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Chang W, Qiao Q, Li Q, Li X, Li Y, Huang X, Wang Y, Li J, Wang B, Wang L. Non-transcriptional regulatory activity of SMAX1 and SMXL2 mediates karrikin-regulated seedling response to red light in Arabidopsis. MOLECULAR PLANT 2024; 17:1054-1072. [PMID: 38807366 DOI: 10.1016/j.molp.2024.05.007] [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: 07/25/2023] [Revised: 04/09/2024] [Accepted: 05/26/2024] [Indexed: 05/30/2024]
Abstract
Karrikins and strigolactones govern plant development and environmental responses through closely related signaling pathways. The transcriptional repressor proteins SUPPRESSOR OF MAX2 1 (SMAX1), SMAX1-like2 (SMXL2), and D53-like SMXLs mediate karrikin and strigolactone signaling by directly binding downstream genes or by inhibiting the activities of transcription factors. In this study, we characterized the non-transcriptional regulatory activities of SMXL proteins in Arabidopsis. We discovered that SMAX1 and SMXL2 with mutations in their ethylene-response factor-associated amphiphilic repression (EAR) motif had undetectable or weak transcriptional repression activities but still partially rescued the hypocotyl elongation defects and fully reversed the cotyledon epinasty defects of the smax1 smxl2 mutant. SMAX1 and SMXL2 directly interact with PHYTOCHROME INTERACTION FACTOR 4 (PIF4) and PIF5 to enhance their protein stability by interacting with phytochrome B (phyB) and suppressing the association of phyB with PIF4 and PIF5. The karrikin-responsive genes were then identified by treatment with GR24ent-5DS, a GR24 analog showing karrikin activity. Interestingly, INDOLE-3-ACETIC ACID INDUCIBLE 29 (IAA29) expression was repressed by GR24ent-5DS treatment in a PIF4- and PIF5-dependent and EAR-independent manner, whereas KARRIKIN UPREGULATED F-BOX 1 (KUF1) expression was induced in a PIF4- and PIF5-independent and EAR-dependent manner. Furthermore, the non-transcriptional regulatory activity of SMAX1, which is independent of the EAR motif, had a global effect on gene expression. Taken together, these results indicate that non-transcriptional regulatory activities of SMAX1 and SMXL2 mediate karrikin-regulated seedling response to red light.
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Affiliation(s)
- Wenwen Chang
- Key Laboratory of Seed Innovation, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiao Qiao
- Key Laboratory of Seed Innovation, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingtian Li
- Yazhouwan National Laboratory, Sanya, Hainan 572024, China
| | - Xin Li
- Key Laboratory of Seed Innovation, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanyan Li
- Key Laboratory of Seed Innovation, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China
| | - Xiahe Huang
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, The Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Yingchun Wang
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, The Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiayang Li
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, The Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; Yazhouwan National Laboratory, Sanya, Hainan 572024, China
| | - Bing Wang
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, The Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Lei Wang
- Key Laboratory of Seed Innovation, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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2
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Park YJ, Nam BE, Park CM. Environmentally adaptive reshaping of plant photomorphogenesis by karrikin and strigolactone signaling. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2024; 66:865-882. [PMID: 38116738 DOI: 10.1111/jipb.13602] [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: 08/06/2023] [Revised: 12/09/2023] [Accepted: 12/18/2023] [Indexed: 12/21/2023]
Abstract
Coordinated morphogenic adaptation of growing plants is critical for their survival and propagation under fluctuating environments. Plant morphogenic responses to light and warm temperatures, termed photomorphogenesis and thermomorphogenesis, respectively, have been extensively studied in recent decades. During photomorphogenesis, plants actively reshape their growth and developmental patterns to cope with changes in light regimes. Accordingly, photomorphogenesis is closely associated with diverse growth hormonal cues. Notably, accumulating evidence indicates that light-directed morphogenesis is profoundly affected by two recently identified phytochemicals, karrikins (KARs) and strigolactones (SLs). KARs and SLs are structurally related butenolides acting as signaling molecules during a variety of developmental steps, including seed germination. Their receptors and signaling mediators have been identified, and associated working mechanisms have been explored using gene-deficient mutants in various plant species. Of particular interest is that the KAR and SL signaling pathways play important roles in environmental responses, among which their linkages with photomorphogenesis are most comprehensively studied during seedling establishment. In this review, we focus on how the phytochemical and light signals converge on the optimization of morphogenic fitness. We also discuss molecular mechanisms underlying the signaling crosstalks with an aim of developing potential ways to improve crop productivity under climate changes.
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Affiliation(s)
- Young-Joon Park
- Department of Smart Farm Science, Kyung Hee University, Yongin, 17104, Korea
| | - Bo Eun Nam
- Department of Biological Sciences, Seoul National University, Seoul, 08826, Korea
| | - Chung-Mo Park
- Department of Chemistry, Seoul National University, Seoul, 08826, Korea
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3
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Li Q, Yu H, Chang W, Chang S, Guzmán M, Faure L, Wallner ES, Yan H, Greb T, Wang L, Yao R, Nelson DC. SMXL5 attenuates strigolactone signaling in Arabidopsis thaliana by inhibiting SMXL7 degradation. MOLECULAR PLANT 2024; 17:631-647. [PMID: 38475994 DOI: 10.1016/j.molp.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 01/10/2024] [Accepted: 03/07/2024] [Indexed: 03/14/2024]
Abstract
Hormone-activated proteolysis is a recurring theme of plant hormone signaling mechanisms. In strigolactone signaling, the enzyme receptor DWARF14 (D14) and an F-box protein, MORE AXILLARY GROWTH2 (MAX2), mark SUPPRESSOR OF MAX2 1-LIKE (SMXL) family proteins SMXL6, SMXL7, and SMXL8 for rapid degradation. Removal of these transcriptional corepressors initiates downstream growth responses. The homologous proteins SMXL3, SMXL4, and SMXL5, however, are resistant to MAX2-mediated degradation. We discovered that the smxl4 smxl5 mutant has enhanced responses to strigolactone. SMXL5 attenuates strigolactone signaling by interfering with AtD14-SMXL7 interactions. SMXL5 interacts with AtD14 and SMXL7, providing two possible ways to inhibit SMXL7 degradation. SMXL5 function is partially dependent on an ethylene-responsive-element binding-factor-associated amphiphilic repression (EAR) motif, which typically mediates interactions with the TOPLESS family of transcriptional corepressors. However, we found that loss of the EAR motif reduces SMXL5-SMXL7 interactions and the attenuation of strigolactone signaling by SMXL5. We hypothesize that integration of SMXL5 into heteromeric SMXL complexes reduces the susceptibility of SMXL6/7/8 proteins to strigolactone-activated degradation and that the EAR motif promotes the formation or stability of these complexes. This mechanism may provide a way to spatially or temporally fine-tune strigolactone signaling through the regulation of SMXL5 expression or translation.
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Affiliation(s)
- Qingtian Li
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA; Yazhouwan National Laboratory, Sanya 572025, China; Hainan Seed Industry Laboratory, Sanya 57205, China.
| | - Haiyang Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, China
| | - Wenwen Chang
- Key Laboratory of Seed Innovation, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sunhyun Chang
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Michael Guzmán
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Lionel Faure
- School of the Sciences, Biology Division, Texas Woman's University, Denton, TX 76204, USA
| | - Eva-Sophie Wallner
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
| | - Heqin Yan
- Yazhouwan National Laboratory, Sanya 572025, China
| | - Thomas Greb
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
| | - Lei Wang
- Key Laboratory of Seed Innovation, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China
| | - Ruifeng Yao
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, China.
| | - David C Nelson
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA.
