1
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Seo PJ, Lee HG, Choi HY, Lee S, Park CM. Complexity of SMAX1 signaling during seedling establishment. TRENDS IN PLANT SCIENCE 2023; 28:902-912. [PMID: 37069002 DOI: 10.1016/j.tplants.2023.03.014] [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: 08/19/2022] [Revised: 03/12/2023] [Accepted: 03/18/2023] [Indexed: 06/19/2023]
Abstract
Karrikins (KARs) are small butenolide compounds identified in the smoke of burning vegetation. Along with the stimulating effects on seed germination, KARs also regulate seedling vigor and adaptive behaviors, such as seedling morphogenesis, root hair development, and stress acclimation. The pivotal KAR signaling repressor, SUPPRESSOR OF MAX2 1 (SMAX1), plays central roles in these developmental and morphogenic processes through an extensive signaling network that governs seedling responses to endogenous and environmental cues. Here, we summarize the versatile roles of SMAX1 reported in recent years and discuss how SMAX1 integrates multiple growth hormone signals into optimizing seedling establishment. We also discuss the evolutionary relevance of the SMAX1-mediated signaling pathways during the colonization of aqueous plants to terrestrial environments.
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Affiliation(s)
- Pil Joon Seo
- Department of Chemistry, Seoul National University, Seoul 08826, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea.
| | - Hong Gil Lee
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea
| | - Hye-Young Choi
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Sangmin Lee
- Bio/Energy R&D Center, Korea Institute of Energy Research, Gwangju 61003, Korea
| | - Chung-Mo Park
- Department of Chemistry, Seoul National University, Seoul 08826, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea.
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2
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Xu P, Hu J, Chen H, Cai W. SMAX1 interacts with DELLA protein to inhibit seed germination under weak light conditions via gibberellin biosynthesis in Arabidopsis. Cell Rep 2023; 42:112740. [PMID: 37405917 DOI: 10.1016/j.celrep.2023.112740] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 01/11/2023] [Accepted: 06/19/2023] [Indexed: 07/07/2023] Open
Abstract
Karrikins (KARs) were first identified as a class of small-molecule chemicals derived from smoke that promote seed germination. However, the implied mechanism is still not well understood. Here, we find that KAR signaling mutants have a lower germination percentage than that of wild type under weak light conditions, and KARs promote seed germination through transcriptional activation of gibberellin (GA) biosynthesis via SMAX1. SMAX1 interacts with the DELLA proteins REPRESSOR of ga1-3-LIKE 1 (RGL1) and RGL3. The interaction enhances the transcriptional activity of SMAX1 and inhibits GIBBERELLIN 3-oxidase 2 (GA3ox2) gene expression. The KAR signaling mutant seed germination defect under weak light is partially rescued by exogenous application of GA3 or by GA3ox2 overexpression, and the rgl1 rgl3 smax1 triple mutant exhibits higher germination rates under weak light than the smax1 mutant. Thus, we show a crosstalk between KAR and GA signaling pathways via a SMAX1-DELLA module in regulating seed germination in Arabidopsis.
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Affiliation(s)
- Peipei Xu
- Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai 200032, China; University of Chinese Academy of Sciences, Beijing 100039, China.
| | - Jinbo Hu
- Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai 200032, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Haiying Chen
- Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai 200032, China
| | - Weiming Cai
- Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai 200032, China.
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3
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GAO X, LIU Y, LIU C, GUO C, ZHANG Y, MA C, DUAN X. Individual and combined effects of arbuscular mycorrhizal fungi and phytohormones on the growth and physiobiochemical characteristics of tea cutting seedlings. FRONTIERS IN PLANT SCIENCE 2023; 14:1140267. [PMID: 37056488 PMCID: PMC10086264 DOI: 10.3389/fpls.2023.1140267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 03/07/2023] [Indexed: 06/19/2023]
Abstract
Both arbuscular mycorrhizal fungi (AMF) and phytohormones collectively regulate plant growth and root development, but their individual and combined effects on tea [Camellia sinensis (L.) O. Kuntze] cutting seedings remain unclear. This study examined the individual and combined effects of two species of AMF (Rhizophagus intraradices, RI and Funneliformis mosseae, FM) and two types of palnt hormones (strigolactones, SLs; polyamines, PAs) on tea cutting seedings, by evaluating the growth and physiobiochemical characteristics of plants treated with the AMFs and/or hormones. The results showed that inoculation with either AMF individually or hormones treatment alone could significantly enhanced mycorrhizal colonization, growth target and physiobiochemical characteristics of tea cutting seedlings. Interestingly, the addition of a combination of AMFs and hormones showed superior effects, while SL and RI exhibited the most improvements to the colonization rate, plant growth, root-morphological traits, root DHA activity, photosynthesis, chlorophyll content, soluble sugar content in leaves, and the activities of antioxidant enzymes (SOD, POD, and CAT), compared to other treatment combinations (SL + FM, PA + RI, and PA + FM). Correlation analyses revealed a significantly (p < 0.05) positive correlation of root AMF colonization with root-related traits (e.g., DHA, root total length, surface area, and volume) and leaf-related traits (e.g., leaf area, shoot biomass, total chlorophyll, and antioxidant enzyme activities). This study demonstrated that while the apllication of individual AMF or plant hormones had a certain good effects on most growth and physiobiochemical characteristics parameters of tea cutting seedings, the additive effect was from specific combined of AMF and plant hormones. These results highlight the possibility for combined of AMF and plant hormones to improve the asexual reproduction of tea plants via cuttings.
