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Xu Y, Hu R, Li S. Regulation of seed coat mucilage production and modification in Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 328:111591. [PMID: 36623642 DOI: 10.1016/j.plantsci.2023.111591] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/13/2022] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
The Arabidopsis seed coat mucilage is a polysaccharide-rich matrix synthesized by the seed coat epidermal cells. It is a specialized cell wall mainly composed of three types of polysaccharides (i. e. pectin, hemicellulose, and cellulose), and represents as an ideal model system for plant cell wall research. A large number of genes responsible for the synthesis and modification of cell wall polysaccharides have been identified using this model system. Moreover, a subset of regulators controlling mucilage production and modification have been characterized, and the underlying transcriptional regulatory mechanisms have been elucidated. This substantially contributes to the understanding of the molecular mechanisms underlying mucilage synthesis and modification. In this review, we concisely summarize the various genes and regulators involved in seed coat cell differentiation, mucilage biosynthesis and modification, and secondary cell wall formation. In particular, we put emphasis on the latest knowledge gained regarding the transcriptional regulation of mucilage production, which is composed of a hierarchal cascade with three-layer transcriptional regulators. Collectively, we propose an updated schematic framework of the genetic regulatory network controlling mucilage production and modification in the Arabidopsis mucilage secretory cells.
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Affiliation(s)
- Yan Xu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Energy Institute, Qingdao 266101, PR China; Qingdao New Energy Shandong Laboratory, Qingdao 266101, PR China
| | - Ruibo Hu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Energy Institute, Qingdao 266101, PR China; Qingdao New Energy Shandong Laboratory, Qingdao 266101, PR China.
| | - Shengjun Li
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Energy Institute, Qingdao 266101, PR China; Qingdao New Energy Shandong Laboratory, Qingdao 266101, PR China.
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Chen JJ, Wang W, Qin WQ, Men SZ, Li HL, Mitsuda N, Ohme-Takagi M, Wu AM. Transcription factors KNAT3 and KNAT4 are essential for integument and ovule formation in Arabidopsis. PLANT PHYSIOLOGY 2023; 191:463-478. [PMID: 36342216 PMCID: PMC9806662 DOI: 10.1093/plphys/kiac513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Integuments form important protective cell layers surrounding the developing ovules in gymno- and angiosperms. Although several genes have been shown to influence the development of integuments, the transcriptional regulatory mechanism is still poorly understood. In this work, we report that the Class II KNOTTED1-LIKE HOMEOBOX (KNOX II) transcription factors KNOTTED1-LIKE HOMEBOX GENE 3 (KNAT3) and KNAT4 regulate integument development in Arabidopsis (Arabidopsis thaliana). KNAT3 and KNAT4 were co-expressed in inflorescences and especially in young developing ovules. The loss-of-function double mutant knat3 knat4 showed an infertility phenotype, in which both inner and outer integuments of the ovule are arrested at an early stage and form an amorphous structure as in the bell1 (bel1) mutant. The expression of chimeric KNAT3- and KNAT4-EAR motif repression domain (SRDX repressors) resulted in severe seed abortion. Protein-protein interaction assays demonstrated that KNAT3 and KNAT4 interact with each other and also with INNER NO OUTER (INO), a key transcription factor required for the outer integument formation. Transcriptome analysis showed that the expression of genes related with integument development is influenced in the knat3 knat4 mutant. The knat3 knat4 mutant also had a lower indole-3-acetic acid (IAA) content, and some auxin signaling pathway genes were downregulated. Moreover, transactivation analysis indicated that KNAT3/4 and INO activate the auxin signaling gene IAA INDUCIBLE 14 (IAA14). Taken together, our study identified KNAT3 and KNAT4 as key factors in integument development in Arabidopsis.
