data to GWAS for seed mass, seed length, and seed width studied in 354 accessions from a sorghum association panel (SAP) that have been genotyped at 265,487 SNPs. We identified nine independent GWAS-based “hotspots” for seed size associations. Targeted resequencing near four association peaks with the most notable linkage disequilibrium provides further support of the role(s) of these regions in the genetic control of sorghum seed size and identifies two candidate causal variants with nonsynonymous mutations. Of nine GWAS hotspots in sorghum, seven have significant correspondence with rice QTL intervals and known genes for components of seed size on orthologous chromosomes. Identifying intersections between positional and association genetic data are a potentially powerful means to mitigate constraints associated with each approach, and nonrandom correspondence of sorghum (panicoid) GWAS signals to rice (oryzoid) QTL adds a new dimension to the ability to leverage genetic data about this important trait across divergent plants.
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Kramer V, Shaw JR, Senior ML, Hannah LC. The sh2-R allele of the maize shrunken-2 locus was caused by a complex chromosomal rearrangement. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2015; 128:445-452. [PMID: 25504539 DOI: 10.1007/s00122-014-2443-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 12/06/2014] [Indexed: 06/04/2023]
Abstract
The mutant that originally defined the shrunken - 2 locus of maize is shown here to be the product of a complex chromosomal rearrangement. The maize shrunken-2 gene (sh2) encodes the large subunit of the heterotetrameric enzyme, adenosine diphosphate glucose pyrophosphorylases and a rate-limiting enzyme in starch biosynthesis. The sh2 gene was defined approximately 72 years ago by the isolation of a loss-of-function allele conditioning a shrunken, but viable seed. In subsequent years, the realization that this allele, termed zsh2-R or sh2-Reference, causes an extremely high level of sucrose to accumulate in the developing seed led to a revolution in the sweet corn industry. Now, the vast majority of sweet corns grown throughout the world contain this mutant allele. Through initial Southern analysis followed by genomic sequencing, the work reported here shows that this allele arose through a complex set of events involving at least three breaks of chromosome 3 as well as an intra-chromosomal inversion. These findings provide an explanation for some previously reported, unexpected observations concerning rates of recombination within and between genes in this region.
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Affiliation(s)
- Vance Kramer
- Syngenta Biotechnology, 3054 East Cornwallis Rd, Durham, NC, 27603, USA
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Enhancing the heat stability and kinetic parameters of the maize endosperm ADP-glucose pyrophosphorylase using iterative saturation mutagenesis. Arch Biochem Biophys 2015; 568:28-37. [DOI: 10.1016/j.abb.2015.01.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/08/2015] [Accepted: 01/11/2015] [Indexed: 11/30/2022]
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Tuncel A, Kawaguchi J, Ihara Y, Matsusaka H, Nishi A, Nakamura T, Kuhara S, Hirakawa H, Nakamura Y, Cakir B, Nagamine A, Okita TW, Hwang SK, Satoh H. The rice endosperm ADP-glucose pyrophosphorylase large subunit is essential for optimal catalysis and allosteric regulation of the heterotetrameric enzyme. PLANT & CELL PHYSIOLOGY 2014; 55:1169-83. [PMID: 24747952 DOI: 10.1093/pcp/pcu057] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Although an alternative pathway has been suggested, the prevailing view is that starch synthesis in cereal endosperm is controlled by the activity of the cytosolic isoform of ADPglucose pyrophosphorylase (AGPase). In rice, the cytosolic AGPase isoform is encoded by the OsAGPS2b and OsAGPL2 genes, which code for the small (S2b) and large (L2) subunits of the heterotetrameric enzyme, respectively. In this study, we isolated several allelic missense and nonsense OsAGPL2 mutants by N-methyl-N-nitrosourea (MNU) treatment of fertilized egg cells and by TILLING (Targeting Induced Local Lesions in Genomes). Interestingly, seeds from three of the missense mutants (two containing T139I and A171V) were severely shriveled and had seed weight and starch content comparable with the shriveled seeds from OsAGPL2 null mutants. Results from kinetic analysis of the purified recombinant enzymes revealed that the catalytic and allosteric regulatory properties of these mutant enzymes were significantly impaired. The missense heterotetramer enzymes and the S2b homotetramer had lower specific (catalytic) activities and affinities for the activator 3-phosphoglycerate (3-PGA). The missense heterotetramer enzymes showed more sensitivity to inhibition by the inhibitor inorganic phosphate (Pi) than the wild-type AGPase, while the S2b homotetramer was profoundly tolerant to Pi inhibition. Thus, our results provide definitive evidence that starch biosynthesis during rice endosperm development is controlled predominantly by the catalytic activity of the cytoplasmic AGPase and its allosteric regulation by the effectors. Moreover, our results show that the L2 subunit is essential for both catalysis and allosteric regulatory properties of the heterotetramer enzyme.