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Affiliation(s)
- Xiubing GAO
- Guizhou Tea Research Institute, Guizhou Province Academy of Agricultural Science, Guiyang, Guizhou, China
- College of Horticalture and Gardening, Yangtze University, Jingzhou, Hubei, China
| | - Yan LIU
- Guizhou Institutes of Biology, Guizhou Academy of Sciences, Guiyang, Guizhou, China
| | - Chunyan LIU
- College of Horticalture and Gardening, Yangtze University, Jingzhou, Hubei, China
| | - Can GUO
- Guizhou Tea Research Institute, Guizhou Province Academy of Agricultural Science, Guiyang, Guizhou, China
| | - Yuan ZHANG
- Guizhou Tea Research Institute, Guizhou Province Academy of Agricultural Science, Guiyang, Guizhou, China
| | - Chiyu MA
- Guizhou Tea Research Institute, Guizhou Province Academy of Agricultural Science, Guiyang, Guizhou, China
| | - Xueyi DUAN
- Guizhou Tea Research Institute, Guizhou Province Academy of Agricultural Science, Guiyang, Guizhou, China
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4
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Yin L, Zander M, Huang SSC, Xie M, Song L, Saldierna Guzmán JP, Hann E, Shanbhag BK, Ng S, Jain S, Janssen BJ, Clark NM, Walley JW, Beddoe T, Bar-Joseph Z, Lewsey MG, Ecker JR. Transcription Factor Dynamics in Cross-Regulation of Plant Hormone Signaling Pathways. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.07.531630. [PMID: 36945593 PMCID: PMC10028877 DOI: 10.1101/2023.03.07.531630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Cross-regulation between hormone signaling pathways is indispensable for plant growth and development. However, the molecular mechanisms by which multiple hormones interact and co-ordinate activity need to be understood. Here, we generated a cross-regulation network explaining how hormone signals are integrated from multiple pathways in etiolated Arabidopsis (Arabidopsis thaliana) seedlings. To do so we comprehensively characterized transcription factor activity during plant hormone responses and reconstructed dynamic transcriptional regulatory models for six hormones; abscisic acid, brassinosteroid, ethylene, jasmonic acid, salicylic acid and strigolactone/karrikin. These models incorporated target data for hundreds of transcription factors and thousands of protein-protein interactions. Each hormone recruited different combinations of transcription factors, a subset of which were shared between hormones. Hub target genes existed within hormone transcriptional networks, exhibiting transcription factor activity themselves. In addition, a group of MITOGEN-ACTIVATED PROTEIN KINASES (MPKs) were identified as potential key points of cross-regulation between multiple hormones. Accordingly, the loss of function of one of these (MPK6) disrupted the global proteome, phosphoproteome and transcriptome during hormone responses. Lastly, we determined that all hormones drive substantial alternative splicing that has distinct effects on the transcriptome compared with differential gene expression, acting in early hormone responses. These results provide a comprehensive understanding of the common features of plant transcriptional regulatory pathways and how cross-regulation between hormones acts upon gene expression.
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Affiliation(s)
- Lingling Yin
- La Trobe Institute for Agriculture and Food, Department of Animal, Plant and Soil Sciences, School of Agriculture Biomedicine and Environment, AgriBio Building, La Trobe University, Melbourne, VIC 3086, Australia
- Australian Research Council Industrial Transformation Research Hub for Medicinal Agriculture, AgriBio Building, La Trobe University, Bundoora, VIC 3086, Australia
| | - Mark Zander
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Present address: Waksman Institute of Microbiology, Department of Plant Biology, Rutgers, The State University of New Jersey, NJ 08854, USA
| | - Shao-shan Carol Huang
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Present address: Department of Biology, New York University, New York, NY 10003, USA
| | - Mingtang Xie
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Present address: Cibus, San Diego, CA 92121, USA
| | - Liang Song
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Present address: Department of Botany, The University of British Columbia, Vancouver, British Columbia, Canada
| | - J. Paola Saldierna Guzmán
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Present address: Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Elizabeth Hann
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Present address: Department of Chemical and Environmental Engineering, Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Bhuvana K. Shanbhag
- La Trobe Institute for Agriculture and Food, Department of Animal, Plant and Soil Sciences, School of Agriculture Biomedicine and Environment, AgriBio Building, La Trobe University, Melbourne, VIC 3086, Australia
- Australian Research Council Industrial Transformation Research Hub for Medicinal Agriculture, AgriBio Building, La Trobe University, Bundoora, VIC 3086, Australia
| | - Sophia Ng
- La Trobe Institute for Agriculture and Food, Department of Animal, Plant and Soil Sciences, School of Agriculture Biomedicine and Environment, AgriBio Building, La Trobe University, Melbourne, VIC 3086, Australia
- Australian Research Council Industrial Transformation Research Hub for Medicinal Agriculture, AgriBio Building, La Trobe University, Bundoora, VIC 3086, Australia
| | - Siddhartha Jain
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Bart J. Janssen
- The New Zealand Institute for Plant & Food Research Limited, Auckland, New Zealand
| | - Natalie M. Clark
- Proteomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA, 02142 USA
- Department of Plant Pathology, Entomology, and Microbiology, Iowa State University, Ames, IA, 50011 USA
| | - Justin W. Walley
- Department of Plant Pathology, Entomology, and Microbiology, Iowa State University, Ames, IA, 50011 USA
| | - Travis Beddoe
- La Trobe Institute for Agriculture and Food, Department of Animal, Plant and Soil Sciences, School of Agriculture Biomedicine and Environment, AgriBio Building, La Trobe University, Melbourne, VIC 3086, Australia