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Affiliation(s)
- Jia-Jun Chen
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
| | - Wei Wang
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå 90183, Sweden
| | - Wen-Qi Qin
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
| | - Shu-Zhen Men
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Hui-Ling Li
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
| | - Nobutaka Mitsuda
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Masaru Ohme-Takagi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Ai-Min Wu
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
- Guangdong Laboratory of Lingnan Modern Agriculture, Guangzhou 510642, China
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Shi L, Chen Y, Hong J, Shen G, Schreiber L, Cohen H, Zhang D, Aharoni A, Shi J. AtMYB31 is a wax regulator associated with reproductive development in Arabidopsis. PLANTA 2022; 256:28. [PMID: 35781548 DOI: 10.1007/s00425-022-03945-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
AtMYB31, a R2R3-MYB transcription factor that modulates wax biosynthesis in reproductive tissues, is involved in seed development in Arabidopsis. R2R3-MYB transcription factors play important roles in plant development; yet, the exact role of each of them remains to be resolved. Here we report that the Arabidopsis AtMYB31 is required for wax biosynthesis in epidermis of reproductive tissues, and is involved in seed development. AtMYB31 was ubiquitously expressed in both vegetative and reproductive tissues with higher expression levels in siliques and seeds, while AtMYB31 was localized to the nucleus and cytoplasm. Loss of function of AtMYB31 reduced wax accumulation in the epidermis of silique and flower tissues, disrupted seed coat epidermal wall development and mucilage production, altered seed proanthocyanidin and polyester content. AtMYB31 could direct activate expressions of several wax biosynthetic target genes. Altogether, AtMYB31, a R2R3-MYB transcription factor, regulates seed development in Arabidopsis.
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Affiliation(s)
- Lei Shi
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yuqin Chen
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jun Hong
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Gaodian Shen
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Lukas Schreiber
- Institute of Cellular and Molecular Botany, University of Bonn, 53115, Bonn, Germany
| | - Hagai Cohen
- Institute of Plant Sciences, Agricultural Research Organization, 7505101, Rishon LeZion, Israel
| | - Dabing Zhang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Asaph Aharoni
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, 76100, Rehovot, Israel.
| | - Jianxin Shi
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Zhang Y, Yin Q, Qin W, Gao H, Du J, Chen J, Li H, Zhou G, Wu H, Wu AM. The Class II KNOX family members KNAT3 and KNAT7 redundantly participate in Arabidopsis seed coat mucilage biosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3477-3495. [PMID: 35188965 DOI: 10.1093/jxb/erac066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
The production of Arabidopsis seed mucilage involves complex polysaccharide biosynthetic pathways and developmental processes in seed epidermal cells. Although the polysaccharide components of Arabidopsis seed mucilage have been identified, their regulatory mechanism requires further investigation. Here, we show that Class II KNOX gene family members KNAT3 and KNAT7 play an essential role in regulating mucilage production in the early developmental stages of Arabidopsis seeds. Double mutant knat3knat7 resulted in defective seed mucilage production and columellae formation, whereas knat3 showed a normal phenotype compared with wild type, and the mucilage thickness in knat7 was slightly disturbed. Rhamnogalacturonan I (RG-I) and its biosynthetic substrates galacturonic acid and rhamnose were reduced in both the adherent and soluble mucilage of knat3knat7. Comparative transcriptome analysis on whole seeds suggested that polysaccharide, glucosinolate and anthocyanin biosynthetic pathways were specifically repressed in knat3knat7. Transient co-expression of KNAT3 and KNAT7 with promoter regions of candidate genes in Arabidopsis protoplasts revealed that both KNAT3 and KNAT7 act as positive regulators of the RG-I biosynthetic gene MUCILAGE-MODIFIED 4 (MUM4, AT1G53500). Collectively, our results demonstrate that KNAT3 and KNAT7 are multifunctional transcription factors in secondary cell wall development and redundantly modulate mucilage biosynthesis in Arabidopsis seeds.