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Affiliation(s)
- Aytug Tuncel
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USAThese authors contributed equally to this work
| | - Joe Kawaguchi
- Faculty of Agriculture, Kyushu University, Fukuoka, 812-8581 JapanThese authors contributed equally to this work
| | - Yasuharu Ihara
- Faculty of Agriculture, Kyushu University, Fukuoka, 812-8581 Japan
| | | | - Aiko Nishi
- Faculty of Agriculture, Kyushu University, Fukuoka, 812-8581 Japan
| | | | - Satoru Kuhara
- Department of Genetic Resources Technology, Kyushu University, Fukuoka, 812-8581 Japan
| | - Hideki Hirakawa
- Kazusa DNA Research Institute, Department of Plant Genome Research, Kisarazu, Japan
| | - Yasunori Nakamura
- Faculty of Bioresource Sciences, Akita Prefectural University, Akita City, 010-0195 Japan
| | - Bilal Cakir
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Ai Nagamine
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USAFaculty of Agriculture, Kyushu University, Fukuoka, 812-8581 Japan
| | - Thomas W Okita
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Seon-Kap Hwang
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Hikaru Satoh
- Faculty of Agriculture, Kyushu University, Fukuoka, 812-8581 Japan
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31
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Bae JM, Kwak MS, Noh SA, Oh MJ, Kim YS, Shin JS. Overexpression of sweetpotato expansin cDNA (IbEXP1) increases seed yield in Arabidopsis. Transgenic Res 2014; 23:657-67. [DOI: 10.1007/s11248-014-9804-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 04/23/2014] [Indexed: 01/20/2023]
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32
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Huang B, Hennen-Bierwagen TA, Myers AM. Functions of multiple genes encoding ADP-glucose pyrophosphorylase subunits in maize endosperm, embryo, and leaf. PLANT PHYSIOLOGY 2014; 164:596-611. [PMID: 24381067 PMCID: PMC3912092 DOI: 10.1104/pp.113.231605] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
ADP-glucose pyrophosphorylase (AGPase) provides the nucleotide sugar ADP-glucose and thus constitutes the first step in starch biosynthesis. The majority of cereal endosperm AGPase is located in the cytosol with a minor portion in amyloplasts, in contrast to its strictly plastidial location in other species and tissues. To investigate the potential functions of plastidial AGPase in maize (Zea mays) endosperm, six genes encoding AGPase large or small subunits were characterized for gene expression as well as subcellular location and biochemical activity of the encoded proteins. Seven transcripts from these genes accumulate in endosperm, including those from shrunken2 and brittle2 that encode cytosolic AGPase and five candidates that could encode subunits of the plastidial enzyme. The amino termini of these five polypeptides directed the transport of a reporter protein into chloroplasts of leaf protoplasts. All seven proteins exhibited AGPase activity when coexpressed in Escherichia coli with partner subunits. Null mutations were identified in the genes agpsemzm and agpllzm and shown to cause reduced AGPase activity in specific tissues. The functioning of these two genes was necessary for the accumulation of normal starch levels in embryo and leaf, respectively. Remnant starch was observed in both instances, indicating that additional genes encode AGPase large and small subunits in embryo and leaf. Endosperm starch was decreased by approximately 7% in agpsemzm- or agpllzm- mutants, demonstrating that plastidial AGPase activity contributes to starch production in this tissue even when the major cytosolic activity is present.
