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Wei J, Zhang Q, Zhang Y, Yang L, Zeng Z, Zhou Y, Chen B. Advance in the Thermoinhibition of Lettuce ( Lactuca sativa L.) Seed Germination. PLANTS (BASEL, SWITZERLAND) 2024; 13:2051. [PMID: 39124169 PMCID: PMC11314492 DOI: 10.3390/plants13152051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Revised: 07/19/2024] [Accepted: 07/23/2024] [Indexed: 08/12/2024]
Abstract
Thermoinhibition refers to the inability of seeds to germinate when inhibited by high temperatures, but when environmental conditions return to normal, the seeds are able to germinate rapidly again, which is different from thermodormancy. Meanwhile, with global warming, the effect of the thermoinhibition phenomenon on the yield and quality of crops in agricultural production is becoming common. Lettuce, as a horticultural crop sensitive to high temperature, is particularly susceptible to the effects of thermoinhibition, resulting in yield reduction. Therefore, it is crucial to elucidate the intrinsic mechanism of action of thermoinhibition in lettuce seeds. This review mainly outlines several factors affecting thermoinhibition of lettuce seed germination, including endosperm hardening, alteration of endogenous or exogenous phytohormone concentrations, action of photosensitizing pigments, production and inhibition of metabolites, maternal effects, genetic expression, and other physical and chemical factors. Finally, we also discuss the challenges and potential of lettuce seed germination thermoinhibition research. The purpose of this study is to provide theoretical support for future research on lettuce seed germination thermoinhibition, and with the aim of revealing the mechanisms and effects behind lettuce seed thermoinhibition. This will enable the identification of more methods to alleviate seed thermoinhibition or the development of superior heat-tolerant lettuce seeds.
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Affiliation(s)
- Jinpeng Wei
- Guangdong Provincial Key Laboratory for Crop Germplasm Resources Preservation and Utilization, Agro-Biological Gene Research Center, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China
| | - Qi Zhang
- Guangdong Provincial Key Laboratory for Crop Germplasm Resources Preservation and Utilization, Agro-Biological Gene Research Center, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Yixin Zhang
- Guangdong Provincial Key Laboratory for Crop Germplasm Resources Preservation and Utilization, Agro-Biological Gene Research Center, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Le Yang
- Guangdong Provincial Key Laboratory for Crop Germplasm Resources Preservation and Utilization, Agro-Biological Gene Research Center, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China
| | - Zhaoqi Zeng
- College of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou 510550, China
| | - Yuliang Zhou
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China
| | - Bingxian Chen
- Guangdong Provincial Key Laboratory for Crop Germplasm Resources Preservation and Utilization, Agro-Biological Gene Research Center, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
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Liu Y, Peng X, Ma A, Liu W, Liu B, Yun DJ, Xu ZY. Type-B response regulator OsRR22 forms a transcriptional activation complex with OsSLR1 to modulate OsHKT2;1 expression in rice. SCIENCE CHINA. LIFE SCIENCES 2023; 66:2922-2934. [PMID: 37924467 DOI: 10.1007/s11427-023-2464-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 10/10/2023] [Indexed: 11/06/2023]
Abstract
Soil salinity severely limits crop yields and quality. Plants have evolved several strategies to mitigate the adverse effects of salinity, including redistribution and compartmentalization of toxic ions using ion-specific transporters. However, the mechanisms underlying the regulation of these ion transporters have not been fully elucidated. Loss-of-function mutants of OsHKT2;1, which is involved in sodium uptake, exhibit strong salt stress-resistant phenotypes. In this study, OsHKT2;1 was identified as a transcriptional target of the type-B response regulator OsRR22. Loss-of-function osrr22 mutants showed resilience to salt stress, and OsRR22-overexpression plants were sensitive to salt stress. OsRR22 was found to activate the expression of OsHKT2;1 by directly binding to the promoter region of OsHKT2;1 via a consensus cis-element of type-B response regulators. Moreover, rice DELLA protein OsSLR1 directly interacted with OsRR22 and functioned as a transcriptional co-activator. This study has uncovered a novel transcriptional regulatory mechanism by which a type-B response regulator controls sodium transport under salinity stress.
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Affiliation(s)
- Yutong Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Xiaoyuan Peng
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Ao Ma
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Wenxin Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Dae-Jin Yun
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
- Department of Biomedical Science and Engineering, Konkuk University, Seoul, 05029, Republic of Korea
| | - Zheng-Yi Xu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China.
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Rehmani MS, Aziz U, Xian B, Shu K. Seed Dormancy and Longevity: A Mutual Dependence or a Trade-Off? PLANT & CELL PHYSIOLOGY 2022; 63:1029-1037. [PMID: 35594901 DOI: 10.1093/pcp/pcac069] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Seed dormancy is an important agronomic trait in cereals and leguminous crops as low levels of seed dormancy during harvest season, coupled with high humidity, can cause preharvest sprouting. Seed longevity is another critical trait for commercial crop propagation and production, directly influencing seed germination and early seedling establishment. Both traits are precisely regulated by the integration of genetic and environmental cues. Despite the significance of these two traits in crop production, the relationship between them at the molecular level is still elusive, even with contradictory conclusions being reported. Some studies have proposed a positive correlation between seed dormancy and longevity in association with differences in seed coat permeability or seed reserve accumulation, whereas an increasing number of studies have highlighted a negative relationship, largely with respect to phytohormone-dependent pathways. In this review paper, we try to provide some insights into the interactions between regulatory mechanisms of genetic and environmental cues, which result in positive or negative relationships between seed dormancy and longevity. Finally, we conclude that further dissection of the molecular mechanism responsible for this apparently contradictory relationship between them is needed.
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Affiliation(s)
- Muhammad Saad Rehmani
- School of Environment and Ecology, Northwestern Polytechnical University, No. 1, Dongxiang Road, Xi'an 710129, China
| | - Usman Aziz
- School of Environment and Ecology, Northwestern Polytechnical University, No. 1, Dongxiang Road, Xi'an 710129, China
| | - BaoShan Xian
- School of Environment and Ecology, Northwestern Polytechnical University, No. 1, Dongxiang Road, Xi'an 710129, China
| | - Kai Shu
- School of Environment and Ecology, Northwestern Polytechnical University, No. 1, Dongxiang Road, Xi'an 710129, China
- Research and Development Institute of Northwestern Polytechnical University in Shenzhen, No. 45, Gaoxin South 9 Road, Shenzhen 518057, China
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Kim JY, Park YJ, Lee JH, Park CM. SMAX1 Integrates Karrikin and Light Signals into GA-Mediated Hypocotyl Growth during Seedling Establishment. PLANT & CELL PHYSIOLOGY 2022; 63:932-943. [PMID: 35477800 DOI: 10.1093/pcp/pcac055] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 03/13/2022] [Accepted: 04/27/2022] [Indexed: 06/14/2023]
Abstract
Morphogenic adaptation of young seedlings to light environments is a critical developmental process that ensures plant survival and propagation, as they emerge from the soil. Photomorphogenic responses are facilitated by a network of light and growth hormonal signals, such as auxin and gibberellic acid (GA). Karrikins (KARs), a group of butenolide compounds produced from burning plant materials in wildfires, are known to stimulate seed germination in fire-prone plant species. Notably, recent studies support that they also regulate seedling growth, while underlying molecular mechanisms have been unexplored yet. Here, we demonstrate that SUPPRESSOR OF MAX2 1 (SMAX1), a negative regulator of KAR signaling, integrates light and KAR signals into GA-DELLA pathways that regulate hypocotyl growth during seedling establishment. We found that SMAX1 facilitates degradation of DELLA proteins in the hypocotyls. Interestingly, light induces the accumulation of SMAX1 proteins, and SMAX1-mediated degradation of DELLA is elevated in seedling establishment during the dark-to-light transition. Our observations indicate that SMAX1-mediated integration of light and KAR signals into GA pathways elaborately modulates seedling establishment.
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Affiliation(s)
- Jae Young Kim
- Department of Chemistry, Seoul National University, Seoul 08826, South Korea
| | - Young-Joon Park
- Department of Chemistry, Seoul National University, Seoul 08826, South Korea
| | - June-Hee Lee
- Department of Chemistry, Seoul National University, Seoul 08826, South Korea
| | - Chung-Mo Park
- Department of Chemistry, Seoul National University, Seoul 08826, South Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, South Korea
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Long W, Yao X, Wang K, Sheng Y, Lv L. De novo transcriptome assembly of the cotyledon of Camellia oleifera for discovery of genes regulating seed germination. BMC PLANT BIOLOGY 2022; 22:265. [PMID: 35643426 PMCID: PMC9145465 DOI: 10.1186/s12870-022-03651-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Camellia oleifera (C.oleifera) is one of the most important wood oil species in the world. C.oleifera was propagated by nurse seedling grafting. Since the morphology of rootstocks has a significant impact on grafting efficiency and seedling quality, it is necessary to understand the molecular mechanism of morphogenesis for cultivating high-quality and controllable rootstocks. However, the genomic resource for this species is relatively limited, which hinders us from fully understanding the molecular mechanisms of seed germination in C.oleifera. RESULTS In this paper, using transcriptome sequencing, we measured the gene expression in the C.oleifera cotyledon in different stages of development and the global gene expression profiles. Approximately 45.4 gigabases (GB) of paired-end clean reads were assembled into 113,582 unigenes with an average length of 396 bp. Six public protein databases annotate 61.5% (68,217) of unigenes. We identified 11,391 differentially expressed genes (DEGs) throughout different stages of germination. Enrichment analysis revealed that DEGs were mainly involved in hormone signal transduction and starch sucrose metabolism pathways. The gravitropism regulator UNE10, the meristem regulators STM, KNAT1, PLT2, and root-specific transcription factor WOX11 all have higher gene expression levels in the CAM2 stage (seed soaking), which indicates that the cotyledon-regulated program for germination had initiated when the seeds were imbibition. Our data showed differentially reprogrammed to multiple hormone-related genes in cotyledons during C.oleifera seed germination. CONCLUSION Cotyledons play vital roles, both as the main nutrient provider and as one primary instructor for seed germination and seedling growth. Together, our study will significantly enrich the genomic resources of Camellia and help us understand the molecular mechanisms of the development in the seed germination and seedling growth of C.oleifera. It is helpful to culture standard and superior quality rootstock for C.oleifera breeding.
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Affiliation(s)
- Wei Long
- Zhejiang Provincial Key Laboratory of Tree Breeding, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400 Zhejiang China
| | - Xiaohua Yao
- Zhejiang Provincial Key Laboratory of Tree Breeding, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400 Zhejiang China
| | - Kailiang Wang
- Zhejiang Provincial Key Laboratory of Tree Breeding, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400 Zhejiang China
| | - Yu Sheng
- Zhejiang Provincial Key Laboratory of Tree Breeding, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400 Zhejiang China
| | - Leyan Lv
- Department of Hydraulic Engineering, Zhejiang Tongji Vocational College of Science and Technology, Hangzhou, 311231 Zhejiang China
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Iwasaki M, Penfield S, Lopez-Molina L. Parental and Environmental Control of Seed Dormancy in Arabidopsis thaliana. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:355-378. [PMID: 35138879 DOI: 10.1146/annurev-arplant-102820-090750] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Seed dormancy-the absence of seed germination under favorable germination conditions-is a plant trait that evolved to enhance seedling survival by avoiding germination under unsuitable environmental conditions. In Arabidopsis, dormancy levels are influenced by the seed coat composition, while the endosperm is essential to repress seed germination of dormant seeds upon their imbibition. Recent research has shown that the mother plant modulates its progeny seed dormancy in response to seasonal temperature changes by changing specific aspects of seed coat and endosperm development. This process involves genomic imprinting by means of epigenetic marks deposited in the seed progeny and regulators previously known to regulate flowering time. This review discusses and summarizes these discoveries and provides an update on our present understanding of the role of DOG1 and abscisic acid, two key contributors to dormancy.