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Nomura T, Seto Y, Kyozuka J. Unveiling the complexity of strigolactones: exploring structural diversity, biosynthesis pathways, and signaling mechanisms. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1134-1147. [PMID: 37877933 DOI: 10.1093/jxb/erad412] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/20/2023] [Indexed: 10/26/2023]
Abstract
Strigolactone is the collective name for compounds containing a butenolide as a part of their structure, first discovered as compounds that induce seed germination of root parasitic plants. They were later found to be rhizosphere signaling molecules that induce hyphal branching of arbuscular mycorrhizal fungi, and, finally, they emerged as a class of plant hormones. Strigolactones are found in root exudates, where they display a great variability in their chemical structure. Their structure varies among plant species, and multiple strigolactones can exist in one species. Over 30 strigolactones have been identified, yet the chemical structure of the strigolactone that functions as an endogenous hormone and is found in the above-ground parts of plants remains unknown. We discuss our current knowledge of the synthetic pathways of diverse strigolactones and their regulation, as well as recent progress in identifying strigolactones as plant hormones. Strigolactone is perceived by the DWARF14 (D14), receptor, an α/β hydrolase which originated by gene duplication of KARRIKIN INSENSITIVE 2 (KAI2). D14 and KAI2 signaling pathways are partially overlapping paralogous pathways. Progress in understanding the signaling mechanisms mediated by two α/β hydrolase receptors as well as remaining challenges in the field of strigolactone research are reviewed.
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Affiliation(s)
- Takahito Nomura
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Japan
| | - Yoshiya Seto
- School of Agriculture, Meiji University, Kawasaki, Japan
| | - Junko Kyozuka
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
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5
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Zhang C, Wang F, Jiao P, Liu J, Zhang H, Liu S, Guan S, Ma Y. The Overexpression of Zea mays Strigolactone Receptor Gene D14 Enhances Drought Resistance in Arabidopsis thaliana L. Int J Mol Sci 2024; 25:1327. [PMID: 38279328 PMCID: PMC10816222 DOI: 10.3390/ijms25021327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/11/2024] [Accepted: 01/16/2024] [Indexed: 01/28/2024] Open
Abstract
Strigolactones (SLs) represent a recently identified class of plant hormones that are crucial for plant tillering and mycorrhizal symbiosis. The D14 gene, an essential receptor within the SLs signaling pathway, has been well-examined in crops, like rice (Oryza sativa L.) and Arabidopsis (Arabidopsis thaliana L.), yet the research on its influence in maize (Zea mays L.) remains scarce. This study successfully clones and establishes Arabidopsis D14 gene overexpression lines (OE lines). When compared with the wild type (WT), the OE lines exhibited significantly longer primary roots during germination. By seven weeks of age, these lines showed reductions in plant height and tillering, alongside slight decreases in rosette and leaf sizes, coupled with early aging symptoms. Fluorescence-based quantitative assays indicated notable hormonal fluctuations in OE lines versus the WT, implying that D14 overexpression disrupts plant hormonal homeostasis. The OE lines, exposed to cold, drought, and sodium chloride stressors during germination, displayed an especially pronounced resistance to drought. The drought resistance of OE lines, as evident from dehydration-rehydration assays, outmatched that of the WT lines. Additionally, under drought conditions, the OE lines accumulated less reactive oxygen species (ROS) as revealed by the assessment of the related physiological and biochemical parameters. Upon confronting the pathogens Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), post-infection, fluorescence quantitative investigations showed a significant boost in the salicylic acid (SA)-related gene expression in OE lines compared to their WT counterparts. Overall, our findings designate the SL receptor D14 as a key upregulator of drought tolerance and a regulator in the biotic stress response, thereby advancing our understanding of the maize SL signaling pathway by elucidating the function of the pivotal D14 gene.
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Affiliation(s)
- Chen Zhang
- College of Life Sciences, Jilin Agricultural University, Changchun 130118, China; (C.Z.); (F.W.)
| | - Fanhao Wang
- College of Life Sciences, Jilin Agricultural University, Changchun 130118, China; (C.Z.); (F.W.)
| | - Peng Jiao
- College of Agronomy, Jilin Agricultural University, Changchun 130118, China; (P.J.); (J.L.); (H.Z.); (S.L.)
- Joint International Research Laboratory of Modern Agricultural Technology, Ministry of Education, Jilin Agricultural University, Changchun 130118, China
| | - Jiaqi Liu
- College of Agronomy, Jilin Agricultural University, Changchun 130118, China; (P.J.); (J.L.); (H.Z.); (S.L.)
- Joint International Research Laboratory of Modern Agricultural Technology, Ministry of Education, Jilin Agricultural University, Changchun 130118, China
| | - Honglin Zhang
- College of Agronomy, Jilin Agricultural University, Changchun 130118, China; (P.J.); (J.L.); (H.Z.); (S.L.)
- Joint International Research Laboratory of Modern Agricultural Technology, Ministry of Education, Jilin Agricultural University, Changchun 130118, China
| | - Siyan Liu
- College of Agronomy, Jilin Agricultural University, Changchun 130118, China; (P.J.); (J.L.); (H.Z.); (S.L.)
- Joint International Research Laboratory of Modern Agricultural Technology, Ministry of Education, Jilin Agricultural University, Changchun 130118, China
| | - Shuyan Guan
- College of Agronomy, Jilin Agricultural University, Changchun 130118, China; (P.J.); (J.L.); (H.Z.); (S.L.)
- Joint International Research Laboratory of Modern Agricultural Technology, Ministry of Education, Jilin Agricultural University, Changchun 130118, China
| | - Yiyong Ma
- College of Agronomy, Jilin Agricultural University, Changchun 130118, China; (P.J.); (J.L.); (H.Z.); (S.L.)
- Joint International Research Laboratory of Modern Agricultural Technology, Ministry of Education, Jilin Agricultural University, Changchun 130118, China
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6
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Fang P, Li M, Guo Q, Wu X, Hu Y, Cheng Y, Xu P. Genome-wide analysis of the SMXL gene family in common bean and identification of karrikin-responsive PvSMXL2 as a negative regulator of PEG-induced drought stress. Gene 2023; 887:147741. [PMID: 37634881 DOI: 10.1016/j.gene.2023.147741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/05/2023] [Accepted: 08/24/2023] [Indexed: 08/29/2023]
Abstract
Common bean (Phaseolus vulgaris L.) is a major legume crop worldwide, but its growth and development frequently face challenges due to abiotic stresses, particularly drought. Proper supplement of copper could mitigate the adverse effects of drought, but excessive accumulation of this metal in plants can be harmful. The suppressor of MAX2 1-like (SMXL) gene family, which plays important roles in various plant processes, including stress responses, remains poorly understood in common bean. In this study, we identified nine orthologues of SMXL genes in common bean, which are located on six chromosomes and classified into four subgroups. Basic molecular properties, including theoretical isoelectric point (PI), molecular weight (MW), grand average of hydropathicity (GVIO), gene structure, and conserved motifs were characterized, and numerous cis-elements in promoters were predicted. The expression patterns of PvSMXL genes were found to be distinct under 10% polyethylene glycol (PEG)-induced drought stress and 200 μM Cu treatments. Most PvSMXLs showed reduced expression in response to Cu treatment, whereas nearly half PvSMXLs exhibited inducible expression under drought stress. PvSMXL2, which exhibited a rapid response to karrikin 1 (KAR1), an active form of the plant growth regulators newly found in the smoke of burning plant material, was down-regulated by both PEG-induced drought and Cu stresses. Transient silencing of PvSMXL2 resulted in enhanced drought stress tolerance without conferring Cu tolerance. These findings provide valuable insights into the functions of SMXL genes in common bean under abiotic stress conditions.
