1
|
Żyła N, Babula-Skowrońska D. Evolutionary Consequences of Functional and Regulatory Divergence of HD-Zip I Transcription Factors as a Source of Diversity in Protein Interaction Networks in Plants. J Mol Evol 2023; 91:581-597. [PMID: 37351602 PMCID: PMC10598176 DOI: 10.1007/s00239-023-10121-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 05/27/2023] [Indexed: 06/24/2023]
Abstract
The HD superfamily has been studied in detail for several decades. The plant-specific HD-Zip I subfamily attracts the most attention because of its involvement in plant development and stress responses. In this review, we provide a comprehensive insight into the evolutionary events responsible for the functional redundancy and diversification of the HD-Zip I genes in regulating various biological processes. We summarized the evolutionary history of the HD-Zip family, highlighting the important role of WGDs in its expansion and divergence of retained duplicates in the genome. To determine the relationship between the evolutionary origin and functional conservation of HD-Zip I in different species, we performed a phylogenetic analysis, compared their expression profiles in different tissues and under stress and traced the role of orthologs and paralogs in regulating developmental processes. We found that HD-Zip I from different species have similar gene structures with a highly conserved HD and Zip, bind to the same DNA sequences and are involved in similar biological processes. However, they exhibit a functional diversity, which is manifested in altered expression patterns. Some of them are involved in the regulation of species-specific leaf morphology and phenotypes. Here, we discuss the role of changes in functional domains involved in DNA binding and protein interaction of HD-Zip I and in cis-regulated regions of its target genes in promoting adaptive innovations through the formation of de novo regulatory systems. Understanding the role of the HD-Zip I subfamily in organism-environment interactions remains a challenge for evolutionary developmental biology (evo-devo).
Collapse
Affiliation(s)
- Natalia Żyła
- Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznan, Poland
| | - Danuta Babula-Skowrońska
- Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznan, Poland.
| |
Collapse
|
2
|
Wang D, Gong Y, Li Y, Nie S. Genome-wide analysis of the homeodomain-leucine zipper family in Lotus japonicus and the overexpression of LjHDZ7 in Arabidopsis for salt tolerance. FRONTIERS IN PLANT SCIENCE 2022; 13:955199. [PMID: 36186025 PMCID: PMC9515785 DOI: 10.3389/fpls.2022.955199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 08/12/2022] [Indexed: 06/16/2023]
Abstract
The homeodomain-leucine zipper (HD-Zip) family participates in plant growth, development, and stress responses. Here, 40 HD-Zip transcription factors of Lotus japonicus were identified and gave an overview of the phylogeny and gene structures. The expression pattern of these candidate genes was determined in different organs and their response to abiotic stresses, including cold, heat, polyethylene glycol and salinity. The expression of the LjHDZ7 was strongly induced by abiotic stress, especially salt stress. Subsequently, LjHDZ7 gene was overexpressed in Arabidopsis. The transgenic plants grew obviously better than Col-0 plants under salt stress. Furthermore, LjHDZ7 transgenic lines accumulated higher proline contents and showed lower electrolyte leakage and MDA contents than Col-0 plants under salt stress. Antioxidant activities of the LjHDZ7 overexpression lines leaf were significantly higher than those of the Col-0 plants under salt stress. The concentration of Na+ ion in LjHDZ7 overexpression lines was significantly lower than that of Col-0 in leaf and root parts. The concentration of K+ ion in LjHDZ7 overexpression lines was significantly higher than that of Col-0 in the leaf parts. Therefore, these results showed that overexpression of LjHDZ7 increased resistance to salt stress in transgenic Arabidopsis plants, and certain genes of this family can be used as valuable tools for improving abiotic stresses.
Collapse
|
3
|
Genome-Wide Analysis of the Homeobox Gene Family and Identification of Drought-Responsive Members in Populus trichocarpa. PLANTS 2021; 10:plants10112284. [PMID: 34834651 PMCID: PMC8653966 DOI: 10.3390/plants10112284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/07/2021] [Accepted: 10/12/2021] [Indexed: 11/16/2022]
Abstract
Homeobox (HB) genes play critical roles in the regulation of plant morphogenesis, growth and development. Here, we identified a total of 156 PtrHB genes from the Populus trichocarpa genome. According to the topologies and taxonomy of the phylogenetic tree constructed by Arabidopsis thaliana HB members, all PtrHB proteins were divided into six subgroups, namely HD-ZIP, ZF-HD, HB-PHD, TALE, WOX and HB-OTHERS. Multiple alignments of conserved homeodomains (HDs) revealed the conserved loci of each subgroup, while gene structure analysis showed similar exon–intron gene structures, and motif analysis indicated the similarity of motif number and pattern in the same subgroup. Promoter analysis indicated that the promoters of PtrHB genes contain a series of cis-acting regulatory elements involved in responding to various abiotic stresses, indicating that PtrHBs had potential functions in these processes. Collinearity analysis revealed that there are 96 pairs of 127 PtrHB genes mainly distributing on Chromosomes 1, 2, and 5. We analyzed the spatio-temporal expression patterns of PtrHB genes, and the virus-induced gene silencing (VIGS) of PtrHB3 gene resulted in the compromised tolerance of poplar seedlings to mannitol treatment. The bioinformatics on PtrHB family and preliminary exploration of drought-responsive genes can provide support for further study of the family in woody plants, especially in drought-related biological processes. It also provides a direction for developing new varieties of poplar with drought resistance. Overall, our results provided significant information for further functional analysis of PtrHB genes in poplar and demonstrated that PtrHB3 is a dominant gene regulating tolerance to water stress treatment in poplar seedlings.
Collapse
|
4
|
Genome-Wide Characterization and Expression Analysis of the HD-ZIP Gene Family in Response to Salt Stress in Pepper. Int J Genomics 2021; 2021:8105124. [PMID: 33604369 PMCID: PMC7869415 DOI: 10.1155/2021/8105124] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 04/18/2020] [Accepted: 12/10/2020] [Indexed: 11/17/2022] Open
Abstract
HD-ZIP is a unique type of transcription factor in plants, which are closely linked to the regulation of plant growth and development, the response to abiotic stress, and disease resistance. However, there is little known about the HD-ZIP gene family of pepper. In this study, 40 HD-ZIP family members were analyzed in the pepper genome. The analysis indicated that the introns number of Ca-HD-ZIP varied from 1 to 17; the number of amino acids was between 119 and 841; the theoretical isoelectric point was between 4.54 and 9.85; the molecular weight was between 14.04 and 92.56; most of them were unstable proteins. The phylogenetic tree divided CaHD-ZIP into 4 subfamilies; 40 CaHD-ZIP genes were located on different chromosomes, and all of them contained the motif 1; two pairs of CaHD-ZIP parallel genes of six paralogism genes were fragment duplications which occurred in 58.28~88.24 million years ago. There were multiple pressure-related action elements upstream of the start codon of the HD-Z-IP family. Protein interaction network proved to be coexpression phenomenon between ATML1 (CaH-DZ22, CaHDZ32) and At4g048909 (CaHDZ12, CaHDZ31), and three regions of them were highly homology. The expression level of CaHD-ZIP gene was different with tissues and developmental stages, which suggested that CaHD-ZIP may be involved in biological functions during pepper progress. In addition, Pepper HD-ZIP I and II genes played a major role in salt stress. CaHDZ03, CaHDZ 10, CaHDZ17, CaHDZ25, CaHDZ34, and CaHDZ35 were significantly induced in response to salt stress. Notably, the expression of CaHDZ07, CaHDZ17, CaHDZ26, and CaHDZ30, homologs of Arabidopsis AtHB12 and AtHB7 genes, was significantly upregulated by salt stresses. CaHDZ03 possesses two closely linked ABA action elements, and its expression level increased significantly at 4 h under salt stress. qRT-P-CR and transcription analysis showed that the expression of CaHDZ03 and CaHDZ10 was upregulated under short-term salt stress, but CaHDZ10 was downregulated with long-term salt stress, which provided a theoretical basis for research the function of Ca-HDZIP in response to abiotic stress.
Collapse
|
5
|
Feng X, Liu W, Dai H, Qiu Y, Zhang G, Chen ZH, Wu F. HvHOX9, a novel homeobox leucine zipper transcription factor, positively regulates aluminum tolerance in Tibetan wild barley. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6057-6073. [PMID: 32588054 DOI: 10.1093/jxb/eraa290] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 06/20/2020] [Indexed: 05/10/2023]
Abstract
Aluminum (Al) toxicity is the primary limiting factor of crop production on acid soils. Tibetan wild barley germplasm is a valuable source of potential genes for breeding barley with acid and Al tolerance. We performed microRNA and RNA sequencing using wild (XZ16, Al-tolerant; XZ61, Al-sensitive) and cultivated (Dayton, Al-tolerant) barley. A novel homeobox-leucine zipper transcription factor, HvHOX9, was identified as a target gene of miR166b and functionally characterized. HvHOX9 was up-regulated by Al stress in XZ16 (but unchanged in XZ61 and Dayton) and was significantly induced only in root tip. Phylogenetic analysis showed that HvHOX9 is most closely related to wheat TaHOX9 and orthologues of HvHOX9 are present in the closest algal relatives of Zygnematophyceae. Barley stripe mosaic virus-induced gene silencing of HvHOX9 in XZ16 led to significantly increased Al sensitivity but did not affect its sensitivity to other metals and low pH. Disruption of HvHOX9 did not change Al concentration in the root cell sap, but led to more Al accumulation in root cell wall after Al exposure. Silencing of HvHOX9 decreased H+ influx after Al exposure. Our findings suggest that miR166b/HvHOX9 play a critical role in Al tolerance by decreasing root cell wall Al binding and increasing apoplastic pH for Al detoxification in the root.