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Affiliation(s)
- Yuanyuan Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University. Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University. Guangzhou, 510642, China
| | - Qi Yin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University. Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University. Guangzhou, 510642, China
| | - Wenqi Qin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University. Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University. Guangzhou, 510642, China
| | - Han Gao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University. Guangzhou, 510642, China
- College of life sciences, South China Agricultural University. Guangzhou, 510642, China
| | - Jinge Du
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China
| | - Jiajun Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University. Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University. Guangzhou, 510642, China
| | - Huiling Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University. Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University. Guangzhou, 510642, China
| | - Gongke Zhou
- College of Resource and Environment, Qingdao Agricultural University, Qingdao, 266109, China
| | - Hong Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University. Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University. Guangzhou, 510642, China
- College of life sciences, South China Agricultural University. Guangzhou, 510642, China
| | - Ai-Min Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University. Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University. Guangzhou, 510642, China
- Guangdong Laboratory of Lingnan Modern Agriculture, Guangzhou 510642, China
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Sun G, Zhang X, Duan H, Gao J, Li N, Su P, Xie H, Li W, Fu Z, Huang Y, Tang J. Dissection of the genetic architecture of peduncle vascular bundle-related traits in maize by a genome-wide association study. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:1042-1053. [PMID: 35080335 PMCID: PMC9129077 DOI: 10.1111/pbi.13782] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 12/20/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
The peduncle vascular system of maize is critical for the transport of photosynthetic products, nutrients, and water from the roots and leaves to the ear. Accordingly, it positively affects the grain yield. However, the genetic basis of peduncle vascular bundle (PVB)-related traits in maize remains unknown. Thus, 15 PVB-related traits of 386 maize inbred lines were investigated at three locations (Yongcheng, 17YC; Kaifeng, 20KF; and Yuanyang, 20YY). The repeatability for the 15 traits ranged from 35.53% to 92.13%. A genome-wide association study was performed and 69 non-redundant quantitative trait loci (QTL) were detected, including 9, 41, and 27 QTL identified at 17YC, 20KF, and 20YY, respectively. These QTL jointly explained 4.72% (SLL) to 37.30% (NSVB) of the phenotypic variation. Eight QTL were associated with the same trait at two locations. Furthermore, four pleiotropic QTL were identified. Moreover, one QTL (qPVB44), associated with NSVB_20KF, was co-localized with a previously reported locus related to kernel width, implying qPVB44 may affect the kernel width by modulating the number of small vascular bundles. Examinations of the 69 QTL identified 348 candidate genes that were classified in five groups. Additionally, 26 known VB-related homologous genes (e.g. VLN2, KNOX1, and UGT72B3) were detected in 20 of the 69 QTL. A comparison of the NSVB between a Zmvln2 EMS mutant and its wild type elucidated the function of the candidate gene ZmVLN2. These results are important for clarifying the genetic basis of PVB-related traits and may be useful for breeding new high-yielding maize cultivars.
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Affiliation(s)
- Gaoyang Sun
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
- College of AgronomySichuan Agricultural UniversityChengduChina
| | - Xuehai Zhang
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
| | - Haiyang Duan
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
| | - Jionghao Gao
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
| | - Na Li
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
| | - Pingping Su
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
| | - Huiling Xie
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
| | - Weihua Li
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
| | - Zhiyuan Fu
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
| | - Yubi Huang
- College of AgronomySichuan Agricultural UniversityChengduChina
| | - Jihua Tang
- National Key Laboratory of Wheat and Maize Crop ScienceCollege of AgronomyHenan Agricultural UniversityZhengzhouChina
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Que F, Liu Q, Zha R, Xiong A, Wei Q. Genome-Wide Identification, Expansion, and Evolution Analysis of Homeobox Gene Family Reveals TALE Genes Important for Secondary Cell Wall Biosynthesis in Moso Bamboo ( Phyllostachys edulis). Int J Mol Sci 2022; 23:ijms23084112. [PMID: 35456930 PMCID: PMC9032839 DOI: 10.3390/ijms23084112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/04/2022] [Accepted: 04/06/2022] [Indexed: 02/06/2023] Open
Abstract
The TALE gene family is a subfamily of the homeobox gene family and has been implicated in regulating plant secondary growth. However, reports about the evolutionary history and function of the TALE gene family in bamboo are limited. Here, the homeobox gene families of moso bamboo Olyra latifolia and Bonia amplexicaulis were identified and compared. Many duplication events and obvious expansions were found in the TALE family of woody bamboo. PhTALEs were found to have high syntenies with TALE genes in rice. Through gene co-expression analysis and quantitative real-time PCR analysis, the candidate PhTALEs were thought to be involved in regulating secondary cell wall development of moso bamboo during the fast-growing stage. Among these candidate PhTALEs, orthologs of OsKNAT7, OSH15, and SH5 in moso bamboo may regulate xylan synthesis by regulating the expression of IRX-like genes. These results suggested that PhTALEs may participate in the secondary cell wall deposition in internodes during the fast-growing stage of moso bamboo. The expansion of the TALE gene family may be implicated in the increased lignification of woody bamboo when divergent from herbaceous bamboos.
