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Kim SH, Lee SH, Park TK, Tian Y, Yu K, Lee BH, Bai MY, Cho SJ, Kim TW. Comparative analysis of BZR1/BES1 family transcription factors in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:747-765. [PMID: 37926922 DOI: 10.1111/tpj.16527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 09/26/2023] [Accepted: 10/23/2023] [Indexed: 11/07/2023]
Abstract
Brassinazole Resistant 1 (BZR1) and bri1 EMS Suppressor 1 (BES1) are key transcription factors that mediate brassinosteroid (BR)-responsive gene expression in Arabidopsis. The BZR1/BES1 family is composed of BZR1, BES1, and four BES1/BZR1 homologs (BEH1-BEH4). However, little is known about whether BEHs are regulated by BR signaling in the same way as BZR1 and BES1. We comparatively analyzed the functional characteristics of six BZR1/BES1 family members and their regulatory mechanisms in BR signaling using genetic and biochemical analyses. We also compared their subcellular localizations regulated by the phosphorylation status, interaction with GSK3-like kinases, and heterodimeric combination. We found that all BZR1/BES1 family members restored the phenotypic defects of bri1-5 by their overexpression. Unexpectedly, BEH2-overexpressing plants showed the most distinct phenotype with enhanced BR responses. RNA-Seq analysis indicated that overexpression of both BZR1 and BEH2 regulates BR-responsive gene expression, but BEH2 has a much greater proportion of BR-independent gene expression than BZR1. Unlike BZR1 and BES1, the BR-regulated subcellular translocation of the four BEHs was not tightly correlated with their phosphorylation status. Notably, BEH1 and BEH2 are predominantly localized in the nucleus, which induces the nuclear accumulation of other BZR1/BES1 family proteins through heterodimerization. Altogether, our comparative analyses suggest that BEH1 and BEH2 play an important role in the functional interaction between BZR1/BES1 family transcription factors.
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Affiliation(s)
- So-Hee Kim
- Department of Life Science, Hanyang University, Seoul, 04763, Republic of Korea
- Research Institute for Convergence of Basic Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Se-Hwa Lee
- Department of Life Science, Hanyang University, Seoul, 04763, Republic of Korea
- Research Institute for Convergence of Basic Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Tae-Ki Park
- Department of Life Science, Hanyang University, Seoul, 04763, Republic of Korea
- Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul, 04763, Republic of Korea
| | - Yanchen Tian
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Kyoungjae Yu
- Department of Life Science, Sogang University, Seoul, 04107, Republic of Korea
| | - Byeong-Ha Lee
- Department of Life Science, Sogang University, Seoul, 04107, Republic of Korea
| | - Ming-Yi Bai
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Sung-Jin Cho
- School of Biological Sciences, College of Natural Sciences, Chungbuk National University, Cheongju, 28644, Republic of Korea
| | - Tae-Wuk Kim
- Department of Life Science, Hanyang University, Seoul, 04763, Republic of Korea
- Research Institute for Convergence of Basic Science, Hanyang University, Seoul, 04763, Republic of Korea
- Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul, 04763, Republic of Korea
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Wang D, Zuo J, Liu S, Wang W, Lu Q, Hao X, Fang Z, Liang T, Sun Y, Guo C, Zhao C, Tang Y. BRI1 EMS SUPPRESSOR1 genes regulate abiotic stress and anther development in wheat ( Triticum aestivum L.). FRONTIERS IN PLANT SCIENCE 2023; 14:1219856. [PMID: 37621887 PMCID: PMC10446898 DOI: 10.3389/fpls.2023.1219856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/14/2023] [Indexed: 08/26/2023]
Abstract
BRI1 EMS SUPPRESSOR1 (BES1) family members are crucial downstream regulators that positively mediate brassinosteroid signaling, playing vital roles in the regulation of plant stress responses and anther development in Arabidopsis. Importantly, the expression profiles of wheat (Triticum aestivum L.) BES1 genes have not been analyzed comprehensively and systematically in response to abiotic stress or during anther development. In this study, we identified 23 BES1-like genes in common wheat, which were unevenly distributed on 17 out of 21 wheat chromosomes. Phylogenetic analysis clustered the BES1 genes into four major clades; moreover, TaBES1-3A2, TaBES1-3B2 and TaBES1-3D2 belonged to the same clade as Arabidopsis BES1/BZR1 HOMOLOG3 (BEH3) and BEH4, which participate in anther development. The expression levels of 23 wheat BES1 genes were assessed using real-time quantitative PCR under various abiotic stress conditions (drought, salt, heat, and cold), and we found that most TaBES1-like genes were downregulated under abiotic stress, particularly during drought stress. We therefore used drought-tolerant and drought-sensitive wheat cultivars to explore TaBES1 expression patterns under drought stress. TaBES1-3B2 and TaBES1-3D2 expression was high in drought-tolerant cultivars but substantially repressed in drought-sensitive cultivars, while TaBES1-6D presented an opposite pattern. Among genes preferentially expressed in anthers, TaBES1-3B2 and TaBES1-3D2 expression was substantially downregulated in thermosensitive genic male-sterile wheat lines compared to common wheat cultivar under sterile conditions, while we detected no obvious differences under fertile conditions. This result suggests that TaBES1-3B2 and TaBES1-3D2 might not only play roles in regulating drought tolerance, but also participate in low temperature-induced male sterility.