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Affiliation(s)
- Mayumi Iwasaki
- Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland;
| | - Steven Penfield
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Luis Lopez-Molina
- Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland;
- Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
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Wang Z, Cao H, Zhang C, Chen F, Liu Y. The SNF5-type protein BUSHY regulates seed germination via the gibberellin pathway and is dependent on HUB1 in Arabidopsis. PLANTA 2022; 255:34. [PMID: 35006338 DOI: 10.1007/s00425-021-03767-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 10/21/2021] [Indexed: 06/14/2023]
Abstract
The SNF5-type protein BUSHY plays a role in the regulation of seed germination via the gibberellin pathway dependent on HUB1 in Arabidopsis thaliana. SWITCH/SUCROSE NONFERMENTING (SWI/SNF) complexes play diverse roles in plant development. Some components have roles in embryo development and seed maturation, however, whether the SNF5-type protein BUSHY (BSH), one of the components, plays a role in Arabidopsis seed related traits is presently unclear. In our study, we show that a loss-of-function mutation in BSH causes increased seed germination in Arabidopsis. BSH transcription was induced by the gibberellin (GA) inhibitor paclobutrazol (PAC) in the seed, and BSH regulates the expression of GA pathway genes, such as Gibberellin 3-Oxidase 1 (GA3OX1), Gibberellic Acid-Stimulated Arabidopsis 4 (GASA4), and GASA6 during seed germination. A genetic analysis showed that seed germination was distinctly improved in the bshga3ox1ga3ox2 triple mutant, indicating that BSH acts partially downstream of GA3OX1 and GA3OX2. Moreover, the regulation of seed germination by BSH in response to PAC is dependent on HUB1. These results provide new insights and clues to understand the mechanisms of phytohormones in the regulation of seed germination.
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Affiliation(s)
- Zhi Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China
| | - Hong Cao
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Cun Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fengying Chen
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yongxiu Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China.
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Patel R, Mehta K, Goswami D, Saraf M. An Anecdote on Prospective Protein Targets for Developing Novel Plant Growth Regulators. Mol Biotechnol 2021; 64:109-129. [PMID: 34561838 DOI: 10.1007/s12033-021-00404-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/15/2021] [Indexed: 11/28/2022]
Abstract
Phytohormones are the main regulatory molecules of core signalling networks associated with plant life cycle regulation. Manipulation of hormone signalling cascade enables the control over physiological traits of plant, which has major applications in field of agriculture and food sustainability. Hence, stable analogues of these hormones are long sought after and many of them are currently known, but the quest for more effective, stable and economically viable analogues is still going on. This search has been further strengthened by the identification of the components of signalling cascade such as receptors, downstream cascade members and transcription factors. Furthermore, many proteins of phytohormone cascades are available in crystallized forms. Such crystallized structures can provide the basis for identification of novel interacting compounds using in silico approach. Plenty of computational tools and bioinformatics software are now available that can aid in this process. Here, the metadata of all the major phytohormone signalling cascades are presented along with discussion on major protein-ligand interactions and protein components that may act as a potential target for manipulation of phytohormone signalling cascade. Furthermore, structural aspects of phytohormones and their known analogues are also discussed that can provide the basis for the synthesis of novel analogues.
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Affiliation(s)
- Rohit Patel
- Department of Microbiology & Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Krina Mehta
- Department of Microbiology & Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Dweipayan Goswami
- Department of Microbiology & Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India.
| | - Meenu Saraf
- Department of Microbiology & Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India.
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Sarwar R, Jiang T, Ding P, Gao Y, Tan X, Zhu K. Genome-wide analysis and functional characterization of the DELLA gene family associated with stress tolerance in B. napus. BMC PLANT BIOLOGY 2021; 21:286. [PMID: 34157966 PMCID: PMC8220683 DOI: 10.1186/s12870-021-03054-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/13/2021] [Indexed: 05/07/2023]
Abstract
BACKGROUND Brassica napus is an essential crop for oil and livestock feed. Eventually, this crop's economic interest is at the most risk due to anthropogenic climate change. DELLA proteins constitute a significant repressor of plant growth to facilitate survival under constant stress conditions. DELLA proteins lack DNA binding domain but can interact with various transcription factors or transcription regulators of different hormonal families. Significant progress has been made on Arabidopsis and cereal plants. However, no comprehensive study regarding DELLA proteins has been delineated in rapeseed. RESULTS In our study, we have identified 10 BnaDELLA genes. All of the BnaDELLA genes are closely related to five AtDELLA genes, suggesting a relative function and structure. Gene duplication and synteny relationship among Brassica. napus, Arabidopsis. thaliana, Brassica rapa, Brassica oleracea, and Brassica nigra genomes were also predicted to provide valuable insights into the BnaDELLA gene family evolutionary characteristics. Chromosomal mapping revealed the uneven distribution of BnaDELLA genes on eight chromosomes, and site-specific selection assessment proposes BnaDELLA genes purifying selection. The motifs composition in all BnaDELLA genes is inconsistent; however, every BnaDELLA gene contains 12 highly conserved motifs, encoding DELLA and GRAS domains. The two known miRNAs (bna-miR6029 and bna-miR603) targets BnaC07RGA and BnaA09GAI, were also predicted. Furthermore, quantitative real-time PCR (qRT-PCR) analysis has exhibited the BnaDELLA genes diverse expression patterns in the root, mature-silique, leaf, flower, flower-bud, stem, shoot-apex, and seed. Additionally, cis-acting element prediction shows that all BnaDELLA genes contain light, stress, and hormone-responsive elements on their promoters. The gene ontology (GO) enrichment report indicated that the BnaDELLA gene family might regulate stress responses. Combine with transcriptomic data used in this study, we detected the distinct expression patterns of BnaDELLA genes under biotic and abiotic stresses. CONCLUSION In this study, we investigate evolution feature, genomic structure, miRNAs targets, and expression pattern of the BnaDELLA gene family in B. napus, which enrich our understanding of BnaDELLA genes in B. napus and suggests modulating individual BnaDELLA expression is a promising way to intensify rapeseed stress tolerance and harvest index.
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Affiliation(s)
- Rehman Sarwar
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Ting Jiang
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Peng Ding
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Yue Gao
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Xiaoli Tan
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Keming Zhu
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China.
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Zhao B, Liu Q, Wang B, Yuan F. Roles of Phytohormones and Their Signaling Pathways in Leaf Development and Stress Responses. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:3566-3584. [PMID: 33739096 DOI: 10.1021/acs.jafc.0c07908] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Phytohormones participate in various processes over the course of a plant's lifecycle. In addition to the five classical phytohormones (auxins, cytokinins, gibberellins, abscisic acid, and ethylene), phytohormones such as brassinosteroids, jasmonic acid, salicylic acid, strigolactones, and peptides also play important roles in plant growth and stress responses. Given the highly interconnected nature of phytohormones during plant development and stress responses, it is challenging to study the biological function of a single phytohormone in isolation. In the current Review, we describe the combined functions and signaling cascades (especially the shared points and pathways) of various phytohormones in leaf development, in particular, during leaf primordium initiation and the establishment of leaf polarity and leaf morphology as well as leaf development under various stress conditions. We propose a model incorporating the roles of multiple phytohormones in leaf development and stress responses to illustrate the underlying combinatorial signaling pathways. This model provides a reference for breeding stress-resistant crops.
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Affiliation(s)
- Boqing Zhao
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, Shandong 250014, P. R. China
| | - Qingyun Liu
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, Shandong 250014, P. R. China
| | - Baoshan Wang
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, Shandong 250014, P. R. China
| | - Fang Yuan
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, Shandong 250014, P. R. China
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Rolly NK, Mun BG, Yun BW. Insights into the Transcriptional Regulation of Branching Hormonal Signaling Pathways Genes under Drought Stress in Arabidopsis. Genes (Basel) 2021; 12:genes12020298. [PMID: 33672598 PMCID: PMC7924062 DOI: 10.3390/genes12020298] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 02/07/2023] Open
Abstract
A large number of hormonal biosynthetic or signaling pathways genes controlling shoot branching are widely known for their roles in regulating plant growth and development, operating in synergetic or antagonistic manner. However, their involvement in abiotic stress response mechanism remains unexplored. Initially, we performed an in silico analysis to identify potential transcription binding sites for the basic leucine zipper 62 transcription factor (bZIP62 TF) in the target branching related genes. The results revealed the presence of cis-regulatory elements specific to two bZIP TFs, AtbZIP18 and AtbZIP69, rather than AtbZIP62. Interestingly, these bZIP TFs were previously proposed to be negatively regulated by the AtbZIP62 TF under salinity in Arabidopsis. Therefore, we investigated the transcriptional regulation of more axillary branching (MAX, strigolactone), PIN-FORMED (PINs, auxin carriers), gibberellic acid (GA)-biosynthetic genes as well as isopentenyltransferase (IPT, cytokinin biosynthesis pathway) genes in response to drought stress in Arabidopsis Col-0 wild type. In addition, in the perspective of exploring the transcriptional interplay of the selected genes with the AtbZIP62, we measured their expression by qPCR in the atbzip62 (lacking the AtbZIP62 gene) background under the same conditions. Our findings revealed that the expression of AtMAX2, AtMAX3, and AtMAX4 was differentially regulated by drought stress between the atbzip62 and Col-0 wild type, but not AtMAX1. Similarly, the transcripts accumulation of AtPIN3 and AtPIN7 (known as auxin efflux carriers), and that of the AtAXR1 showed similar regulation patterns in atbzip62. However, AtPIN1 expression was downregulated in Col-0, but no change was observed in atbzip62. Furthermore, AtIPT5 and AtIPT7 exhibited a differential transcripts accumulation pattern in atbzip62 and Col-0 wild type (WT). In the same way, the expression of the GA biosynthetic genes AtGA2ox1 and AtGA20ox2, and that of AtRGA1 were differentially regulated in atbzip62 compared to the Col-0. Meanwhile, AtGA2ox1 showed a similar expression pattern with Col-0. Therefore, all results suggest PIN, MAX, IPT, and GA-biosynthetic genes, which are differentially regulated by AtbZIP62 transcription factor, as emerging candidate genes that could be involved in drought stress response mechanism in Arabidopsis.
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Affiliation(s)
- Nkulu Kabange Rolly
- Laboratory of Plant Functional Genomics, School of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (N.K.R.); (B.-G.M.)
- Department of Southern Area Crop Science, National Institute of Crop Science, RDA, Miryang 50424, Korea
- National Laboratory of Seed Testing, National Seed Service, SENASEM, Ministry of Agriculture, Kinshasa 904KIN1, Democratic Republic of the Congo
| | - Bong-Gyu Mun
- Laboratory of Plant Functional Genomics, School of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (N.K.R.); (B.-G.M.)
| | - Byung-Wook Yun
- Laboratory of Plant Functional Genomics, School of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (N.K.R.); (B.-G.M.)