Collapse
Affiliation(s)
- Xue Feng
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Wenxing Liu
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Huaxin Dai
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Yue Qiu
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Guoping Zhang
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, China
| | - Zhong-Hua Chen
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Feibo Wu
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China
| |
Collapse
|
6
|
The HD-ZIP II Transcription Factors Regulate Plant Architecture through the Auxin Pathway. Int J Mol Sci 2020; 21:ijms21093250. [PMID: 32375344 PMCID: PMC7246542 DOI: 10.3390/ijms21093250] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/29/2020] [Accepted: 05/02/2020] [Indexed: 11/17/2022] Open
Abstract
The homeodomain-leucine zipper (HD-ZIP) family transcription factors play important roles in plant growth and development. However, the underlying mechanisms remain largely unclear. Here we found that ATHB2, encoding a HD-ZIP transcription factor, is an early auxin responsive gene. Phenotypic analyses show that overexpression of ATHB2 impairs plant architecture, including reduced plant height and small leaves, and also reduces auxin response in leaves when grown in soil. Simultaneously, the seedlings with chemical induction of ATHB2 exhibit abnormal root gravitropism, a typical auxin-related phenotype. We further show that the auxin response pattern is altered in roots of the inducible ATHB2 seedlings. Consistently, the transcript levels of some auxin biosynthetic and transport genes are significantly decreased in these transgenic seedlings. Further, protein and promoter sequence analyses in common wheat showed that the HD-ZIP II subfamily transcription factors have highly conserved motifs and most of these encoding gene promoters contain the canonical auxin-responsive elements. Expression analyses confirm that some of these HD-ZIP II genes are indeed regulated by auxin in wheat. Together, our results suggest that the HD-ZIP II subfamily transcription factors regulate plant development possibly through the auxin pathway in plants.
Collapse
|
7
|
Gong S, Ding Y, Hu S, Ding L, Chen Z, Zhu C. The role of HD-Zip class I transcription factors in plant response to abiotic stresses. PHYSIOLOGIA PLANTARUM 2019; 167:516-525. [PMID: 30851063 DOI: 10.1111/ppl.12965] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 03/02/2019] [Accepted: 03/07/2019] [Indexed: 05/27/2023]
Abstract
Abiotic stresses usually affect plant growth and development, indirectly or directly causing crop production reduction and even plant death. To survive, plants utilize different mechanisms to adapt themselves to continuously changing surrounding environmental stresses. Homeodomain-leucine zipper (HD-Zip) transcription factors are unique to the plant kingdom and divided into four different subfamilies (HD-Zip I∼IV). Many HD-Zip I members have been shown to play critical roles in the regulation of plant developmental processes, signaling networks and responses to environmental stresses. This review focuses on the role of HD-Zip I transcription factors in plant responses to various abiotic stresses, including abscisic acid-mediated stress, drought and cold stress, oxidative stress, helping to identify the potential regulatory mechanisms that alleviate abiotic stress in plants.
Collapse
Affiliation(s)
- Shaohua Gong
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, 310018, China
| | - Yanfei Ding
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, 310018, China
| | - Shanshan Hu
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, 310018, China
| | - Lihong Ding
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, 310018, China
| | - Zhixiang Chen
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, 310018, China
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Cheng Zhu
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, 310018, China
| |
Collapse
|
8
|
Yang M, Huang C, Wang M, Fan H, Wan S, Wang Y, He J, Guan R. Fine mapping of an up-curling leaf locus (BnUC1) in Brassica napus. BMC PLANT BIOLOGY 2019; 19:324. [PMID: 31324149 PMCID: PMC6642557 DOI: 10.1186/s12870-019-1938-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/11/2019] [Indexed: 05/07/2023]
Abstract
BACKGROUND Leaf shape development research is important because leaf shapes such as moderate curling can help to improve light energy utilization efficiency. Leaf growth and development includes initiation of the leaf primordia and polar differentiation of the proximal-distal, adaxial-abaxial, and centrolateral axes. Changes in leaf adaxial-abaxial polarity formation, auxin synthesis and signaling pathways, and development of sclerenchyma and cuticle can cause abnormal leaf shapes such as up-curling leaf. Although many genes related to leaf shape development have been reported, the detailed mechanism of leaf development is still unclear. Here, we report an up-curling leaf mutant plant from our Brassica napus germplasm. We studied its inheritance, mapped the up-curling leaf locus BnUC1, built near-isogenic lines for the Bnuc1 mutant, and evaluated the effect of the dominant leaf curl locus on leaf photosynthetic efficiency and agronomic traits. RESULTS The up-curling trait was controlled by one dominant locus in a progeny population derived from NJAU5734 and Zhongshuang 11 (ZS11). This BnUC1 locus was mapped in an interval of 2732.549 kb on the A05 chromosome of B. napus using Illumina Brassica 60 K Bead Chip Array. To fine map BnUC1, we designed 201 simple sequence repeat (SSR) primers covering the mapping interval. Among them, 16 polymorphic primers that narrowed the mapping interval to 54.8 kb were detected using a BC6F2 family population with 654 individuals. We found six annotated genes in the mapping interval using the B. napus reference genome, including BnaA05g18250D and BnaA05g18290D, which bioinformatics and gene expression analyses predicted may be responsible for leaf up-curling. The up-curling leaf trait had negative effects on the agronomic traits of 30 randomly selected individuals from the BC6F2 population. The near-isogenic line of the up-curling leaf (ZS11-UC1) was constructed to evaluate the effect of BnUC1 on photosynthetic efficiency. The results indicated that the up-curling leaf trait locus was beneficial to improve the photosynthetic efficiency. CONCLUSIONS An up-curling leaf mutant Bnuc1 was controlled by one dominant locus BnUC1. This locus had positive effects on photosynthetic efficiency, negative effects on some agronomic traits, and may help to increase planting density in B. napus.
Collapse
Affiliation(s)
- Mao Yang
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095 China
| | - Chengwei Huang
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095 China
| | - Mingming Wang
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095 China
| | - Hao Fan
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095 China
| | - Shubei Wan
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095 China
| | - Yangming Wang
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095 China
| | - Jianbo He
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095 China
| | - Rongzhan Guan
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095 China
| |
Collapse
|
9
|
Song A, Li P, Xin J, Chen S, Zhao K, Wu D, Fan Q, Gao T, Chen F, Guan Z. Transcriptome-Wide Survey and Expression Profile Analysis of Putative Chrysanthemum HD-Zip I and II Genes. Genes (Basel) 2016; 7:genes7050019. [PMID: 27196930 PMCID: PMC4880839 DOI: 10.3390/genes7050019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 04/05/2016] [Accepted: 05/03/2016] [Indexed: 12/30/2022] Open
Abstract
The homeodomain-leucine zipper (HD-Zip) transcription factor family is a key transcription factor family and unique to the plant kingdom. It consists of a homeodomain and a leucine zipper that serve in combination as a dimerization motif. The family can be classified into four subfamilies, and these subfamilies participate in the development of hormones and mediation of hormone action and are involved in plant responses to environmental conditions. However, limited information on this gene family is available for the important chrysanthemum ornamental species (Chrysanthemum morifolium). Here, we characterized 17 chrysanthemum HD-Zip genes based on transcriptome sequences. Phylogenetic analyses revealed that 17 CmHB genes were distributed in the HD-Zip subfamilies I and II and identified two pairs of putative orthologous proteins in Arabidopsis and chrysanthemum and four pairs of paralogous proteins in chrysanthemum. The software MEME was used to identify 7 putative motifs with E values less than 1e-3 in the chrysanthemum HD-Zip factors, and they can be clearly classified into two groups based on the composition of the motifs. A bioinformatics analysis predicted that 8 CmHB genes could be targeted by 10 miRNA families, and the expression of these 17 genes in response to phytohormone treatments and abiotic stresses was characterized. The results presented here will promote research on the various functions of the HD-Zip gene family members in plant hormones and stress responses.
Collapse
Affiliation(s)
- Aiping Song
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Peiling Li
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Jingjing Xin
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Sumei Chen
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Kunkun Zhao
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Dan Wu
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Qingqing Fan
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Tianwei Gao
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Fadi Chen
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Zhiyong Guan
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| |
Collapse
|
10
|
Plackett ARG, Di Stilio VS, Langdale JA. Ferns: the missing link in shoot evolution and development. FRONTIERS IN PLANT SCIENCE 2015; 6:972. [PMID: 26594222 PMCID: PMC4635223 DOI: 10.3389/fpls.2015.00972] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 10/23/2015] [Indexed: 05/02/2023]
Abstract
Shoot development in land plants is a remarkably complex process that gives rise to an extreme diversity of forms. Our current understanding of shoot developmental mechanisms comes almost entirely from studies of angiosperms (flowering plants), the most recently diverged plant lineage. Shoot development in angiosperms is based around a layered multicellular apical meristem that produces lateral organs and/or secondary meristems from populations of founder cells at its periphery. In contrast, non-seed plant shoots develop from either single apical initials or from a small population of morphologically distinct apical cells. Although developmental and molecular information is becoming available for non-flowering plants, such as the model moss Physcomitrella patens, making valid comparisons between highly divergent lineages is extremely challenging. As sister group to the seed plants, the monilophytes (ferns and relatives) represent an excellent phylogenetic midpoint of comparison for unlocking the evolution of shoot developmental mechanisms, and recent technical advances have finally made transgenic analysis possible in the emerging model fern Ceratopteris richardii. This review compares and contrasts our current understanding of shoot development in different land plant lineages with the aim of highlighting the potential role that the fern C. richardii could play in shedding light on the evolution of underlying genetic regulatory mechanisms.
Collapse
Affiliation(s)
- Andrew R. G. Plackett
- Department of Plant Sciences, University of OxfordOxford, UK
- *Correspondence: Andrew R. G. Plackett,
| | | | | |
Collapse
|
11
|
Abstract
The green lineage of chlorophyte algae and streptophytes form a large and diverse clade with multiple independent transitions to produce multicellular and/or macroscopically complex organization. In this review, I focus on two of the best-studied multicellular groups of green algae: charophytes and volvocines. Charophyte algae are the closest relatives of land plants and encompass the transition from unicellularity to simple multicellularity. Many of the innovations present in land plants have their roots in the cell and developmental biology of charophyte algae. Volvocine algae evolved an independent route to multicellularity that is captured by a graded series of increasing cell-type specialization and developmental complexity. The study of volvocine algae has provided unprecedented insights into the innovations required to achieve multicellularity.