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Affiliation(s)
- Dezhou Wang
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- The Municipal Key Laboratory of the Molecular Genetics of Hybrid Wheat, Hubei Collaborative Innovation Center for Grain Industry, Beijing, China
| | - Jinghong Zuo
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- The Municipal Key Laboratory of the Molecular Genetics of Hybrid Wheat, Hubei Collaborative Innovation Center for Grain Industry, Beijing, China
| | - Shan Liu
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- The Municipal Key Laboratory of the Molecular Genetics of Hybrid Wheat, Hubei Collaborative Innovation Center for Grain Industry, Beijing, China
| | - Weiwei Wang
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- The Municipal Key Laboratory of the Molecular Genetics of Hybrid Wheat, Hubei Collaborative Innovation Center for Grain Industry, Beijing, China
| | - Qing Lu
- Agriculture College, Yangtze University, Jingzhou, China
| | - Xiaocong Hao
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- The Municipal Key Laboratory of the Molecular Genetics of Hybrid Wheat, Hubei Collaborative Innovation Center for Grain Industry, Beijing, China
| | - Zhaofeng Fang
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- The Municipal Key Laboratory of the Molecular Genetics of Hybrid Wheat, Hubei Collaborative Innovation Center for Grain Industry, Beijing, China
| | - Ting Liang
- Agriculture College, Yangtze University, Jingzhou, China
| | - Yue Sun
- Agriculture College, Yangtze University, Jingzhou, China
| | - Chunman Guo
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- The Municipal Key Laboratory of the Molecular Genetics of Hybrid Wheat, Hubei Collaborative Innovation Center for Grain Industry, Beijing, China
| | - Changping Zhao
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- The Municipal Key Laboratory of the Molecular Genetics of Hybrid Wheat, Hubei Collaborative Innovation Center for Grain Industry, Beijing, China
| | - Yimiao Tang
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- The Municipal Key Laboratory of the Molecular Genetics of Hybrid Wheat, Hubei Collaborative Innovation Center for Grain Industry, Beijing, China
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Gao Y, He X, Lv H, Liu H, Li Y, Hu Y, Liu Y, Huang Y, Zhang J. Epi-Brassinolide Regulates ZmC4 NADP-ME Expression through the Transcription Factors ZmbHLH157 and ZmNF-YC2. Int J Mol Sci 2023; 24:ijms24054614. [PMID: 36902048 PMCID: PMC10002761 DOI: 10.3390/ijms24054614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 03/05/2023] Open
Abstract
Maize is a main food and feed crop with great production potential and high economic benefits. Improving its photosynthesis efficiency is crucial for increasing yield. Maize photosynthesis occurs mainly through the C4 pathway, and NADP-ME (NADP-malic enzyme) is a key enzyme in the photosynthetic carbon assimilation pathway of C4 plants. ZmC4-NADP-ME catalyzes the release of CO2 from oxaloacetate into the Calvin cycle in the maize bundle sheath. Brassinosteroid (BL) can improve photosynthesis; however, its molecular mechanism of action remains unclear. In this study, transcriptome sequencing of maize seedlings treated with epi-brassinolide (EBL) showed that differentially expressed genes (DEGs) were significantly enriched in photosynthetic antenna proteins, porphyrin and chlorophyll metabolism, and photosynthesis pathways. The DEGs of C4-NADP-ME and pyruvate phosphate dikinase in the C4 pathway were significantly enriched in EBL treatment. Co-expression analysis showed that the transcription level of ZmNF-YC2 and ZmbHLH157 transcription factors was increased under EBL treatment and moderately positively correlated with ZmC4-NADP-ME. Transient overexpression of protoplasts revealed that ZmNF-YC2 and ZmbHLH157 activate C4-NADP-ME promoters. Further experiments showed ZmNF-YC2 and ZmbHLH157 transcription factor binding sites on the -1616 bp and -1118 bp ZmC4 NADP-ME promoter. ZmNF-YC2 and ZmbHLH157 were screened as candidate transcription factors mediating brassinosteroid hormone regulation of the ZmC4 NADP-ME gene. The results provide a theoretical basis for improving maize yield using BR hormones.