- Correspondence: ; Tel.: +82-53-950-5712
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Gibberellin Signaling Repressor LlDELLA1 Controls the Flower and Pod Development of Yellow Lupine ( Lupinus luteus L.). Int J Mol Sci 2020; 21:ijms21051815. [PMID: 32155757 PMCID: PMC7084671 DOI: 10.3390/ijms21051815] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 02/28/2020] [Accepted: 03/04/2020] [Indexed: 01/02/2023] Open
Abstract
Precise control of generative organ development is of great importance for the productivity of crop plants, including legumes. Gibberellins (GAs) play a key role in the regulation of flowering, and fruit setting and development. The major repressors of GA signaling are DELLA proteins. In this paper, the full-length cDNA of LlDELLA1 gene in yellow lupine (Lupinus luteus L.) was identified. Nuclear-located LlDELLA1 was clustered in a second phylogenetic group. Further analyses revealed the presence of all conserved motifs and domains required for the GA-dependent interaction with Gibberellin Insensitive Dwarf1 (GID1) receptor, and involved in the repression function of LlDELLA1. Studies on expression profiles have shown that fluctuating LlDELLA1 transcript level favors proper flower and pod development. Accumulation of LlDELLA1 mRNA slightly decreases from the flower bud stage to anther opening (dehiscence), while there is rapid increase during pollination, fertilization, as well as pod setting and early development. LlDELLA1 expression is downregulated during late pod development. The linkage of LlDELLA1 activity with cellular and tissue localization of gibberellic acid (GA3) offers a broader insight into the functioning of the GA pathway, dependent on the organ and developmental stage. Our analyses provide information that may be valuable in improving the agronomic properties of yellow lupine.
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13
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Chahtane H, Nogueira Füller T, Allard PM, Marcourt L, Ferreira Queiroz E, Shanmugabalaji V, Falquet J, Wolfender JL, Lopez-Molina L. The plant pathogen Pseudomonas aeruginosa triggers a DELLA-dependent seed germination arrest in Arabidopsis. eLife 2018; 7:37082. [PMID: 30149837 PMCID: PMC6128175 DOI: 10.7554/elife.37082] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/30/2018] [Indexed: 11/23/2022] Open
Abstract
To anticipate potential seedling damage, plants block seed germination under unfavorable conditions. Previous studies investigated how seed germination is controlled in response to abiotic stresses through gibberellic and abscisic acid signaling. However, little is known about whether seeds respond to rhizosphere bacterial pathogens. We found that Arabidopsis seed germination is blocked in the vicinity of the plant pathogen Pseudomonas aeruginosa. We identified L-2-amino-4-methoxy-trans-3-butenoic acid (AMB), released by P. aeruginosa, as a biotic compound triggering germination arrest. We provide genetic evidence that in AMB-treated seeds DELLA factors promote the accumulation of the germination repressor ABI5 in a GA-independent manner. AMB production is controlled by the quorum sensing system IQS. In vitro experiments show that the AMB-dependent germination arrest protects seedlings from damage induced by AMB. We discuss the possibility that this could serve as a protective response to avoid severe seedling damage induced by AMB and exposure to a pathogen. The plant embryo within a seed is well protected. While it cannot stay within the seed forever, the embryo can often wait for the right conditions before it develops into a seedling and continues its life cycle. Indeed, plants have evolved several ways to time this process – which is known as germination – to maximize the chances that their seedlings will survive. For example, if the environment is too hot or too dark, the seed will make a hormone that stops it from germinating. In addition to environmental factors like light and temperature, a seed in the real word is continuously confronted with soil microbes that may harm or benefit the plant. However, few researchers have asked whether seeds control their germination in response to other living organisms. The bacterium Pseudomonas aeruginosa lives in a wide spectrum of environments, including the soil, and can cause diseases in both and plants and animals. Chahtane et al. now report that seeds of the model plant Arabidopsis thaliana do indeed repress their germination when this microbe is present. Specifically, the seeds respond to a molecule released from the bacteria called L-2-amino-4-methoxy-trans-3-butenoic acid, or AMB for short. Like the bacteria, AMB is harmful to young seedlings, but Chahtane et al. showed that the embryo within the seed is protected from its toxic effects. Further experiments revealed that the seed's response to the bacterial molecule requires many of the same signaling components that repress germination when environmental conditions are unfavorable. However, Chahtane et al. note that AMB activates these components in an unusual way that they still do not understand. The genes that control the production of AMB are known to also control how bacterial populations behave as they accumulate to high densities. It is therefore likely that Pseudomonas aeruginosa would make AMB if it reached a high density in the soil. This raises the possibility that plants have specifically evolved to stop germination if there are enough microbes nearby to pose a risk of disease. This hypothesis, however, is only one of several possible explanations and remains speculative at this stage; further work is now needed to evaluate it. Nevertheless, identifying how AMB interferes with the signaling components that control germination and plant growth may guide the design of new herbicides that could, for example, control weeds in the farming industry.
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Affiliation(s)
- Hicham Chahtane
- Department of Plant Biology, University of Geneva, Geneva, Switzerland.,Institute for Genetics and Genomics in Geneva, University of Geneva, Geneva, Switzerland
| | - Thanise Nogueira Füller
- Department of Plant Biology, University of Geneva, Geneva, Switzerland.,Institute for Genetics and Genomics in Geneva, University of Geneva, Geneva, Switzerland
| | - Pierre-Marie Allard
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Laurence Marcourt
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Emerson Ferreira Queiroz
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Venkatasalam Shanmugabalaji
- Department of Plant Biology, University of Geneva, Geneva, Switzerland.,Institute for Genetics and Genomics in Geneva, University of Geneva, Geneva, Switzerland
| | | | - Jean-Luc Wolfender
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Luis Lopez-Molina
- Department of Plant Biology, University of Geneva, Geneva, Switzerland.,Institute for Genetics and Genomics in Geneva, University of Geneva, Geneva, Switzerland
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14
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Munz E, Rolletschek H, Oeltze-Jafra S, Fuchs J, Guendel A, Neuberger T, Ortleb S, Jakob PM, Borisjuk L. A functional imaging study of germinating oilseed rape seed. THE NEW PHYTOLOGIST 2017; 216:1181-1190. [PMID: 28800167 DOI: 10.1111/nph.14736] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/04/2017] [Indexed: 05/24/2023]
Abstract
Germination, the process whereby a dry, quiescent seed springs to life, has been a focus of plant biologist for many years, yet the early events following water uptake, during which metabolism of the embryo is restarted, remain enigmatic. Here, the nature of the cues required for this restarting in oilseed rape (Brassica napus) seed has been investigated. A holistic in vivo approach was designed to display the link between the entry and allocation of water, metabolic events and structural changes occurring during germination. For this, we combined functional magnetic resonance imaging with Fourier transform infrared microscopy, fluorescence-based respiration mapping, computer-aided seed modeling and biochemical tools. We uncovered an endospermal lipid gap, which channels water to the radicle tip, from whence it is distributed via embryonic vasculature toward cotyledon tissues. The resumption of respiration is initiated first in the endosperm, only later spreading to the embryo. Sugar metabolism and lipid utilization are linked to the spatiotemporal sequence of tissue rehydration. Together, this imaging study provides insights into the spatial aspects of key events in oilseed rape seeds leading to germination. It demonstrates how seed architecture predetermines the pattern of water intake, which sets the stage for the orchestrated restart of life.
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Affiliation(s)
- Eberhard Munz
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Gatersleben, Germany
- Institute of Experimental Physics 5, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Hardy Rolletschek
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Gatersleben, Germany
| | - Steffen Oeltze-Jafra
- Innovation Center Computer Assisted Surgery, University of Leipzig, Semmelweisstraße 14, 04103, Leipzig, Germany
| | - Johannes Fuchs
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Gatersleben, Germany
| | - André Guendel
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Gatersleben, Germany
| | - Thomas Neuberger
- Huck Institutes of the Life Sciences, 113 Chandlee Lab, University Park, PA, 16802, USA
| | - Stefan Ortleb
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Gatersleben, Germany
| | - Peter M Jakob
- Institute of Experimental Physics 5, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ljudmilla Borisjuk
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Gatersleben, Germany
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15
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Penfield S. Revealing the water uptake pathways of seeds with high resolution magnetic resonance imaging. THE NEW PHYTOLOGIST 2017; 216:965-966. [PMID: 29110309 DOI: 10.1111/nph.14819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Affiliation(s)
- Steven Penfield
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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16
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Salem MA, Li Y, Wiszniewski A, Giavalisco P. Regulatory-associated protein of TOR (RAPTOR) alters the hormonal and metabolic composition of Arabidopsis seeds, controlling seed morphology, viability and germination potential. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:525-545. [PMID: 28845535 DOI: 10.1111/tpj.13667] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/04/2017] [Accepted: 05/18/2017] [Indexed: 06/07/2023]
Abstract
Target of Rapamycin (TOR) is a positive regulator of growth and development in all eukaryotes, which positively regulates anabolic processes like protein synthesis, while repressing catabolic processes, including autophagy. To better understand TOR function we decided to analyze its role in seed development and germination. We therefore performed a detailed phenotypic analysis using mutants of the REGULATORY-ASSOCIATED PROTEIN OF TOR 1B (RAPTOR1B), a conserved TOR interactor, acting as a scaffold protein, which recruits substrates for the TOR kinase. Our results show that raptor1b plants produced seeds that were delayed in germination and less resistant to stresses, leading to decreased viability. These physiological phenotypes were accompanied by morphological changes including decreased seed-coat pigmentation and reduced production of seed-coat mucilage. A detailed molecular analysis revealed that many of these morphological changes were associated with significant changes of the metabolic content of raptor1b seeds, including elevated levels of free amino acids, as well as reduced levels of protective secondary metabolites and storage proteins. Most of these observed changes were accompanied by significantly altered phytohormone levels in the raptor1b seeds, with increases in abscisic acid, auxin and jasmonic acid, which are known to inhibit germination. Delayed germination and seedling growth, observed in the raptor1b seeds, could be partially restored by the exogenous supply of gibberellic acid, indicating that TOR is at the center of a regulatory hub controlling seed metabolism, maturation and germination.
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Affiliation(s)
- Mohamed A Salem
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
- Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Kasr El-Aini Street, Cairo, 11562, Egypt
| | - Yan Li
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Andrew Wiszniewski
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Patrick Giavalisco
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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17
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Nelson SK, Steber CM. Transcriptional mechanisms associated with seed dormancy and dormancy loss in the gibberellin-insensitive sly1-2 mutant of Arabidopsis thaliana. PLoS One 2017. [PMID: 28628628 PMCID: PMC5476249 DOI: 10.1371/journal.pone.0179143] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
While widespread transcriptome changes were previously observed with seed dormancy loss, this study specifically characterized transcriptional changes associated with the increased seed dormancy and dormancy loss of the gibberellin (GA) hormone-insensitive sleepy1-2 (sly1-2) mutant. The SLY1 gene encodes the F-box subunit of an SCF E3 ubiquitin ligase needed for GA-triggered proteolysis of DELLA repressors of seed germination. DELLA overaccumulation in sly1-2 seeds leads to increased dormancy that can be rescued without DELLA protein destruction either by overexpression of the GA receptor, GA-INSENSITIVE DWARF1b (GID1b-OE) (74% germination) or by extended dry after-ripening (11 months, 51% germination). After-ripening of sly1 resulted in different transcriptional changes in early versus late Phase II of germination that were consistent with the processes known to occur. Approximately half of the transcriptome changes with after-ripening appear to depend on SLY1-triggered DELLA proteolysis. Given that many of these SLY1/GA-dependent changes are genes involved in protein translation, it appears that GA signaling increases germination capacity in part by activating translation. While sly1-2 after-ripening was associated with transcript-level changes in 4594 genes over two imbibition timepoints, rescue of sly1-2 germination by GID1b-OE was associated with changes in only 23 genes. Thus, a big change in sly1-2 germination phenotype can occur with relatively little change in the global pattern of gene expression during the process of germination. Most GID1b-OE-responsive transcripts showed similar changes with after-ripening in early Phase II of imbibition, but opposite changes with after-ripening by late Phase II. This suggests that GID1b-OE stimulates germination early in imbibition, but may later trigger negative feedback regulation.