- Australian Research Council Industrial Transformation Research Hub for Medicinal Agriculture, AgriBio Building, La Trobe University, Bundoora, VIC 3086, Australia
| | - Ziv Bar-Joseph
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Mathew G. Lewsey
- La Trobe Institute for Agriculture and Food, Department of Animal, Plant and Soil Sciences, School of Agriculture Biomedicine and Environment, AgriBio Building, La Trobe University, Melbourne, VIC 3086, Australia
- Australian Research Council Industrial Transformation Research Hub for Medicinal Agriculture, AgriBio Building, La Trobe University, Bundoora, VIC 3086, Australia
- Australian Research Council Centre of Excellence in Plants For Space, AgriBio Building, La Trobe University, Bundoora, VIC 3086, Australia
| | - Joseph R. Ecker
- Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Genomic Analysis Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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5
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Zheng X, Liu F, Yang X, Li W, Chen S, Yue X, Jia Q, Sun X. The MAX2-KAI2 module promotes salicylic acid-mediated immune responses in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023. [PMID: 36738234 DOI: 10.1111/jipb.13463] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Arabidopsis MORE AXILLARY GROWTH2 (MAX2) is a key component in the strigolactone (SL) and karrikin (KAR) signaling pathways and regulates the degradation of SUPPRESSOR OF MAX2 1/SMAX1-like (SMAX1/SMXL) proteins, which are transcriptional co-repressors that regulate plant architecture, as well as abiotic and biotic stress responses. The max2 mutation reduces resistance against Pseudomonas syringae pv. tomato (Pst). To uncover the mechanism of MAX2-mediated resistance, we evaluated the resistance of various SL and KAR signaling pathway mutants. The resistance of SL-deficient mutants and of dwarf 14 (d14) was similar to that of the wild-type, whereas the resistance of the karrikin insensitive 2 (kai2) mutant was compromised, demonstrating that the KAR signaling pathway, not the SL signaling pathway, positively regulates the immune response. We measured the resistance of smax1 and smxl mutants, as well as the double, triple, and quadruple mutants with max2, which revealed that both the smax1 mutant and smxl6/7/8 triple mutant rescue the low resistance phenotype of max2 and that SMAX1 accumulation diminishes resistance. The susceptibility of smax1D, containing a degradation-insensitive form of SMAX1, further confirmed the SMAX1 function in the resistance. The relationship between the accumulation of SMAX1/SMXLs and disease resistance suggested that the inhibitory activity of SMAX1 to resistance requires SMXL6/7/8. Moreover, the exogenous application of KAR2 enhanced resistance against Pst, but KAR-induced resistance depended on salicylic acid (SA) signaling. Inhibition of karrikin signaling delayed SA-mediated defense responses and inhibited pathogen-induced protein biosynthesis. Together, we propose that the MAX2-KAI2-SMAX1 complex regulates resistance with the assistance of SMXL6/7/8 and SA signaling and that SMAX1/SMXLs possibly form a multimeric complex with their target transcription factors to fine tune immune responses.
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Affiliation(s)
- Xiujuan Zheng
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - Fangqian Liu
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - Xianfeng Yang
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - Weiqiang Li
- Jilin Da'an Agro-ecosystem National Observation Research Station, Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China
| | - Sique Chen
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - Xinwu Yue
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - Qi Jia
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - Xinli Sun
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
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6
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Li Z, Pi Y, Zhai C, Xu D, Ma W, Chen H, Li Y, Wu H. The strigolactone receptor SlDWARF14 plays a role in photosynthetic pigment accumulation and photosynthesis in tomato. PLANT CELL REPORTS 2022; 41:2089-2105. [PMID: 35907035 DOI: 10.1007/s00299-022-02908-4] [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: 04/06/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Tomato DWARF14 regulates the development of roots, shoot branches and leaves, and also plays a role in photosynthetic pigment accumulation and photosynthetic capacity. Strigolactones (SLs) are a novel class of plant hormones. DWARF14 (D14) is the only SL receptor identified to date, but it is not functionally analyzed in tomato (Solanum lycopersicum). In the present study, we identified the potential SL receptor in tomato by bioinformatic analysis, which was designated as SlD14. SlD14 was expressed in roots, stems, flowers and developing fruits, with the highest expression level in leaves. sld14 mutant plants produced by the CRISPR/Cas9 system displayed reduced plant height and root biomass, increased shoot branching and altered leaf shape comparing with WT plants. The cytokinin biosynthetic gene ISOPENTENYLTRANSFERASE 3 (SlIPT3), auxin biosynthetic genes FLOOZY (SlFZY) and TRYPTOPHAN AMINOTRANSFERASE RELATED 1 (SlTAR1) and several auxin transport genes SlPINs, which are involved in branch formation, showed higher expression levels in the sld14 plant stem. In addition, sld14 plants exhibited light-green leaves, reduced chlorophyll and carotenoid contents, abnormal chloroplast structure and reduced photosynthetic capacity. Transcriptomic analysis showed that the transcript levels of six chlorophyll biosynthetic genes, three carotenoid biosynthetic genes and numerous chlorophyll a/b-binding protein genes were decreased in sld14 plants. These results suggest that tomato SL receptor gene SlD14 not only regulates the development of roots, shoot branches and leaves, but also plays a role in regulating photosynthetic pigment accumulation and photosynthetic capacity.