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Affiliation(s)
- Feng Que
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China; (F.Q.); (Q.L.); (R.Z.)
| | - Qingnan Liu
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China; (F.Q.); (Q.L.); (R.Z.)
| | - Ruofei Zha
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China; (F.Q.); (Q.L.); (R.Z.)
| | - Aisheng Xiong
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- Correspondence: (A.X.); (Q.W.)
| | - Qiang Wei
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China; (F.Q.); (Q.L.); (R.Z.)
- Correspondence: (A.X.); (Q.W.)
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Zhuang Y, Lian W, Tang X, Qi G, Wang D, Chai G, Zhou G. MYB42 inhibits hypocotyl cell elongation by coordinating brassinosteroid homeostasis and signalling in Arabidopsis thaliana. ANNALS OF BOTANY 2022; 129:403-413. [PMID: 34922335 PMCID: PMC8944714 DOI: 10.1093/aob/mcab152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS The precise control of brassinosteroid (BR) homeostasis and signalling is a prerequisite for hypocotyl cell elongation in plants. Arabidopsis MYB42 and its paralogue MYB85 were previously identified to be positive regulators of secondary cell wall formation during mature stages. Here, we aim to reveal the role of MYB42 and MYB85 in hypocotyl elongation during the seedling stage and clarify how MYB42 coordinates BR homeostasis and signalling to regulate this process. METHODS Histochemical analysis of proMYB42-GUS transgenic plants was used for determination of the MYB42 expression pattern. The MYB42, 85 overexpression, double mutant and some crossing lines were generated for phenotypic observation and transcriptome analysis. Transcription activation assays, quantitative PCR (qPCR), chromatin immunoprecipitation (ChIP)-qPCR and electrophoretic mobility shift assays (EMSAs) were conducted to determine the relationship of MYB42 and BRASSINAZOLE-RESISTANT 1 (BZR1), a master switch activating BR signalling. KEY RESULTS MYB42 and MYB85 redundantly and negatively regulate hypocotyl cell elongation. They function in hypocotyl elongation by mediating BR signalling. MYB42 transcription was suppressed by BR treatment or in bzr1-1D (a gain-of-function mutant of BZR1), and mutation of both MYB42 and MYB85 enhanced the dwarf phenotype of the BR receptor mutant bri1-5. BZR1 directly repressed MYB42 expression in response to BR. Consistently, hypocotyl length of bzr1-1D was increased by simultaneous mutation of MYB42 and MYB85, but was reduced by overexpression of MYB42. Expression of a number of BR-regulated BZR1 (non-)targets associated with hypocotyl elongation was suppressed by MYB42, 85. Furthermore, MYB42 enlarged its action in BR signalling through feedback repression of BR accumulation and activation of DOGT1/UGT73C5, a BR-inactivating enzyme. CONCLUSIONS MYB42 inhibits hypocotyl elongation by coordinating BR homeostasis and signalling during primary growth. The present study shows an MYB42, 85-mediated multilevel system that contributes to fine regulation of BR-induced hypocotyl elongation.