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Affiliation(s)
- Sven K. Nelson
- Molecular Plant Sciences Program, Washington State University, Pullman, Washington, United States of America
| | - Camille M. Steber
- Molecular Plant Sciences Program, Washington State University, Pullman, Washington, United States of America
- USDA-ARS, Wheat Health, Genetics, and Quality Research Unit, Pullman, Washington, United States of America
- Department of Crop and Soil Science, Washington State University, Pullman, Washington, United States of America
- * E-mail:
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18
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Plum Fruit Development Occurs via Gibberellin-Sensitive and -Insensitive DELLA Repressors. PLoS One 2017; 12:e0169440. [PMID: 28076366 PMCID: PMC5226729 DOI: 10.1371/journal.pone.0169440] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 12/17/2016] [Indexed: 01/16/2023] Open
Abstract
Fruit growth depends on highly coordinated hormonal activities. The phytohormone gibberellin (GA) promotes growth by triggering degradation of the growth-repressing DELLA proteins; however, the extent to which such proteins contribute to GA-mediated fruit development remains to be clarified. Three new plum genes encoding DELLA proteins, PslGAI, PslRGL and PslRGA were isolated and functionally characterized. Analysis of expression profile during fruit development suggested that PslDELLA are transcriptionally regulated during flower and fruit ontogeny with potential positive regulation by GA and ethylene, depending on organ and developmental stage. PslGAI and PslRGL deduced proteins contain all domains present in typical DELLA proteins. However, PslRGA exhibited a degenerated DELLA domain and subsequently lacks in GID1–DELLA interaction property. PslDELLA–overexpression in WT Arabidopsis caused dramatic disruption in overall growth including root length, stem elongation, plant architecture, flower structure, fertility, and considerable retardation in development due to dramatic distortion in GA-metabolic pathway. GA treatment enhanced PslGAI/PslRGL interaction with PslGID1 receptors, causing protein destabilization and relief of growth-restraining effect. By contrast, PslRGA protein was not degraded by GA due to its inability to interact with PslGID1. Relative to other PslDELLA–mutants, PslRGA–plants displayed stronger constitutive repressive growth that was irreversible by GA application. The present results describe additional complexities in GA-signalling during plum fruit development, which may be particularly important to optimize successful reproductive growth.
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19
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Wang Z, Chen F, Li X, Cao H, Ding M, Zhang C, Zuo J, Xu C, Xu J, Deng X, Xiang Y, Soppe WJJ, Liu Y. Arabidopsis seed germination speed is controlled by SNL histone deacetylase-binding factor-mediated regulation of AUX1. Nat Commun 2016; 7:13412. [PMID: 27834370 PMCID: PMC5114640 DOI: 10.1038/ncomms13412] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 09/30/2016] [Indexed: 12/22/2022] Open
Abstract
Histone acetylation is known to affect the speed of seed germination, but the molecular regulatory basis of this remains ambiguous. Here we report that loss of function of two histone deacetylase-binding factors, SWI-INDEPENDENT3 (SIN3)-LIKE1 (SNL1) and SNL2, results in accelerated radicle protrusion and growth during seed germination. AUXIN RESISTANT 1 (AUX1) is identified as a key factor in this process, enhancing germination speed downstream of SNL1 and SNL2. AUX1 expression and histone H3 acetylation at lysines 9 and 18 is regulated by SNL1 and SNL2. The D-type cyclins encoding genes CYCD1;1 and CYCD4;1 display increased expression in AUX1 over-expression lines and the snl1snl2 double mutant. Accordingly, knockout of CYCD4;1 reduces seed germination speed of AUX1 over-expression lines and snl1snl2 suggesting the importance of cell cycling for radicle protrusion during seed germination. Together, our work identifies AUX1 as a link between histone acetylation mediated by SNL1 and SNL2, and radicle growth promoted by CYCD1;1 and CYCD4;1 during seed germination. Histone acetylation influences the speed of seed germination. Here, Wang et al. show that loss of the SNL1/SNL2 histone deacetylase binding factors accelerates seed germination and provide evidence that they act by regulating the expression of AUX1 which in turn influences cell division.
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Affiliation(s)
- Zhi Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Fengying Chen
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaoying Li
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Cao
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Meng Ding
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Cun Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinghong Zuo
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaonan Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jimei Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Deng
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yong Xiang
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Wim J J Soppe
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.,Institute of Molecular Physiology and Biotechnology of Plants (IMBIO), University of Bonn, 53115 Bonn, Germany
| | - Yongxiu Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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20
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Kim SI, Kwak JS, Song JT, Seo HS. The E3 SUMO ligase AtSIZ1 functions in seed germination in Arabidopsis. PHYSIOLOGIA PLANTARUM 2016; 158:256-271. [PMID: 27130140 DOI: 10.1111/ppl.12462] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 02/16/2016] [Accepted: 03/22/2016] [Indexed: 05/20/2023]
Abstract
Seed germination is an important stage in the lifecycle of a plant because it determines subsequent vegetative growth and reproduction. Here, we show that the E3 SUMO ligase AtSIZ1 regulates seed dormancy and germination. The germination rates of the siz1 mutants were less than 50%, even after a short period of ripening. However, their germination rates increased to wild-type levels after cold stratification or long periods of ripening. In addition, exogenous gibberellin (GA) application improved the germination rates of the siz1 mutants to the wild-type level. In transgenic plants, suppression of AtSIZ1 caused rapid post-translational decay of SLEEPY1 (SLY1), a positive regulator of GA signaling, during germination, and inducible AtSIZ1 overexpression led to increased SLY1 levels. In addition, overexpressing wild-type SLY1 in transgenic sly1 mutants increased their germination ratios to wild-type levels, whereas the germination ratio of transgenic sly1 mutants overexpressing mSLY1 was similar to that of sly1. The germination ratios of siz1 mutant seeds in immature developing siliques were much lower than those of the wild-type. Moreover, SLY1 and DELAY OF GERMINATION 1 (DOG1) transcript levels were reduced in the siz1 mutants, whereas the transcript levels of DELLA and ABSCISIC ACID INSENSITIVE 3 (ABI3) were higher than those of the wild-type. Taken together, these results indicate that the reduced germination of the siz1 mutants results from impaired GA signaling due to low SLY1 levels and activity, as well as hyperdormancy due to high levels of expression of dormancy-related genes including DOG1.
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Affiliation(s)
- Sung-Il Kim
- Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul, 151-921, Korea
| | - Jun Soo Kwak
- Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul, 151-921, Korea
| | - Jong Tae Song
- School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Korea
| | - Hak Soo Seo
- Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul, 151-921, Korea.
- Bio-MAX Institute, Seoul National University, Seoul, 151-818, Korea.
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21
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Dave A, Vaistij FE, Gilday AD, Penfield SD, Graham IA. Regulation of Arabidopsis thaliana seed dormancy and germination by 12-oxo-phytodienoic acid. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2277-84. [PMID: 26873978 PMCID: PMC4809285 DOI: 10.1093/jxb/erw028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We previously demonstrated that the oxylipin 12-oxo-phytodienoic acid (OPDA) acts along with abscisic acid to regulate seed germination in Arabidopsis thaliana, but the mechanistic details of this synergistic interaction remain to be elucidated. Here, we show that OPDA acts through the germination inhibition effects of abscisic acid, the abscisic acid-sensing ABI5 protein, and the gibberellin-sensing RGL2 DELLA protein. We further demonstrate that OPDA also acts through another dormancy-promoting factor, MOTHER-OF-FT-AND-TFL1 (MFT). Both abscisic acid and MFT positively feed back into the OPDA pathway by promoting its accumulation. These results confirm the central role of OPDA in regulating seed dormancy and germination in A. thaliana and underline the complexity of interactions between OPDA and other dormancy-promoting factors such as abscisic acid, RGL2, and MFT.
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Affiliation(s)
- Anuja Dave
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Fabián E Vaistij
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Alison D Gilday
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Steven D Penfield
- Department of Crop Genetics, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Ian A Graham
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
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22
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Marín-de la Rosa N, Pfeiffer A, Hill K, Locascio A, Bhalerao RP, Miskolczi P, Grønlund AL, Wanchoo-Kohli A, Thomas SG, Bennett MJ, Lohmann JU, Blázquez MA, Alabadí D. Genome Wide Binding Site Analysis Reveals Transcriptional Coactivation of Cytokinin-Responsive Genes by DELLA Proteins. PLoS Genet 2015; 11:e1005337. [PMID: 26134422 PMCID: PMC4489807 DOI: 10.1371/journal.pgen.1005337] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 06/05/2015] [Indexed: 11/19/2022] Open
Abstract
The ability of plants to provide a plastic response to environmental cues relies on the connectivity between signaling pathways. DELLA proteins act as hubs that relay environmental information to the multiple transcriptional circuits that control growth and development through physical interaction with transcription factors from different families. We have analyzed the presence of one DELLA protein at the Arabidopsis genome by chromatin immunoprecipitation coupled to large-scale sequencing and we find that it binds at the promoters of multiple genes. Enrichment analysis shows a strong preference for cis elements recognized by specific transcription factor families. In particular, we demonstrate that DELLA proteins are recruited by type-B ARABIDOPSIS RESPONSE REGULATORS (ARR) to the promoters of cytokinin-regulated genes, where they act as transcriptional co-activators. The biological relevance of this mechanism is underpinned by the necessity of simultaneous presence of DELLAs and ARRs to restrict root meristem growth and to promote photomorphogenesis. Plants respond to environmental cues by modulating transcriptional circuits. One mechanism for such modulation involves DELLA proteins. They are promiscuous interactors of transcription factors and, in most cases, this interaction impairs the recognition of the DNA target sequences. Here we show that DELLA proteins are also recruited to multiple locations of the genome where they act as transcriptional coactivators, and we demonstrate how physical interaction with type-B ARRs is relevant for the regulation of meristem maintenance and photomorphogenesis.