Collapse
Affiliation(s)
- James G Umen
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| |
Collapse
|
12
|
Noy-Malka C, Yaari R, Itzhaki R, Mosquna A, Auerbach Gershovitz N, Katz A, Ohad N. A single CMT methyltransferase homolog is involved in CHG DNA methylation and development of Physcomitrella patens. PLANT MOLECULAR BIOLOGY 2014; 84:719-35. [PMID: 24370935 DOI: 10.1007/s11103-013-0165-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 12/12/2013] [Indexed: 05/20/2023]
Abstract
C-5 DNA methylation is an essential mechanism controlling gene expression and developmental programs in a variety of organisms. Though the role of DNA methylation has been intensively studied in mammals and Arabidopsis, little is known about the evolution of this mechanism. The chromomethylase (CMT) methyltransferase family is unique to plants and was found to be involved in DNA methylation in Arabidopsis, maize and tobacco. The moss Physcomitrella patens, a model for early terrestrial plants, harbors a single homolog of the CMT protein family designated as PpCMT. Our phylogenetic analysis suggested that the CMT family is unique to embryophytes and its earliest known member PpCMT belongs to the CMT3 subfamily. Thus, P. patens may serve as a model to study the ancient functions of the CMT3 family. We have generated a ΔPpcmt deletion mutant which demonstrated that PpCMT is essential for P. patens protonema and gametophore development and is involved in CHG methylation as demonstrated at four distinct genomic loci. PpCMT protein accumulation pattern correlated with proliferating cells and was sub-localized to the nucleus as predicted from its function. Taken together, our results suggested that CHG DNA methylation mediated by CMT has been employed early in land plant evolution to control developmental programs during both the vegetative and reproductive haploid phases along the plant life cycle.
Collapse
Affiliation(s)
- Chen Noy-Malka
- Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, 69978, Tel-Aviv, Israel
| | | | | | | | | | | | | |
Collapse
|
13
|
Liu W, Fu R, Li Q, Li J, Wang L, Ren Z. Genome-wide identification and expression profile of homeodomain-leucine zipper Class I gene family in Cucumis sativus. Gene 2013; 531:279-87. [DOI: 10.1016/j.gene.2013.08.089] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 08/17/2013] [Accepted: 08/28/2013] [Indexed: 12/28/2022]
|
14
|
Li Z, Jiang H, Zhou L, Deng L, Lin Y, Peng X, Yan H, Cheng B. Molecular evolution of the HD-ZIP I gene family in legume genomes. Gene 2013; 533:218-28. [PMID: 24095777 DOI: 10.1016/j.gene.2013.09.084] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 09/22/2013] [Accepted: 09/24/2013] [Indexed: 11/26/2022]
Abstract
Homeodomain leucine zipper I (HD-ZIP I) genes were used to increase the plasticity of plants by mediating external signals and regulating growth in response to environmental conditions. The way genomic histories drove the evolution of the HD-ZIP I family in legume species was described; HD-ZIP I genes were searched in Lotus japonicus, Medicago truncatula, Cajanus cajan and Phaseolus vulgaris, and then divided into five clades through phylogenetic analysis. Microsynteny analysis was made based on genomic segments containing the HD-ZIP I genes. Some pairs turned out to conform with syntenic genome regions, while others corresponded to those that were inverted, expanded, or contracted after the divergence of legumes. Besides, we dated their duplications by Ks analysis and demonstrated that all the blocks were formed after the monocot-dicot split; we observed Ka/Ks ratios representing strong purifying selections in the four legume species which might have been followed by gene loss and rearrangement.
Collapse
Affiliation(s)
- Zhen Li
- Key Lab of Crop Biology, School of Life Sciences, Anhui Agricultural University, Hefei 230036, China
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Zalewski CS, Floyd SK, Furumizu C, Sakakibara K, Stevenson DW, Bowman JL. Evolution of the class IV HD-zip gene family in streptophytes. Mol Biol Evol 2013; 30:2347-65. [PMID: 23894141 PMCID: PMC3773374 DOI: 10.1093/molbev/mst132] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Class IV homeodomain leucine zipper (C4HDZ) genes are plant-specific transcription factors that, based on phenotypes in Arabidopsis thaliana, play an important role in epidermal development. In this study, we sampled all major extant lineages and their closest algal relatives for C4HDZ homologs and phylogenetic analyses result in a gene tree that mirrors land plant evolution with evidence for gene duplications in many lineages, but minimal evidence for gene losses. Our analysis suggests an ancestral C4HDZ gene originated in an algal ancestor of land plants and a single ancestral gene was present in the last common ancestor of land plants. Independent gene duplications are evident within several lineages including mosses, lycophytes, euphyllophytes, seed plants, and, most notably, angiosperms. In recently evolved angiosperm paralogs, we find evidence of pseudogenization via mutations in both coding and regulatory sequences. The increasing complexity of the C4HDZ gene family through the diversification of land plants correlates to increasing complexity in epidermal characters.
Collapse
Affiliation(s)
| | - Sandra K. Floyd
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Chihiro Furumizu
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Keiko Sakakibara
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
- Graduate School of Science, University of Tokyo, Hongo, Tokyo, Japan
| | | | - John L. Bowman
- Section of Plant Biology, University of California, Davis
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| |
Collapse
|
16
|
Zhang S, Haider I, Kohlen W, Jiang L, Bouwmeester H, Meijer AH, Schluepmann H, Liu CM, Ouwerkerk PBF. Function of the HD-Zip I gene Oshox22 in ABA-mediated drought and salt tolerances in rice. PLANT MOLECULAR BIOLOGY 2012; 80:571-85. [PMID: 23109182 DOI: 10.1007/s11103-012-9967-1] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 09/04/2012] [Indexed: 05/02/2023]
Abstract
Oshox22 belongs to the homeodomain-leucine zipper (HD-Zip) family I of transcription factors, most of which have unknown functions. Here we show that the expression of Oshox22 is strongly induced by salt stress, abscisic acid (ABA), and polyethylene glycol treatment (PEG), and weakly by cold stress. Trans-activation assays in yeast and transient expression analyses in rice protoplasts demonstrated that Oshox22 is able to bind the CAAT(G/C)ATTG element and acts as a transcriptional activator that requires both the HD and Zip domains. Rice plants homozygous for a T-DNA insertion in the promoter region of Oshox22 showed reduced Oshox22 expression and ABA content, decreased sensitivity to ABA, and enhanced tolerance to drought and salt stresses at the seedling stage. In contrast, transgenic rice over-expressing Oshox22 showed increased sensitivity to ABA, increased ABA content, and decreased drought and salt tolerances. Based on these results, we conclude that Oshox22 affects ABA biosynthesis and regulates drought and salt responses through ABA-mediated signal transduction pathways.
Collapse
Affiliation(s)
- Shuxin Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Systematic analysis of sequences and expression patterns of drought-responsive members of the HD-Zip gene family in maize. PLoS One 2011; 6:e28488. [PMID: 22164299 PMCID: PMC3229603 DOI: 10.1371/journal.pone.0028488] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 11/09/2011] [Indexed: 02/07/2023] Open
Abstract
Background Members of the homeodomain-leucine zipper (HD-Zip) gene family encode transcription factors that are unique to plants and have diverse functions in plant growth and development such as various stress responses, organ formation and vascular development. Although systematic characterization of this family has been carried out in Arabidopsis and rice, little is known about HD-Zip genes in maize (Zea mays L.). Methods and Findings In this study, we described the identification and structural characterization of HD-Zip genes in the maize genome. A complete set of 55 HD-Zip genes (Zmhdz1-55) were identified in the maize genome using Blast search tools and categorized into four classes (HD-Zip I-IV) based on phylogeny. Chromosomal location of these genes revealed that they are distributed unevenly across all 10 chromosomes. Segmental duplication contributed largely to the expansion of the maize HD-ZIP gene family, while tandem duplication was only responsible for the amplification of the HD-Zip II genes. Furthermore, most of the maize HD-Zip I genes were found to contain an overabundance of stress-related cis-elements in their promoter sequences. The expression levels of the 17 HD-Zip I genes under drought stress were also investigated by quantitative real-time PCR (qRT-PCR). All of the 17 maize HD-ZIP I genes were found to be regulated by drought stress, and the duplicated genes within a sister pair exhibited the similar expression patterns, suggesting their conserved functions during the process of evolution. Conclusions Our results reveal a comprehensive overview of the maize HD-Zip gene family and provide the first step towards the selection of Zmhdz genes for cloning and functional research to uncover their roles in maize growth and development.
Collapse
|
18
|
Nicotra AB, Leigh A, Boyce CK, Jones CS, Niklas KJ, Royer DL, Tsukaya H. The evolution and functional significance of leaf shape in the angiosperms. FUNCTIONAL PLANT BIOLOGY : FPB 2011; 38:535-552. [PMID: 32480907 DOI: 10.1071/fp11057] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 05/30/2011] [Indexed: 05/18/2023]
Abstract
Angiosperm leaves manifest a remarkable diversity of shapes that range from developmental sequences within a shoot and within crown response to microenvironment to variation among species within and between communities and among orders or families. It is generally assumed that because photosynthetic leaves are critical to plant growth and survival, variation in their shape reflects natural selection operating on function. Several non-mutually exclusive theories have been proposed to explain leaf shape diversity. These include: thermoregulation of leaves especially in arid and hot environments, hydraulic constraints, patterns of leaf expansion in deciduous species, biomechanical constraints, adaptations to avoid herbivory, adaptations to optimise light interception and even that leaf shape variation is a response to selection on flower form. However, the relative importance, or likelihood, of each of these factors is unclear. Here we review the evolutionary context of leaf shape diversification, discuss the proximal mechanisms that generate the diversity in extant systems, and consider the evidence for each the above hypotheses in the context of the functional significance of leaf shape. The synthesis of these broad ranging areas helps to identify points of conceptual convergence for ongoing discussion and integrated directions for future research.