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Affiliation(s)
- Pingping Fang
- Key Laboratory of Specialty Agri-Product Quality and Hazard Controlling Technology of Zhejiang, College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Minxuan Li
- Key Laboratory of Specialty Agri-Product Quality and Hazard Controlling Technology of Zhejiang, College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Qinwei Guo
- Quzhou Key Laboratory for Germplasm Innovation and Utilization of Crop, Institute of Vegetables, Quzhou Academy of Agricultural and Forestry Sciences, Quzhou 324000, PR China
| | - Xinyang Wu
- Key Laboratory of Specialty Agri-Product Quality and Hazard Controlling Technology of Zhejiang, College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Yannan Hu
- Key Laboratory of Specialty Agri-Product Quality and Hazard Controlling Technology of Zhejiang, College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Yusu Cheng
- Key Laboratory of Specialty Agri-Product Quality and Hazard Controlling Technology of Zhejiang, College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China
| | - Pei Xu
- Key Laboratory of Specialty Agri-Product Quality and Hazard Controlling Technology of Zhejiang, College of Life Sciences, China Jiliang University, Hangzhou 310018, PR China.
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7
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Basso MF, Contaldi F, Lo Celso F, Baratto CM, Grossi-de-Sa MF, Barone G, Ferrante A, Martinelli F. Identification and expression profile of the SMAX/SMXL family genes in chickpea and lentil provide important players of biotechnological interest involved in plant branching. PLANTA 2023; 259:1. [PMID: 37966555 PMCID: PMC10651550 DOI: 10.1007/s00425-023-04277-y] [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: 08/17/2023] [Accepted: 10/28/2023] [Indexed: 11/16/2023]
Abstract
MAIN CONCLUSION SMAX/SMXL family genes were successfully identified and characterized in the chickpea and lentil and gene expression data revealed several genes associated with the modulation of plant branching and powerful targets for use in transgenesis and genome editing. Strigolactones (SL) play essential roles in plant growth, rooting, development, and branching, and are associated with plant resilience to abiotic and biotic stress conditions. Likewise, karrikins (KAR) are "plant smoke-derived molecules" that act in a hormonal signaling pathway similar to SL playing an important role in seed germination and hairy root elongation. The SMAX/SMXL family genes are part of these two signaling pathways, in addition to some of these members acting in a still little known SL- and KAR-independent signaling pathway. To date, the identification and functional characterization of the SMAX/SMXL family genes has not been performed in the chickpea and lentil. In this study, nine SMAX/SMXL genes were systematically identified and characterized in the chickpea and lentil, and their expression profiles were explored under different unstressless or different stress conditions. After a comprehensive in silico characterization of the genes, promoters, proteins, and protein-protein interaction network, the expression profile for each gene was determined using a meta-analysis from the RNAseq datasets and complemented with real-time PCR analysis. The expression profiles of the SMAX/SMXL family genes were very dynamic in different chickpea and lentil organs, with some genes assuming a tissue-specific expression pattern. In addition, these genes were significantly modulated by different stress conditions, indicating that SMAX/SMXL genes, although working in three distinct signaling pathways, can act to modulate plant resilience. Most CaSMAX/SMXL and partner genes such as CaTiE1 and CaLAP1, have a positive correlation with the plant branching level, while most LcSMAX/SMXL genes were less correlated with the plant branching level. The SMXL6, SMXL7, SMXL8, TiE1, LAP1, BES1, and BRC1 genes were highlighted as powerful targets for use in transgenesis and genome editing aiming to develop chickpea and lentil cultivars with improved architecture. Therefore, this study presented a detailed characterization of the SMAX/SMXL genes in the chickpea and lentil, and provided new insights for further studies focused on each SMAX/SMXL gene.
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Affiliation(s)
| | - Felice Contaldi
- Department of Biology, University of Florence, 50019, Sesto Fiorentino, Italy
| | - Fabrizio Lo Celso
- Department of Physics and Chemical, University of Palermo, Viale Delle Scienze, Edificio 17, 90128, Palermo, Italy
| | - César Milton Baratto
- University of Western Santa Catarina, Biotechnological Center, UNOESC, Videira, SC, 89566-252, Brazil
| | | | - Giampaolo Barone
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Viale Delle Scienze, Edificio 17, 90128, Palermo, Italy
| | - Antonio Ferrante
- Department of Agricultural and Environmental Sciences, University of Milan, Via Festa del Perdono, 20122, Milan, Italy
| | - Federico Martinelli
- Department of Biology, University of Florence, 50019, Sesto Fiorentino, Italy.
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8
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Kun Yuan, Zhang H, Yu C, Luo N, Yan J, Zheng S, Hu Q, Zhang D, Kou L, Meng X, Jing Y, Chen M, Ban X, Yan Z, Lu Z, Wu J, Zhao Y, Liang Y, Wang Y, Xiong G, Chu J, Wang E, Li J, Wang B. Low phosphorus promotes NSP1-NSP2 heterodimerization to enhance strigolactone biosynthesis and regulate shoot and root architecture in rice. MOLECULAR PLANT 2023; 16:1811-1831. [PMID: 37794682 DOI: 10.1016/j.molp.2023.09.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 08/18/2023] [Accepted: 09/28/2023] [Indexed: 10/06/2023]
Abstract
Phosphorus is an essential macronutrient for plant development and metabolism, and plants have evolved ingenious mechanisms to overcome phosphate (Pi) starvation. However, the molecular mechanisms underlying the regulation of shoot and root architecture by low phosphorus conditions and the coordinated utilization of Pi and nitrogen remain largely unclear. Here, we show that Nodulation Signaling Pathway 1 (NSP1) and NSP2 regulate rice tiller number by promoting the biosynthesis of strigolactones (SLs), a class of phytohormones with fundamental effects on plant architecture and environmental responses. We found that NSP1 and NSP2 are induced by Oryza sativa PHOSPHATE STARVATION RESPONSE2 (OsPHR2) in response to low-Pi stress and form a complex to directly bind the promoters of SL biosynthesis genes, thus markedly increasing SL biosynthesis in rice. Interestingly, the NSP1/2-SL signaling module represses the expression of CROWN ROOTLESS 1 (CRL1), a newly identified early SL-responsive gene in roots, to restrain lateral root density under Pi deficiency. We also demonstrated that GR244DO treatment under normal conditions inhibits the expression of OsNRTs and OsAMTs to suppress nitrogen absorption but enhances the expression of OsPTs to promote Pi absorption, thus facilitating the balance between nitrogen and phosphorus uptake in rice. Importantly, we found that NSP1p:NSP1 and NSP2p:NSP2 transgenic plants show improved agronomic traits and grain yield under low- and medium-phosphorus conditions. Taken together, these results revealed a novel regulatory mechanism of SL biosynthesis and signaling in response to Pi starvation, providing genetic resources for improving plant architecture and nutrient-use efficiency in low-Pi environments.