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Affiliation(s)
- Nora Marín-de la Rosa
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), Valencia, Spain
| | - Anne Pfeiffer
- Department of Stem Cell Biology, Centre for Organismal Studies Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Kristine Hill
- School of Biosciences and Centre for Plant Integrative Biology, University of Nottingham, Nottingham, United Kingdom
| | - Antonella Locascio
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), Valencia, Spain
| | - Rishikesh P. Bhalerao
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Sveriges Lantbruksuniversitet, Umeå, Sweden
- College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Pal Miskolczi
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Sveriges Lantbruksuniversitet, Umeå, Sweden
| | | | | | | | - Malcolm J. Bennett
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Sveriges Lantbruksuniversitet, Umeå, Sweden
- College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Jan U. Lohmann
- Department of Stem Cell Biology, Centre for Organismal Studies Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Miguel A. Blázquez
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), Valencia, Spain
- * E-mail:
| | - David Alabadí
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), Valencia, Spain
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23
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Lee HG, Lee K, Seo PJ. The Arabidopsis MYB96 transcription factor plays a role in seed dormancy. PLANT MOLECULAR BIOLOGY 2015; 87:371-81. [PMID: 25616734 DOI: 10.1007/s11103-015-0283-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 01/07/2015] [Indexed: 05/18/2023]
Abstract
Seed dormancy facilitates to endure environmental disadvantages by confining embryonic growth until the seeds encounter favorable environmental conditions for germination. Abscisic acid (ABA) and gibberellic acid (GA) play a pivotal role in the determination of the seed dormancy state. ABA establishes seed dormancy, while GA triggers seed germination. Here, we demonstrate that MYB96 contributes to the fine-tuning of seed dormancy regulation through the coordination of ABA and GA metabolism. The MYB96-deficient myb96-1 seeds germinated earlier than wild-type seeds, whereas delayed germination was observed in the activation-tagging myb96-1D seeds. The differences in germination rate disappeared after stratification or after-ripening. The MYB96 transcription factor positively regulates ABA biosynthesis genes 9-CIS-EPOXYCAROTENOID DIOXYGENASE 2 (NCED2), NCED5, NCED6, and NCED9, and also affects GA biosynthetic genes GA3ox1 and GA20ox1. Notably, MYB96 directly binds to the promoters of NCED2 and NCED6, primarily modulating ABA biosynthesis, which subsequently influences GA metabolism. In agreement with this, hyperdormancy of myb96-1D seeds was recovered by an ABA biosynthesis inhibitor fluridone, while hypodormancy of myb96-1 seeds was suppressed by a GA biosynthesis inhibitor paclobutrazol (PAC). Taken together, the metabolic balance of ABA and GA underlies MYB96 control of primary seed dormancy.
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Affiliation(s)
- Hong Gil Lee
- Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju, 561-756, Republic of Korea
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24
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Boccaccini A, Santopolo S, Capauto D, Lorrai R, Minutello E, Belcram K, Palauqui JC, Costantino P, Vittorioso P. Independent and interactive effects of DOF affecting germination 1 (DAG1) and the Della proteins GA insensitive (GAI) and Repressor of ga1-3 (RGA) in embryo development and seed germination. BMC PLANT BIOLOGY 2014; 14:200. [PMID: 25064446 PMCID: PMC4222566 DOI: 10.1186/s12870-014-0200-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/16/2014] [Indexed: 05/22/2023]
Abstract
BACKGROUND The transcription factor DOF AFFECTING GERMINATION1 (DAG1) is a repressor of seed germination acting downstream of the master repressor PHYTOCROME INTERACTING FACTOR3-LIKE 5 (PIL5). Among others, PIL5 induces the expression of the genes encoding the two DELLA proteins GA INSENSITIVE 1 (GAI) and REPRESSOR OF ga1-3 (RGA). RESULTS Based on the properties of gai-t6 and rga28 mutant seeds, we show here that the absence of RGA severely increases dormancy, while lack of GAI only partially compensates RGA inactivation. In addition, the germination properties of the dag1rga28 double mutant are different from those of the dag1 and rga28 single mutants, suggesting that RGA and DAG1 act in independent branches of the PIL5-controlled germination pathway. Surprisingly, the dag1gai-t6 double mutant proved embryo-lethal, suggesting an unexpected involvement of (a possible complex between) DAG1 and GAI in embryo development. CONCLUSIONS Rather than overlapping functions as previously suggested, we show that RGA and GAI play distinct roles in seed germination, and that GAI interacts with DAG1 in embryo development.
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Affiliation(s)
- Alessandra Boccaccini
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Silvia Santopolo
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Davide Capauto
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Riccardo Lorrai
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Emanuele Minutello
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Katia Belcram
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Bâtiment 2, INRA, Centre de Versailles-Grignon, Route de St-Cyr (RD10), Versailles Cedex, 78026, France
| | - Jean-Cristophe Palauqui
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Bâtiment 2, INRA, Centre de Versailles-Grignon, Route de St-Cyr (RD10), Versailles Cedex, 78026, France
| | - Paolo Costantino
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Paola Vittorioso
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
- Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
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25
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Chen M, Maodzeka A, Zhou L, Ali E, Wang Z, Jiang L. Removal of DELLA repression promotes leaf senescence in Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 219-220:26-34. [PMID: 24576761 DOI: 10.1016/j.plantsci.2013.11.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 10/19/2013] [Accepted: 11/24/2013] [Indexed: 05/23/2023]
Abstract
Leaf senescence is an integrated response of leaf cells to developmental age and various internal and environmental signals. However, the role of gibberellins (GA) in leaf senescence is not clear. In the current study, we investigated the effect of DELLA on leaf senescence. Compared with the wild type (WT), leaf senescence occurred earlier in the mutant ga1-3 gai-t6 rga-t2 rgl1-1 rgl2-1 (abbreviated as Q-DELLA/ga1-3) whose DELLA repression was removed, whereas leaf senescence was retarded in the mutant ga1-3 whose GA biosynthesis was blocked and whose DELLA proteins accumulated abnormally. During leaf senescence, SAG12 and SAG29 were upregulated in Q-DELLA/ga1-3 and downregulated in ga1-3 plants. The Q-DELLA/ga1-3 senescent leaves contained more sugar but less chlorophyll and fatty acids (FAs) than those of ga1-3 and WT. Both absolute and relative contents of C18:3 in Q-DELLA/ga1-3 senescent leaves were lower compared with those of the WT and ga1-3 leaves. The genes regulating FA β-oxidation in Q-DELLA/ga1-3, such as KAT2, LACS6, LACS7, ACX1, ACX2 and MAP2, were significantly upregulated. The removal of DELLA repression highly upregulated certain genes on various hormone pathways, suggesting that GA signaling acts upstream of the jasmonic acid, salicylic acid, and ethylene pathways in regulating leaf senescence.
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Affiliation(s)
- Mingxun Chen
- College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China
| | - Antony Maodzeka
- College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China
| | - Longhua Zhou
- College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China
| | - Essa Ali
- College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China
| | - Zhong Wang
- College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China
| | - Lixi Jiang
- College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China.
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26
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Chitnis VR, Gao F, Yao Z, Jordan MC, Park S, Ayele BT. After-ripening induced transcriptional changes of hormonal genes in wheat seeds: the cases of brassinosteroids, ethylene, cytokinin and salicylic acid. PLoS One 2014; 9:e87543. [PMID: 24498132 PMCID: PMC3907488 DOI: 10.1371/journal.pone.0087543] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 12/30/2013] [Indexed: 11/19/2022] Open
Abstract
Maintenance and release of seed dormancy is regulated by plant hormones; their levels and seed sensitivity being the critical factors. This study reports transcriptional regulation of brassinosteroids (BR), ethylene (ET), cytokinin (CK) and salicylic acid (SA) related wheat genes by after-ripening, a period of dry storage that decays dormancy. Changes in the expression of hormonal genes due to seed after-ripening did not occur in the anhydrobiotic state but rather in the hydrated state. After-ripening induced dormancy decay appears to be associated with imbibition mediated increase in the synthesis and signalling of BR, via transcriptional activation of de-etiolated2, dwarf4 and brassinosteroid signaling kinase, and repression of brassinosteroid insensitive 2. Our analysis is also suggestive of the significance of increased ET production, as reflected by enhanced transcription of 1-aminocyclopropane-1-carboxylic acid oxidase in after-ripened seeds, and tight regulation of seed response to ET in regulating dormancy decay. Differential transcriptions of lonely guy, zeatin O-glucosyltransferases and cytokinin oxidases, and pseudo-response regulator between dormant and after-ripened seeds implicate CK in the regulation of seed dormancy in wheat. Our analysis also reflects the association of dormancy decay in wheat with seed SA level and NPR independent SA signaling that appear to be regulated transcriptionally by phenylalanine ammonia lyase, and whirly and suppressor of npr1 inducible1 genes, respectively. Co-expression clustering of the hormonal genes implies the significance of synergistic and antagonistic interaction between the different plant hormones in regulating wheat seed dormancy. These results contribute to further our understanding of the molecular features controlling seed dormancy in wheat.
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Affiliation(s)
- Vijaya R. Chitnis
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Feng Gao
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Zhen Yao
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Mark C. Jordan
- Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, Manitoba, Canada
| | - Seokhoon Park
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Belay T. Ayele
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
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Differential control of seed primary dormancy in Arabidopsis ecotypes by the transcription factor SPATULA. Proc Natl Acad Sci U S A 2013; 110:10866-71. [PMID: 23754415 DOI: 10.1073/pnas.1301647110] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Freshly matured seeds exhibit primary dormancy, which prevents germination until environmental conditions are favorable. The establishment of dormancy occurs during seed development and involves both genetic and environmental factors that impact on the ratio of two antagonistic phytohormones: abscisic acid (ABA), which promotes dormancy, and gibberellic acid, which promotes germination. Although our understanding of dormancy breakage in mature seeds is well advanced, relatively little is known about the mechanisms involved in establishing dormancy during seed maturation. We previously showed that the SPATULA (SPT) transcription factor plays a key role in regulating seed germination. Here we investigate its role during seed development and find that, surprisingly, it has opposite roles in setting dormancy in Landsberg erecta and Columbia Arabidopsis ecotypes. We also find that SPT regulates expression of five transcription factor encoding genes: ABA-INSENSITIVE4 (ABI4) and ABI5, which mediate ABA signaling; REPRESSOR-OF-GA (RGA) and RGA-LIKE3 involved in gibberellic acid signaling; and MOTHER-OF-FT-AND-TFL1 (MFT) that we show here promotes Arabidopsis seed dormancy. Although ABI4, RGA, and MFT are repressed by SPT, ABI5 and RGL3 are induced. Furthermore, we show that RGA, MFT, and ABI5 are direct targets of SPT in vivo. We present a model in which SPT drives two antagonistic "dormancy-repressing" and "dormancy-promoting" routes that operate simultaneously in freshly matured seeds. Each of these routes has different impacts and this in turn explains the opposite effect of SPT on seed dormancy of the two ecotypes analyzed here.
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28
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Foley ME, Chao WS, Horvath DP, Doğramaci M, Anderson JV. The transcriptomes of dormant leafy spurge seeds under alternating temperature are differentially affected by a germination-enhancing pretreatment. JOURNAL OF PLANT PHYSIOLOGY 2013; 170:539-547. [PMID: 23261266 DOI: 10.1016/j.jplph.2012.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 11/19/2012] [Accepted: 11/20/2012] [Indexed: 06/01/2023]
Abstract
Seed dormancy is an important stage in the life cycle of many non-domesticated plants, often characterized by the temporary failure to germinate under conditions that normally favor the process. Pre-treating dormant imbibed seeds at a constant temperate accelerated germination of leafy spurge seeds under alternating temperatures. However, dormant seeds will also germinate without a pre-treatment, albeit at a much slower rate, which gives rise to longer periods of imbibition before germination. Transcriptome analyses on seeds exposed to prolonged imbibition highlighted pathways associated with phenylpropanoid biosynthesis and interacting networks of genes involved in plant defense. In addition to the many pathways associated with phenylpropanoid biosynthesis enriched with down-regulated genes upon germination, there were also numerous pathways enriched with up-regulated genes associated with energy metabolism, such as glycolysis. Transcriptome data further suggest that metabolism and signaling by the plant hormones ethylene, gibberellin, and abscisic acid are involved in the developmental transition from dormancy to germination. More specifically, sub-network enrichment analysis identified ABI3 as a central hub of a sub-network at germination including several down-regulated genes such as DELLA (i.e., RGL2), which represses gibberellin signaling processes required for germination. The 595-fold increase in the expression of ACC oxidase (ACO4) at germination also suggests an important role for ethylene biosynthesis in germinating leafy surge seeds. Furthermore, the 10-578-fold difference in expression of many genes such as HY5 and Histone H3 between two populations at germination, which were treated with and without a constant temperature germination-enhancing pretreatment, revealed disparate impacts on various biosynthetic, growth, signaling, and response processes. Overall, our results indicate a constant temperature pretreatment (20°C for 21d) is not required for germination of leafy spurge seeds at an alternating temperature. However, the presence or absence of the pretreatment does affect the rate of germination and the germination transcriptional programs.