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Affiliation(s)
- Yamei Zhuang
- College of Resources and Environment, Qingdao Agricultural University, Qingdao, China
- Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Wenjun Lian
- College of Resources and Environment, Qingdao Agricultural University, Qingdao, China
| | - Xianfeng Tang
- Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Guang Qi
- State Key Laboratory of Wheat and Maize Crop Science and College of Agronomy, Henan Agricultural University, Zhengzhou, China
| | - Dian Wang
- College of Agronomy, Qingdao Agricultural University, Qingdao, China
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Nookaraju A, Pandey SK, Ahlawat YK, Joshi CP. Understanding the Modus Operandi of Class II KNOX Transcription Factors in Secondary Cell Wall Biosynthesis. PLANTS (BASEL, SWITZERLAND) 2022; 11:493. [PMID: 35214825 PMCID: PMC8880547 DOI: 10.3390/plants11040493] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/27/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Lignocellulosic biomass from the secondary cell walls of plants has a veritable potential to provide some of the most appropriate raw materials for producing second-generation biofuels. Therefore, we must first understand how plants synthesize these complex secondary cell walls that consist of cellulose, hemicellulose, and lignin in order to deconstruct them later on into simple sugars to produce bioethanol via fermentation. Knotted-like homeobox (KNOX) genes encode homeodomain-containing transcription factors (TFs) that modulate various important developmental processes in plants. While Class I KNOX TF genes are mainly expressed in the shoot apical meristems of both monocot and eudicot plants and are involved in meristem maintenance and/or formation, Class II KNOXTF genes exhibit diverse expression patterns and their precise functions have mostly remained unknown, until recently. The expression patterns of Class II KNOX TF genes in Arabidopsis, namely KNAT3, KNAT4, KNAT5, and KNAT7, suggest that TFs encoded by at least some of these genes, such as KNAT7 and KNAT3, may play a significant role in secondary cell wall formation. Specifically, the expression of the KNAT7 gene is regulated by upstream TFs, such as SND1 and MYB46, while KNAT7 interacts with other cell wall proteins, such as KNAT3, MYB75, OFPs, and BLHs, to regulate secondary cell wall formation. Moreover, KNAT7 directly regulates the expression of some xylan synthesis genes. In this review, we summarize the current mechanistic understanding of the roles of Class II KNOX TFs in secondary cell wall formation. Recent success with the genetic manipulation of Class II KNOX TFs suggests that this may be one of the biotechnological strategies to improve plant feedstocks for bioethanol production.
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Affiliation(s)
- Akula Nookaraju
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931, USA; (A.N.); (S.K.P.); (Y.K.A.)
- Kaveri Seed Company Limited, Secunderabad 500003, Telangana, India
| | - Shashank K. Pandey
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931, USA; (A.N.); (S.K.P.); (Y.K.A.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 87 Umeå, Sweden
| | - Yogesh K. Ahlawat
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931, USA; (A.N.); (S.K.P.); (Y.K.A.)
- Department of Horticultural Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Chandrashekhar P. Joshi
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931, USA; (A.N.); (S.K.P.); (Y.K.A.)