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Affiliation(s)
- Kun Yuan
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hao Zhang
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaoji Yu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Nan Luo
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jijun Yan
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Shuang Zheng
- University of Chinese Academy of Sciences, Beijing 100049, China; National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, SIBS, Chinese Academy of Sciences, Shanghai 200032, China
| | - Qingliang Hu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Dahan Zhang
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liquan Kou
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiangbing Meng
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanhui Jing
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Mingjiang Chen
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Xinwei Ban
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zongyun Yan
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Zefu Lu
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jian Wu
- Guangdong Laboratory for Lingnan Modern Agriculture, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, China
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Yan Liang
- College of Life Sciences, Shandong Agriculture University, Tai'an, Shandong 271018, China
| | - Yonghong Wang
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; College of Life Sciences, Shandong Agriculture University, Tai'an, Shandong 271018, China
| | - Guosheng Xiong
- Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing 210095, China
| | - Jinfang Chu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ertao Wang
- University of Chinese Academy of Sciences, Beijing 100049, China; National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, SIBS, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jiayang Li
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Yazhouwan National Laboratory, Sanya, Hainan 572024, China
| | - Bing Wang
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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9
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Basso MF, Contaldi F, Celso FL, Karalija E, Paz-Carrasco LC, Barone G, Ferrante A, Martinelli F. Expression profile of the NCED/CCD genes in chickpea and lentil during abiotic stress reveals a positive correlation with increased plant tolerance. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 336:111817. [PMID: 37562731 DOI: 10.1016/j.plantsci.2023.111817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/28/2023] [Accepted: 08/03/2023] [Indexed: 08/12/2023]
Abstract
Carotenoid cleavage dioxygenase (CCD) gene family is organized in two subfamilies: (i) 9-cis epoxycarotenoid dioxygenase (NCED) genes and (ii) CCD genes. NCED genes are essential for catalyzing the first step of the abscisic-acid (ABA) biosynthesis, while CCD genes produce precursors of the strigolactones hormone. The functional characterization of these gene subfamilies has not been yet performed in chickpea and lentil. Herein, were identified and systematically characterized two NCED and five CCD genes in the chickpea and two NCED and six CCD genes in lentil. After in silico sequence analysis and phylogeny, the expression profile of the NCED/CCD genes was determined by meta-analysis and real-time PCR in plants under different stress conditions. Sequence data revealed that NCED/CCD genes are highly conserved between chickpea and lentil. This conservation was observed both at gene and protein sequence levels and phylogenetic relationships. Analysis of the promoter sequences revealed that all NCED/CCD genes have a considerable number of cis-regulatory elements responsive to biotic and abiotic stress. Protein sequence analysis evidenced that NCED/CCD genes share several conserved motifs and that they have a highly interconnected interaction network. Furthermore, the three-dimensional structure of these proteins was determined and indicated that some proteins have structures with considerable similarity. The meta-analysis revealed that NCED/CCD genes are dynamically modulated in different organs and under different stress conditions, but they have a positive correlation with plant tolerance. In accordance, real-time PCR data showed that both NCED and CCD genes are differentially modulated in plants under drought stress. In particular, CaNCED2, CaCCD5, LcNCED2, LcCCD1, and LcCCD2 genes have a positive correlation with improved plant tolerance to drought stress. Therefore, this study presented a detailed characterization of the chickpea and lentil NCED/CCD genes and provided new insights to improve abiotic stress tolerance in these two important crops.
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Affiliation(s)
- Marcos Fernando Basso
- Department of Biology, University of Florence, Sesto Fiorentino 50019, Florence, Italy; University of Western Santa Catarina, Biotechnological Center, UNOESC, Videira, SC 89566-252, Brazil
| | - Felice Contaldi
- Department of Biology, University of Florence, Sesto Fiorentino 50019, Florence, Italy
| | - Fabrizio Lo Celso
- Department of Physics and Chemical, University of Palermo, Viale delle Scienze, Edificio 17, 90128 Palermo, Italy
| | - Erna Karalija
- Department of Biology, University of Florence, Sesto Fiorentino 50019, Florence, Italy; Department of Biology, Faculty of science, University of Sarajevo, Zmaja od Bosne 33-35, 71000 Sarajevo, Bosnia and Herzegovina
| | - Lenin Celiano Paz-Carrasco
- National Institute of Agricultural Research (INIAP), Plant Pathology Department and Rice Breeding Program, Km 26 vía Duran-Tambo, Yaguachi, Guayas, Ecuador
| | - Giampaolo Barone
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Viale delle Scienze, Edificio 17, 90128 Palermo, Italy
| | - Antonio Ferrante
- Department of Agricultural and Environmental Sciences, Università degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy
| | - Federico Martinelli
- Department of Biology, University of Florence, Sesto Fiorentino 50019, Florence, Italy.
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10
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Drummond RSM, Lee HW, Luo Z, Dakin JF, Janssen BJ, Snowden KC. Varying the expression pattern of the strigolactone receptor gene DAD2 results in phenotypes distinct from both wild type and knockout mutants. FRONTIERS IN PLANT SCIENCE 2023; 14:1277617. [PMID: 37900765 PMCID: PMC10600376 DOI: 10.3389/fpls.2023.1277617] [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: 08/14/2023] [Accepted: 09/22/2023] [Indexed: 10/31/2023]
Abstract
The action of the petunia strigolactone (SL) hormone receptor DAD2 is dependent not only on its interaction with the PhMAX2A and PhD53A proteins, but also on its expression patterns within the plant. Previously, in a yeast-2-hybrid system, we showed that a series of a single and double amino acid mutants of DAD2 had altered interactions with these binding partners. In this study, we tested the mutants in two plant systems, Arabidopsis and petunia. Testing in Arabidopsis was enabled by creating a CRISPR-Cas9 knockout mutant of the Arabidopsis strigolactone receptor (AtD14). We produced SL receptor activity in both systems using wild type and mutant genes; however, the mutants had functions largely indistinguishable from those of the wild type. The expression of the wild type DAD2 from the CaMV 35S promoter in dad2 petunia produced plants neither quite like the dad2 mutant nor the V26 wild type. These plants had greater height and leaf size although branch number and the plant shape remained more like those of the mutant. These traits may be valuable in the context of a restricted area growing system such as controlled environment agriculture.
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Affiliation(s)
- Revel S. M. Drummond
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | | | | | | | | | - Kimberley C. Snowden
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
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11
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Varshney K, Gutjahr C. KAI2 Can Do: Karrikin Receptor Function in Plant Development and Response to Abiotic and Biotic Factors. PLANT & CELL PHYSIOLOGY 2023; 64:984-995. [PMID: 37548562 PMCID: PMC10504578 DOI: 10.1093/pcp/pcad077] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/02/2023] [Accepted: 07/14/2023] [Indexed: 08/08/2023]
Abstract
The α/β hydrolase KARRIKIN INSENSITIVE 2 (KAI2) functions as a receptor for a yet undiscovered phytohormone, provisionally termed KAI2 ligand (KL). In addition, it perceives karrikin, a butenolide compound found in the smoke of burnt plant material. KAI2-mediated signaling is involved in regulating seed germination and in shaping seedling and adult plant morphology, both above and below ground. It also governs responses to various abiotic stimuli and stresses and shapes biotic interactions. KAI2-mediated signaling is being linked to an elaborate cross-talk with other phytohormone pathways such as auxin, gibberellin, abscisic acid, ethylene and salicylic acid signaling, in addition to light and nutrient starvation signaling. Further connections will likely be revealed in the future. This article summarizes recent advances in unraveling the function of KAI2-mediated signaling and its interaction with other signaling pathways.