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Affiliation(s)
- Michael E Foley
- USDA-Agricultural Research Service, Biosciences Research Lab, Sunflower and Plant Biology Research Unit, 1605 Albrecht Boulevard, Fargo, ND 58102-2765, USA.
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29
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Liu A, Gao F, Kanno Y, Jordan MC, Kamiya Y, Seo M, Ayele BT. Regulation of wheat seed dormancy by after-ripening is mediated by specific transcriptional switches that induce changes in seed hormone metabolism and signaling. PLoS One 2013; 8:e56570. [PMID: 23437172 PMCID: PMC3577873 DOI: 10.1371/journal.pone.0056570] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/14/2013] [Indexed: 01/14/2023] Open
Abstract
Treatments that promote dormancy release are often correlated with changes in seed hormone content and/or sensitivity. To understand the molecular mechanisms underlying the role of after-ripening (seed dry storage) in triggering hormone related changes and dormancy decay in wheat (Triticum aestivum), temporal expression patterns of genes related to abscisic acid (ABA), gibberellin (GA), jasmonate and indole acetic acid (IAA) metabolism and signaling, and levels of the respective hormones were examined in dormant and after-ripened seeds in both dry and imbibed states. After-ripening mediated developmental switch from dormancy to germination appears to be associated with declines in seed sensitivity to ABA and IAA, which are mediated by transcriptional repressions of PROTEIN PHOSPHATASE 2C, SNF1-RELATED PROTEIN KINASE2, ABA INSENSITIVE5 and LIPID PHOSPHATE PHOSPHTASE2, and AUXIN RESPONSE FACTOR and RELATED TO UBIQUITIN1 genes. Transcriptomic analysis of wheat seed responsiveness to ABA suggests that ABA inhibits the germination of wheat seeds partly by repressing the transcription of genes related to chromatin assembly and cell wall modification, and activating that of GA catabolic genes. After-ripening induced seed dormancy decay in wheat is also associated with the modulation of seed IAA and jasmonate contents. Transcriptional control of members of the ALLENE OXIDE SYNTHASE, 3-KETOACYL COENZYME A THIOLASE, LIPOXYGENASE and 12-OXOPHYTODIENOATE REDUCTASE gene families appears to regulate seed jasmonate levels. Changes in the expression of GA biosynthesis genes, GA 20-OXIDASE and GA 3-OXIDASE, in response to after-ripening implicate this hormone in enhancing dormancy release and germination. These findings have important implications in the dissection of molecular mechanisms underlying regulation of seed dormancy in cereals.
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Affiliation(s)
- Aihua Liu
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Feng Gao
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Yuri Kanno
- RIKEN Plant Science Center, Tsurumi, Yokohama, Japan
| | - Mark C. Jordan
- Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, Manitoba, Canada
| | - Yuji Kamiya
- RIKEN Plant Science Center, Tsurumi, Yokohama, Japan
| | - Mitsunori Seo
- RIKEN Plant Science Center, Tsurumi, Yokohama, Japan
| | - Belay T. Ayele
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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30
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Seung D, Risopatron JPM, Jones BJ, Marc J. Circadian clock-dependent gating in ABA signalling networks. PROTOPLASMA 2012; 249:445-57. [PMID: 21773710 DOI: 10.1007/s00709-011-0304-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 07/01/2011] [Indexed: 05/08/2023]
Abstract
Plant growth and development are intimately attuned to fluctuations in environmental variables such as light, temperature and water availability. A broad range of signalling and dynamic response mechanisms allows them to adjust their physiology so that growth and reproductive capacity are optimised for the prevailing conditions. Many of the response mechanisms are mediated by the plant hormones. The hormone abscisic acid (ABA) plays a dominant role in fundamental processes such as seed dormancy and germination, regulation of stomatal movements and enhancing drought tolerance in response to the osmotic stresses that result from water deficit, salinity and freezing. Whereas plants maintain a constant vigilance, there is emerging evidence that the capacity to respond is gated by the circadian clock so that it varies with diurnal fluctuations in light, temperature and water status. Clock regulation enables plants to anticipate regular diurnal fluctuations and thereby presumably to maximise metabolic efficiency. Circadian clock-dependent gating appears to regulate the ABA signalling network at numerous points, including metabolism, transport, perception and activity of the hormone. In this review, we summarise the basic principles and recent progress in elucidating the molecular mechanisms of circadian gating of the ABA response network and how it can affect fundamental processes in plant growth and development.
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Affiliation(s)
- David Seung
- School of Biological Sciences, The University of Sydney, Sydney, Australia
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31
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Schwechheimer C. Gibberellin signaling in plants - the extended version. FRONTIERS IN PLANT SCIENCE 2012; 2:107. [PMID: 22645560 PMCID: PMC3355746 DOI: 10.3389/fpls.2011.00107] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 12/13/2011] [Indexed: 05/23/2023]
Abstract
The plant hormone gibberellin (GA) controls major aspects of plant growth such as germination, elongation growth, flower development, and flowering time. In recent years, a number of studies have revealed less apparent roles for GA in a surprisingly broad set of developmental as well as cell biological processes. The identification of GA receptor proteins on the one end of the signaling cascade, DELLA proteins as central repressors of the pathway and transcription regulators such as the phytochrome interacting factors and the GATA-type transcription factors GNC and CGA1/GNL on the current other end of the signaling cascade have extended our knowledge about how GA and DELLAs regulate a diverse set of plant responses.
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Affiliation(s)
- Claus Schwechheimer
- Plant Systems Biology, Center for Life and Food Sciences Weihenstephan, Technische Universität MünchenFreising, Germany
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32
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Gallego-Bartolomé J, Arana MV, Vandenbussche F, Zádníková P, Minguet EG, Guardiola V, Van Der Straeten D, Benkova E, Alabadí D, Blázquez MA. Hierarchy of hormone action controlling apical hook development in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 67:622-34. [PMID: 21535259 DOI: 10.1111/j.1365-313x.2011.04621.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The apical hook develops in the upper part of the hypocotyl when seeds buried in the soil germinate, and serves to protect cotyledons and the shoot apical meristem from possible damage caused by pushing through the soil. The curvature is formed through differential cell growth that occurs at the two opposite sides of the hypocotyl, and it is established by a gradient of auxin activity and refined by the coordinated action of auxin and ethylene. Here we show that gibberellins (GAs) promote hook development through the transcriptional regulation of several genes of the ethylene and auxin pathways in Arabidopsis. The level of GA activity determines the speed of hook formation and the extent of the curvature during the formation phase independently of ethylene, probably by modulating auxin transport and response through HLS1, PIN3, and PIN7. Moreover, GAs cooperate with ethylene in preventing hook opening, in part through the induction of ethylene production mediated by ACS5/ETO2 and ACS8.
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Affiliation(s)
- Javier Gallego-Bartolomé
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
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33
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He D, Han C, Yao J, Shen S, Yang P. Constructing the metabolic and regulatory pathways in germinating rice seeds through proteomic approach. Proteomics 2011; 11:2693-713. [DOI: 10.1002/pmic.201000598] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 02/23/2011] [Accepted: 04/12/2011] [Indexed: 12/15/2022]
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34
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van der Schoot C, Rinne PLH. Dormancy cycling at the shoot apical meristem: transitioning between self-organization and self-arrest. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2011; 180:120-31. [PMID: 21421354 DOI: 10.1016/j.plantsci.2010.08.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Revised: 08/15/2010] [Accepted: 08/17/2010] [Indexed: 05/04/2023]
Abstract
To survive winter deciduous perennials of the temperate zones cease growth and acquire a cold-acclimated state. Timing of these events is guided by sensory systems in the leaves that register critical alterations in photoperiod. Growth cessation on its own is not sufficient to develop adequate freezing tolerance, which requires entry of the shoot apical meristem (SAM) into dormancy. To fully appreciate perennial dormancy as a precondition for cold acclimation it is necessary to assess how it is brought about in a timely fashion, what the nature of it is, and how it is released. Short day (SD) exposure results in growth cessation, bud set, dormancy establishment at the SAM, and a moderate to high level of freezing tolerance. Subsequent chilling releases the SAM from dormancy and enhances freezing tolerance further. Recent investigations indicate that dormancy is a state of self-arrest that is brought about by an enzyme-based system which disrupts the intrinsic signal network of the SAM. Release from this state requires a complimentary enzyme-based system that is preformed during SD and mobilized by chilling. These findings are in agreement with the paradigm of dormancy cycling, which defines the seasonal alternations at the SAM as transitions between states of self-organization and self-arrest. The success of this survival strategy is based on the adequate scheduling of a complex array of events. The appreciation is growing that this involves signal cascades that are, mutatis mutandis, also recruited in floral evocation in many annuals, including Arabidopsis. A heuristic model is presented of dormancy cycling at the SAM, which depicts crucial molecular and cellular events that drive the cycle.
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Affiliation(s)
- Christiaan van der Schoot
- Department of Plant & Environmental Sciences, Norwegian University of Life Sciences, PO Box 5003, 1432 Ås, Norway.
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35
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Lee KP, Piskurewicz U, Turečková V, Strnad M, Lopez-Molina L. A seed coat bedding assay shows that RGL2-dependent release of abscisic acid by the endosperm controls embryo growth in Arabidopsis dormant seeds. Proc Natl Acad Sci U S A 2010; 107:19108-13. [PMID: 20956298 PMCID: PMC2973907 DOI: 10.1073/pnas.1012896107] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Seed dormancy is an ecologically important adaptive trait in plants whereby germination is repressed even under favorable germination conditions such as imbibition with water. In Arabidopsis and most plant species, dormancy absolutely requires an unidentified seed coat germination-repressive activity and constitutively higher abscisic acid (ABA) levels upon seed imbibition. The mechanisms underlying these processes and their possible relationship are incompletely understood. We developed a "seed coat bedding" assay monitoring the growth of dissected embryos cultured on a layer of seed coats, allowing combinatorial experiments using dormant, nondormant, and various genetically modified seed coat and embryonic materials. This assay, combined with direct ABA measurements, revealed that, upon imbibition, dormant coats, unlike nondormant coats, actively produce and release ABA to repress embryo germination, whatever the embryo origin, i.e., from dormant, nondormant, or never dormant aba seeds, unable to synthesize ABA. The persistent high ABA levels in imbibed dormant seeds requires the permanent expression of the DELLA gene RGL2, where it remains insensitive to gibberellins (GA) unlike in nondormant seeds. These findings present the seed coat as an organ actively controlling germination upon seed imbibition and provide a framework to investigate how environmental factors break seed dormancy.
