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Palayam M, Yan L, Nagalakshmi U, Gilio AK, Cornu D, Boyer FD, Dinesh-Kumar SP, Shabek N. Structural insights into strigolactone catabolism by carboxylesterases reveal a conserved conformational regulation. Nat Commun 2024; 15:6500. [PMID: 39090154 PMCID: PMC11294565 DOI: 10.1038/s41467-024-50928-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 07/18/2024] [Indexed: 08/04/2024] Open
Abstract
Phytohormone levels are regulated through specialized enzymes, participating not only in their biosynthesis but also in post-signaling processes for signal inactivation and cue depletion. Arabidopsis thaliana (At) carboxylesterase 15 (CXE15) and carboxylesterase 20 (CXE20) have been shown to deplete strigolactones (SLs) that coordinate various growth and developmental processes and function as signaling molecules in the rhizosphere. Here, we elucidate the X-ray crystal structures of AtCXE15 (both apo and SL intermediate bound) and AtCXE20, revealing insights into the mechanisms of SL binding and catabolism. The N-terminal regions of CXE15 and CXE20 exhibit distinct secondary structures, with CXE15 characterized by an alpha helix and CXE20 by an alpha/beta fold. These structural differences play pivotal roles in regulating variable SL hydrolysis rates. Our findings, both in vitro and in planta, indicate that a transition of the N-terminal helix domain of CXE15 between open and closed forms facilitates robust SL hydrolysis. The results not only illuminate the distinctive process of phytohormone breakdown but also uncover a molecular architecture and mode of plasticity within a specific class of carboxylesterases.
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Affiliation(s)
- Malathy Palayam
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA, USA
| | - Linyi Yan
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA, USA
| | - Ugrappa Nagalakshmi
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA, USA
| | - Amelia K Gilio
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA, USA
| | - David Cornu
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - François-Didier Boyer
- Institut de Chimie des Substances Naturelles, Université Paris-Saclay, CNRS UPR 2301, Gif-sur-Yvette, France
| | - Savithramma P Dinesh-Kumar
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA, USA
- The Genome Center, University of California-Davis, Davis, CA, USA
| | - Nitzan Shabek
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA, USA.
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2
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Guillory A, Lopez-Obando M, Bouchenine K, Le Bris P, Lécureuil A, Pillot JP, Steinmetz V, Boyer FD, Rameau C, de Saint Germain A, Bonhomme S. SUPPRESSOR OF MAX2 1-LIKE (SMXL) homologs are MAX2-dependent repressors of Physcomitrium patens growth. THE PLANT CELL 2024; 36:1655-1672. [PMID: 38242840 PMCID: PMC11062456 DOI: 10.1093/plcell/koae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 01/21/2024]
Abstract
SUPPRESSOR OF MAX2 (SMAX)1-LIKE (SMXL) proteins are a plant-specific clade of type I HSP100/Clp-ATPases. SMXL genes are present in virtually all land plant genomes. However, they have mainly been studied in angiosperms. In Arabidopsis (Arabidopsis thaliana), 3 functional SMXL subclades have been identified: SMAX1/SMXL2, SMXL345, and SMXL678. Of these, 2 subclades ensure endogenous phytohormone signal transduction. SMAX1/SMXL2 proteins are involved in KAI2 ligand (KL) signaling, while SMXL678 proteins are involved in strigolactone (SL) signaling. Many questions remain regarding the mode of action of these proteins, as well as their ancestral roles. We addressed these questions by investigating the functions of the 4 SMXL genes in the moss Physcomitrium patens. We demonstrate that PpSMXL proteins are involved in the conserved ancestral MAX2-dependent KL signaling pathway and negatively regulate growth. However, PpSMXL proteins expressed in Arabidopsis cannot replace SMAX1 or SMXL2 function in KL signaling, whereas they can functionally replace SMXL4 and SMXL5 and restore root growth. Therefore, the molecular functions of SMXL proteins are conserved, but their interaction networks are not. Moreover, the PpSMXLC/D clade positively regulates SL signal transduction in P. patens. Overall, our data reveal that SMXL proteins in moss mediate crosstalk between the SL and KL signaling pathways.