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Boehlein SK, Shaw JR, Georgelis N, Hannah LC. Enhanced heat stability and kinetic parameters of maize endosperm ADPglucose pyrophosphorylase by alteration of phylogenetically identified amino acids. Arch Biochem Biophys 2013; 543:1-9. [PMID: 24378757 DOI: 10.1016/j.abb.2013.12.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 12/12/2013] [Accepted: 12/20/2013] [Indexed: 10/25/2022]
Abstract
ADP-glucose pyrophosphorylase (AGPase) controls the rate-limiting step in starch biosynthesis and is regulated at various levels. Cereal endosperm enzymes, in contrast to other plant AGPases, are particularly heat labile and transgenic studies highlight the importance of temperature for cereal yield. Previously, a phylogenetic approach identified Type II and positively selected amino acid positions in the large subunit of maize endosperm AGPase. Glycogen content, kinetic parameters and heat stability were measured in AGPases having mutations in these sites and interesting differences were observed. This study expands on our earlier evolutionary work by determining how all Type II and positively selected sites affect kinetic constants, heat stability and catalytic rates at increased temperatures. Variants with enhanced properties were identified and combined into one gene, designated Sh2-E. Enhanced properties include: heat stability, enhanced activity at 37 °C, activity at 55 °C, reduced Ka and activity in the absence of activator. The resulting enzyme exhibited all improved properties of the various individual changes. Additionally, Sh2-E was expressed with a small subunit variant with enhanced enzyme properties resulting in an enzyme that has exceptional heat stability, a high catalytic rate at increased temperatures and significantly decreased Km values for both substrates in the absence of the activator.
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Affiliation(s)
- Susan K Boehlein
- 1253 Fifield Hall, University of Florida, Gainesville, FL 32611, USA
| | - Janine R Shaw
- 1253 Fifield Hall, University of Florida, Gainesville, FL 32611, USA
| | | | - L Curtis Hannah
- 1253 Fifield Hall, University of Florida, Gainesville, FL 32611, USA.
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Kang G, Liu G, Peng X, Wei L, Wang C, Zhu Y, Ma Y, Jiang Y, Guo T. Increasing the starch content and grain weight of common wheat by overexpression of the cytosolic AGPase large subunit gene. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2013; 73:93-8. [PMID: 24080395 DOI: 10.1016/j.plaphy.2013.09.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 09/10/2013] [Indexed: 05/07/2023]
Abstract
ADP-glucose pyrophosphorylase (AGPase) catalyzes the first committed step of starch synthesis. AGPase is a heterotetramer composed of two large subunits and two small subunits, has cytosolic and plastidial isoforms, and is detected mainly in the cytosol of endosperm in cereal crops. To investigate the effects of AGPase cytosolic large subunit gene (LSU I) on starch biosynthesis in higher plant, in this study, a TaLSU I gene from wheat was overexpressed under the control of an endosperm-specific promoter in a wheat cultivar (Yumai 34). PCR, Southern blot, and real-time RT-PCR analyses indicated that the transgene was integrated into the genome of transgenic plants and was overexpressed in their progeny. The overexpression of the TaLSU I gene remarkably enhanced AGPase activity, endosperm starch weight, grain number per spike, and single grain weight. Therefore, we conclude that overexpression of the TaLSU I gene enhances the starch biosynthesis in endosperm of wheat grains, having potential applications in wheat breeding to develop a high-yield wheat cultivar with high starch weight and kernel weight.
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Affiliation(s)
- Guozhang Kang
- The National Engineering Research Centre for Wheat, Henan Agricultural University, #63 Nongye Road, Zhengzhou, Henan Province 450002, China.
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35
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Tuncel A, Okita TW. Improving starch yield in cereals by over-expression of ADPglucose pyrophosphorylase: expectations and unanticipated outcomes. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 211:52-60. [PMID: 23987811 DOI: 10.1016/j.plantsci.2013.06.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 06/13/2013] [Accepted: 06/17/2013] [Indexed: 05/09/2023]
Abstract
Significant improvements in crop productivity are required to meet the nutritional requirements of a growing world population. This challenge is magnified by an increased demand for bioenergy as a means to mitigate carbon inputs into the environment. Starch is a major component of the harvestable organs of many crop plants, and various endeavors have been taken to improve the yields of starchy organs through the manipulation of starch synthesis. Substantial efforts have centered on the starch regulatory enzyme ADPglucose pyrophosphorylase (AGPase) due to its pivotal role in starch biosynthesis. These efforts include over-expression of this enzyme in cereal plants such as maize, rice and wheat as well as potato and cassava, as they supply the bulk of the staple food worldwide. In this perspective, we describe efforts to increase starch yields in cereal grains by first providing an introduction about the importance of source-sink relationship and the motives behind the efforts to alter starch biosynthesis and turnover in leaves. We then discuss the catalytic and regulatory properties of AGPase and the molecular approaches used to enhance starch synthesis by manipulation of this process during grain filling using seed-specific promoters. Several studies have demonstrated increases in starch content per seed using endosperm-specific promoters, but other studies have demonstrated an increase in seed number with only marginal impact on seed weight. Potential mechanisms that may be responsible for this paradoxical increase in seed number will also be discussed. Finally, we describe current efforts and future prospects to improve starch yield in cereals. These efforts include further enhancement of starch yield in rice by augmenting the process of ADPglucose transport into amyloplast as well as other enzymes involved in photoassimilate partitioning in seeds.