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Affiliation(s)
- Yuanfen Gao
- College of Life Science, Sichuan Agricultural University, Ya’an 625000, China
| | - Xuewu He
- College of Life Science, Sichuan Agricultural University, Ya’an 625000, China
| | - Huayang Lv
- College of Life Science, Sichuan Agricultural University, Ya’an 625000, China
| | - Hanmei Liu
- College of Life Science, Sichuan Agricultural University, Ya’an 625000, China
| | - Yangping Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Yufeng Hu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Yinghong Liu
- Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Yubi Huang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
- Correspondence: (Y.H.); (J.Z.)
| | - Junjie Zhang
- College of Life Science, Sichuan Agricultural University, Ya’an 625000, China
- Correspondence: (Y.H.); (J.Z.)
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Korwin Krukowski P, Visentin I, Russo G, Minerdi D, Bendahmane A, Schubert A, Cardinale F. Transcriptome Analysis Points to BES1 as a Transducer of Strigolactone Effects on Drought Memory in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2023; 63:1873-1889. [PMID: 35489066 DOI: 10.1093/pcp/pcac058] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 04/09/2022] [Accepted: 04/29/2022] [Indexed: 05/21/2023]
Abstract
Strigolactones (SLs) are carotenoid-derived phytohormones governing a wide range of physiological processes, including drought-associated stomatal closure. We have previously shown in tomato that SLs regulate the so-called after-effect of drought, whereby stomatal conductance is not completely restored for some time during recovery after a drought spell, irrespective of the water potential. To ease the elucidation of its molecular underpinnings, we investigated whether this SL effect is conserved in Arabidopsis thaliana by contrasting the physiological performances of the wild-type with SL-depleted (more axillary growth 4, max4) and insensitive (dwarf 14, d14) mutants in a drought and recovery protocol. Physiological analyses showed that SLs are important to achieve a complete after-effect in A. thaliana, while transcriptome results suggested that the SL-dependent modulation of drought responses extends to a large subset (about 4/5) of genes displaying memory transcription patterns. Among these, we show that the activation of over 30 genes related to abscisic acid metabolism and signaling strongly depends on SL signaling. Furthermore, by using promoter-enrichment tools, we identified putative cis- and trans-acting factors that may be important in the SL-dependent and SL-independent regulation of genes during drought and recovery. Finally, in order to test the accuracy of our bioinformatic prediction, we confirmed one of the most promising transcription factor candidates mediating SL signaling effects on transcriptional drought memory-BRI-EMS SUPPRESSOR1 (BES1). Our findings reveal that SLs are master regulators of Arabidopsis transcriptional memory upon drought and that this role is partially mediated by the BES1 transcription factor.
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Affiliation(s)
- Paolo Korwin Krukowski
- PlantStressLab, DISAFA-University of Turin, Largo Paolo Braccini 2, Grugliasco (TO) I-10095, Italy
| | - Ivan Visentin
- PlantStressLab, DISAFA-University of Turin, Largo Paolo Braccini 2, Grugliasco (TO) I-10095, Italy
| | - Giulia Russo
- PlantStressLab, DISAFA-University of Turin, Largo Paolo Braccini 2, Grugliasco (TO) I-10095, Italy
| | - Daniela Minerdi
- PlantStressLab, DISAFA-University of Turin, Largo Paolo Braccini 2, Grugliasco (TO) I-10095, Italy
| | - Abdelhafid Bendahmane
- Biology Department, Institute of Plant Sciences-Paris-Saclay, CS80004, Gif-sur-Yvette Cedex 91192, France
| | - Andrea Schubert
- PlantStressLab, DISAFA-University of Turin, Largo Paolo Braccini 2, Grugliasco (TO) I-10095, Italy
| | - Francesca Cardinale
- PlantStressLab, DISAFA-University of Turin, Largo Paolo Braccini 2, Grugliasco (TO) I-10095, Italy
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Otani Y, Kawanishi M, Kamimura M, Sasaki A, Nakamura Y, Nakamura T, Okamoto S. Behavior and possible function of Arabidopsis BES1/BZR1 homolog 2 in brassinosteroid signaling. PLANT SIGNALING & BEHAVIOR 2022; 17:2084277. [PMID: 35695417 PMCID: PMC9196799 DOI: 10.1080/15592324.2022.2084277] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
- Yui Otani
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
| | - Mika Kawanishi
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
| | - Miyu Kamimura
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
| | - Azusa Sasaki
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Yasushi Nakamura
- Department of Japanese Food Culture, Faculty of Letters, Kyoto Prefectural University, Kyoto, Japan
| | - Takako Nakamura
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Shigehisa Okamoto
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