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Affiliation(s)
- Ambre Guillory
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan 31326, France
| | - Mauricio Lopez-Obando
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
- Institut de biologie moléculaire des plantes (IBMP), CNRS, University of Strasbourg, 12 rue du Général Zimmer, 67000 Strasbourg, France
| | - Khalissa Bouchenine
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Philippe Le Bris
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Alain Lécureuil
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Jean-Paul Pillot
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Vincent Steinmetz
- CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - François-Didier Boyer
- CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Catherine Rameau
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Alexandre de Saint Germain
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Sandrine Bonhomme
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
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3
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Homma M, Uchida K, Wakabayashi T, Mizutani M, Takikawa H, Sugimoto Y. 2-oxoglutarate-dependent dioxygenases and BAHD acyltransferases drive the structural diversification of orobanchol in Fabaceae plants. FRONTIERS IN PLANT SCIENCE 2024; 15:1392212. [PMID: 38699535 PMCID: PMC11063326 DOI: 10.3389/fpls.2024.1392212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 04/03/2024] [Indexed: 05/05/2024]
Abstract
Strigolactones (SLs), a class of plant apocarotenoids, serve dual roles as rhizosphere-signaling molecules and plant hormones. Orobanchol, a major naturally occurring SL, along with its various derivatives, has been detected in the root exudates of plants of the Fabaceae family. Medicaol, fabacyl acetate, and orobanchyl acetate were identified in the root exudates of barrel medic (Medicago truncatula), pea (Pisum sativum), and cowpea (Vigna unguiculata), respectively. Although the biosynthetic pathway leading to orobanchol production has been elucidated, the biosynthetic pathways of the orobanchol derivatives have not yet been fully elucidated. Here, we report the identification of 2-oxoglutarate-dependent dioxygenases (DOXs) and BAHD acyltransferases responsible for converting orobanchol to these derivatives in Fabaceae plants. First, the metabolic pathways downstream of orobanchol were analyzed using substrate feeding experiments. Prohexadione, an inhibitor of DOX inhibits the conversion of orobanchol to medicaol in barrel medic. The DOX inhibitor also reduced the formation of fabacyl acetate and fabacol, a precursor of fabacyl acetate, in pea. Subsequently, we utilized a dataset based on comparative transcriptome analysis to select a candidate gene encoding DOX for medicaol synthase in barrel medic. Recombinant proteins of the gene converted orobanchol to medicaol. The candidate genes encoding DOX and BAHD acyltransferase for fabacol synthase and fabacol acetyltransferase, respectively, were selected by co-expression analysis in pea. The recombinant proteins of the candidate genes converted orobanchol to fabacol and acetylated fabacol. Furthermore, fabacol acetyltransferase and its homolog in cowpea acetylated orobanchol. The kinetics and substrate specificity analyses revealed high affinity and strict recognition of the substrates of the identified enzymes. These findings shed light on the molecular mechanisms underlying the structural diversity of SLs.
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Affiliation(s)
- Masato Homma
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Kiyono Uchida
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Takatoshi Wakabayashi
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Masaharu Mizutani
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Hirosato Takikawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yukihiro Sugimoto
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
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4
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Stirling SA, Guercio AM, Patrick RM, Huang XQ, Bergman ME, Dwivedi V, Kortbeek RWJ, Liu YK, Sun F, Tao WA, Li Y, Boachon B, Shabek N, Dudareva N. Volatile communication in plants relies on a KAI2-mediated signaling pathway. Science 2024; 383:1318-1325. [PMID: 38513014 DOI: 10.1126/science.adl4685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 02/08/2024] [Indexed: 03/23/2024]
Abstract
Plants are constantly exposed to volatile organic compounds (VOCs) that are released during plant-plant communication, within-plant self-signaling, and plant-microbe interactions. Therefore, understanding VOC perception and downstream signaling is vital for unraveling the mechanisms behind information exchange in plants, which remain largely unexplored. Using the hormone-like function of volatile terpenoids in reproductive organ development as a system with a visual marker for communication, we demonstrate that a petunia karrikin-insensitive receptor, PhKAI2ia, stereospecifically perceives the (-)-germacrene D signal, triggering a KAI2-mediated signaling cascade and affecting plant fitness. This study uncovers the role(s) of the intermediate clade of KAI2 receptors, illuminates the involvement of a KAI2ia-dependent signaling pathway in volatile communication, and provides new insights into plant olfaction and the long-standing question about the nature of potential endogenous KAI2 ligand(s).