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Affiliation(s)
- Zhifei Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ying Pi
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Changsheng Zhai
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Dong Xu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Wenyao Ma
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Hong Chen
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Yi Li
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, CT, 06269, USA
| | - Han Wu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
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7
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Bonhomme S, Guillory A. Synthesis and signalling of strigolactone and KAI2-ligand signals in bryophytes. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4487-4495. [PMID: 35524989 DOI: 10.1093/jxb/erac186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 05/04/2022] [Indexed: 06/14/2023]
Abstract
Strigolactones (SLs), long known as butenolide rhizospheric signals, have been recognized since 2008 as a class of hormones regulating many aspects of plant development. Many authors also anticipate 'KAI2-ligand' (KL) as a novel class of phytohormones; however, this ligand remains elusive. Core genes of SL and KL pathways, first described in angiosperms, are found in all land plants and some even in green algae. This review reports current knowledge of these pathways in bryophytes. Data on the pathways mostly come from two models: the moss Physcomitrium patens and the liverwort Marchantia. Gene targeting methods have allowed functional analyses of both models. Recent work in Marchantia suggests that SLs' ancestral role was to recruit beneficial microbes as arbuscular mycorrhizal fungi. In contrast, the hormonal role of SLs observed in P. patens is probably a result of convergent evolution. Evidence for a functional KL pathway in both bryophyte models is very recent. Nevertheless, many unknowns remain and warrant a more extensive investigation of SL and KL pathways in various land plant lineages.
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Affiliation(s)
- Sandrine Bonhomme
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Ambre Guillory
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
- Laboratoire des Interactions Plantes - Microbes - Environnement (LIPME), Université de Toulouse, INRAE, CNRS, 24 Chemin de Borde Rouge, 31320 Castanet-Tolosan, France
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8
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Comparative Transcriptome Analysis of Two Kalanchoë Species during Plantlet Formation. PLANTS 2022; 11:plants11131643. [PMID: 35807595 PMCID: PMC9268976 DOI: 10.3390/plants11131643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 11/29/2022]
Abstract
Few species in the Kalanchoë genus form plantlets on their leaf margins as an asexual reproduction strategy. The limited molecular studies on plantlet formation show that an organogenesis ortholog, SHOOTMERISTEMLESS (STM) and embryogenesis genes, such as LEAFY COTYLEDON1 (LEC1) and FUSCA3 are recruited during plantlet formation. To understand the mechanisms of two Kalanchoë plantlet-forming species with different modes of plantlet formation, RNA-sequencing analysis was performed. Differentially expressed genes between the developmental stages were clustered in K. daigremontiana (Raym.-Hamet and H. Perrier) and K. pinnata (Lam. Pers.), respectively. Of these gene clusters, GO terms that may be involved in plantlet formation of both species, such as signaling, response to wounding, reproduction, regulation of hormone level, and response to karrikin were overrepresented. Compared with the common GO terms, there were more unique GO terms overrepresented during the plantlet formation of each species. A more in-depth investigation is required to understand how these pathways are participating in plantlet formation. Nonetheless, this transcriptome analysis is presented as a reliable basis for future studies on plantlet formation and development in two Kalanchoë plantlet-forming species.
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9
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Cabrera J, Conesa CM, Del Pozo JC. May the dark be with roots: a perspective on how root illumination may bias in vitro research on plant-environment interactions. THE NEW PHYTOLOGIST 2022; 233:1988-1997. [PMID: 34942016 DOI: 10.1111/nph.17936] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 12/16/2021] [Indexed: 06/14/2023]
Abstract
Roots anchor plants to the soil, providing them with nutrients and water while creating a defence network and facilitating beneficial interactions with a multitude of living organisms and climatological conditions. To facilitate morphological and molecular studies, root research has been conducted using in vitro systems. However, under natural conditions, roots grow in the dark, mainly in the absence of illumination, except for the relatively low illumination of the upper soil surface, and this has been largely ignored. Here, we discuss the results found over the last decade on how experimental exposure of roots to light may bias root development and responses through the alteration of hormonal signalling, cytoskeleton organization, reactive oxygen species or the accumulation of flavonoids, among other factors. Illumination alters the uptake of nutrients or water, and also affects the response of the roots to abiotic stresses and root interactions with the microbiota. Furthermore, we review in vitro systems created to maintain roots in darkness, and provide a comparative analysis of root transcriptomes obtained with these devices. Finally, we identify other experimental variables that should be considered to better mimic soil conditions, whose improvement would benefit studies using in vitro cultivation or enclosed ecosystems.