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Affiliation(s)
- Aytug Tuncel
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, United States
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36
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Modulation of allosteric regulation by E38K and G101N mutations in the potato tuber ADP-glucose pyrophosphorylase. Biosci Biotechnol Biochem 2013; 77:1854-9. [PMID: 24018661 DOI: 10.1271/bbb.130276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The higher plant ADP-glucose (ADPG) pyrophosphorylase (AGPase), composed of two small subunits and two large subunits (LSs), produces ADPG, the sole substrate for starch biosynthesis from α-D-glucose 1-phosphate and ATP. This enzyme controls a key step in starch synthesis as its catalytic activity is activated by 3-phosphoglycerate (3-PGA) and inhibited by orthophosphate (Pi). Previously, two mutations in the LS of potato AGPase (PLS), PLS-E38K and PLS-G101N, were found to increase sensitivity to 3-PGA activation and tolerance to Pi inhibition. In the present study, the double mutated enzyme (PLS-E38K/G101N) was evaluated. In a complementation assay of ADPG synthesis in an Escherichia coli mutant defective in the synthesis of ADPG, expression of PLS-E38K/G101N mediated higher glycogen production than wild-type potato AGPase (PLS-WT) and the single mutant enzymes, PLS-E38K and PLS-G101N, individually. Purified PLS-E38K/G101N showed higher sensitivity to 3-PGA activation and tolerance to Pi inhibition than PLS-E38K or PLS-G101N. Moreover, the enzyme activities of PLS-E38K, PLS-G101N, and PLS-E38K/G101N were more readily stimulated by other major phosphate-ester metabolites, such as fructose 6-phosphate, fructose 2,6-bisphosphate, and ribose 5-phosphate, than was that of PLS-WT. Hence, although the specific enzyme activities of the LS mutants toward 3-PGA were impaired to some extent by the mutations, our results suggest that their enhanced allosteric regulatory properties and the broadened effector selectivity gained by the same mutations not only offset the lowered enzyme catalytic turnover rates but also increase the net performance of potato AGPase in vivo in view of increased glycogen production in bacterial cells.
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37
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Dawar C, Jain S, Kumar S. Insight into the 3D structure of ADP-glucose pyrophosphorylase from rice (Oryza sativa L.). J Mol Model 2013; 19:3351-3367. [PMID: 23674369 DOI: 10.1007/s00894-013-18517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 04/04/2013] [Indexed: 05/26/2023]
Abstract
ADP-glucose pyrophosphorylase (E.C. 2.7.7.27; AGPase) is a key regulatory enzyme that catalyzes the rate-limiting step of starch biosynthesis in higher plants. AGPase consists of pair of small (SS) and large (LS) subunits thereby constituting a heterotetrameric structure. No crystal structure of the native heterotetrameric enzyme is available for any species, thus limiting the complete understanding of structure-function relationships of this enzyme. In this study, an attempt was made to deduce the heterotetrameric assembly of AGPase in rice. Homology modeling of the three-dimensional structure of the LS and SS was performed using the Swiss Model Server, and the models were evaluated and docked using GRAMM-X to obtain the stable heterodimer orientation (LS as receptor and SS as ligand) and then the heterotetrameric orientation. The initial heterotetrameric orientation was further refined using the RosettaDock Server. MD simulation of the representative heterodimer/tetramer was performed using NAMD, which indicated that the tail-to-tail interaction of LS and SS was more stable than the head-to-head orientation, and the heterotetramer energy was also minimized to -767,011 kcal mol(-1). Subunit-subunit interaction studies were then carried out using the programs NACCESS and Dimplot. A total of 57 interface residues were listed in SS and 63 in LS. The residues plotted by Dimplot were similar to those listed by NACCESS. Multiple sequence alignment of the sequences of LS and SS from potato, maize and rice validated the interactions inferred in the study. RMSD of 1.093 Å was obtained on superimposition of the deduced heterotetramer on the template homo-tetramer (1YP2), showing the similarity between the two structures.