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Affiliation(s)
- Shannon A Stirling
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
| | - Angelica M Guercio
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA 95616, USA
| | - Ryan M Patrick
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Xing-Qi Huang
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Matthew E Bergman
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Varun Dwivedi
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Ruy W J Kortbeek
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Yi-Kai Liu
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Fuai Sun
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA 95616, USA
| | - W Andy Tao
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
| | - Ying Li
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Benoît Boachon
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
- Université Jean Monnet Saint-Etienne, CNRS, LBVpam UMR 5079, F-42023 Saint-Etienne, France
| | - Nitzan Shabek
- Department of Plant Biology, College of Biological Sciences, University of California-Davis, Davis, CA 95616, USA
| | - Natalia Dudareva
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
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5
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Melville KT, Kamran M, Yao J, Costa M, Holland M, Taylor NL, Fritz G, Flematti GR, Waters MT. Perception of butenolides by Bacillus subtilis via the α/β hydrolase RsbQ. Curr Biol 2024; 34:623-631.e6. [PMID: 38183985 DOI: 10.1016/j.cub.2023.12.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/06/2023] [Accepted: 12/12/2023] [Indexed: 01/08/2024]
Abstract
The regulation of behavioral and developmental decisions by small molecules is common to all domains of life. In plants, strigolactones and karrikins are butenolide growth regulators that influence several aspects of plant growth and development, as well as interactions with symbiotic fungi.1,2,3 DWARF14 (D14) and KARRIKIN INSENSITIVE2 (KAI2) are homologous enzyme-receptors that perceive strigolactones and karrikins, respectively, and that require hydrolase activity to effect signal transduction.4,5,6,7 RsbQ, a homolog of D14 and KAI2 from the gram-positive bacterium Bacillus subtilis, regulates growth responses to nutritional stress via the alternative transcription factor SigmaB (σB).8,9 However, the molecular function of RsbQ is unknown. Here, we show that RsbQ perceives butenolide compounds that are bioactive in plants. RsbQ is thermally destabilized by the synthetic strigolactone GR24 and its desmethyl butenolide equivalent dGR24. We show that, like D14 and KAI2, RsbQ is a functional butenolide hydrolase that undergoes covalent modification of the catalytic histidine residue. Exogenous application of both GR24 and dGR24 inhibited the endogenous signaling function of RsbQ in vivo, with dGR24 being 10-fold more potent. Application of dGR24 to B. subtilis phenocopied loss-of-function rsbQ mutations and led to a significant downregulation of σB-regulated transcripts. We also discovered that exogenous butenolides promoted the transition from planktonic to biofilm growth. Our results suggest that butenolides may serve as inter-kingdom signaling compounds between plants and bacteria to help shape rhizosphere communities.
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Affiliation(s)
- Kim T Melville
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Muhammad Kamran
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Jiaren Yao
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Marianne Costa
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Madeleine Holland
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Nicolas L Taylor
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia; Institute of Agriculture, The University of Western Australia, Perth WA 6009, Australia
| | - Georg Fritz
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - 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.