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Ahlawat YK, Nookaraju A, Harman-Ware AE, Doeppke C, Biswal AK, Joshi CP. Genetic Modification of KNAT7 Transcription Factor Expression Enhances Saccharification and Reduces Recalcitrance of Woody Biomass in Poplars. FRONTIERS IN PLANT SCIENCE 2021; 12:762067. [PMID: 34795688 PMCID: PMC8594486 DOI: 10.3389/fpls.2021.762067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
The precise role of KNAT7 transcription factors (TFs) in regulating secondary cell wall (SCW) biosynthesis in poplars has remained unknown, while our understanding of KNAT7 functions in other plants is continuously evolving. To study the impact of genetic modifications of homologous and heterologous KNAT7 gene expression on SCW formation in transgenic poplars, we prepared poplar KNAT7 (PtKNAT7) overexpression (PtKNAT7-OE) and antisense suppression (PtKNAT7-AS) vector constructs for the generation of transgenic poplar lines via Agrobacterium-mediated transformation. Since the overexpression of homologous genes can sometimes result in co-suppression, we also overexpressed Arabidopsis KNAT7 (AtKNAT7-OE) in transgenic poplars. In all these constructs, the expression of KNAT7 transgenes was driven by developing xylem (DX)-specific promoter, DX15. Compared to wild-type (WT) controls, many SCW biosynthesis genes downstream of KNAT7 were highly expressed in poplar PtKNAT7-OE and AtKNAT7-OE lines. Yet, no significant increase in lignin content of woody biomass of these transgenic lines was observed. PtKNAT7-AS lines, however, showed reduced expression of many SCW biosynthesis genes downstream of KNAT7 accompanied by a reduction in lignin content of wood compared to WT controls. Syringyl to Guaiacyl lignin (S/G) ratios were significantly increased in all three KNAT7 knockdown and overexpression transgenic lines than WT controls. These transgenic lines were essentially indistinguishable from WT controls in terms of their growth phenotype. Saccharification efficiency of woody biomass was significantly increased in all transgenic lines than WT controls. Overall, our results demonstrated that developing xylem-specific alteration of KNAT7 expression affects the expression of SCW biosynthesis genes, impacting at least the lignification process and improving saccharification efficiency, hence providing one of the powerful tools for improving bioethanol production from woody biomass of bioenergy crops and trees.
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Affiliation(s)
- Yogesh Kumar Ahlawat
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, United States
- Department of Horticultural Sciences, University of Florida, Gainesville, FL, United States
| | | | - Anne E. Harman-Ware
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Crissa Doeppke
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Ajaya K. Biswal
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Chandrashekhar P. Joshi
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, United States
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Sterol Glucosyltransferases Tailor Polysaccharide Accumulation in Arabidopsis Seed Coat Epidermal Cells. Cells 2021; 10:cells10102546. [PMID: 34685527 PMCID: PMC8533880 DOI: 10.3390/cells10102546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/15/2021] [Accepted: 09/17/2021] [Indexed: 11/17/2022] Open
Abstract
The conjugation of sterols with a Glc moiety is catalyzed by sterol glucosyltransferases (SGTs). A portion of the resulting steryl glucosides (SG) are then esterified with a long-chain fatty acid to form acyl-SG (ASG). SG and ASG are prevalent components of plant cellular membranes and influence their organization and functional properties. Mutant analysis had previously inferred that two Arabidopsis SGTs, UGT80A2 and UGT80B1/TT15, could have specialized roles in the production of SG in seeds, despite an overlap in their enzymatic activity. Here, we establish new roles for both enzymes in the accumulation of polysaccharides in seed coat epidermal cells (SCEs). The rhamnogalacturonan-I (RG-I) content of the inner layer of seed mucilage was higher in ugt80A2, whereas RG-I accumulation was lower in mutants of UGT80B1, with double mutant phenotypes indicating that UGT80A2 acts independently from UGT80B1. In contrast, an additive phenotype was observed in double mutants for increased galactoglucomannan (GGM) content. Double mutants also exhibited increased polymer density within the inner mucilage layer. In contrast, cell wall defects were only observed in mutants defective for UGT80B1, while more mucilage cellulose was only observed when UGT80A2 was mutated. The generation of a range of phenotypic effects, simultaneously within a single cell type, demonstrates that the adjustment of the SG and ASG composition of cellular membranes by UGT80A2 and UGT80B1 tailors polysaccharide accumulation in Arabidopsis seeds.