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Affiliation(s)
- Chhavi Dawar
- Bioinformatics Section, CCS Haryana Agricultural University, Hisar 125004, India
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Rani S, Sharma P, Sharma A, Chatrath R. Comparative computational analysis of ADP Glucose Pyrophosphorylase in plants. Bioinformation 2013; 9:572-6. [PMID: 23888098 PMCID: PMC3717185 DOI: 10.6026/97320630009572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 04/11/2013] [Accepted: 04/22/2013] [Indexed: 11/23/2022] Open
Abstract
ADP-glucose pyrophosphorylase (AGPase), a key enzyme involved in higher plant starch biosynthesis, is composed of pairs of
large (LS) and small subunits (SS). Ample evidence has shown that the AGPase catalyzes the rate limiting step in starch
biosynthesis in higher plants. In this study, we compiled detailed comparative information about ADP glucose pyrophosphorylase
in selected plants by analyzing their structural features e.g. amino acid content, physico-chemical properties, secondary structural
features and phylogenetic classification. Functional analysis of these proteins includes identification of important 10 to 20 amino
acids long motifs arise because specific residues and regions proved to be important for the biological function of a group of
proteins, which are conserved in both structure and sequence during evolution. Phylogenetic analysis depicts two main clusters.
Cluster I encompasses large subunits (LS) while cluster II contains small subunits (SS).
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Affiliation(s)
- Saroj Rani
- Biotechnology Unit, Directorate of Wheat Research Karnal, Haryana, India ; Department of Biotechnology, Maharishi Markandeshwar University Mullana, Ambala, India
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Bahaji A, Li J, Sánchez-López ÁM, Baroja-Fernández E, Muñoz FJ, Ovecka M, Almagro G, Montero M, Ezquer I, Etxeberria E, Pozueta-Romero J. Starch biosynthesis, its regulation and biotechnological approaches to improve crop yields. Biotechnol Adv 2013; 32:87-106. [PMID: 23827783 DOI: 10.1016/j.biotechadv.2013.06.006] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 06/21/2013] [Indexed: 01/08/2023]
Abstract
Structurally composed of the glucose homopolymers amylose and amylopectin, starch is the main storage carbohydrate in vascular plants, and is synthesized in the plastids of both photosynthetic and non-photosynthetic cells. Its abundance as a naturally occurring organic compound is surpassed only by cellulose, and represents both a cornerstone for human and animal nutrition and a feedstock for many non-food industrial applications including production of adhesives, biodegradable materials, and first-generation bioethanol. This review provides an update on the different proposed pathways of starch biosynthesis occurring in both autotrophic and heterotrophic organs, and provides emerging information about the networks regulating them and their interactions with the environment. Special emphasis is given to recent findings showing that volatile compounds emitted by microorganisms promote both growth and the accumulation of exceptionally high levels of starch in mono- and dicotyledonous plants. We also review how plant biotechnologists have attempted to use basic knowledge on starch metabolism for the rational design of genetic engineering traits aimed at increasing starch in annual crop species. Finally we present some potential biotechnological strategies for enhancing starch content.
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Affiliation(s)
- Abdellatif Bahaji
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain
| | - Jun Li
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain
| | - Ángela María Sánchez-López
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain
| | - Edurne Baroja-Fernández
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain
| | - Francisco José Muñoz
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain
| | - Miroslav Ovecka
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain; Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacky University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - Goizeder Almagro
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain
| | - Manuel Montero
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain
| | - Ignacio Ezquer
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain
| | - Ed Etxeberria
- University of Florida, Institute of Food and Agricultural Sciences, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred, FL 33850-2299, USA
| | - Javier Pozueta-Romero
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain.