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6
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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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7
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Mashiguchi K, Morita R, Tanaka K, Kodama K, Kameoka H, Kyozuka J, Seto Y, Yamaguchi S. Activation of Strigolactone Biosynthesis by the DWARF14-LIKE/KARRIKIN-INSENSITIVE2 Pathway in Mycorrhizal Angiosperms, but Not in Arabidopsis, a Non-mycorrhizal Plant. PLANT & CELL PHYSIOLOGY 2023; 64:1066-1078. [PMID: 37494415 PMCID: PMC10504576 DOI: 10.1093/pcp/pcad079] [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: 12/29/2022] [Revised: 07/14/2023] [Accepted: 07/24/2023] [Indexed: 07/28/2023]
Abstract
Strigolactones (SLs) are a class of plant hormones that regulate many aspects of plant growth and development. SLs also improve symbiosis with arbuscular mycorrhizal fungi (AMF) in the rhizosphere. Recent studies have shown that the DWARF14-LIKE (D14L)/KARRIKIN-INSENSITIVE2 (KAI2) family, paralogs of the SL receptor D14, are required for AMF colonization in several flowering plants, including rice. In this study, we found that (-)-GR5, a 2'S-configured enantiomer of a synthetic SL analog (+)-GR5, significantly activated SL biosynthesis in rice roots via D14L. This result is consistent with a recent report, showing that the D14L pathway positively regulates SL biosynthesis in rice. In fact, the SL levels tended to be lower in the roots of the d14l mutant under both inorganic nutrient-deficient and -sufficient conditions. We also show that the increase in SL levels by (-)-GR5 was observed in other mycorrhizal plant species. In contrast, the KAI2 pathway did not upregulate the SL level and the expression of SL biosynthetic genes in Arabidopsis, a non-mycorrhizal plant. We also examined whether the KAI2 pathway enhances SL biosynthesis in the liverwort Marchantia paleacea, where SL functions as a rhizosphere signaling molecule for AMF. However, the SL level and SL biosynthetic genes were not positively regulated by the KAI2 pathway. These results imply that the activation of SL biosynthesis by the D14L/KAI2 pathway has been evolutionarily acquired after the divergence of bryophytes to efficiently promote symbiosis with AMF, although we cannot exclude the possibility that liverworts have specifically lost this regulatory system.
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Affiliation(s)
- Kiyoshi Mashiguchi
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577 Japan
| | - Ryo Morita
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577 Japan
| | - Kai Tanaka
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577 Japan
| | - Kyoichi Kodama
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577 Japan
| | - Hiromu Kameoka
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577 Japan
| | - Junko Kyozuka
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577 Japan
| | - Yoshiya Seto
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577 Japan
- School of Agriculture, Meiji University, 1-1-1 Higashi-mita, Tama-ku, Kawasaki, Kanagawa, 214-8571 Japan
| | - Shinjiro Yamaguchi
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577 Japan
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8
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Guercio AM, Palayam M, Shabek N. Strigolactones: diversity, perception, and hydrolysis. PHYTOCHEMISTRY REVIEWS : PROCEEDINGS OF THE PHYTOCHEMICAL SOCIETY OF EUROPE 2023; 22:339-360. [PMID: 37201177 PMCID: PMC10191409 DOI: 10.1007/s11101-023-09853-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 01/03/2023] [Indexed: 05/20/2023]
Abstract
Strigolactones (SLs) are a unique and novel class of phytohormones that regulate numerous processes of growth and development in plants. Besides their endogenous functions as hormones, SLs are exuded by plant roots to stimulate critical interactions with symbiotic fungi but can also be exploited by parasitic plants to trigger their seed germination. In the past decade, since their discovery as phytohormones, rapid progress has been made in understanding the SL biosynthesis and signaling pathway. Of particular interest are the diversification of natural SLs and their exact mode of perception, selectivity, and hydrolysis by their dedicated receptors in plants. Here we provide an overview of the emerging field of SL perception with a focus on the diversity of canonical, non-canonical, and synthetic SL probes. Moreover, this review offers useful structural insights into SL perception, the precise molecular adaptations that define receptor-ligand specificities, and the mechanisms of SL hydrolysis and its attenuation by downstream signaling components.