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Liu Y, Liu Z, Zhu X, Hu X, Zhang H, Guo Q, Yada RY, Cui SW. Seed coat mucilages: Structural, functional/bioactive properties, and genetic information. Compr Rev Food Sci Food Saf 2021; 20:2534-2559. [PMID: 33836113 DOI: 10.1111/1541-4337.12742] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 02/04/2023]
Abstract
Seed coat mucilages are mainly polysaccharides covering the outer layer of the seeds to facilitate seed hydration and germination, thereby improving seedling emergence and reducing seedling mortality. Four types of polysaccharides are found in mucilages including xylan, pectin, glucomannan, and cellulose. Recently, mucilages from flaxseed, yellow mustard seed, chia seed, and so on, have been used extensively in the areas of food, pharmaceutical, and cosmetics contributing to stability, texture, and appearance. This review, for the first time, addresses the similarities and differences in physicochemical properties, molecular structure, and functional/bioactive properties of mucilages among different sources; highlights their structure and function relationships; and systematically summarizes the related genetic information, aiming with the intent to explore the potential functions thereby extending their future industrial applications.
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Affiliation(s)
- Yan Liu
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science and Technology, Tianjin, China
| | - Zhenfei Liu
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science and Technology, Tianjin, China
| | - Xuerui Zhu
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science and Technology, Tianjin, China
| | - Xinzhong Hu
- College of Food Engineering & Nutrition Science, Shaanxi Normal University, Shaanxi, China
| | - Hui Zhang
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instruments and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Qingbin Guo
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Technology, Tianjin University of Science and Technology, Tianjin, China
| | - Rickey Y Yada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Steve W Cui
- Guelph Research and Development Centre, Agri- and Agri-food Canada, Guelph, Ontario, Canada
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Tang X, Wang C, Liu Y, He G, Ma N, Chai G, Li S, Xu H, Zhou G. Brassinosteroid Signaling Converges With Auxin-Mediated C3H17 to Regulate Xylem Formation in Populus. FRONTIERS IN PLANT SCIENCE 2020; 11:586014. [PMID: 33193536 PMCID: PMC7652770 DOI: 10.3389/fpls.2020.586014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/29/2020] [Indexed: 05/05/2023]
Abstract
Brassinosteroid (BR) signaling has long been reported to have an effect on xylem development, but the detailed mechanism remains unclear, especially in tree species. In this study, we find PdC3H17, which was demonstrated to mediate xylem formation driven by auxin in our previous report, is also involved in BR-promoted xylem development. Y1H analysis, EMSA, and transcription activation assay confirmed that PdC3H17 was directly targeted by PdBES1, which is a key transcriptional regulator in BR signaling. Tissue specificity expression analysis and in situ assay revealed that PdC3H17 had an overlapping expression profile with PdBES1. Hormone treatment examinations verified that xylem phenotypes in PdC3H17 transgenic plants, which were readily apparent in normal condition, were attenuated by treatment with either brassinolide or the BR biosynthesis inhibitor propiconazole. The subsequent quantitative real-time polymerase chain reaction (qRT-PCR) analyses further revealed that BR converged with PdC3H17 to influence transcription of downstream xylem-related genes. Additionally, the enhancement of xylem differentiation by auxin in PdC3H17 overexpression plants was significantly attenuated compared with wild-type and dominant negative plants due to BR deficiency, which suggested that the BR- and auxin-responsive gene PdC3H17 acted as an mediation of these two hormones to facilitate xylem development. Taken together, our results demonstrate that BR signaling converges with auxin-mediated PdC3H17 to regulate xylem formation in Populus and thus provide insight into the regulation mechanism of BRs and the crosstalk with auxin signaling on xylem formation.
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Affiliation(s)
- Xianfeng Tang
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Institute of Energy Technology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Congpeng Wang
- College of Resources and Environment, Qingdao Agricultural University, Qingdao, China
| | - Yu Liu
- College of Resources and Environment, Qingdao Agricultural University, Qingdao, China
| | - Guo He
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Institute of Energy Technology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Nana Ma
- State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai’an, China
| | - Guohua Chai
- College of Resources and Environment, Qingdao Agricultural University, Qingdao, China
| | - Shengjun Li
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Institute of Energy Technology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Hua Xu
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Institute of Energy Technology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- *Correspondence: Hua Xu,
| | - Gongke Zhou
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Institute of Energy Technology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- College of Resources and Environment, Qingdao Agricultural University, Qingdao, China
- Gongke Zhou,
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