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Affiliation(s)
- Keun Pyo Lee
- Département de Biologie Végétale, Université de Genève, 1211 Geneva 4, Switzerland; and
| | - Urszula Piskurewicz
- Département de Biologie Végétale, Université de Genève, 1211 Geneva 4, Switzerland; and
| | - Veronika Turečková
- Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 783 71 Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 783 71 Olomouc, Czech Republic
| | - Luis Lopez-Molina
- Département de Biologie Végétale, Université de Genève, 1211 Geneva 4, Switzerland; and
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36
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Pawłowski TA. Proteomic approach to analyze dormancy breaking of tree seeds. PLANT MOLECULAR BIOLOGY 2010; 73:15-25. [PMID: 20306286 DOI: 10.1007/s11103-010-9623-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 03/05/2010] [Indexed: 05/29/2023]
Abstract
In forest broadleaves from the temperate zone, a large number of species exhibit seed dormancy phenomena. Tree seeds show some of the most pronounced and complicated forms of dormancy in the plant kingdom. Many seeds are deeply physiologically dormant whatever their moisture level and age. However, dormancy can usually be overcome by a cold or warm stratification for several months. The transition from seed dormancy to germination is a multi-step process. In combination with the availability of genome sequence data, proteomics has opened up enormous possibilities for identifying the total set of expressed proteins as well as expression changes during dormancy breaking. The proteomic approach used for analysis of dormancy breaking of tree seeds offers new data allowing better understanding of the mechanism of deep physiological dormancy. The results of proteomic studies on dormancy breaking and the presence of abscisic and gibberellic acids in tree seeds (beech Fagus sylvatica L., Norway maple Acer platanoides L. and sycamore Acer pseudoplatanus L.), help to explain this process better. Most of the changes in protein expression were observed at the end of stratification and in the germinated seeds. This is the most active period of dormancy breaking when seeds pass from the quiescent state to germination. The analysis of the proteins' function showed that the mechanism of seed dormancy breaking involves many processes. Energy metabolism, proteasome, transcription, protein synthesis, signal transduction and methionine metabolism proteins have a special importance.
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37
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38
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A combinatorial interplay among the 1-aminocyclopropane-1-carboxylate isoforms regulates ethylene biosynthesis in Arabidopsis thaliana. Genetics 2009; 183:979-1003. [PMID: 19752216 DOI: 10.1534/genetics.109.107102] [Citation(s) in RCA: 212] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Ethylene (C(2)H(4)) is a unique plant-signaling molecule that regulates numerous developmental processes. The key enzyme in the two-step biosynthetic pathway of ethylene is 1-aminocyclopropane-1-carboxylate synthase (ACS), which catalyzes the conversion of S-adenosylmethionine (AdoMet) to ACC, the precursor of ethylene. To understand the function of this important enzyme, we analyzed the entire family of nine ACS isoforms (ACS1, ACS2, ACS4-9, and ACS11) encoded in the Arabidopsis genome. Our analysis reveals that members of this protein family share an essential function, because individual ACS genes are not essential for Arabidopsis viability, whereas elimination of the entire gene family results in embryonic lethality. Phenotypic characterization of single and multiple mutants unmasks unique but overlapping functions of the various ACS members in plant developmental events, including multiple growth characteristics, flowering time, response to gravity, disease resistance, and ethylene production. Ethylene acts as a repressor of flowering by regulating the transcription of the FLOWERING LOCUS C. Each single and high order mutant has a characteristic molecular phenotype with unique and overlapping gene expression patterns. The expression of several genes involved in light perception and signaling is altered in the high order mutants. These results, together with the in planta ACS interaction map, suggest that ethylene-mediated processes are orchestrated by a combinatorial interplay among ACS isoforms that determines the relative ratio of homo- and heterodimers (active or inactive) in a spatial and temporal manner. These subunit isoforms comprise a combinatorial code that is a central regulator of ethylene production during plant development. The lethality of the null ACS mutant contrasts with the viability of null mutations in key components of the ethylene signaling apparatus, strongly supporting the view that ACC, the precursor of ethylene, is a primary regulator of plant growth and development.
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39
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Penfield S, King J. Towards a systems biology approach to understanding seed dormancy and germination. Proc Biol Sci 2009; 276:3561-9. [PMID: 19605392 DOI: 10.1098/rspb.2009.0592] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Seed germination is the first adaptive decision in the development of many land plants. Advances in genetics and molecular physiology have taught us much about the control of germination using the model plant Arabidopsis thaliana. Here we review the current state of the art with an emphasis on mechanistic considerations and explore the potential impact of a systems biology approach to the problem.
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Affiliation(s)
- Steven Penfield
- Department of Biology, Centre for Novel Agricultural Products, University of York, PO Box 373, York YO10 5YW, UK.
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40
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Piskurewicz U, Turecková V, Lacombe E, Lopez-Molina L. Far-red light inhibits germination through DELLA-dependent stimulation of ABA synthesis and ABI3 activity. EMBO J 2009; 28:2259-71. [PMID: 19556968 DOI: 10.1038/emboj.2009.170] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 05/27/2009] [Indexed: 11/09/2022] Open
Abstract
Under the canopy, far-red (FR) light represses seed germination by inactivating phytochrome photoreceptors. This elicits a decrease in gibberellins (GA) levels and an increase in abscisic acid (ABA) levels. GA promotes germination by enhancing the proteasome-mediated destruction of DELLA repressors. ABA prevents germination by stimulating the expression of ABI repressors. How phytochromes elicit changes in hormone levels or how GA- and ABA-dependent signals are coordinated to repress germination remains poorly understood. We show that repression of germination by FR light involves stabilized DELLA factors GAI, RGA and RGL2 that stimulate endogenous ABA synthesis. In turn, ABA blocks germination through the transcription factor ABI3. The role of PIL5, a basic helix-loop-helix transcription factor stimulating GAI and RGA expression, is significant, provided GA synthesis is high enough; otherwise, high GAI and RGA protein levels persist to block germination. Under white light, GAI and RGA driven by the RGL2 promoter can substitute for RGL2 to promote ABA synthesis and repress germination, consistent with the recent findings with RGL2. The three DELLA factors inhibit testa rupture whereas ABI3 blocks endosperm rupture.
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Affiliation(s)
- Urszula Piskurewicz
- Département de Biologie Végétale, Université de Genève, Genève 4, Switzerland
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41
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Penfield S, Hall A. A role for multiple circadian clock genes in the response to signals that break seed dormancy in Arabidopsis. THE PLANT CELL 2009; 21:1722-32. [PMID: 19542296 PMCID: PMC2714941 DOI: 10.1105/tpc.108.064022] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 05/08/2009] [Accepted: 05/29/2009] [Indexed: 05/18/2023]
Abstract
Plant seeds can sense diverse environmental signals and integrate the information to regulate developmental responses, such as dormancy and germination. The circadian clock confers a growth advantage on plants and uses environmental information for entrainment. Here, we show that normal circadian clock gene function is essential for the response to dormancy-breaking signals in seeds. We show that mutations in the clock genes LATE ELONGATED HYPOCOTYL, CIRCADIAN CLOCK ASSOCIATED1 (CCA1), and GIGANTEA (GI) cause germination defects in response to low temperature, alternating temperatures, and dry after-ripening. We demonstrate that the transcriptional clock is arrested in an evening-like state in dry seeds but rapidly entrains to light/dark cycles in ambient temperatures upon imbibition. Consistent with a role for clock genes in seed dormancy control, CCA1 expression is transcriptionally induced in response to dry after-ripening and that after-ripening affects the amplitude of subsequent transcriptional clock gene oscillations. Control of abscisic acid- and gibberellin-related gene expression in seeds requires normal circadian function, and GI and TIMING OF CAB EXPRESSION1 regulate the response to ABA and GA in seeds. We conclude that circadian clock genes play a key role in the integration of environmental signaling controlling dormancy release in plants.
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Affiliation(s)
- Steven Penfield
- Department of Biology, Centre for Novel Agricultural Products, University of York, YO105YW United Kingdom.
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42
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Franklin KA. Light and temperature signal crosstalk in plant development. CURRENT OPINION IN PLANT BIOLOGY 2009; 12:63-8. [PMID: 18951837 DOI: 10.1016/j.pbi.2008.09.007] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 09/05/2008] [Accepted: 09/11/2008] [Indexed: 05/18/2023]
Abstract
Light and temperature are two of the most important environmental stimuli regulating plant development. Recent advances have suggested considerable interaction between these signalling pathways at the molecular level. Studies of both flowering and germination have shown the phytochrome family of plant photoreceptors to display altered functional hierarchies at different growth temperatures. The existence of common signalling components in both light and temperature sensing has additionally been proposed. More recently, light quality signals have been shown to regulate plant-freezing tolerance in an ambient temperature-dependent manner. Together, these data suggest that complex crosstalk between light-signalling and temperature-signalling pathways is fundamental to the growth and development of plants in natural environments.
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43
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Achard P, Genschik P. Releasing the brakes of plant growth: how GAs shutdown DELLA proteins. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:1085-92. [PMID: 19043067 DOI: 10.1093/jxb/ern301] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Bioactive gibberellins (GAs) are tetracyclic diterpenoid plant hormones that promote important processes of plant growth and development, such as seed germination, growth through elongation, and floral transition. Thus, mutant plants that are affected in GA biosynthesis or signalling exhibit altered seed germination and, at the adult stage, are dwarf and dark green and also show delayed flowering. The components of the GA metabolism and signalling pathways are reviewed here and recent findings regarding the regulation and possible mode of action of DELLA proteins are discussed.
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Affiliation(s)
- P Achard
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Propre de Recherche 2357, Conventionné avec l'Université Louis Pasteur, F-67084 Strasbourg, France
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44
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Zhang H, Yang Y, Zhang Z, Chen J, Wang XC, Huang R. Expression of the ethylene response factor gene TSRF1 enhances abscisic acid responses during seedling development in tobacco. PLANTA 2008; 228:777-87. [PMID: 18597110 DOI: 10.1007/s00425-008-0779-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Accepted: 06/22/2008] [Indexed: 05/08/2023]
Abstract
Ethylene response factor (ERF) proteins function as multiple regulators in the interaction of different stress-responsive pathways. During investigating the interaction of ethylene and abscisic acid (ABA) pathways, several GCC-box-binding repressors of ERF proteins have been reported to repress both ethylene- and ABA-related responses, but it is unclear how GCC-box-binding activator ERF proteins are involved in this interaction. Previously, we isolated an ERF protein tomato stress-responsive factor 1 (TSRF1) from tomato by yeast one hybrid, and showed that TSRF1 as a transcriptional activator physically interacts with GCC box, and activates the expression of GCC box-containing genes and enhances resistance to pathogens, while ABA treatment alters the binding ability of TSRF1 with this element and decreases resistance to pathogen Ralstonia solanacearum. Here, we further report that TSRF1 is able to interact with a GCC box-like sequence (indicated as CE1/GCC in this paper) containing the core sequence of ZmABI4-binding-CE1-like element, and regulates ABA responses. Overexpression of TSRF1 in tobacco enhances ABA sensitivity during germination, cotyledon expansion and root elongation. Biochemical and molecular analyses demonstrate that TSRF1 interacts with CE1/GCC. Importantly, ABA treatment enhances the interaction of TSRF1 with the ABA-responsive element and subsequently increasing the expression of ABA-responsive or CE1/GCC-containing genes. In addition, TSRF1 also promotes the expression of senescence-associated genes and tobacco seedling senescence in response to ABA. These results show that TSRF1, a GCC-box-binding activator in plant pathogen resistance, positively regulates ABA-related plant developmental processes.