Collapse
Affiliation(s)
- Adrienne B Nicotra
- Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Andrea Leigh
- School of the Environment, University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - C Kevin Boyce
- Department of the Geophysical Sciences, 5734 S. Ellis Avenue, Chicago, IL 60637, USA
| | - Cynthia S Jones
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Road, Unit-3043, Storrs, CT 06269, USA
| | - Karl J Niklas
- Department of Plant Biology, Cornell University, 412 Mann Library Building, Cornell University, Ithaca, NY 14853, USA
| | - Dana L Royer
- Department of Earth and Environmental Sciences, Wesleyan University, 265 Church Street, Middletown, CT 06459, USA
| | - Hirokazu Tsukaya
- Graduate School of Science, University of Tokyo, Science Build #2, 7-3-1 Hongo, Tokyo 113-0033, Japan
| |
Collapse
|
19
|
Magnani E, Barton MK. A per-ARNT-sim-like sensor domain uniquely regulates the activity of the homeodomain leucine zipper transcription factor REVOLUTA in Arabidopsis. THE PLANT CELL 2011; 23:567-82. [PMID: 21357492 PMCID: PMC3077777 DOI: 10.1105/tpc.110.080754] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 01/18/2011] [Accepted: 02/07/2011] [Indexed: 05/23/2023]
Abstract
Class III homeodomain leucine zipper (HD-ZIP III) transcription factors regulate critical developmental programs in plants; these include leaf polarity, polarity along the shoot-root axis, and stem cell specification and proliferation. One of the defining features of HD-ZIP III proteins is the presence of a Per-ARNT-Sim-like (PAS-like) MEKHLA domain at the C terminus. PAS-like domains are known to respond to a variety of chemical and physical stimuli. Here, we provide evidence that the MEKHLA domain acts as a negative regulator of Arabidopsis thaliana HD-ZIP III REVOLUTA activity. Based on experiments in yeast and plants, we propose a model in which the MEKHLA domain inhibits dimerization through a sequence-independent steric masking mechanism. This inhibition is relieved in response to a cellular signal that requires the C terminus of the MEKHLA domain for its perception. Overexpression experiments suggest that this signal is unequally distributed and/or sensed in the plant. Our data show that the function of the REVOLUTA MEKHLA domain differs among other HD-ZIP III family members; this difference may explain the genetic differences that have been observed among family members. This finding, combined with our phylogenetic analysis, suggests that REVOLUTA is the latest type of HD-ZIP III protein to have evolved in land plants.
Collapse
|
20
|
Côté CL, Boileau F, Roy V, Ouellet M, Levasseur C, Morency MJ, Cooke JEK, Séguin A, MacKay JJ. Gene family structure, expression and functional analysis of HD-Zip III genes in angiosperm and gymnosperm forest trees. BMC PLANT BIOLOGY 2010; 10:273. [PMID: 21143995 PMCID: PMC3017839 DOI: 10.1186/1471-2229-10-273] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 12/11/2010] [Indexed: 05/03/2023]
Abstract
BACKGROUND Class III Homeodomain Leucine Zipper (HD-Zip III) proteins have been implicated in the regulation of cambium identity, as well as primary and secondary vascular differentiation and patterning in herbaceous plants. They have been proposed to regulate wood formation but relatively little evidence is available to validate such a role. We characterised and compared HD-Zip III gene family in an angiosperm tree, Populus spp. (poplar), and the gymnosperm Picea glauca (white spruce), representing two highly evolutionarily divergent groups. RESULTS Full-length cDNA sequences were isolated from poplar and white spruce. Phylogenetic reconstruction indicated that some of the gymnosperm sequences were derived from lineages that diverged earlier than angiosperm sequences, and seem to have been lost in angiosperm lineages. Transcript accumulation profiles were assessed by RT-qPCR on tissue panels from both species and in poplar trees in response to an inhibitor of polar auxin transport. The overall transcript profiles HD-Zip III complexes in white spruce and poplar exhibited substantial differences, reflecting their evolutionary history. Furthermore, two poplar sequences homologous to HD-Zip III genes involved in xylem development in Arabidopsis and Zinnia were over-expressed in poplar plants. PtaHB1 over-expression produced noticeable effects on petiole and primary shoot fibre development, suggesting that PtaHB1 is involved in primary xylem development. We also obtained evidence indicating that expression of PtaHB1 affected the transcriptome by altering the accumulation of 48 distinct transcripts, many of which are predicted to be involved in growth and cell wall synthesis. Most of them were down-regulated, as was the case for several of the poplar HD-Zip III sequences. No visible physiological effect of over-expression was observed on PtaHB7 transgenic trees, suggesting that PtaHB1 and PtaHB7 likely have distinct roles in tree development, which is in agreement with the functions that have been assigned to close homologs in herbaceous plants. CONCLUSIONS This study provides an overview of HD-zip III genes related to woody plant development and identifies sequences putatively involved in secondary vascular growth in angiosperms and in gymnosperms. These gene sequences are candidate regulators of wood formation and could be a source of molecular markers for tree breeding related to wood properties.
Collapse
Affiliation(s)
- Caroline L Côté
- Département des Sciences du Bois et de la Forêt, Université Laval, 2405 rue de la Terrasse, Québec, QC G1V0A6, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Prigge MJ, Bezanilla M. Evolutionary crossroads in developmental biology: Physcomitrella patens. Development 2010; 137:3535-43. [DOI: 10.1242/dev.049023] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The moss Physcomitrella patens has recently emerged as a powerful genetically tractable model plant system. As a member of the bryophytes, P. patens provides a unique opportunity to study the evolution of a myriad of plant traits, such as polarized cell growth, gametophyte-to-sporophyte transitions, and sperm-to-pollen transition. The availability of a complete genome sequence, together with the ability to perform gene targeting efficiently in P. patens has spurred a flurry of elegant reverse genetic studies in this plant model that address a variety of key questions in plant developmental biology.
Collapse
Affiliation(s)
- Michael J. Prigge
- Section of Cell and Developmental Biology, University of California, San Diego, CA 92093-0116, USA
| | | |
Collapse
|
22
|
Richardt S, Timmerhaus G, Lang D, Qudeimat E, Corrêa LGG, Reski R, Rensing SA, Frank W. Microarray analysis of the moss Physcomitrella patens reveals evolutionarily conserved transcriptional regulation of salt stress and abscisic acid signalling. PLANT MOLECULAR BIOLOGY 2010; 72:27-45. [PMID: 19806323 DOI: 10.1007/s11103-009-9550-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Accepted: 09/03/2009] [Indexed: 05/03/2023]
Abstract
Regulatory networks of salt stress and abscisic acid (ABA) responses have previously been analyzed in seed plants. Here, we report microarray expression profiles of 439 genes encoding transcription-associated proteins (TAPs) in response to salt stress and ABA in the salt-tolerant moss Physcomitrella patens. Fourteen and 56 TAP genes were differentially expressed within 60 min of NaCl and ABA treatment, respectively, indicating that these responses are regulated at the transcriptional level. Overlapping expression profiles, as well as the up-regulation of ABA biosynthesis genes, suggest that ABA mediates the salt stress responses in P. patens. Comparison to public gene expression data of Arabidopsis thaliana and phylogenetic analyses suggest that the role of DREB-like, Dof, and bHLH TAPs in salt stress responses have been conserved during embryophyte evolution, and that the function of ABI3-like, bZIP, HAP3, and CO-like TAPs in seed development and flowering emerged from pre-existing ABA and light signalling pathways.
Collapse
Affiliation(s)
- Sandra Richardt
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104, Freiburg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Mukherjee K, Brocchieri L, Bürglin TR. A comprehensive classification and evolutionary analysis of plant homeobox genes. Mol Biol Evol 2009; 26:2775-94. [PMID: 19734295 PMCID: PMC2775110 DOI: 10.1093/molbev/msp201] [Citation(s) in RCA: 265] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The full complement of homeobox transcription factor sequences, including genes and pseudogenes, was determined from the analysis of 10 complete genomes from flowering plants, moss, Selaginella, unicellular green algae, and red algae. Our exhaustive genome-wide searches resulted in the discovery in each class of a greater number of homeobox genes than previously reported. All homeobox genes can be unambiguously classified by sequence evolutionary analysis into 14 distinct classes also characterized by conserved intron–exon structure and by unique codomain architectures. We identified many new genes belonging to previously defined classes (HD-ZIP I to IV, BEL, KNOX, PLINC, WOX). Other newly identified genes allowed us to characterize PHD, DDT, NDX, and LD genes as members of four new evolutionary classes and to define two additional classes, which we named SAWADEE and PINTOX. Our comprehensive analysis allowed us to identify several newly characterized conserved motifs, including novel zinc finger motifs in SAWADEE and DDT. Members of the BEL and KNOX classes were found in Chlorobionta (green plants) and in Rhodophyta. We found representatives of the DDT, WOX, and PINTOX classes only in green plants, including unicellular green algae, moss, and vascular plants. All 14 homeobox gene classes were represented in flowering plants, Selaginella, and moss, suggesting that they had already differentiated in the last common ancestor of moss and vascular plants.
Collapse
Affiliation(s)
- Krishanu Mukherjee
- Genetics Institute, Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, USA.
| | | | | |
Collapse
|
24
|
Niklas KJ, Kutschera U. The evolutionary development of plant body plans. FUNCTIONAL PLANT BIOLOGY : FPB 2009; 36:682-695. [PMID: 32688680 DOI: 10.1071/fp09107] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 06/12/2009] [Indexed: 05/05/2023]
Abstract
Evolutionary developmental biology, cladistic analyses, and paleontological insights make it increasingly clear that regulatory mechanisms operating during embryogenesis and early maturation tend to be highly conserved over great evolutionary time scales, which can account for the conservative nature of the body plans in the major plant and animal clades. At issue is whether morphological convergences in body plans among evolutionarily divergent lineages are the result of adaptive convergence or 'genome recall' and 'process orthology'. The body plans of multicellular photosynthetic eukaryotes ('plants') are reviewed, some of their important developmental/physiological regulatory mechanisms discussed, and the evidence that some of these mechanisms are phyletically ancient examined. We conclude that endosymbiotic lateral gene transfers, gene duplication and functional divergence, and the co-option of ancient gene networks were key to the evolutionary divergence of plant lineages.
Collapse
Affiliation(s)
- Karl J Niklas
- Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA
| | - Ulrich Kutschera
- Institute of Biology, University of Kassel, Heinrich-Plett-Strasse 40, D-34109 Kassel, Germany
| |
Collapse
|
25
|
Jain M, Tyagi AK, Khurana JP. Genome-wide identification, classification, evolutionary expansion and expression analyses of homeobox genes in rice. FEBS J 2008; 275:2845-61. [PMID: 18430022 DOI: 10.1111/j.1742-4658.2008.06424.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Homeobox genes play a critical role in regulating various aspects of plant growth and development. In the present study, we identified a total of 107 homeobox genes in the rice genome and grouped them into ten distinct subfamilies based upon their domain composition and phylogenetic analysis. A significantly large number of homeobox genes are located in the duplicated segments of the rice genome, which suggests that the expansion of homeobox gene family, in large part, might have occurred due to segmental duplications in rice. Furthermore, microarray analysis was performed to elucidate the expression profiles of these genes in different tissues and during various stages of vegetative and reproductive development. Several genes with predominant expression during various stages of panicle and seed development were identified. At least 37 homeobox genes were found to be differentially expressed significantly (more than two-fold; P < 0.05) under various abiotic stress conditions. The results of the study suggest a critical role of homeobox genes in reproductive development and abiotic stress signaling in rice, and will facilitate the selection of candidate genes of agronomic importance for functional validation.