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Affiliation(s)
- Kartikye Varshney
- Department of Root Biology and Symbiosis, Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, Am Mühlenberg 1, Potsdam-Golm 14476, Germany
| | - Caroline Gutjahr
- Department of Root Biology and Symbiosis, Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, Am Mühlenberg 1, Potsdam-Golm 14476, Germany
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12
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Huizinga S, Bouwmeester HJ. Role of Strigolactones in the Host Specificity of Broomrapes and Witchweeds. PLANT & CELL PHYSIOLOGY 2023; 64:936-954. [PMID: 37319019 PMCID: PMC10504575 DOI: 10.1093/pcp/pcad058] [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: 05/11/2023] [Revised: 06/05/2023] [Accepted: 06/14/2023] [Indexed: 06/17/2023]
Abstract
Root parasitic plants of the Orobanchaceae, broomrapes and witchweeds, pose a severe problem to agriculture in Europe, Asia and especially Africa. These parasites are totally dependent on their host for survival, and therefore, their germination is tightly regulated by host presence. Indeed, their seeds remain dormant in the soil until a host root is detected through compounds called germination stimulants. Strigolactones (SLs) are the most important class of germination stimulants. They play an important role in planta as a phytohormone and, upon exudation from the root, function in the recruitment of symbiotic arbuscular mycorrhizal fungi. Plants exude mixtures of various different SLs, possibly to evade detection by these parasites and still recruit symbionts. Vice versa, parasitic plants must only respond to the SL composition that is exuded by their host, or else risk germination in the presence of non-hosts. Therefore, parasitic plants have evolved an entire clade of SL receptors, called HTL/KAI2s, to perceive the SL cues. It has been demonstrated that these receptors each have a distinct sensitivity and specificity to the different known SLs, which possibly allows them to recognize the SL-blend characteristic of their host. In this review, we will discuss the molecular basis of SL sensitivity and specificity in these parasitic plants through HTL/KAI2s and review the evidence that these receptors contribute to host specificity of parasitic plants.
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Affiliation(s)
- Sjors Huizinga
- Plant Hormone Biology Group, Green Life Sciences Cluster, Swammerdam Institute for Life Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Harro J Bouwmeester
- Plant Hormone Biology Group, Green Life Sciences Cluster, Swammerdam Institute for Life Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
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13
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Ma B, Zhu J, Huang X. Diversification of plant SUPPRESSOR OF MAX2 1 (SMAX1)-like genes and genome-wide identification and characterization of cotton SMXL gene family. BMC PLANT BIOLOGY 2023; 23:419. [PMID: 37691127 PMCID: PMC10494346 DOI: 10.1186/s12870-023-04421-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 08/25/2023] [Indexed: 09/12/2023]
Abstract
BACKGROUND Strigolactones (SLs) are a recently discovered class of plant hormones. SUPPRESSOR OF MAX2 1 (SMAX1)-like proteins, key component of the SL signaling pathway, have been studied extensively for their roles in regulating plant growth and development, such as plant branching. However, systematic identification and functional characterization of SMXL genes in cotton (Gossypium sp.), an important fiber and oil crop, has rarely been conducted. RESULTS We identified 210 SMXL genes from 21 plant genomes and examined their evolutionary relationships. The structural characteristics of the SMXL genes and their encoded proteins exhibited both consistency and diversity. All plant SMXL proteins possess a conserved Clp-N domain, P-loop NTPase, and EAR motif. We identified 63 SMXL genes in cotton and classified these into four evolutionary branches. Gene expression analysis revealed tissue-specific expression patterns of GhSMXL genes, with some upregulated in response to GR24 treatment. Protein co-expression network analysis showed that GhSMXL6, GhSMXL7-1, and GhSMXL7-2 mainly interact with proteins functioning in growth and development, while virus-induced gene silencing revealed that GhSMAX1-1 and GhSMAX1-2 suppress the growth and development of axillary buds. CONCLUSIONS SMXL gene family members show evolutionary diversification through the green plant lineage. GhSMXL6/7-1/7-2 genes play critical roles in the SL signaling pathway, while GhSMXL1-1 and GhSMXL1-2 function redundantly in growth of axillary buds. Characterization of the cotton SMXL gene family provides new insights into their roles in responding to SL signals and in plant growth and development. Genes identified in this study could be used as the candidate genes for improvement of plant architecture and crop yield.
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Affiliation(s)
- Bin Ma
- College of Life Sciences, Shihezi University, Shihezi, 832003, China
- Center for Crop Biotechnology, College of Agriculture, Anhui Science and Technology University, Fengyang, 233100, China
| | - Jianbo Zhu
- College of Life Sciences, Shihezi University, Shihezi, 832003, China
| | - Xianzhong Huang
- Center for Crop Biotechnology, College of Agriculture, Anhui Science and Technology University, Fengyang, 233100, China.
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14
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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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15
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Barbier F, Fichtner F, Beveridge C. The strigolactone pathway plays a crucial role in integrating metabolic and nutritional signals in plants. NATURE PLANTS 2023; 9:1191-1200. [PMID: 37488268 DOI: 10.1038/s41477-023-01453-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 05/24/2023] [Indexed: 07/26/2023]
Abstract
Strigolactones are rhizosphere signals and phytohormones that play crucial roles in plant development. They are also well known for their role in integrating nitrate and phosphate signals to regulate shoot and root development. More recently, sugars and citrate (an intermediate of the tricarboxylic acid cycle) were reported to inhibit the strigolactone response, with dramatic effects on shoot architecture. This Review summarizes the discoveries recently made concerning the mechanisms through which the strigolactone pathway integrates sugar, metabolite and nutrient signals. We highlight here that strigolactones and MAX2-dependent signalling play crucial roles in mediating the impacts of nutritional and metabolic cues on plant development and metabolism. We also discuss and speculate concerning the role of these interactions in plant evolution and adaptation to their environment.
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Affiliation(s)
- Francois Barbier
- School of Biological Sciences, University of Queensland, St Lucia, Queensland, Australia.