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Affiliation(s)
- Javier Cabrera
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria/Consejo Superior de Investigaciones Científicas (UPM-INIA/CSIC), UPM, Campus de Montegancedo, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Carlos M Conesa
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria/Consejo Superior de Investigaciones Científicas (UPM-INIA/CSIC), UPM, Campus de Montegancedo, Pozuelo de Alarcón, 28223, Madrid, Spain
- Escuela Técnica Superior de Ingeniería Agronómica, Agroambiental y de Biosistemas (ETSIAAB), Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Juan C Del Pozo
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria/Consejo Superior de Investigaciones Científicas (UPM-INIA/CSIC), UPM, Campus de Montegancedo, Pozuelo de Alarcón, 28223, Madrid, Spain
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10
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Guercio AM, Torabi S, Cornu D, Dalmais M, Bendahmane A, Le Signor C, Pillot JP, Le Bris P, Boyer FD, Rameau C, Gutjahr C, de Saint Germain A, Shabek N. Structural and functional analyses explain Pea KAI2 receptor diversity and reveal stereoselective catalysis during signal perception. Commun Biol 2022; 5:126. [PMID: 35149763 PMCID: PMC8837635 DOI: 10.1038/s42003-022-03085-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/28/2022] [Indexed: 11/10/2022] Open
Abstract
KAI2 proteins are plant α/β hydrolase receptors which perceive smoke-derived butenolide signals and endogenous, yet unidentified KAI2-ligands (KLs). The number of functional KAI2 receptors varies among species and KAI2 gene duplication and sub-functionalization likely plays an adaptative role by altering specificity towards different KLs. Legumes represent one of the largest families of flowering plants and contain many agronomic crops. Prior to their diversification, KAI2 underwent duplication resulting in KAI2A and KAI2B. Here we demonstrate that Pisum sativum KAI2A and KAI2B are active receptors and enzymes with divergent ligand stereoselectivity. KAI2B has a higher affinity for and hydrolyses a broader range of substrates including strigolactone-like stereoisomers. We determine the crystal structures of PsKAI2B in apo and butenolide-bound states. The biochemical, structural, and mass spectra analyses of KAI2s reveal a transient intermediate on the catalytic serine and a stable adduct on the catalytic histidine, confirming its role as a bona fide enzyme. Our work uncovers the stereoselectivity of ligand perception and catalysis by diverged KAI2 receptors and proposes adaptive sensitivity to KAR/KL and strigolactones by KAI2B.
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Affiliation(s)
- Angelica M Guercio
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA, 95616, USA
| | - Salar Torabi
- Plant Genetics, TUM School of Life Sciences, Technical University of Munich (TUM), 85354, Freising, Germany
| | - David Cornu
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Marion Dalmais
- Institute of Plant Sciences Paris-Saclay, INRAE, CNRS, Université Paris-Saclay, 91405, Orsay, France
| | - Abdelhafid Bendahmane
- Institute of Plant Sciences Paris-Saclay, INRAE, CNRS, Université Paris-Saclay, 91405, Orsay, France
| | - Christine Le Signor
- Agroecologie, AgroSup Dijon, INRAE, Université Bourgogne Franche Comte, 21000, Dijon, France
| | - Jean-Paul Pillot
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Philippe Le Bris
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - François-Didier Boyer
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198, Gif-sur-Yvette, France
| | - Catherine Rameau
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Caroline Gutjahr
- Plant Genetics, TUM School of Life Sciences, Technical University of Munich (TUM), 85354, Freising, Germany
| | | | - Nitzan Shabek
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA, 95616, USA.
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11
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Guillory A, Bonhomme S. Phytohormone biosynthesis and signaling pathways of mosses. PLANT MOLECULAR BIOLOGY 2021; 107:245-277. [PMID: 34245404 DOI: 10.1007/s11103-021-01172-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
Most known phytohormones regulate moss development. We present a comprehensive view of the synthesis and signaling pathways for the most investigated of these compounds in mosses, focusing on the model Physcomitrium patens. The last 50 years of research have shown that most of the known phytohormones are synthesized by the model moss Physcomitrium patens (formerly Physcomitrella patens) and regulate its development, in interaction with responses to biotic and abiotic stresses. Biosynthesis and signaling pathways are best described in P. patens for the three classical hormones auxins, cytokinins and abscisic acid. Furthermore, their roles in almost all steps of development, from early filament growth to gametophore development and sexual reproduction, have been the focus of much research effort over the years. Evidence of hormonal roles exist for ethylene and for CLE signaling peptides, as well as for salicylic acid, although their possible effects on development remain unclear. Production of brassinosteroids by P. patens is still debated, and modes of action for these compounds are even less known. Gibberellin biosynthesis and signaling may have been lost in P. patens, while gibberellin precursors such as ent-kaurene derivatives could be used as signals in a yet to discover pathway. As for jasmonic acid, it is not used per se as a hormone in P. patens, but its precursor OPDA appears to play a corresponding role in defense against abiotic stress. We have tried to gather a comprehensive view of the biosynthesis and signaling pathways for all these compounds in mosses, without forgetting strigolactones, the last class of plant hormones to be reported. Study of the strigolactone response in P. patens points to a novel signaling compound, the KAI2-ligand, which was likely employed as a hormone prior to land plant emergence.
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Affiliation(s)
- Ambre Guillory
- INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), Université Paris-Saclay, 78000, Versailles, France
| | - Sandrine Bonhomme
- INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), Université Paris-Saclay, 78000, Versailles, France.