Collapse
Affiliation(s)
- Mukesh Jain
- Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi South Campus, India
| | | | | |
Collapse
|
26
|
Abstract
Leaves and stems are ultimately derived from the shoot apical meristem (SAM); leaves arise from the peripheral zone of the SAM and stem tissue is derived from both the peripheral and central zones of the SAM. Both the peripheral and central regions of the SAM are formed during embryogenesis when the basic body plan of the plant is established. Interplay between points of maximal concentration of auxin and specific patterns of transcription of both auxin-responsive transcription factors and other patterning genes subdivide the embryo along both the apical-basal and central-peripheral axes. Differential gene expression along these axes leads to the differentiation of tissues, lateral organs, meristems, and boundary regions, each with varying responsiveness to auxin. Subsequent shoot growth and development is a reiteration of basic patterning processes established during embryogenesis.
Collapse
Affiliation(s)
- John L Bowman
- 1School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia.
| | | |
Collapse
|
27
|
Agalou A, Purwantomo S, Overnäs E, Johannesson H, Zhu X, Estiati A, de Kam RJ, Engström P, Slamet-Loedin IH, Zhu Z, Wang M, Xiong L, Meijer AH, Ouwerkerk PBF. A genome-wide survey of HD-Zip genes in rice and analysis of drought-responsive family members. PLANT MOLECULAR BIOLOGY 2008; 66:87-103. [PMID: 17999151 DOI: 10.1007/s11103-007-9255-7] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2007] [Accepted: 10/25/2007] [Indexed: 05/20/2023]
Abstract
The homeodomain leucine zipper (HD-Zip) genes encode transcription factors that have diverse functions in plant development and have often been implicated in stress adaptation. The HD-Zip genes are the most abundant group of homeobox (HB) genes in plants and do not occur in other eukaryotes. This paper describes the complete annotation of the HD-Zip families I, II and III from rice and compares these gene families with Arabidopsis in a phylogeny reconstruction. Orthologous pairs of rice and Arabidopsis HD-Zip genes were predicted based on neighbour joining and maximum parsimony (MP) trees with support of conserved intron-exon organization. Additionally, a number of HD-Zip genes appeared to be unique to rice. Searching of EST and cDNA databases and expression analysis using RT-PCR showed that 30 out of 31 predicted rice HD-Zip genes are expressed. Most HD-Zip genes were broadly expressed in mature plants and seedlings, but others showed more organ specific patterns. Like in Arabidopsis and other dicots, a subset of the rice HD-Zip I and II genes was found to be regulated by drought stress. We identified both drought-induced and drought-repressed HD-Zip genes and demonstrate that these genes are differentially regulated in drought-sensitive versus drought-tolerant rice cultivars. The drought-repressed HD-Zip family I gene, Oshox4, was selected for promoter-GUS analysis, showing that drought-responsiveness of Oshox4 is controlled by the promoter and that Oshox4 expression is predominantly vascular-specific. Loss-of-function analysis of Oshox4 revealed no specific phenotype, but overexpression analysis suggested a role for Oshox4 in elongation and maturation processes.
Collapse
Affiliation(s)
- Adamantia Agalou
- Institute of Biology, Clusius Laboratory, Leiden University, PO Box 9505, 2300 RA, Leiden, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Abstract
Arabidopsis class III homeodomain-leucine zipper (HD-Zip III) proteins play overlapping, distinct, and antagonistic roles in key aspects of development that have evolved during land plant evolution. To better understand this gene family's role in plant evolution and development as well as to address broader questions of how duplicated genes functionally diversify, we investigated the evolutionary history of this gene family. Phylogenetic analyses including homologs from diverse land plants indicate that a gene duplication event before the angiosperm--gymnosperm split gave rise to two gene lineages that diversified during angiosperm plant radiation. Heterologous expression of an HD-Zip III gene from the nonvascular plant moss within the Arabidopsis HD-zip III revoluta mutant modified but did not complement the phenotype. Comparison of the expression domains of flowering and nonflowering plant homologs indicate an ancestral role in vascular development and organ initiation but not in specifying organ polarity, a prominent role for angiosperm homologs.
Collapse
Affiliation(s)
- Michael J Prigge
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | | |
Collapse
|
29
|
Wenkel S, Emery J, Hou BH, Evans MMS, Barton MK. A feedback regulatory module formed by LITTLE ZIPPER and HD-ZIPIII genes. THE PLANT CELL 2007; 19:3379-90. [PMID: 18055602 PMCID: PMC2174893 DOI: 10.1105/tpc.107.055772] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 10/23/2007] [Accepted: 11/08/2007] [Indexed: 05/19/2023]
Abstract
The Arabidopsis thaliana REVOLUTA (REV) protein is a member of the class III homeodomain-leucine zipper (HD-ZIPIII) proteins. REV is a potent regulator of leaf polarity and vascular development. Here, we report the identification of a gene family that encodes small leucine zipper-containing proteins (LITTLE ZIPPER [ZPR] proteins) where the leucine zipper is similar to that found in REV, PHABULOSA, and PHAVOLUTA proteins. The transcript levels of the ZPR genes increase in response to activation of a steroid-inducible REV protein. We show that the ZPR proteins interact with REV in vitro and that ZPR3 prevents DNA binding by REV in vitro. Overexpression of ZPR proteins in Arabidopsis results in phenotypes similar to those seen when HD-ZIPIII function is reduced. We propose a negative feedback model in which REV promotes transcription of the ZPR genes. The ZPR proteins in turn form heterodimers with the REV protein, preventing it from binding DNA. The HD-ZIPIII/ZPR regulatory module would serve not only to dampen the effect of fluctuations in HD-ZIPIII protein levels but more importantly would provide a potential point of regulation (control over the ratio of inactive heterodimers to active homodimers) that could be influenced by other components of the pathway governing leaf polarity.
Collapse
Affiliation(s)
- Stephan Wenkel
- Department of Plant Biology, Carnegie Institution, Stanford, California 94305, USA
| | | | | | | | | |
Collapse
|
30
|
Ariel FD, Manavella PA, Dezar CA, Chan RL. The true story of the HD-Zip family. TRENDS IN PLANT SCIENCE 2007; 12:419-26. [PMID: 17698401 DOI: 10.1016/j.tplants.2007.08.003] [Citation(s) in RCA: 355] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Revised: 05/24/2007] [Accepted: 08/03/2007] [Indexed: 05/04/2023]
Abstract
The HD-Zip family of transcription factors is unique to the plant kingdom. These proteins exhibit the singular combination of a homeodomain with a leucine zipper acting as a dimerization motif. They can be classified into four subfamilies, according to a set of distinctive features that include DNA-binding specificities, gene structures, additional common motifs and physiological functions. Some HD-Zip proteins participate in organ and vascular development or meristem maintenance. Others mediate the action of hormones or are involved in responses to environmental conditions. Here, we review recent data for this family of transcription factors from a wide variety of plant species to unravel their crucial role in plant development.
Collapse
Affiliation(s)
- Federico D Ariel
- Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, CONICET, CC 242 Ciudad Universitaria, 3000, Santa Fe, Argentina
| | | | | | | |
Collapse
|
31
|
Tsujimoto R, Yamazaki H, Maeda SI, Omata T. Distinct roles of nitrate and nitrite in regulation of expression of the nitrate transport genes in the moss Physcomitrella patens. PLANT & CELL PHYSIOLOGY 2007; 48:484-97. [PMID: 17289796 DOI: 10.1093/pcp/pcm019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Five NRT2 genes and three Nar2 genes, encoding putative high-affinity nitrate transporters, and the respective cDNAs were identified and characterized in Physcomitrella patens. The deduced moss NRT2 and NAR2 proteins were more similar to the corresponding proteins of higher plants than to those of the green alga Chlamydomonas reinhardtii. Expression of all the genes was inhibited by ammonium added to the medium. The regulation by ammonium was abolished by an inhibitor of glutamine synthetase, but the effect of this inhibitor was counteracted by an inhibitor of glutamate synthase. Negative correlation was observed between the glutamine content of protonemata and the transcript levels of PpNRT2 and PpNar2. These results indicated that glutamine is the signal for repression of the genes. All the genes except PpNRT2;5 showed transient expression stimulated by nitrate but not by nitrite, peaking at 2-4 h after the medium was deprived of ammonium. When the glutamine synthetase inhibitor was used to inhibit assimilation of the ammonium generated intracellularly from nitrate or nitrite, the second phase of activation of genes became manifest at approximately 8 h after the medium was deprived of ammonium. Surprisingly, both nitrate and nitrite stimulated gene expression at this stage. PpNRT2;5 was distinct from the other genes in that its expression is sharply induced by nitrite, is strictly dependent on nitrite or nitrate, and is much less susceptible to the feedback regulation, retaining a constant level in nitrate-containing medium. These results indicated that P. patens has multiple mechanisms for sensing nitrate and nitrite.
Collapse
Affiliation(s)
- Ryoma Tsujimoto
- Laboratory of Molecular Plant Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
| | | | | | | |
Collapse
|
32
|
Floyd SK, Bowman JL. Distinct developmental mechanisms reflect the independent origins of leaves in vascular plants. Curr Biol 2006; 16:1911-7. [PMID: 17027487 DOI: 10.1016/j.cub.2006.07.067] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Revised: 06/28/2006] [Accepted: 07/24/2006] [Indexed: 11/24/2022]
Abstract
Vascular plants diverged more than 400 million years ago into two lineages, the lycophytes and the euphyllophytes . Leaf-like organs evolved independently in these two groups . Microphylls in lycophytes are hypothesized to have originated as lateral outgrowths of tissue that later became vascularized (the enation theory) or through the sterilization of sporangia (the sterilization hypothesis) . Megaphylls in euphyllophytes are thought to represent modified lateral branches . The fossil record also indicates that the seed plant megaphyll evolved uniquely in the ancestor of seed plants, independent of megaphylls in ferns, because seed plants evolved from leafless progymnosperm ancestors . Surprisingly, a recent study of KNOX and ARP gene expression in a lycophyte was reported to indicate recruitment of a similar mechanism for determinacy in both types of leaves . We examined the expression of Class III HD-Zip genes in the lycophyte Selaginella kraussiana and in two gymnosperms, Ginkgo and Pseudotsuga. Our data indicate that mechanisms promoting leaf initiation, vascularization, and polarity are quite different in lycophytes and seed plants, consistent with the hypotheses that megaphylls originated as lateral branches whereas microphylls originated as tissue outgrowths.