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40
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Deciphering the kinetic mechanisms controlling selected plant ADP-glucose pyrophosphorylases. Arch Biochem Biophys 2013; 535:215-26. [DOI: 10.1016/j.abb.2013.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 04/03/2013] [Accepted: 04/04/2013] [Indexed: 11/22/2022]
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41
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Multigene engineering of starch biosynthesis in maize endosperm increases the total starch content and the proportion of amylose. Transgenic Res 2013; 22:1133-42. [DOI: 10.1007/s11248-013-9717-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 05/28/2013] [Indexed: 12/22/2022]
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42
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Insight into the 3D structure of ADP-glucose pyrophosphorylase from rice (Oryza sativa L.). J Mol Model 2013; 19:3351-67. [PMID: 23674369 DOI: 10.1007/s00894-013-1851-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 04/04/2013] [Indexed: 10/26/2022]
Abstract
ADP-glucose pyrophosphorylase (E.C. 2.7.7.27; AGPase) is a key regulatory enzyme that catalyzes the rate-limiting step of starch biosynthesis in higher plants. AGPase consists of pair of small (SS) and large (LS) subunits thereby constituting a heterotetrameric structure. No crystal structure of the native heterotetrameric enzyme is available for any species, thus limiting the complete understanding of structure-function relationships of this enzyme. In this study, an attempt was made to deduce the heterotetrameric assembly of AGPase in rice. Homology modeling of the three-dimensional structure of the LS and SS was performed using the Swiss Model Server, and the models were evaluated and docked using GRAMM-X to obtain the stable heterodimer orientation (LS as receptor and SS as ligand) and then the heterotetrameric orientation. The initial heterotetrameric orientation was further refined using the RosettaDock Server. MD simulation of the representative heterodimer/tetramer was performed using NAMD, which indicated that the tail-to-tail interaction of LS and SS was more stable than the head-to-head orientation, and the heterotetramer energy was also minimized to -767,011 kcal mol(-1). Subunit-subunit interaction studies were then carried out using the programs NACCESS and Dimplot. A total of 57 interface residues were listed in SS and 63 in LS. The residues plotted by Dimplot were similar to those listed by NACCESS. Multiple sequence alignment of the sequences of LS and SS from potato, maize and rice validated the interactions inferred in the study. RMSD of 1.093 Å was obtained on superimposition of the deduced heterotetramer on the template homo-tetramer (1YP2), showing the similarity between the two structures.
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Seferoglu AB, Baris I, Morgil H, Tulum I, Ozdas S, Cevahir G, Kavakli IH. Transcriptional regulation of the ADP-glucose pyrophosphorylase isoforms in the leaf and the stem under long and short photoperiod in lentil. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 205-206:29-37. [PMID: 23498860 DOI: 10.1016/j.plantsci.2013.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 01/19/2013] [Accepted: 01/22/2013] [Indexed: 05/23/2023]
Abstract
ADP-glucose pyrophosphorylase (AGPase) is a key enzyme in plant starch biosynthesis. It contains large (LS) and small (SS) subunits encoded by two different genes. In this study, we explored the transcriptional regulation of both the LS and SS subunits of AGPase in stem and leaf under different photoperiods length in lentil. To this end, we first isolated and characterized different isoforms of the LS and SS of lentil AGPase and then we performed quantitative real time PCR (qPCR) to see the effect of photoperiod length on the transcription of the AGPase isforms under the different photoperiod regimes in lentil. Analysis of the qPCR results revealed that the transcription of different isoforms of the LSs and the SSs of lentil AGPase are differentially regulated when photoperiod shifted from long-day to short-day in stem and leaves. While transcript levels of LS1 and SS2 in leaf significantly decreased, overall transcript levels of SS1 increased in short-day regime. Our results indicated that day length affects the transcription of lentil AGPase isoforms differentially in stems and leaves most likely to supply carbon from the stem to other tissues to regulate carbon metabolism under short-day conditions.