- ARC Centre of Excellence for Plant Success in Nature and Agriculture, University of Queensland, St Lucia, Queensland, Australia.
| | - Franziska Fichtner
- Institute of Plant Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christine Beveridge
- School of Biological Sciences, University of Queensland, St Lucia, Queensland, Australia
- ARC Centre of Excellence for Plant Success in Nature and Agriculture, University of Queensland, St Lucia, Queensland, Australia
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16
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Waters MT, Nelson DC. Karrikin perception and signalling. THE NEW PHYTOLOGIST 2023; 237:1525-1541. [PMID: 36333982 DOI: 10.1111/nph.18598] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
Karrikins (KARs) are a class of butenolide compounds found in smoke that were first identified as seed germination stimulants for fire-following species. Early studies of KARs classified the germination and postgermination responses of many plant species and investigated crosstalk with plant hormones that regulate germination. The discovery that Arabidopsis thaliana responds to KARs laid the foundation for identifying mutants with altered KAR responses. Genetic analysis of KAR signalling revealed an unexpected link to strigolactones (SLs), a class of carotenoid-derived plant hormones. Substantial progress has since been made towards understanding how KARs are perceived and regulate plant growth, in no small part due to advances in understanding SL perception. KAR and SL signalling systems are evolutionarily related and retain a high degree of similarity. There is strong evidence that KARs are natural analogues of an endogenous signal(s), KAI2 ligand (KL), which remains unknown. KAR/KL signalling regulates many developmental processes in plants including germination, seedling photomorphogenesis, and root and root hair growth. KAR/KL signalling also affects abiotic stress responses and arbuscular mycorrhizal symbiosis. Here, we summarise the current knowledge of KAR/KL signalling and discuss current controversies and unanswered questions in this field.
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Affiliation(s)
- Mark T Waters
- School of Molecular Sciences, University of Western Australia, Perth, WA, 6009, Australia
| | - David C Nelson
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
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17
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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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18
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Feng Z, Liang X, Tian H, Watanabe Y, Nguyen KH, Tran CD, Abdelrahman M, Xu K, Mostofa MG, Ha CV, Mochida K, Tian C, Tanaka M, Seki M, Liang Z, Miao Y, Tran LSP, Li W. SUPPRESSOR of MAX2 1 (SMAX1) and SMAX1-LIKE2 (SMXL2) Negatively Regulate Drought Resistance in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2023; 63:1900-1913. [PMID: 35681253 DOI: 10.1093/pcp/pcac080] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/13/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Recent investigations in Arabidopsis thaliana suggest that SUPPRESSOR of MORE AXILLARY GROWTH 2 1 (SMAX1) and SMAX1-LIKE2 (SMXL2) are negative regulators of karrikin (KAR) and strigolactone (SL) signaling during plant growth and development, but their functions in drought resistance and related mechanisms of action remain unclear. To understand the roles and mechanisms of SMAX1 and SMXL2 in drought resistance, we investigated the drought-resistance phenotypes and transcriptome profiles of smax1 smxl2 (s1,2) double-mutant plants in response to drought stress. The s1,2 mutant plants showed enhanced drought-resistance and lower leaf water loss when compared with wild-type (WT) plants. Transcriptome comparison of rosette leaves from the s1,2 mutant and the WT under normal and dehydration conditions suggested that the mechanism related to cuticle formation was involved in drought resistance. This possibility was supported by enhanced cuticle formation in the rosette leaves of the s1,2 mutant. We also found that the s1,2 mutant plants were more sensitive to abscisic acid in assays of stomatal closure, cotyledon opening, chlorophyll degradation and growth inhibition, and they showed a higher reactive oxygen species detoxification capacity than WT plants. In addition, the s1,2 mutant plants had longer root hairs and a higher root-to-shoot ratio than the WT plants, suggesting that the mutant had a greater capacity for water absorption than the WT. Taken together, our results indicate that SMAX1 and SMXL2 negatively regulate drought resistance, and disruption of these KAR- and SL-signaling-related genes may therefore provide a novel means for improving crop drought resistance.
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Affiliation(s)
- Zhonghui Feng
- Jilin Daan Agro-ecosystem National Observation Research Station, Changchun Jingyuetan Remote Sensing Experiment Station, Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 4888 Shengbei Street, Changchun 130102, China
- College of Life Science, Baicheng Normal University, No. 57, Zhongxing West Road, Taobei District, Baicheng 137000, China
- University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Xiaohan Liang
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, No. 85 Jinming Road, Kaifeng 475004, China
| | - Hongtao Tian
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, No. 85 Jinming Road, Kaifeng 475004, China
| | - Yasuko Watanabe
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, 230-0045 Japan
| | - Kien Huu Nguyen
- National Key Laboratory for Plant Cell Biotechnology, Agricultural Genetics Institute, Vietnam Academy of Agricultural Science, Pham Van Dong Street, Hanoi 100000, Vietnam
| | - Cuong Duy Tran
- Genetic Engineering Department, Agricultural Genetics Institute, Vietnamese Academy of Agricultural Science, Pham Van Dong Street, Hanoi 100000, Vietnam
| | - Mostafa Abdelrahman
- Botany Department, Faculty of Science, Aswan University, Aswan 81528, Egypt
- Molecular Biotechnology Program, Faculty of Science, Galala University, Suze, New Galala 43511, Egypt
| | - Kun Xu
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, No. 85 Jinming Road, Kaifeng 475004, China
| | - Mohammad Golam Mostofa
- Institute of Genomics for Crop Abiotic Stress Tolerance, Texas Tech University, 1006 Canton Ave, Lubbock, TX 79409, USA
| | - Chien Van Ha
- Institute of Genomics for Crop Abiotic Stress Tolerance, Texas Tech University, 1006 Canton Ave, Lubbock, TX 79409, USA
| | - Keiichi Mochida
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, 230-0045 Japan
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka-tyo, Totsuka, Yokohama, 244-0813 Japan
- RIKEN Baton Zone Program, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, 230-0045 Japan
- School of Information and Data Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521 Japan
| | - Chunjie Tian
- Jilin Daan Agro-ecosystem National Observation Research Station, Changchun Jingyuetan Remote Sensing Experiment Station, Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 4888 Shengbei Street, Changchun 130102, China
| | - Maho Tanaka
- Plant Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, 230-0045 Japan
- Plant Epigenome Regulation Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Motoaki Seki
- Plant Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, 230-0045 Japan
- Plant Epigenome Regulation Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Zhengwei Liang
- Jilin Daan Agro-ecosystem National Observation Research Station, Changchun Jingyuetan Remote Sensing Experiment Station, Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 4888 Shengbei Street, Changchun 130102, China
| | - Yuchen Miao
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, No. 85 Jinming Road, Kaifeng 475004, China
| | - Lam-Son Phan Tran
- Institute of Genomics for Crop Abiotic Stress Tolerance, Texas Tech University, 1006 Canton Ave, Lubbock, TX 79409, USA
| | - Weiqiang Li
- Jilin Daan Agro-ecosystem National Observation Research Station, Changchun Jingyuetan Remote Sensing Experiment Station, Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 4888 Shengbei Street, Changchun 130102, China
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, No. 85 Jinming Road, Kaifeng 475004, China
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19
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Tripathi DK, Yadav SR, Mochida K, Tran LSP. Plant Growth Regulators: True Managers of Plant Life. PLANT & CELL PHYSIOLOGY 2023; 63:1757-1760. [PMID: 36478104 DOI: 10.1093/pcp/pcac170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Affiliation(s)
- Durgesh Kumar Tripathi
- Crop Nanobiology and Molecular Stress Physiology Laboratory, Amity Institute of Organic Agriculture, Amity University Uttar Pradesh, Sector-125, Noida 201313, India
| | - Shri Ram Yadav
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Keiichi Mochida
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045 Japan
- Microalgae Production Control Technology Laboratory, RIKEN Baton Zone Program, Yokohama 230-0045 Japan
- Kihara Institute for Biological Research, Yokohama City University, Yokohama 244-0813, Japan
- School of Information and Data Sciences, Nagasaki University, Nagasaki 852-8521 Japan
| | - Lam-Son Phan Tran
- Department of Plant and Soil Science, Institute of Genomics for Crop Abiotic Stress Tolerance, Texas Tech University, Lubbock, TX 79409, USA
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20
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The Strigolactone Pathway Is a Target for Modifying Crop Shoot Architecture and Yield. BIOLOGY 2023; 12:biology12010095. [PMID: 36671787 PMCID: PMC9855930 DOI: 10.3390/biology12010095] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/05/2023] [Accepted: 01/05/2023] [Indexed: 01/11/2023]
Abstract
Due to their sessile nature, plants have developed the ability to adapt their architecture in response to their environment. Branching is an integral component of plant architecture, where hormonal signals tightly regulate bud outgrowth. Strigolactones (SLs), being a novel class of phytohormone, are known to play a key role in branching decisions, where they act as a negative regulator of bud outgrowth. They can achieve this by modulating polar auxin transport to interrupt auxin canalisation, and independently of auxin by acting directly within buds by promoting the key branching inhibitor TEOSINTE BRANCHED1. Buds will grow out in optimal conditions; however, when conditions are sub-optimal, SL levels increase to restrict branching. This can be a problem in agricultural applications, as reductions in branching can have deleterious effects on crop yield. Variations in promoter elements of key SL-related genes, such as IDEAL PLANT ARCHITECTURE1, have been identified to promote a phenotype with enhanced yield performance. In this review we highlight how this knowledge can be applied using new technologies to develop new genetic variants for improving crop shoot architecture and yield.