Collapse
Affiliation(s)
- Sandra K Floyd
- University of California, Davis, Section of Plant Biology, One Shields Avenue, Davis, California 95616, USA
| | | |
Collapse
|
33
|
Nakamura M, Katsumata H, Abe M, Yabe N, Komeda Y, Yamamoto KT, Takahashi T. Characterization of the class IV homeodomain-Leucine Zipper gene family in Arabidopsis. PLANT PHYSIOLOGY 2006; 141:1363-75. [PMID: 16778018 PMCID: PMC1533922 DOI: 10.1104/pp.106.077388] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The Arabidopsis (Arabidopsis thaliana) genome contains 16 genes belonging to the class IV homeodomain-Leucine zipper gene family. These include GLABRA2, ANTHOCYANINLESS2, FWA, ARABIDOPSIS THALIANA MERISTEM LAYER1 (ATML1), and PROTODERMAL FACTOR2 (PDF2). Our previous study revealed that atml1 pdf2 double mutants have severe defects in the shoot epidermal cell differentiation. Here, we have characterized additional members of this gene family, which we designated HOMEODOMAIN GLABROUS1 (HDG1) through HDG12. Analyses of transgenic Arabidopsis plants carrying the gene-specific promoter fused to the bacterial beta-glucuronidase reporter gene revealed that some of the promoters have high activities in the epidermal layer of the shoot apical meristem and developing shoot organs, while others are temporarily active during reproductive organ development. Expression profiles of highly conserved paralogous gene pairs within the family were found to be not necessarily overlapping. Analyses of T-DNA insertion mutants of these HDG genes revealed that all mutants except hdg11 alleles exhibit no abnormal phenotypes. hdg11 mutants show excess branching of the trichome. This phenotype is enhanced in hdg11 hdg12 double mutants. Double mutants were constructed for other paralogous gene pairs and genes within the same subfamily. However, novel phenotypes were observed only for hdg3 atml1 and hdg3 pdf2 mutants that both exhibited defects in cotyledon development. These observations suggest that some of the class IV homeodomain-Leucine zipper members act redundantly with other members of the family during various aspects of cell differentiation. DNA-binding sites were determined for two of the family members using polymerase chain reaction-assisted DNA selection from random oligonucleotides with their recombinant proteins. The binding sites were found to be similar to those previously identified for ATML1 and PDF2, which correspond to the pseudopalindromic sequence 5'-GCATTAAATGC-3' as the preferential binding site.
Collapse
Affiliation(s)
- Miyuki Nakamura
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | | | | | | | | | | | | |
Collapse
|
34
|
Floyd SK, Zalewski CS, Bowman JL. Evolution of class III homeodomain-leucine zipper genes in streptophytes. Genetics 2006; 173:373-88. [PMID: 16489224 PMCID: PMC1461458 DOI: 10.1534/genetics.105.054239] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Accepted: 02/16/2006] [Indexed: 01/07/2023] Open
Abstract
Land plants underwent tremendous evolutionary change following the divergence of the ancestral lineage from algal relatives. Several important developmental innovations appeared as the embryophyte clade diversified, leading to the appearance of new organs and tissue types. To understand how these changes came about, we need to identify the fundamental genetic developmental programs that are responsible for growth, patterning, and differentiation and describe how these programs were modified and elaborated through time to produce novel morphologies. Class III homeodomain-leucine zipper (class III HD-Zip) genes, identified in the model plant Arabidopsis thaliana, provide good candidates for basic land plant patterning genes. We show that these genes may have evolved in a common ancestor of land plants and their algal sister group and that the gene family has diversified as land plant lineages have diversified. Phylogenetic analysis, expression data from nonflowering lineages, and evidence from Arabidopsis and other flowering plants indicate that class III HD-Zip genes acquired new functions in sporophyte apical growth, vascular patterning and differentiation, and leaf development. Modification of expression patterns that accompanied diversification of class III HD-Zip genes likely played an important role in the evolution of land plant form.
Collapse
Affiliation(s)
- Sandra K Floyd
- Section of Plant Biology, University of California, Davis, California 95616, USA
| | | | | |
Collapse
|
35
|
Mukherjee K, Bürglin TR. MEKHLA, a novel domain with similarity to PAS domains, is fused to plant homeodomain-leucine zipper III proteins. PLANT PHYSIOLOGY 2006; 140:1142-50. [PMID: 16607028 PMCID: PMC1435804 DOI: 10.1104/pp.105.073833] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Homeodomain (HD) proteins play important roles in the development of plants, fungi, and animals. Here we identify a novel domain, MEKHLA, in the C terminus of HD-Leu zipper (HD-ZIP) III plant HD proteins that shares similarity with a group of bacterial proteins and a protein from the green alga Chlamydomonas reinhardtii. The group of bacterial MEKHLA proteins is found in cyanobacteria and other bacteria often found associated with plants. Phylogenetic analysis suggests that a MEKHLA protein transferred, possibly from a cyanobacterium or an early chloroplast, into the nuclear genome of an early plant in a first step, and attached itself to the C terminus of an HD-ZIP IV homeobox gene in a second step. Further position-specific iterated-BLAST searches with the bacterial MEKHLA proteins revealed a subregion within the MEKHLA domain that shares significant similarity with the PAS domain. The PAS domain is a sensory module found in many proteins through all kingdoms of life. It is involved in light, oxygen, and redox potential sensation. The fact that HD-ZIP III proteins are transcription factors that have this sensory domain attached to their C terminus uncovers a potential new signaling pathway in plants.
Collapse
Affiliation(s)
- Krishanu Mukherjee
- Department of Biosciences and Nutrition and Center for Genomics and Bioinformatics, Karolinska Institutet, SE-141 57 Huddinge, Sweden
| | | |
Collapse
|
36
|
Yang Y, Yu X, Wu P. Comparison and evolution analysis of two rice subspecies LATERAL ORGAN BOUNDARIES domain gene family and their evolutionary characterization from Arabidopsis. Mol Phylogenet Evol 2005; 39:248-62. [PMID: 16290186 DOI: 10.1016/j.ympev.2005.09.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 09/27/2005] [Accepted: 09/27/2005] [Indexed: 11/27/2022]
Abstract
The plant specific LATERAL ORGAN BOUNDARIES (LOB) domain (LBD) gene family has a potential role in lateral organ development. Thirty-five LBD genes in a japonica rice (Nipponbare) (designated OsJLBD) and in an indica rice (9311) (designated OsILBD) were identified based on the current databases of the two rice subspecies. A new rice LBD gene with two LOB domains and two predicted coiled coil structures in both subspecies was found, which is not found in other plant species based on the current NCBI Genbank database. OsJLBD and OsILBD genes have similar chromosomal distribution pattern. Both OsJLBD and OsILBD genes can be divided into 7 subclasses (classes Ia-e, II and III (see )) and no subclass-specific expression pattern was observed. No introns have been predicted in all class Ie genes in both OsJLBD and OsILBD subfamilies. The genome and tandem duplication has contributed to the neofunctionalization and formation of new rice subclasses, but the mechanism of diploidization and limited tandem duplication have contributed to fewer LBD genes in rice than in Arabidopsis. Functional studies of genes in subclasses may help to determine whether special sequence structure (intron-exon, spacing characters of motifs) has caused special expression pattern of subclasses.
Collapse
Affiliation(s)
- Yi Yang
- The Key State Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Kaixuan Road #268, Huajiachi Cam, Hangzhou, Zhejiang 310029, P.R. China
| | | | | |
Collapse
|
37
|
Henriksson E, Olsson ASB, Johannesson H, Johansson H, Hanson J, Engström P, Söderman E. Homeodomain leucine zipper class I genes in Arabidopsis. Expression patterns and phylogenetic relationships. PLANT PHYSIOLOGY 2005; 139:509-18. [PMID: 16055682 PMCID: PMC1203399 DOI: 10.1104/pp.105.063461] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Members of the homeodomain leucine zipper (HDZip) family of transcription factors are present in a wide range of plants, from mosses to higher plants, but not in other eukaryotes. The HDZip genes act in developmental processes, including vascular tissue and trichome development, and several of them have been suggested to be involved in the mediation of external signals to regulate plant growth. The Arabidopsis (Arabidopsis thaliana) genome contains 47 HDZip genes, which, based on sequence criteria, have been grouped into four different classes: HDZip I to IV. In this article, we present an overview of the class I HDZip genes in Arabidopsis. We describe their expression patterns, transcriptional regulation properties, duplication history, and phylogeny. The phylogeny of HDZip class I genes is supported by data on the duplication history of the genes, as well as the intron/exon patterning of the HDZip-encoding motifs. The HDZip class I genes were found to be widely expressed and partly to have overlapping expression patterns at the organ level. Further, abscisic acid or water deficit treatments and different light conditions affected the transcript levels of a majority of the HDZip I genes. Within the gene family, our data show examples of closely related HDZip genes with similarities in the function of the gene product, but a divergence in expression pattern. In addition, six HDZip class I proteins tested were found to be activators of gene expression. In conclusion, several HDZip I genes appear to regulate similar cellular processes, although in different organs or tissues and in response to different environmental signals.
Collapse
Affiliation(s)
- Eva Henriksson
- Department of Physiological Botany, Evolutionary Biology Centre, University of Uppsala, Sweden
| | | | | | | | | | | | | |
Collapse
|
38
|
Richard O, Paquet N, Haudecoeur E, Charrier B. Organization and Expression of the GSK3/Shaggy Kinase Gene Family in the Moss Physcomitrella patens Suggest Early Gene Multiplication in Land Plants and an Ancestral Response to Osmotic Stress. J Mol Evol 2005; 61:99-113. [PMID: 16007489 DOI: 10.1007/s00239-004-0302-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Accepted: 03/02/2005] [Indexed: 10/25/2022]
Abstract
GSK3/Shaggy kinases are involved in a wide range of fundamental processes in animal development and metabolism. In angiosperm plants, these kinases are encoded by moderate-sized gene families, which appear to have a complex set of functions. Here, we present the characterization of five members of the GSK3/Shaggy gene family in the bryophyte Physcomitrella patens. The P. patens GSK3/Shaggy kinases (PpSK) are organized in a group of closely related paralogues with respect to their gene sequence and structure. Indeed, a phylogenetic analysis of the GSK3/Shaggy kinase sequences from plants and animals showed that the five PpSK proteins are monophyletic, and closer to subgroups I and IV described in angiosperms. Expression analyses performed by quantitative real-time RT-PCR on a wide range of growing conditions showed that PpSK genes responded only to either desiccation, PEG or sorbitol. As demonstrated by both inductions of marker genes and protonemal cell plasmolyses, these treatments resulted in a hyperosmotic stress. Altogether, these data suggest that (1) GSK3/Shaggy kinase gene multiplication occurred early in plant evolution, before the separation between bryophytes and vascular plants, and (2) both gene loss and duplication occurred in the ancestor of P. patens along with functional gene diversification in angiosperms. However, conservation of the transcriptional responses between Physcomitrella and Arabidopsis suggests the identification of an ancestral response of the GSK3/Shaggy kinases genes to osmotic stress.