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Liu C, Bai L, Cao P, Li S, Huang SX, Wang J, Li L, Zhang J, Zhao J, Song J, Sun P, Zhang Y, Zhang H, Guo X, Yang X, Tan X, Liu W, Wang X, Xiang W. Novel Plant Growth Regulator Guvermectin from Plant Growth-Promoting Rhizobacteria Boosts Biomass and Grain Yield in Rice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:16229-16240. [PMID: 36515163 DOI: 10.1021/acs.jafc.2c07072] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Food is a fundamental human right, and global food security is threatened by crop production. Plant growth regulators (PGRs) play an essential role in improving crop yield and quality, and this study reports on a novel PGR, termed guvermectin (GV), isolated from plant growth-promoting rhizobacteria, which can promote root and coleoptile growth, tillering, and early maturing in rice. GV is a nucleoside analogue like cytokinin (CK), but it was found that GV significantly promoted root and hypocotyl growth, which is different from the function of CK in Arabidopsis. The Arabidopsis CK receptor triple mutant ahk2-2 ahk3-3 cre1-12 still showed a GV response. Moreover, GV led different growth-promoting traits from auxin, gibberellin (GA), and brassinosteroid (BR) in Arabidopsis and rice. The results from a four-year field trial involving 28 rice varieties showed that seed-soaking treatment with GV increased the yields by 6.2 to 19.6%, outperforming the 4.0 to 10.8% for CK, 1.6 to 16.9% for BR, and 2.2 to 7.1% for GA-auxin-BR mixture. Transcriptome analysis demonstrated that GV induced different transcriptome patterns from CK, auxin, BR, and GA, and SAUR genes may regulate GV-mediated plant growth and development. This study suggests that GV represents a novel PGR with a unique signal perception and transduction pathway in plants.
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Affiliation(s)
- Chongxi Liu
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Lu Bai
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Peng Cao
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Shanshan Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Sheng-Xiong Huang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Jidong Wang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Science, Huzhou University, Huzhou 313000, China
| | - Lei Li
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Ji Zhang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Junwei Zhao
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Jia Song
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Peng Sun
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Yanyan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Hui Zhang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Xiaowei Guo
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Xilang Yang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Xinqiu Tan
- Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha 410125, China
| | - Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiangjing Wang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Wensheng Xiang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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Conway SJ, Walcher-Chevillet CL, Salome Barbour K, Kramer EM. Brassinosteroids regulate petal spur length in Aquilegia by controlling cell elongation. ANNALS OF BOTANY 2021; 128:931-942. [PMID: 34508638 PMCID: PMC8577200 DOI: 10.1093/aob/mcab116] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/10/2021] [Indexed: 05/26/2023]
Abstract
BACKGROUND AND AIMS Aquilegia produce elongated, three-dimensional petal spurs that fill with nectar to attract pollinators. Previous studies have shown that the diversity of spur length across the Aquilegia genus is a key innovation that is tightly linked with its recent and rapid diversification into new ranges, and that evolution of increased spur lengths is achieved via anisotropic cell elongation. Previous work identified a brassinosteroid response transcription factor as being enriched in the early developing spur cup. Brassinosteroids are known to be important for cell elongation, suggesting that brassinosteroid-mediated response may be an important regulator of spur elongation and potentially a driver of spur length diversity in Aquilegia. In this study, we investigated the role of brassinosteroids in the development of the Aquilegia coerulea petal spur. METHODS We exogenously applied the biologically active brassinosteroid brassinolide to developing petal spurs to investigate spur growth under high hormone conditions. We used virus-induced gene silencing and gene expression experiments to understand the function of brassinosteroid-related transcription factors in A. coerulea petal spurs. KEY RESULTS We identified a total of three Aquilegia homologues of the BES1/BZR1 protein family and found that these genes are ubiquitously expressed in all floral tissues during development, yet, consistent with the previous RNAseq study, we found that two of these paralogues are enriched in early developing petals. Exogenously applied brassinosteroid increased petal spur length due to increased anisotropic cell elongation as well as cell division. We found that targeting of the AqBEH genes with virus-induced gene silencing resulted in shortened petals, a phenotype caused in part by a loss of cell anisotropy. CONCLUSIONS Collectively, our results support a role for brassinosteroids in anisotropic cell expansion in Aquilegia petal spurs and highlight the brassinosteroid pathway as a potential player in the diversification of petal spur length in Aquilegia.
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Affiliation(s)
- Stephanie J Conway
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
| | - Cristina L Walcher-Chevillet
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
- 10x Genomics Inc., 6230 Stoneridge Mall Road, Pleasanton, CA 94588, USA
| | - Kate Salome Barbour
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
- Abramson Cancer Center, University of Pennsylvania, 3400 Civic Center Blvd., Philadelphia, PA 19104, USA
| | - Elena M Kramer
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
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