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12
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Hull R, Choi J, Paszkowski U. Conditioning plants for arbuscular mycorrhizal symbiosis through DWARF14-LIKE signalling. CURRENT OPINION IN PLANT BIOLOGY 2021; 62:102071. [PMID: 34186295 PMCID: PMC8425181 DOI: 10.1016/j.pbi.2021.102071] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/11/2021] [Accepted: 05/24/2021] [Indexed: 06/13/2023]
Abstract
The evolutionarily ancient α/β hydrolase DWARF14-LIKE (D14L) is indispensable for the perception of beneficial arbuscular mycorrhizal (AM) fungi in the rhizosphere, and for a range of developmental processes. Variants of D14L recognise natural strigolactones and the smoke constituent karrikin, both classified as butenolides, and additional unknown ligand(s), critical for symbiosis and development. Recent advances in the understanding of downstream effects of D14L signalling include biochemical evidence for the degradation of the repressor SMAX1. Indeed, genetic removal of rice SMAX1 leads to the de-repression of symbiosis programmes and to the simultaneous increase in strigolactone production. As strigolactones are key to attraction of the fungus in the rhizosphere, the D14L signalling pathway appears to coordinate fungal stimulation and root symbiotic competency. Here, we discuss the possible integrative roles of D14L signalling in conditioning plants for AM symbiosis.
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Affiliation(s)
- Raphaella Hull
- Crop Science Centre, Department of Plant Sciences, University of Cambridge, Lawrence Weaver Road, Cambridge CB3 0LE, UK
| | - Jeongmin Choi
- Crop Science Centre, Department of Plant Sciences, University of Cambridge, Lawrence Weaver Road, Cambridge CB3 0LE, UK
| | - Uta Paszkowski
- Crop Science Centre, Department of Plant Sciences, University of Cambridge, Lawrence Weaver Road, Cambridge CB3 0LE, UK.
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13
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Yao J, Scaffidi A, Meng Y, Melville KT, Komatsu A, Khosla A, Nelson DC, Kyozuka J, Flematti GR, Waters MT. Desmethyl butenolides are optimal ligands for karrikin receptor proteins. THE NEW PHYTOLOGIST 2021; 230:1003-1016. [PMID: 33474738 DOI: 10.1111/nph.17224] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/16/2021] [Indexed: 05/25/2023]
Abstract
Strigolactones and karrikins are butenolide molecules that regulate plant growth. They are perceived by the α/β-hydrolase DWARF14 (D14) and its homologue KARRIKIN INSENSITIVE2 (KAI2), respectively. Plant-derived strigolactones have a butenolide ring with a methyl group that is essential for bioactivity. By contrast, karrikins are abiotic in origin, and the butenolide methyl group is nonessential. KAI2 is probably a receptor for an endogenous butenolide, but the identity of this compound remains unknown. Here we characterise the specificity of KAI2 towards differing butenolide ligands using genetic and biochemical approaches. We find that KAI2 proteins from multiple species are most sensitive to desmethyl butenolides that lack a methyl group. Desmethyl-GR24 and desmethyl-CN-debranone are active by KAI2 but not D14. They are more potent KAI2 agonists compared with their methyl-substituted reference compounds both in vitro and in plants. The preference of KAI2 for desmethyl butenolides is conserved in Selaginella moellendorffii and Marchantia polymorpha, suggesting that it is an ancient trait in land plant evolution. Our findings provide insight into the mechanistic basis for differential ligand perception by KAI2 and D14, and support the view that the endogenous substrates for KAI2 and D14 have distinct chemical structures and biosynthetic origins.
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Affiliation(s)
- Jiaren Yao
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, WA, 6009, Australia
| | - Adrian Scaffidi
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Yongjie Meng
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, WA, 6009, Australia
| | - Kim T Melville
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, WA, 6009, Australia
| | - Aino Komatsu
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan
| | - Aashima Khosla
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
| | - David C Nelson
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
| | - Junko Kyozuka
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan
| | - Gavin R Flematti
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Mark T Waters
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, WA, 6009, Australia
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14
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Bouwmeester H, Li C, Thiombiano B, Rahimi M, Dong L. Adaptation of the parasitic plant lifecycle: germination is controlled by essential host signaling molecules. PLANT PHYSIOLOGY 2021; 185:1292-1308. [PMID: 33793901 PMCID: PMC8133609 DOI: 10.1093/plphys/kiaa066] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/12/2020] [Indexed: 05/25/2023]
Abstract
Parasitic plants are plants that connect with a haustorium to the vasculature of another, host, plant from which they absorb water, assimilates, and nutrients. Because of this parasitic lifestyle, parasitic plants need to coordinate their lifecycle with that of their host. Parasitic plants have evolved a number of host detection/host response mechanisms of which the germination in response to chemical host signals in one of the major families of parasitic plants, the Orobanchaceae, is a striking example. In this update review, we discuss these germination stimulants. We review the different compound classes that function as germination stimulants, how they are produced, and in which host plants. We discuss why they are reliable signals, how parasitic plants have evolved mechanisms that detect and respond to them, and whether they play a role in host specificity. The advances in the knowledge underlying this signaling relationship between host and parasitic plant have greatly improved our understanding of the evolution of plant parasitism and are facilitating the development of more effective control measures in cases where these parasitic plants have developed into weeds.