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21
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Xu P, Jinbo H, Cai W. Karrikin signaling regulates hypocotyl shade avoidance response by modulating auxin homeostasis in Arabidopsis. THE NEW PHYTOLOGIST 2022; 236:1748-1761. [PMID: 36068957 DOI: 10.1111/nph.18459] [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: 04/06/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
Shade affects all aspects of plant growth and development, including seed germination, hypocotyl elongation, petiole growth, leaf hyponasty, and flowering time. Here, we found that mutations in the key Arabidopsis karrikins signal perception-associated KARRIKIN INSENSITIVE 2 (KAI2) gene, encoding an α/β-fold hydrolase, and the MORE AXILLARY GROWTH 2 (MAX2) gene, encoding an F-box protein, led to greater hypocotyl elongation under shade avoidance conditions. We further verified that these phenotypes were caused by perception of the endogenous KAI2-ligands (KLs), and that this phenotype is independent of strigolactone biosynthetic or signaling pathways. Upon perception of a KL, it is probable that the target protein forms a complex with the KAI2/MAX2 proteins, which are degraded through the action of the 26S proteasome. We demonstrated that SUPPRESSOR OF MAX2-1 (SMAX1) is the degradation target for the KAI2/MAX2 complex in the context of shade avoidance. KAI2 and MAX2 require SMAX1 to limit the hypocotyl growth associated with shade avoidance. Treatment with l-kynurenine, an inhibitor of auxin accumulation, partially restored elongation of kai2 mutant hypocotyls under simulated shade. Furthermore, KAI2 is involved in regulating auxin accumulation and polar auxin transport, which may contribute to the hypocotyl shade response. In addition, SMAX1 gene overexpression promoted the hypocotyl shade response. RNA-sequencing analysis revealed that SMAX1-overexpression affected the expression of many auxin homeostasis genes, especially under simulated shade. Altogether, our data support the conclusion that KL signaling regulates shade avoidance by modulating auxin homeostasis in the hypocotyl.
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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, Shanghai, 200032, China
| | - Hu Jinbo
- Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100039, 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, Shanghai, 200032, China
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22
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Trasoletti M, Visentin I, Campo E, Schubert A, Cardinale F. Strigolactones as a hormonal hub for the acclimation and priming to environmental stress in plants. PLANT, CELL & ENVIRONMENT 2022; 45:3611-3630. [PMID: 36207810 PMCID: PMC9828678 DOI: 10.1111/pce.14461] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/29/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Strigolactones are phytohormones with many attributed roles in development, and more recently in responses to environmental stress. We will review evidence of the latter in the frame of the classic distinction among the three main stress acclimation strategies (i.e., avoidance, tolerance and escape), by taking osmotic stress in its several facets as a non-exclusive case study. The picture we will sketch is that of a hormonal family playing important roles in each of the mechanisms tested so far, and influencing as well the build-up of environmental memory through priming. Thus, strigolactones appear to be backstage operators rather than frontstage players, setting the tune of acclimation responses by fitting them to the plant individual history of stress experience.
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Affiliation(s)
| | | | - Eva Campo
- DISAFA, PlantStressLabTurin UniversityTurinItaly
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23
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Martinez SE, Conn CE, Guercio AM, Sepulveda C, Fiscus CJ, Koenig D, Shabek N, Nelson DC. A KARRIKIN INSENSITIVE2 paralog in lettuce mediates highly sensitive germination responses to karrikinolide. PLANT PHYSIOLOGY 2022; 190:1440-1456. [PMID: 35809069 PMCID: PMC9516758 DOI: 10.1093/plphys/kiac328] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
Karrikins (KARs) are chemicals in smoke that can enhance germination of many plants. Lettuce (Lactuca sativa) cv. Grand Rapids germinates in response to nanomolar karrikinolide (KAR1). Lettuce is much less responsive to KAR2 or a mixture of synthetic strigolactone analogs, rac-GR24. We investigated the molecular basis of selective and sensitive KAR1 perception in lettuce. The lettuce genome contains two copies of KARRIKIN INSENSITIVE2 (KAI2), which in Arabidopsis (Arabidopsis thaliana) encodes a receptor that is required for KAR responses. LsKAI2b is more highly expressed than LsKAI2a in dry achenes and during early stages of imbibition. Through cross-species complementation assays in Arabidopsis, we found that an LsKAI2b transgene confers robust responses to KAR1, but LsKAI2a does not. Therefore, LsKAI2b likely mediates KAR1 responses in lettuce. We compared homology models of KAI2 proteins from lettuce and a fire-follower, whispering bells (Emmenanthe penduliflora). This identified pocket residues 96, 124, 139, and 161 as candidates that influence the ligand specificity of KAI2. Further support for the importance of these residues was found through a broader comparison of pocket residues among 281 KAI2 proteins from 184 asterid species. Almost all KAI2 proteins had either Tyr or Phe identity at position 124. Genes encoding Y124-type KAI2 are more broadly distributed in asterids than in F124-type KAI2. Substitutions at residues 96, 124, 139, and 161 in Arabidopsis KAI2 produced a broad array of responses to KAR1, KAR2, and rac-GR24. This suggests that the diverse ligand preferences observed among KAI2 proteins in plants could have evolved through relatively few mutations.