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Affiliation(s)
- Hongbo Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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45
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Piskurewicz U, Jikumaru Y, Kinoshita N, Nambara E, Kamiya Y, Lopez-Molina L. The gibberellic acid signaling repressor RGL2 inhibits Arabidopsis seed germination by stimulating abscisic acid synthesis and ABI5 activity. THE PLANT CELL 2008; 20:2729-45. [PMID: 18941053 PMCID: PMC2590721 DOI: 10.1105/tpc.108.061515] [Citation(s) in RCA: 304] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 09/19/2008] [Accepted: 10/06/2008] [Indexed: 05/18/2023]
Abstract
Seed germination is antagonistically controlled by the phytohormones gibberellic acid (GA) and abscisic acid (ABA). GA promotes seed germination by enhancing the proteasome-mediated destruction of RGL2 (for RGA-LIKE2), a key DELLA factor repressing germination. By contrast, ABA blocks germination by inducing ABI5 (for ABA-INSENSITIVE5), a basic domain/leucine zipper transcription factor repressing germination. Decreased GA synthesis leads to an increase in endogenous ABA levels through a stabilized RGL2, a process that may involve XERICO, a RING-H2 zinc finger factor promoting ABA synthesis. In turn, increased endogenous ABA synthesis is necessary to elevate not only ABI5 RNA and protein levels but also, critically, those of RGL2. Increased ABI5 protein is ultimately responsible for preventing seed germination when GA levels are reduced. However, overexpression of ABI5 was not sufficient to repress germination, as ABI5 activity requires phosphorylation. The endogenous ABI5 phosphorylation and inhibition of germination could be recapitulated by the addition of a SnRK2 protein kinase to the ABI5 overexpression line. In sleepy1 mutant seeds, RGL2 overaccumulates; germination of these seeds can occur under conditions that produce low ABI5 expression. These data support the notion that ABI5 acts as the final common repressor of germination in response to changes in ABA and GA levels.
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Affiliation(s)
- Urszula Piskurewicz
- Université de Genève, Département de Biologie Végétale, 1211 Geneva 4, Switzerland
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46
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Argyris J, Dahal P, Hayashi E, Still DW, Bradford KJ. Genetic variation for lettuce seed thermoinhibition is associated with temperature-sensitive expression of abscisic Acid, gibberellin, and ethylene biosynthesis, metabolism, and response genes. PLANT PHYSIOLOGY 2008; 148:926-47. [PMID: 18753282 PMCID: PMC2556833 DOI: 10.1104/pp.108.125807] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 08/25/2008] [Indexed: 05/19/2023]
Abstract
Lettuce (Lactuca sativa 'Salinas') seeds fail to germinate when imbibed at temperatures above 25 degrees C to 30 degrees C (termed thermoinhibition). However, seeds of an accession of Lactuca serriola (UC96US23) do not exhibit thermoinhibition up to 37 degrees C in the light. Comparative genetics, physiology, and gene expression were analyzed in these genotypes to determine the mechanisms governing the regulation of seed germination by temperature. Germination of the two genotypes was differentially sensitive to abscisic acid (ABA) and gibberellin (GA) at elevated temperatures. Quantitative trait loci associated with these phenotypes colocated with a major quantitative trait locus (Htg6.1) from UC96US23 conferring germination thermotolerance. ABA contents were elevated in Salinas seeds that exhibited thermoinhibition, consistent with the ability of fluridone (an ABA biosynthesis inhibitor) to improve germination at high temperatures. Expression of many genes involved in ABA, GA, and ethylene biosynthesis, metabolism, and response was differentially affected by high temperature and light in the two genotypes. In general, ABA-related genes were more highly expressed when germination was inhibited, and GA- and ethylene-related genes were more highly expressed when germination was permitted. In particular, LsNCED4, a gene encoding an enzyme in the ABA biosynthetic pathway, was up-regulated by high temperature only in Salinas seeds and also colocated with Htg6.1. The temperature sensitivity of expression of LsNCED4 may determine the upper temperature limit for lettuce seed germination and may indirectly influence other regulatory pathways via interconnected effects of increased ABA biosynthesis.
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Affiliation(s)
- Jason Argyris
- Department of Plant Sciences, University of California, Davis, CA 95616-8780, USA
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47
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Rieu I, Eriksson S, Powers SJ, Gong F, Griffiths J, Woolley L, Benlloch R, Nilsson O, Thomas SG, Hedden P, Phillips AL. Genetic analysis reveals that C19-GA 2-oxidation is a major gibberellin inactivation pathway in Arabidopsis. THE PLANT CELL 2008; 20:2420-36. [PMID: 18805991 PMCID: PMC2570722 DOI: 10.1105/tpc.108.058818] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 08/22/2008] [Accepted: 09/05/2008] [Indexed: 05/18/2023]
Abstract
Bioactive hormone concentrations are regulated both at the level of hormone synthesis and through controlled inactivation. Based on the ubiquitous presence of 2beta-hydroxylated gibberellins (GAs), a major inactivating pathway for the plant hormone GA seems to be via GA 2-oxidation. In this study, we used various approaches to determine the role of C(19)-GA 2-oxidation in regulating GA concentration and GA-responsive plant growth and development. We show that Arabidopsis thaliana has five C(19)-GA 2-oxidases, transcripts for one or more of which are present in all organs and at all stages of development examined. Expression of four of the five genes is subject to feed-forward regulation. By knocking out all five Arabidopsis C(19)-GA 2-oxidases, we show that C(19)-GA 2-oxidation limits bioactive GA content and regulates plant development at various stages during the plant life cycle: C(19)-GA 2-oxidases prevent seed germination in the absence of light and cold stimuli, delay the vegetative and floral phase transitions, limit the number of flowers produced per inflorescence, and suppress elongation of the pistil prior to fertilization. Under GA-limited conditions, further roles are revealed, such as limiting elongation of the main stem and side shoots. We conclude that C(19)-GA 2-oxidation is a major GA inactivation pathway regulating development in Arabidopsis.
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Affiliation(s)
- Ivo Rieu
- Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
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48
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Achard P, Gong F, Cheminant S, Alioua M, Hedden P, Genschik P. The cold-inducible CBF1 factor-dependent signaling pathway modulates the accumulation of the growth-repressing DELLA proteins via its effect on gibberellin metabolism. THE PLANT CELL 2008; 20:2117-29. [PMID: 18757556 PMCID: PMC2553604 DOI: 10.1105/tpc.108.058941] [Citation(s) in RCA: 440] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 08/01/2008] [Accepted: 08/09/2008] [Indexed: 05/17/2023]
Abstract
Plants have evolved robust mechanisms to respond and adapt to unfavorable environmental conditions, such as low temperature. The C-repeat/drought-responsive element binding factor CBF1/DREB1b gene encodes a transcriptional activator transiently induced by cold that controls the expression of a set of genes responding to low temperature (the CBF regulon). Constitutive expression of CBF1 confers freezing tolerance but also slows growth. Here, we propose that low temperature-induced CBF1 expression restrains growth at least in part by allowing the accumulation of DELLAs, a family of nuclear growth-repressing proteins, the degradation of which is stimulated by gibberellin (GA). We show that cold/CBF1 enhances the accumulation of a green fluorescent protein (GFP)-tagged DELLA protein (GFP-RGA) by reducing GA content through stimulating expression of GA-inactivating GA 2-oxidase genes. Accordingly, transgenic plants that constitutively express CBF1 accumulate less bioactive GA and as a consequence exhibit dwarfism and late flowering. Both phenotypes are suppressed when CBF1 is expressed in a line lacking two DELLA proteins, GA-INSENSITIVE and REPRESSOR OF GA1-3. In addition, we show that DELLAs contribute significantly to CBF1-induced cold acclimation and freezing tolerance by a mechanism that is distinct from the CBF regulon. We conclude that DELLAs are components of the CBF1-mediated cold stress response.
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Affiliation(s)
- Patrick Achard
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Propre de Recherche 2357, Conventioné avec l'Université Louis Pasteur, 67084 Strasbourg, France
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49
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Abstract
Since the discovery of the physical interaction between phytochrome B and the basic helix-loop-helix (bHLH) transcription factor (TF) PIF3 a decade ago, plant phytochrome-signalling research has largely focused on understanding the mechanisms through which phytochromes and members of this bHLH family signal. This concerted effort has revealed how phytochrome and bHLH TF control gene expression and plant growth, and has assigned precise roles to a number of genes in the PIF3-like bHLH TF clade. This work has focused largely on cell autonomous signalling events; however, to synchronize plant growth and developmental events at the tissue and organ level, temporal and spatial signal integration is crucial. This review brings together current knowledge of phytochrome signalling through phytochrome-interacting factors (PIFs)/phytochrome-interacting factor-like (PILs), and it evaluates the current evidence for cross-tissue signal integration.
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Affiliation(s)
- Eve-Marie Josse
- Institute of Molecular Plant Sciences, Edinburgh University, Kings Buildings, Mayfield Road, Edinburgh, EH9 3 JR, UK
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50
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Rieu I, Ruiz-Rivero O, Fernandez-Garcia N, Griffiths J, Powers SJ, Gong F, Linhartova T, Eriksson S, Nilsson O, Thomas SG, Phillips AL, Hedden P. The gibberellin biosynthetic genes AtGA20ox1 and AtGA20ox2 act, partially redundantly, to promote growth and development throughout the Arabidopsis life cycle. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 53:488-504. [PMID: 18069939 DOI: 10.1111/j.1365-313x.2007.03356.x] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The activity of the gibberellin (GA) biosynthetic enzymes GA 20-oxidases (GA20ox) is of particular importance in determining GA concentration in many plant species. In Arabidopsis these enzymes are encoded by a family of five genes: AtGA20ox1-AtGA20ox5. Transcript analysis indicated that they have different expression patterns and may thus participate differentially in GA-regulated developmental processes. We have used reverse genetics to determine the physiological roles of AtGA20ox1 and AtGA20ox2, the most highly expressed GA20ox genes during vegetative and early reproductive development. AtGA20ox1 and AtGA20ox2 act redundantly to promote hypocotyl and internode elongation, flowering time, elongation of anther filaments, the number of seeds that develop per silique and elongation of siliques, with AtGA20ox1 making the greater contribution to internode and filament elongation, and AtGA20ox2 making the greater contribution to flowering time and silique length. Pollination of the double mutant with wild-type pollen indicated that the GA promoting silique elongation is of maternal origin. The ga20ox2 phenotype revealed that GA promotes the number of stem internodes that elongate upon bolting, and does so independently of its effect on internode elongation. Comparison of the phenotype of the double mutant with that of the highly GA-deficient ga1-3 mutant indicates that other GA20ox genes contribute to all the developmental processes examined, and, in some cases such as root growth and leaf expansion, make major contributions, as these processes were unaffected in the double mutant. In addition, the effects of the mutations are mitigated by the homeostatic mechanism that acts on expression of other GA dioxygenase and GID1 receptor genes.
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Affiliation(s)
- Ivo Rieu
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
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