Collapse
Affiliation(s)
- Odile Richard
- Institut de Biotechnologie des Plantes, Bât. 630, UMR CNRS 8618, Université Paris-Sud, 91405, Orsay Cedex, France
| | | | | | | |
Collapse
|
39
|
Zobell O, Coupland G, Reiss B. The family of CONSTANS-like genes in Physcomitrella patens. PLANT BIOLOGY (STUTTGART, GERMANY) 2005; 7:266-75. [PMID: 15912446 DOI: 10.1055/s-2005-865621] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The CONSTANS (CO) gene plays a central role in the regulation of flowering time in Arabidopsis, and is a member of a family of 17 CO-like genes. CO and CO-like genes have been found in all flowering plants, but not in yeast and animals. To address the question of the origin of CO, we analysed this gene family in the moss Physcomitrella patens, a phylogenetically distant organism. Database searches in EST libraries that almost completely covered the Physcomitrella transcriptome, and Southern blotting, identified only three genes that had all of the hallmarks of CO. Further analysis demonstrated that these are most similar to CO-like genes AtCOL3/AtCOL4/AtCOL5, a group of Arabidopsis genes closely related to, but distinct from CO, suggesting that the CO branch of the AtCOL phylogeny does not exist in the Physcomitrella genome. Since 17 COL genes occur in Arabidopsis and only three closely related and two distantly related genes were found in Physcomitrella, the family of CO-like proteins appears to be smaller in Physcomitrella than in Arabidopsis, in agreement with observations made with other gene families. The data also indicate that CO-like genes must have existed in the common ancestor of bryophytes and flowering plants, and that CO originated in the group of CO-like genes represented by AtCOL3/AtCOL4/AtCOL5. Furthermore, expression of the three closely related Physcomitrella homologues is regulated by light, suggesting that the role of CO in flowering time control was probably derived from an ancestral function in light signal transduction.
Collapse
Affiliation(s)
- O Zobell
- Max-Planck-Institut für Züchtungsforschung, Department of Plant Developmental Biology, Carl-von-Linné-Weg 10, 50829 Köln, Germany
| | | | | |
Collapse
|
40
|
Prigge MJ, Otsuga D, Alonso JM, Ecker JR, Drews GN, Clark SE. Class III homeodomain-leucine zipper gene family members have overlapping, antagonistic, and distinct roles in Arabidopsis development. THE PLANT CELL 2005; 17:61-76. [PMID: 15598805 PMCID: PMC544490 DOI: 10.1105/tpc.104.026161] [Citation(s) in RCA: 497] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2004] [Accepted: 10/10/2004] [Indexed: 05/18/2023]
Abstract
The Arabidopsis thaliana genome contains five class III homeodomain-leucine zipper genes. We have isolated loss-of-function alleles for each family member for use in genetic analysis. This gene family regulates apical embryo patterning, embryonic shoot meristem formation, organ polarity, vascular development, and meristem function. Genetic analyses revealed a complex pattern of overlapping functions, some of which are not readily inferred by phylogenetic relationships or by gene expression patterns. The PHABULOSA and PHAVOLUTA genes perform overlapping functions with REVOLUTA, whereas the PHABULOSA, PHAVOLUTA, and CORONA/ATHB15 genes perform overlapping functions distinct from REVOLUTA. Furthermore, ATHB8 and CORONA encode functions that are both antagonistic to those of REVOLUTA within certain tissues and overlapping with REVOLUTA in other tissues. Differences in expression patterns explain some of these genetic interactions, whereas other interactions are likely attributable to differences in protein function as indicated by cross-complementation studies.
Collapse
Affiliation(s)
- Michael J Prigge
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, An Arbor, Michigan 48109-1048, USA
| | | | | | | | | | | |
Collapse
|
41
|
Rocha GCG, Corrêa RL, Borges ACN, Sá CBPD, Alves-Ferreira M. Identification and characterization of homeobox genes in Eucalyptus. Genet Mol Biol 2005. [DOI: 10.1590/s1415-47572005000400005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
|
42
|
Hattori M, Hasebe M, Sugita M. Identification and characterization of cDNAs encoding pentatricopeptide repeat proteins in the basal land plant, the moss Physcomitrella patens. Gene 2004; 343:305-11. [PMID: 15588585 DOI: 10.1016/j.gene.2004.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Revised: 09/06/2004] [Accepted: 09/17/2004] [Indexed: 11/28/2022]
Abstract
A large gene family encoding proteins with a pentatricopeptide repeat (PPR) motif exists in flowering plants but not in algae, fungi, or animals. This suggests that PPR protein genes expanded vastly during the evolution of the land plants. To investigate this possibility, we analysed PPR protein genes in the basal land plant, the moss Physcomitrella patens. An extensive survey of the Physcomitrella expressed sequence tag (EST) databases revealed 36 ESTs encoding PPR proteins. This indicates that a large gene family of PPR proteins originated before the divergence of the vascular plant and moss lineages. We also characterized five full-length cDNAs encoding PPR proteins, designated PPR513-10, PPR566-6, PPR868-14, PPR986-12, and PPR423-6. Intracellular localization analysis demonstrated two PPR proteins in chloroplasts (cp), whereas the cellular localization of the other three PPR proteins is unclear. The genes of the cp-localized PPR513-10 and PPR566-6 were expressed differentially in protonemata grown under different light-dark conditions, suggesting they have distinctive functions in cp. This is the first report and analysis of genes encoding PPR proteins in bryophytes.
Collapse
Affiliation(s)
- Mitsuru Hattori
- Center for Gene Research, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | | | | |
Collapse
|
43
|
Narita NN, Moore S, Horiguchi G, Kubo M, Demura T, Fukuda H, Goodrich J, Tsukaya H. Overexpression of a novel small peptide ROTUNDIFOLIA4 decreases cell proliferation and alters leaf shape in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 38:699-713. [PMID: 15125775 DOI: 10.1111/j.1365-313x.2004.02078.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Leaf shape is determined by polar cell expansion and polar cell proliferation along the leaf axes. However, the genes controlling polar cell proliferation during leaf morphogenesis are largely unknown. We identified a dominant mutant of Arabidopsis thaliana, rotundifolia4-1D (rot4-1D), which possessed short leaves and floral organs. We showed that the altered leaf shape is caused by reduced cell proliferation, specifically in the longitudinal (proximal-distal) axis of the leaf, suggesting that the ROT4 gene controls polar cell proliferation in lateral organs. The ROT4 open-reading frame (ORF) encodes a novel small peptide that had not been identified in the Arabidopsis genome annotation. Overexpression of a ROT4-green fluorescence protein (GFP) fusion protein in transgenic plants recapitulated the rot4 phenotype, suggesting that ROT4 acts to restrict cell proliferation. The ROT4-GFP fusion protein localized to the plasma membrane when expressed in transgenic Arabidopsis plants. Phylogenetic analysis indicates that ROT4 defines a novel seed plant-specific family of small peptides with 22 members in Arabidopsis, ROT FOUR LIKE1-22 (RTFL1-22). All RTFL members share a conserved 29-amino acid domain, the RTF domain, and overexpression of the ROT4 RTF domain alone is sufficient to confer a rot4-1D phenotype. Loss-of-function mutations in several RTFL genes were aphenotypic, suggesting that there may be some functional redundancy between family members. Analyses by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization revealed that ROT4 is expressed in the shoot apex and young leaves of wild-type plants, consistent with a role for ROT4 in controlling polarity-dependent cell proliferation during wild-type leaf morphogenesis.
Collapse
Affiliation(s)
- Noriyuki N Narita
- National Institute for Basic Biology/Center for Integrated Bioscience, Okazaki, Aichi 444-8585, Japan
| | | | | | | | | | | | | | | |
Collapse
|
44
|
Zhong R, Ye ZH. amphivasal vascular bundle 1, a Gain-of-Function Mutation of the IFL1/REV Gene, Is Associated with Alterations in the Polarity of Leaves, Stems and Carpels. ACTA ACUST UNITED AC 2004; 45:369-85. [PMID: 15111711 DOI: 10.1093/pcp/pch051] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In Arabidopsis stems, the vascular bundles in the stele are arranged in a ring-like pattern and the vascular tissues in each bundle are organized in a collateral pattern. We have shown previously that the semidominant amphivasal vascular bundle 1 (avb1) mutation transforms the collateral vascular bundles into amphivasal bundles and disrupts the ring-like arrangement of vascular bundles in the stele. In this study, we show that the avb1 mutation occurred in the putative microRNA 165 target sequence in the IFL1/REV gene and caused an amino acid substitution in the putative sterol/lipid-binding START domain. We present direct evidence that the wild-type IFL1/REV mRNA was cleaved within the microRNA 165 target sequence and the avb1 mutation resulted in an inhibition of cleavage and a higher level accumulation of full-length mRNA, suggesting a role of microRNA 165 in the regulation of IFL1/REV gene expression. In addition to an alteration in vascular patterning, the avb1 mutation also caused dramatic changes in fiber cell wall thickening and organ polarity, including aberrant formation and proliferation of cauline leaves and branches, production of trumpet-shaped leaves with reversed adaxial-abaxial identity, ectopic growth of carpel-like structures on the outer surface of carpels, and fasciation of inflorescence. Ectopic overexpression of the avb1 mutant cDNA not only phenocopied most of the avb1 mutant phenotypes but also led to additional novel phenotypes such as formation of leaves with extremely narrow blades and ectopic production of branches in the axil of siliques. Taken together, these results suggest that the avb1 gain-of-function mutation of the IFL1/REV gene alters the positional information that determines vascular patterning and organ polarity.