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Affiliation(s)
- Angelica M Guercio
- Department of Plant Biology, College of Biological Sciences, University of California - Davis, Davis, CA 95616, USA
| | - Malathy Palayam
- Department of Plant Biology, College of Biological Sciences, University of California - Davis, Davis, CA 95616, USA
| | - Nitzan Shabek
- Department of Plant Biology, College of Biological Sciences, University of California - Davis, Davis, CA 95616, USA
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9
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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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10
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Abdelrahman M, Mostofa MG, Tran CD, El-Sayed M, Li W, Sulieman S, Tanaka M, Seki M, Tran LSP. The Karrikin Receptor Karrikin Insensitive2 Positively Regulates Heat Stress Tolerance in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2023; 63:1914-1926. [PMID: 35880749 DOI: 10.1093/pcp/pcac112] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 06/23/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
In this study, we investigated the potential role of the karrikin receptor KARRIKIN INSENSITIVE2 (KAI2) in the response of Arabidopsis seedlings to high-temperature stress. We performed phenotypic, physiological and transcriptome analyses of Arabidopsis kai2 mutants and wild-type (WT) plants under control (kai2_C and WT_C, respectively) and 6- and 24-h heat stress conditions (kai2_H6, kai2_H24, WT_H6 and WT_H24, respectively) to understand the basis for KAI2-regulated heat stress tolerance. We discovered that the kai2 mutants exhibited hypersensitivity to high-temperature stress relative to WT plants, which might be associated with a more highly increased leaf surface temperature and cell membrane damage in kai2 mutant plants. Next, we performed comparative transcriptome analysis of kai2_C, kai2_H6, kai2_H24, WT_C, WT_H6 and WT_H24 to identify transcriptome differences between WT and kai2 mutants in response to heat stress. K-mean clustering of normalized gene expression separated the investigated genotypes into three clusters based on heat-treated and non-treated control conditions. Within each cluster, the kai2 mutants were separated from WT plants, implying that kai2 mutants exhibited distinct transcriptome profiles relative to WT plants. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed a repression in 'misfolded protein binding', 'heat shock protein binding', 'unfolded protein binding' and 'protein processing in endoplasmic reticulum' pathways, which was consistent with the downregulation of several genes encoding heat shock proteins and heat shock transcription factors in the kai2 mutant versus WT plants under control and heat stress conditions. Our findings suggest that chemical or genetic manipulation of KAI2 signaling may provide a novel way to improve heat tolerance in plants.
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Affiliation(s)
- Mostafa Abdelrahman
- Faculty of Science, Galala University, Suez, El Sokhna 43511, Egypt
- Botany Department, Faculty of Science, Aswan University, Aswan 81528, Egypt
| | - Mohammad Golam Mostofa
- Department of Plant and Soil Science, Institute of Genomics for Crop Abiotic Stress Tolerance, Texas Tech University, Lubbock, TX 79409, USA
| | - Cuong Duy Tran
- Genetic Engineering Department, Agricultural Genetics Institute, Vietnamese Academy of Agricultural Science, Pham Van Dong Street, Hanoi 100000, Viet Nam
| | - Magdi El-Sayed
- Faculty of Science, Galala University, Suez, El Sokhna 43511, Egypt
| | - Weiqiang Li
- Jilin Da'an 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, Changchun 130102, China
- State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, Kaifeng 475001, China
| | - Saad Sulieman
- Department of Agronomy, Faculty of Agriculture, University of Khartoum, Shambat, Khartoum North 13314, Sudan
| | - Maho Tanaka
- Plant Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045 Japan
- Plant Epigenome Regulation Laboratory, RIKEN Cluster for Pioneering Research, Saitama, 351-0198 Japan
| | - Motoaki Seki
- Plant Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045 Japan
- Plant Epigenome Regulation Laboratory, RIKEN Cluster for Pioneering Research, Saitama, 351-0198 Japan
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, 244-0813 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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11
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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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12
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Li XR, Sun J, Albinsky D, Zarrabian D, Hull R, Lee T, Jarratt-Barnham E, Chiu CH, Jacobsen A, Soumpourou E, Albanese A, Kohlen W, Luginbuehl LH, Guillotin B, Lawrensen T, Lin H, Murray J, Wallington E, Harwood W, Choi J, Paszkowski U, Oldroyd GED. Nutrient regulation of lipochitooligosaccharide recognition in plants via NSP1 and NSP2. Nat Commun 2022; 13:6421. [PMID: 36307431 PMCID: PMC9616857 DOI: 10.1038/s41467-022-33908-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 10/07/2022] [Indexed: 12/25/2022] Open