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Affiliation(s)
- Ayse Bengisu Seferoglu
- Koc University, Department of Chemical and Biological Engineering, Rumeli Feneri Yolu, 34450 Sariyer, Istanbul, Turkey
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Li J, Baroja-Fernández E, Bahaji A, Muñoz FJ, Ovecka M, Montero M, Sesma MT, Alonso-Casajús N, Almagro G, Sánchez-López AM, Hidalgo M, Zamarbide M, Pozueta-Romero J. Enhancing sucrose synthase activity results in increased levels of starch and ADP-glucose in maize (Zea mays L.) seed endosperms. PLANT & CELL PHYSIOLOGY 2013; 54:282-94. [PMID: 23292602 DOI: 10.1093/pcp/pcs180] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Sucrose synthase (SuSy) is a highly regulated cytosolic enzyme that catalyzes the conversion of sucrose and a nucleoside diphosphate into the corresponding nucleoside diphosphate glucose and fructose. In cereal endosperms, it is widely assumed that the stepwise reactions of SuSy, UDPglucose pyrophosphorylase and ADPglucose (ADPG) pyrophosphorylase (AGP) take place in the cytosol to convert sucrose into ADPG necessary for starch biosynthesis, although it has also been suggested that SuSy may participate in the direct conversion of sucrose into ADPG. In this study, the levels of the major primary carbon metabolites, and the activities of starch metabolism-related enzymes were assessed in endosperms of transgenic maize plants ectopically expressing StSUS4, which encodes a potato SuSy isoform. A total of 29 fertile lines transformed with StSUS4 were obtained, five of them containing a single copy of the transgene that was still functional after five generations. The number of seeds per ear of the five transgenic lines containing a single StSUS4 copy was comparable with that of wild-type (WT) control seeds. However, transgenic seeds accumulated 10-15% more starch at the mature stage, and contained a higher amylose/amylopectin balance than WT seeds. Endosperms of developing StSUS4-expressing seeds exhibited a significant increase in SuSy activity, and in starch and ADPG contents when compared with WT endosperms. No significant changes could be detected in the transgenic seeds in the content of soluble sugars, and in activities of starch metabolism-related enzymes when compared with WT seeds. A suggested metabolic model is presented wherein both AGP and SuSy are involved in the production of ADPG linked to starch biosynthesis in maize endosperm cells.
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Affiliation(s)
- Jun Li
- Instituto de Agrobiotecnología, Universidad Pública de Navarra/Consejo Superior de Investigaciones Científicas/Gobierno de Navarra, Mutiloako etorbidea zenbaki gabe, 31192 Mutiloabeti, Nafarroa, Spain
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Weber N, Halpin C, Hannah LC, Jez JM, Kough J, Parrott W. Editor's choice: Crop genome plasticity and its relevance to food and feed safety of genetically engineered breeding stacks. PLANT PHYSIOLOGY 2012; 160:1842-53. [PMID: 23060369 PMCID: PMC3510115 DOI: 10.1104/pp.112.204271] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 10/02/2012] [Indexed: 05/22/2023]
Affiliation(s)
- Natalie Weber
- Pioneer Hi-Bred International, Wilmington, Delaware 19880, USA
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46
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Hannah LC, Futch B, Bing J, Shaw JR, Boehlein S, Stewart JD, Beiriger R, Georgelis N, Greene T. A shrunken-2 transgene increases maize yield by acting in maternal tissues to increase the frequency of seed development. THE PLANT CELL 2012; 24:2352-63. [PMID: 22751213 PMCID: PMC3406911 DOI: 10.1105/tpc.112.100602] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 05/17/2012] [Accepted: 06/15/2012] [Indexed: 05/19/2023]
Abstract
The maize (Zea mays) shrunken-2 (Sh2) gene encodes the large subunit of the rate-limiting starch biosynthetic enzyme, ADP-glucose pyrophosphorylase. Expression of a transgenic form of the enzyme with enhanced heat stability and reduced phosphate inhibition increased maize yield up to 64%. The extent of the yield increase is dependent on temperatures during the first 4 d post pollination, and yield is increased if average daily high temperatures exceed 33 °C. As found in wheat (Triticum aestivum) and rice (Oryza sativa), this transgene increases maize yield by increasing seed number. This result was surprising, since an entire series of historic observations at the whole-plant, enzyme, gene, and physiological levels pointed to Sh2 playing an important role only in the endosperm. Here, we present several lines of evidence that lead to the conclusion that the Sh2 transgene functions in maternal tissue to increase seed number and, in turn, yield. Furthermore, the transgene does not increase ovary number; rather, it increases the probability that a seed will develop. Surprisingly, the number of fully developed seeds is only ∼50% of the number of ovaries in wild-type maize. This suggests that increasing the frequency of seed development is a feasible agricultural target, especially under conditions of elevated temperatures.
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Affiliation(s)
- L Curtis Hannah
- Department of Horticultural Sciences, University of Florida, Gainesville, Florida 32611, USA.