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Affiliation(s)
- Harro Bouwmeester
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Changsheng Li
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Benjamin Thiombiano
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Mehran Rahimi
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Lemeng Dong
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
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15
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Arabidopsis SMAX1 overaccumulation suppresses rosette shoot branching and promotes leaf and petiole elongation. Biochem Biophys Res Commun 2021; 553:44-50. [PMID: 33756344 DOI: 10.1016/j.bbrc.2021.03.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 03/01/2021] [Indexed: 12/21/2022]
Abstract
ARABIDOPSIS SMAX1/SMXL (SUPPRESSOR OF MAX2 1/SMAX1-LIKE) proteins function as transcriptional repressors in karrikin and strigolactone (SL) signaling pathways and regulate plant architecture. MAX2 is a common factor in the two signaling pathways and a component of the SCF complex that modulates the proteasome-mediated degradation of SMAX1/SMXLs. SMXL6, 7, and 8 proteins promote shoot branching and inhibit petiole elongation. Our study found that the accumulation of SMAX1 suppresses rosette shoot branching and increases cauline branches on the primary inflorescence stem, plant height, petiole length, and leaf length/width ratio. The SMAX1 accumulation enhances the expression of BRC1, HB53, HB40, and HB21 that modulate shoot branching. SMAX1 also regulates the expression of the genes involved in auxin transport, cytokinin signaling pathway, and SL biosynthesis. The expression analyses of these genes suggest that excessive SMAX1 should accelerate the transport of auxin and the biosynthesis of SL in plants. High SL concentration suppresses the bud development in smax1D mutant that accumulates SMAX1 protein in plant. However, the effects of cytokinin and auxin on shoot branching remain elusive in the mutant with excessive SMAX1. SMAX1 regulates leaf shape and petiole length via modulating TCP1 expression. Our findings reveal a novel function of SMAX1 and new mechanism of shoot branching.
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16
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Rahimi M, Bouwmeester H. Are sesquiterpene lactones the elusive KARRIKIN-INSENSITIVE2 ligand? PLANTA 2021; 253:54. [PMID: 33521891 PMCID: PMC7847861 DOI: 10.1007/s00425-021-03571-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/08/2021] [Indexed: 05/15/2023]
Abstract
MAIN CONCLUSION The sunflower sesquiterpene lactones 8-epixanthatin and tomentosin can bind to the hydrophobic pocket of sunflower KAI2 with an affinity much higher than for the exogenous ligand KAR. Sesquiterpene lactones (STLs) are secondary plant metabolites with a wide range of biological, such as anti-microbial, activities. Intriguingly, the STLs have also been implicated in plant development: in several Asteraceae, STL levels correlate with the photo-inhibition of hypocotyl elongation. Although this effect was suggested to be due to auxin transport inhibition, there is no structural-functional evidence for this claim. Intriguingly, the light-induced inhibition of hypocotyl elongation in Arabidopsis has been ascribed to HYPOSENSITIVE TO LIGHT/KARRIKIN-INSENSITIVE2 (HTL/KAI2) signaling. KAI2 was discovered because of its affinity to the smoke-derived karrikin (KAR), though it is generally assumed that KAI2 has another, endogenous but so far elusive, ligand rather than the exogenous KARs. Here, we postulate that the effect of STLs on hypocotyl elongation is mediated through KAI2 signaling. To support this hypothesis, we have generated homology models of the sunflower KAI2s (HaKAI2s) and used them for molecular docking studies with STLs. Our results show that particularly two sunflower STLs, 8-epixanthatin and tomentosin, can bind to the hydrophobic pockets of HaKAI2s with high affinity. Our results are in line with a recent study, showing that these two STLs accumulate in the light-exposed hypocotyls of sunflower. This finding sheds light on the effect of STLs in hypocotyl elongation that has been reported for many decades but without conclusive insight in the elusive mechanism underlying this effect.
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Affiliation(s)
- Mehran Rahimi
- Plant Hormone Biology Group, Green Life Sciences Cluster, Swammerdam Institute for Life Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Harro Bouwmeester
- Plant Hormone Biology Group, Green Life Sciences Cluster, Swammerdam Institute for Life Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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17
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Bose U, Juhász A, Broadbent JA, Komatsu S, Colgrave ML. Multi-Omics Strategies for Decoding Smoke-Assisted Germination Pathways and Seed Vigour. Int J Mol Sci 2020; 21:E7512. [PMID: 33053786 PMCID: PMC7593932 DOI: 10.3390/ijms21207512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/07/2020] [Accepted: 10/09/2020] [Indexed: 01/02/2023] Open
Abstract
The success of seed germination and the successful establishment of seedlings across diverse environmental conditions depends on seed vigour, which is of both economic and ecologic importance. The smoke-derived exogenous compound karrikins (KARs) and the endogenous plant hormone strigolactone (SL) are two classes of butanolide-containing molecules that follow highly similar signalling pathways to control diverse biological activities in plants. Unravelling the precise mode-of-action of these two classes of molecules in model species has been a key research objective. However, the specific and dynamic expression of biomolecules upon stimulation by these signalling molecules remains largely unknown. Genomic and post-genomic profiling approaches have enabled mining and association studies across the vast genetic diversity and phenotypic plasticity. Here, we review the background of smoke-assisted germination and vigour and the current knowledge of how plants perceive KAR and SL signalling and initiate the crosstalk with the germination-associated hormone pathways. The recent advancement of 'multi-omics' applications are discussed in the context of KAR signalling and with relevance to their adoption for superior agronomic trait development. The remaining challenges and future opportunities for integrating multi-omics datasets associated with their application in KAR-dependent seed germination and abiotic stress tolerance are also discussed.