Collapse
Affiliation(s)
- Ruiqin Zhong
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA
| | | |
Collapse
|
45
|
Sakakibara K, Nishiyama T, Sumikawa N, Kofuji R, Murata T, Hasebe M. Involvement of auxin and a homeodomain-leucine zipper I gene in rhizoid development of the moss Physcomitrella patens. Development 2003; 130:4835-46. [PMID: 12917289 DOI: 10.1242/dev.00644] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Differentiation of epidermal cells is important for plants because they are in direct contact with the environment. Rhizoids are multicellular filaments that develop from the epidermis in a wide range of plants, including pteridophytes, bryophytes, and green algae; they have similar functions to root hairs in vascular plants in that they support the plant body and are involved in water and nutrient absorption. In this study, we examined mechanisms underlying rhizoid development in the moss, Physcomitrella patens, which is the only land plant in which high-frequency gene targeting is possible. We found that rhizoid development can be split into two processes: determination and differentiation. Two types of rhizoids with distinct developmental patterns (basal and mid-stem rhizoids) were recognized. The development of basal rhizoids from epidermal cells was induced by exogenous auxin, while that of mid-stem rhizoids required an unknown factor in addition to exogenous auxin. Once an epidermal cell had acquired a rhizoid initial cell fate, expression of the homeodomain-leucine zipper I gene Pphb7 was induced. Analysis of Pphb7 disruptant lines showed that Pphb7 affects the induction of pigmentation and the increase in the number and size of chloroplasts, but not the position or number of rhizoids. This is the first report on the involvement of a homeodomain-leucine zipper I gene in epidermal cell differentiation.
Collapse
|
46
|
Emery JF, Floyd SK, Alvarez J, Eshed Y, Hawker NP, Izhaki A, Baum SF, Bowman JL. Radial Patterning of Arabidopsis Shoots by Class III HD-ZIP and KANADI Genes. Curr Biol 2003; 13:1768-74. [PMID: 14561401 DOI: 10.1016/j.cub.2003.09.035] [Citation(s) in RCA: 755] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Shoots of all land plants have a radial pattern that can be considered to have an adaxial (central)-abaxial (peripheral) polarity. In Arabidopsis, gain-of-function alleles of PHAVOLUTA and PHABULOSA, members of the class III HD-ZIP gene family, result in adaxialization of lateral organs. Conversely, loss-of-function alleles of the KANADI genes cause an adaxialization of lateral organs. Thus, the class III HD-ZIP and KANADI genes comprise a genetic system that patterns abaxial-adaxial polarity in lateral organs produced from the apical meristem. RESULTS We show that gain-of-function alleles of REVOLUTA, another member of the class III HD-ZIP gene family, are characterized by adaxialized lateral organs and alterations in the radial patterning of vascular bundles in the stem. The gain-of-function phenotype can be obtained by changing only the REVOLUTA mRNA sequence and without changing the protein sequence; this finding indicates that this phenotype is likely mediated through an interference with microRNA binding. Loss of KANADI activity results in similar alterations in vascular patterning as compared to REVOLUTA gain-of-function alleles. Simultaneous loss-of-function of PHABULOSA, PHAVOLUTA, and REVOLUTA abaxializes cotyledons, abolishes the formation of the primary apical meristem, and in severe cases, eliminates bilateral symmetry; these phenotypes implicate these three genes in radial patterning of both embryonic and postembryonic growth. CONCLUSIONS Based on complementary vascular and leaf phenotypes of class III HD-ZIP and KANADI mutants, we propose that a common genetic program dependent upon miRNAs governs adaxial-abaxial patterning of leaves and radial patterning of stems in the angiosperm shoot. This finding implies that a common patterning mechanism is shared between apical and vascular meristems.
Collapse
Affiliation(s)
- John F Emery
- Section of Plant Biology, University of California, Davis, Davis, CA 95616, USA
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Bayarsaihan D, Enkhmandakh B, Makeyev A, Greally JM, Leckman JF, Ruddle FH. Homez, a homeobox leucine zipper gene specific to the vertebrate lineage. Proc Natl Acad Sci U S A 2003; 100:10358-63. [PMID: 12925734 PMCID: PMC193566 DOI: 10.1073/pnas.1834010100] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This work describes a vertebrate homeobox gene, designated Homez (homeodomain leucine zipper-encoding gene), that encodes a protein with an unusual structural organization. There are several regions within Homez, including three atypical homeodomains, two leucine zipper-like motifs, and an acidic domain. The gene is ubiquitously expressed in human and murine tissues, although the expression pattern is more restricted during mouse development. Genomic analysis revealed that human and mouse genes are located at 14q11.2 and 14C, respectively, and are composed of two exons. The zebrafish and pufferfish homologs share high similarity to mammalian sequences, particularly within the homeodomain sequences. Based on homology of homeodomains and on the similarity in overall protein structure, we delineate Homez and members of ZHX family of zinc finger homeodomain factors as a subset within the superfamily of homeobox-containing proteins. The type and composition of homeodomains in the Homez subfamily are vertebrate-specific. Phylogenetic analysis indicates that Homez lineage was separated from related genes >400 million years ago before separation of ray- and lobe-finned fishes. We apply a duplication-degeneration-complementation model to explain how this family of genes has evolved.
Collapse
Affiliation(s)
- Dashzeveg Bayarsaihan
- Department of Molecular, Cellular, and Developmental Biology, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA.
| | | | | | | | | | | |
Collapse
|
48
|
Nishiyama T, Fujita T, Shin-I T, Seki M, Nishide H, Uchiyama I, Kamiya A, Carninci P, Hayashizaki Y, Shinozaki K, Kohara Y, Hasebe M. Comparative genomics of Physcomitrella patens gametophytic transcriptome and Arabidopsis thaliana: implication for land plant evolution. Proc Natl Acad Sci U S A 2003; 100:8007-12. [PMID: 12808149 PMCID: PMC164703 DOI: 10.1073/pnas.0932694100] [Citation(s) in RCA: 279] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mosses and flowering plants diverged >400 million years ago. The mosses have haploid-dominant life cycles, whereas the flowering plants are diploid-dominant. The common ancestors of land plants have been inferred to be haploid-dominant, suggesting that genes used in the diploid body of flowering plants were recruited from the genes used in the haploid body of the ancestors during the evolution of land plants. To assess this evolutionary hypothesis, we constructed an EST library of the moss Physcomitrella patens, and compared the moss transcriptome to the genome of Arabidopsis thaliana. We constructed full-length enriched cDNA libraries from auxin-treated, cytokinin-treated, and untreated gametophytes of P. patens, and sequenced both ends of >40,000 clones. These data, together with the mRNA sequences in the public databases, were assembled into 15,883 putative transcripts. Sequence comparisons of A. thaliana and P. patens showed that at least 66% of the A. thaliana genes had homologues in P. patens. Comparison of the P. patens putative transcripts with all known proteins, revealed 9,907 putative transcripts with high levels of similarity to vascular plant genes, and 850 putative transcripts with high levels of similarity to other organisms. The haploid transcriptome of P. patens appears to be quite similar to the A. thaliana genome, supporting the evolutionary hypothesis. Our study also revealed that a number of genes are moss specific and were lost in the flowering plant lineage.
Collapse
Affiliation(s)
- Tomoaki Nishiyama
- Division of Speciation Mechanisms 2 and Computer Laboratory, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Ito M, Sato Y, Matsuoka M. Involvement of homeobox genes in early body plan of monocot. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 218:1-35. [PMID: 12199516 DOI: 10.1016/s0074-7696(02)18010-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Homeobox genes are known as transcriptional regulators that are involved in various aspects of developmental processes in many organisms. In plants, many types of homeobox genes have been identified, and mutational or expression pattern analyses of these genes have indicated the involvement of several classes of homeobox genes in developmental processes. The fundamental body plan of plants is established during embryogenesis, whereas morphogenetic events in the shoot apical meristem (SAM) continue after embryogenesis. Knotted1-like homeobox genes (knox genes) are preferentially expressed in both the SAM and the immature embryo. Therefore, these genes are considered to be key regulators of plant morphogenesis. In this review, we discuss the regulatory role of knox genes and other types of homeobox genes in SAM establishment during embryogenesis and SAM maintenance after embryogenesis, mainly in rice.
Collapse
Affiliation(s)
- Momoyo Ito
- BioScience Center, Nagoya University, Chikusa, Japan
| | | | | |
Collapse
|
50
|
Iwakawa H, Ueno Y, Semiarti E, Onouchi H, Kojima S, Tsukaya H, Hasebe M, Soma T, Ikezaki M, Machida C, Machida Y. The ASYMMETRIC LEAVES2 gene of Arabidopsis thaliana, required for formation of a symmetric flat leaf lamina, encodes a member of a novel family of proteins characterized by cysteine repeats and a leucine zipper. PLANT & CELL PHYSIOLOGY 2002; 43:467-78. [PMID: 12040093 DOI: 10.1093/pcp/pcf077] [Citation(s) in RCA: 263] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The ASYMMETRIC LEAVES2 (AS2) gene of Arabidopsis thaliana is involved in the establishment of the leaf venation system, which includes the prominent midvein, as well as in the development of a symmetric lamina. The gene product also represses the expression of class 1 knox homeobox genes in leaves. We have characterized the AS2 gene, which appears to encode a novel protein with cysteine repeats (designated the C-motif) and a leucine-zipper-like sequence in the amino-terminal half of the primary sequence. The Arabidopsis genome contains 42 putative genes that potentially encode proteins with conserved amino acid sequences that include the C-motif and the leucine-zipper-like sequence in the amino-terminal half. Thus, the AS2 protein belongs to a novel family of proteins that we have designated the AS2 family. Members of this family except AS2 also have been designated ASLs (AS2-like proteins). Transcripts of AS2 were detected mainly in adaxial domains of cotyledonary primordia. Green fluorescent protein-fused AS2 was concentrated in plant cell nuclei. Overexpression of AS2 cDNA in transgenic Arabidopsis plants resulted in upwardly curled leaves, which differed markedly from the downwardly curled leaves generated by loss-of-function mutation of AS2. Our results suggest that AS2 functions in the transcription of a certain gene(s) in plant nuclei and thereby controls the formation of a symmetric flat leaf lamina and the establishment of a prominent midvein and other patterns of venation.
Collapse
Affiliation(s)
- Hidekazu Iwakawa
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|