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47
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Nucleotide polymorphisms in OsAGP genes and their possible association with grain weight of rice. J Cereal Sci 2012. [DOI: 10.1016/j.jcs.2012.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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48
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Gámez-Arjona FM, Li J, Raynaud S, Baroja-Fernández E, Muñoz FJ, Ovecka M, Ragel P, Bahaji A, Pozueta-Romero J, Mérida Á. Enhancing the expression of starch synthase class IV results in increased levels of both transitory and long-term storage starch. PLANT BIOTECHNOLOGY JOURNAL 2011; 9:1049-60. [PMID: 21645200 DOI: 10.1111/j.1467-7652.2011.00626.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Starch is an important renewable raw material with an increasing number of applications. Several attempts have been made to obtain plants that produce modified versions of starch or higher starch yield. Most of the approaches designed to increase the levels of starch have focused on the increment of the amount of ADP-glucose or ATP available for starch biosynthesis. In this work, we show that the overexpression of starch synthase class IV (SSIV) increases the levels of starch accumulated in the leaves of Arabidopsis by 30%-40%. In addition, SSIV-overexpressing lines display a higher rate of growth. The increase in starch content as a consequence of enhanced SSIV expression is also observed in long-term storage starch organs such as potato tubers. Overexpression of SSIV in potato leads to increased tuber starch content on a dry weight basis and to increased yield of starch production in terms of tons of starch/hectare. These results identify SSIV as one of the regulatory steps involved in the control of the amount of starch accumulated in plastids.
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Slewinski TL. Diverse functional roles of monosaccharide transporters and their homologs in vascular plants: a physiological perspective. MOLECULAR PLANT 2011; 4:641-62. [PMID: 21746702 DOI: 10.1093/mp/ssr051] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Vascular plants contain two gene families that encode monosaccharide transporter proteins. The classical monosaccharide transporter(-like) gene superfamily is large and functionally diverse, while the recently identified SWEET transporter family is smaller and, thus far, only found to transport glucose. These transporters play essential roles at many levels, ranging from organelles to the whole plant. Many family members are essential for cellular homeostasis and reproductive success. Although most transporters do not directly participate in long-distance transport, their indirect roles greatly impact carbon allocation and transport flux to the heterotrophic tissues of the plant. Functional characterization of some members from both gene families has revealed their diverse roles in carbohydrate partitioning, phloem function, resource allocation, plant defense, and sugar signaling. This review highlights the broad impacts and implications of monosaccharide transport by describing some of the functional roles of the monosaccharide transporter(-like) superfamily and the SWEET transporter family.
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Affiliation(s)
- Thomas L Slewinski
- Department of Plant Biology, Cornell University, 262 Plant Science Building, Ithaca, NY 14853, USA.
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Corbi J, Debieu M, Rousselet A, Montalent P, Le Guilloux M, Manicacci D, Tenaillon MI. Contrasted patterns of selection since maize domestication on duplicated genes encoding a starch pathway enzyme. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2011; 122:705-22. [PMID: 21060986 DOI: 10.1007/s00122-010-1480-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 10/22/2010] [Indexed: 05/08/2023]
Abstract
Maize domestication from teosinte (Zea mays ssp. parviglumis) was accompanied by an increase of kernel size in landraces. Subsequent breeding has led to a diversification of kernel size and starch content among major groups of inbred lines. We aim at investigating the effect of domestication on duplicated genes encoding a key enzyme of the starch pathway, the ADP-glucose pyrophosphorylase (AGPase). Three pairs of paralogs encode the AGPase small (SSU) and large (LSU) subunits mainly expressed in the endosperm, the embryo and the leaf. We first validated the putative sequence of LSU(leaf) through a comparative expression assay of the six genes. Second, we investigated the patterns of molecular evolution on a 2 kb coding region homologous among the six genes in three panels: teosintes, landraces, and inbred lines. We corrected for demographic effects by relying on empirical distributions built from 580 previously sequenced ESTs. We found contrasted patterns of selection among duplicates: three genes exhibit patterns of directional selection during domestication (SSU(end), LSU(emb)) or breeding (LSU(leaf)), two exhibit patterns consistent with diversifying (SSU(leaf)) and balancing selection (SSU(emb)) accompanying maize breeding. While patterns of linkage disequilibrium did not reveal sign of coevolution between genes expressed in the same organ, we detected an excess of non-synonymous substitutions in the small subunit functional domains highlighting their role in AGPase evolution. Our results offer a different picture on AGPase evolution than the one depicted at the Angiosperm level and reveal how genetic redundancy can provide flexibility in the response to selection.
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Affiliation(s)
- J Corbi
- CNRS, UMR 0320/UMR 8120 Génétique Végétale, Ferme du Moulon, Gif sur Yvette, France
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