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Affiliation(s)
- Utpal Bose
- CSIRO Agriculture and Food, 306 Carmody Rd, St Lucia, QLD 4067, Australia; (U.B.); (J.A.B.)
| | - Angéla Juhász
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, School of Science, Edith Cowan University, Joondalup, WA 6027, Australia;
| | - James A. Broadbent
- CSIRO Agriculture and Food, 306 Carmody Rd, St Lucia, QLD 4067, Australia; (U.B.); (J.A.B.)
| | - Setsuko Komatsu
- Department of Environmental and Food Sciences, Fukui University of Technology, Fukui 910-8505, Japan
| | - Michelle L. Colgrave
- CSIRO Agriculture and Food, 306 Carmody Rd, St Lucia, QLD 4067, Australia; (U.B.); (J.A.B.)
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, School of Science, Edith Cowan University, Joondalup, WA 6027, Australia;
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18
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The karrikin signaling regulator SMAX1 controls Lotus japonicus root and root hair development by suppressing ethylene biosynthesis. Proc Natl Acad Sci U S A 2020; 117:21757-21765. [PMID: 32817510 DOI: 10.1073/pnas.2006111117] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
An evolutionarily ancient plant hormone receptor complex comprising the α/β-fold hydrolase receptor KARRIKIN INSENSITIVE 2 (KAI2) and the F-box protein MORE AXILLARY GROWTH 2 (MAX2) mediates a range of developmental responses to smoke-derived butenolides called karrikins (KARs) and to yet elusive endogenous KAI2 ligands (KLs). Degradation of SUPPRESSOR OF MAX2 1 (SMAX1) after ligand perception is considered to be a key step in KAR/KL signaling. However, molecular events which regulate plant development downstream of SMAX1 removal have not been identified. Here we show that Lotus japonicus SMAX1 is specifically degraded in the presence of KAI2 and MAX2 and plays an important role in regulating root and root hair development. smax1 mutants display very short primary roots and elongated root hairs. Their root transcriptome reveals elevated ethylene responses and expression of ACC Synthase 7 (ACS7), which encodes a rate-limiting enzyme in ethylene biosynthesis. smax1 mutants release increased amounts of ethylene and their root phenotype is rescued by treatment with ethylene biosynthesis and signaling inhibitors. KAR treatment induces ACS7 expression in a KAI2-dependent manner and root developmental responses to KAR treatment depend on ethylene signaling. Furthermore, in Arabidopsis, KAR-induced root hair elongation depends on ACS7 Thus, we reveal a connection between KAR/KL and ethylene signaling in which the KAR/KL signaling module (KAI2-MAX2-SMAX1) regulates the biosynthesis of ethylene to fine-tune root and root hair development, which are important for seedling establishment at the beginning of the plant life cycle.
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19
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Spring O, Schmauder K, Lackus ND, Schreiner J, Meier C, Wellhausen J, Smith LV, Frey M. Spatial and developmental synthesis of endogenous sesquiterpene lactones supports function in growth regulation of sunflower. PLANTA 2020; 252:2. [PMID: 32504343 PMCID: PMC7275010 DOI: 10.1007/s00425-020-03409-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 05/29/2020] [Indexed: 05/28/2023]
Abstract
Tissue-specific occurrence and formation of endogenous sesquiterpene lactones has been assessed and suggests physiological function as antagonists of auxin-induced plant growth in sunflower. Sunflower, Helianthus annuus, accumulate high concentrations of bioactive sesquiterpene lactones (STL) in glandular trichomes, but in addition, structurally different STL occur in only trace amounts in the inner tissues. The spatial and temporal production of these endogenous STL during early phases of plant development is widely unknown and their physiological function as putative natural growth regulators is yet speculative. By means of HPLC and MS analysis it was shown that costunolide, dehydrocostuslactone, 8-epixanthatin and tomentosin are already present in dry seeds and can be extracted in low amounts from cotyledons, hypocotyls and roots of seedlings during the first days after germination. Semi-quantitative and RT-qPCR experiments with genes of the key enzymes of two independent routes of the endogenous STL biosynthesis confirmed the early and individual expression in these organs and revealed a gradual down regulation during the first 72-96 h after germination. Light irradiation of the plants led to a fast, but transient increase of STL in parts of the hypocotyl which correlated with growth retardation of the stem. One-sided external application of costunolide on hypocotyls conferred reduced growth of the treated side, thus resulting in the curving of the stem towards the side of the application. This indicates the inhibiting effects of STL on plant growth. The putative function of endogenous STL in sunflower as antagonists of auxin in growth processes is discussed.
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Affiliation(s)
- Otmar Spring
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70593, Stuttgart, Germany.
| | - Katharina Schmauder
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70593, Stuttgart, Germany
| | - Nathalie D Lackus
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70593, Stuttgart, Germany
| | - Jasmin Schreiner
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70593, Stuttgart, Germany
| | - Carolin Meier
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70593, Stuttgart, Germany
| | - Jan Wellhausen
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70593, Stuttgart, Germany
| | - Lisa V Smith
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70593, Stuttgart, Germany
| | - Maximilian Frey
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70593, Stuttgart, Germany
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