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Affiliation(s)
- Stephanie E Martinez
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA
| | - Caitlin E Conn
- Department of Biology, Berry College, Mount Berry, Georgia 30149, USA
| | - Angelica M Guercio
- Department of Plant Biology, University of California, Davis, California 95616, USA
| | - Claudia Sepulveda
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA
| | - Christopher J Fiscus
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA
| | - Daniel Koenig
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA
| | - Nitzan Shabek
- Department of Plant Biology, University of California, Davis, California 95616, USA
| | - David C Nelson
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA
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24
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Genome-Wide Identification of SMXL Gene Family in Soybean and Expression Analysis of GmSMXLs under Shade Stress. PLANTS 2022; 11:plants11182410. [PMID: 36145811 PMCID: PMC9500757 DOI: 10.3390/plants11182410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 09/02/2022] [Accepted: 09/07/2022] [Indexed: 11/17/2022]
Abstract
SMXL6,7,8 are important target proteins in strigolactone (SL) signal pathway, which negatively regulate the reception and response of SL signal, and play an important role in regulating plant branching. However, there is a relative lack of research on soybean SMXL gene family. In this study, 31 soybean SMXL genes were identified by phylogenetic analysis and divided into three groups. Based on the analysis of GmSMXL gene’s structure and motif composition, it was found that the GmSMXL members in the same group were similar. The results of cis-element analysis showed that GmSMXL genes may regulate the growth and development of soybean by responding to hormones and environment. Based on the tissue specificity analysis and GR24 treatment, the results showed that four GmSMXLs in G1 group were predominantly expressed in stems, axillary buds and leaves and involved in SL signal pathway. Finally, under shading stress, the expression of four genes in G1 group was slightly different in different varieties, which may be the reason for the difference in branching ability of different varieties under shading stress. We have systematically studied the SMXL gene family in soybean, which may lay a foundation for the study of the function of GmSMXL gene in the future.
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25
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Ogawa S, Cui S, White ARF, Nelson DC, Yoshida S, Shirasu K. Strigolactones are chemoattractants for host tropism in Orobanchaceae parasitic plants. Nat Commun 2022; 13:4653. [PMID: 35970835 PMCID: PMC9378612 DOI: 10.1038/s41467-022-32314-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 07/26/2022] [Indexed: 12/17/2022] Open
Abstract
Parasitic plants are worldwide threats that damage major agricultural crops. To initiate infection, parasitic plants have developed the ability to locate hosts and grow towards them. This ability, called host tropism, is critical for parasite survival, but its underlying mechanism remains mostly unresolved. To characterise host tropism, we used the model facultative root parasite Phtheirospermum japonicum, a member of the Orobanchaceae. Here, we show that strigolactones (SLs) function as host-derived chemoattractants. Chemotropism to SLs is also found in Striga hermonthica, a parasitic member of the Orobanchaceae, but not in non-parasites. Intriguingly, chemotropism to SLs in P. japonicum is attenuated in ammonium ion-rich conditions, where SLs are perceived, but the resulting asymmetrical accumulation of the auxin transporter PIN2 is diminished. P. japonicum encodes putative receptors that sense exogenous SLs, whereas expression of a dominant-negative form reduces its chemotropic ability. We propose a function for SLs as navigators for parasite roots.
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Affiliation(s)
- Satoshi Ogawa
- RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan
| | - Songkui Cui
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Alexandra R F White
- 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
| | - Satoko Yoshida
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan.,PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, 332-0012, Japan
| | - Ken Shirasu
- RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan. .,Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.
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26
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White ARF, Mendez JA, Khosla A, Nelson DC. Rapid analysis of strigolactone receptor activity in a Nicotiana benthamiana dwarf14 mutant. PLANT DIRECT 2022; 6:e389. [PMID: 35355884 PMCID: PMC8948499 DOI: 10.1002/pld3.389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 12/03/2021] [Accepted: 02/17/2022] [Indexed: 05/29/2023]
Abstract
DWARF14 (D14) is an ɑ/β-hydrolase and receptor for the plant hormone strigolactone (SL) in angiosperms. Upon SL perception, D14 works with MORE AXILLARY GROWTH2 (MAX2) to trigger polyubiquitination and degradation of DWARF53(D53)-type proteins in the SUPPRESSOR OF MAX2 1-LIKE (SMXL) family. We used CRISPR-Cas9 to generate knockout alleles of the two homoeologous D14 genes in the Nicotiana benthamiana genome. The Nbd14a,b double mutant had several phenotypes that are consistent with the loss of SL perception in other plants, including increased axillary bud outgrowth, reduced height, shortened petioles, and smaller leaves. A ratiometric fluorescent reporter system was used to monitor degradation of SMXL7 from Arabidopsis thaliana (AtSMXL7) after transient expression in N. benthamiana and treatment with the strigolactone analog GR24. AtSMXL7 was degraded after treatment with GR245DS, which has the stereochemical configuration of natural SLs, as well as its enantiomer GR24 ent-5DS. In Nbd14a,b leaves, AtSMXL7 abundance was unaffected by rac-GR24 or either GR24 stereoisomer. Transient coexpression of AtD14 with the AtSMXL7 reporter in Nbd14a,b restored the degradation response to rac-GR24, but required an active catalytic triad. We used this platform to evaluate the ability of several AtD14 mutants that had not been characterized in plants to target AtSMXL7 for degradation.
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Affiliation(s)
- Alexandra R. F. White
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCaliforniaUSA
| | - Jose A. Mendez
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCaliforniaUSA
| | - Aashima Khosla
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCaliforniaUSA
| | - David C. Nelson
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCaliforniaUSA
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27
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Temmerman A, Guillory A, Bonhomme S, Goormachtig S, Struk S. Masks Start to Drop: Suppressor of MAX2 1-Like Proteins Reveal Their Many Faces. FRONTIERS IN PLANT SCIENCE 2022; 13:887232. [PMID: 35645992 PMCID: PMC9133912 DOI: 10.3389/fpls.2022.887232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 04/25/2022] [Indexed: 05/11/2023]
Abstract
Although the main players of the strigolactone (SL) signaling pathway have been characterized genetically, how they regulate plant development is still poorly understood. Of central importance are the SUPPRESSOR OF MAX2 1-LIKE (SMXL) proteins that belong to a family of eight members in Arabidopsis thaliana, of which one subclade is involved in SL signaling and another one in the pathway of the chemically related karrikins. Through proteasomal degradation of these SMXLs, triggered by either DWARF14 (D14) or KARRIKIN INSENSITIVE2 (KAI2), several physiological processes are controlled, such as, among others, shoot and root architecture, seed germination, and seedling photomorphogenesis. Yet another clade has been shown to be involved in vascular development, independently of the D14 and KAI2 actions and not relying on proteasomal degradation. Despite their role in several aspects of plant development, the exact molecular mechanisms by which SMXLs regulate them are not completely unraveled. To fill the major knowledge gap in understanding D14 and KAI2 signaling, SMXLs are intensively studied, making it challenging to combine all the insights into a coherent characterization of these important proteins. To this end, this review provides an in-depth exploration of the recent data regarding their physiological function, evolution, structure, and molecular mechanism. In addition, we propose a selection of future perspectives, focusing on the apparent localization of SMXLs in subnuclear speckles, as observed in transient expression assays, which we couple to recent advances in the field of biomolecular condensates and liquid-liquid phase separation.
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Affiliation(s)
- Arne Temmerman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB-Center for Plant Systems Biology, Ghent, Belgium
| | - Ambre Guillory
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), Versailles, France
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Sandrine Bonhomme
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), Versailles, France
| | - Sofie Goormachtig
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB-Center for Plant Systems Biology, Ghent, Belgium
| | - Sylwia Struk
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB-Center for Plant Systems Biology, Ghent, Belgium
- *Correspondence: Sylwia Struk,
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