Abstract
Many plants associate with arbuscular mycorrhizal fungi for nutrient acquisition, while legumes also associate with nitrogen-fixing rhizobial bacteria. Both associations rely on symbiosis signaling and here we show that cereals can perceive lipochitooligosaccharides (LCOs) for activation of symbiosis signaling, surprisingly including Nod factors produced by nitrogen-fixing bacteria. However, legumes show stringent perception of specifically decorated LCOs, that is absent in cereals. LCO perception in plants is activated by nutrient starvation, through transcriptional regulation of Nodulation Signaling Pathway (NSP)1 and NSP2. These transcription factors induce expression of an LCO receptor and act through the control of strigolactone biosynthesis and the karrikin-like receptor DWARF14-LIKE. We conclude that LCO production and perception is coordinately regulated by nutrient starvation to promote engagement with mycorrhizal fungi. Our work has implications for the use of both mycorrhizal and rhizobial associations for sustainable productivity in cereals.
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Affiliation(s)
- Xin-Ran Li
- grid.5335.00000000121885934Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR UK
| | - Jongho Sun
- grid.5335.00000000121885934Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR UK
| | - Doris Albinsky
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Darius Zarrabian
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Raphaella Hull
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Tak Lee
- grid.5335.00000000121885934Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR UK ,grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Edwin Jarratt-Barnham
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Chai Hao Chiu
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Amy Jacobsen
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Eleni Soumpourou
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Alessio Albanese
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Wouter Kohlen
- grid.4818.50000 0001 0791 5666Laboratory for Molecular Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands
| | - Leonie H. Luginbuehl
- grid.14830.3e0000 0001 2175 7246John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Bruno Guillotin
- grid.503344.50000 0004 0445 6769Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, Castanet-Tolosan, France ,grid.137628.90000 0004 1936 8753Present Address: NYU-Center of Genomic and System Biology, 12 Waverly Place, New York, NY USA
| | - Tom Lawrensen
- grid.14830.3e0000 0001 2175 7246John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Hui Lin
- grid.14830.3e0000 0001 2175 7246John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Jeremy Murray
- grid.14830.3e0000 0001 2175 7246John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Emma Wallington
- grid.17595.3f0000 0004 0383 6532NIAB, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Wendy Harwood
- grid.14830.3e0000 0001 2175 7246John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Jeongmin Choi
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Uta Paszkowski
- grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
| | - Giles E. D. Oldroyd
- grid.5335.00000000121885934Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR UK ,grid.5335.00000000121885934Crop Science Centre, University of Cambridge, 93 Lawrence Weaver Road, Cambridge, CB3 0LE UK
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13
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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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14
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Bürger M, Honda K, Kondoh Y, Hong S, Watanabe N, Osada H, Chory J. Crystal structure of Arabidopsis DWARF14-LIKE2 (DLK2) reveals a distinct substrate binding pocket architecture. PLANT DIRECT 2022; 6:e446. [PMID: 36172078 PMCID: PMC9470386 DOI: 10.1002/pld3.446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/14/2022] [Accepted: 08/17/2022] [Indexed: 06/16/2023]
Abstract
In Arabidopsis thaliana, the Sigma factor B regulator RsbQ-like family of α/β hydrolases contains the strigolactone (SL) receptor DWARF14 (AtD14), the karrikin receptor KARRIKIN INSENSITIVE2 (AtKAI2), and DWARF14-LIKE2 (AtDLK2), a protein of unknown function. Despite very similar protein folds, AtD14 and AtKAI2 differ in size and architecture of their ligand binding pockets, influencing their substrate specificity. We present the 1.5 Å crystal structure of AtDLK2, revealing the smallest ligand binding pocket in the protein family, bordered by two unique glycine residues. We identified a gatekeeper residue in the protein's lid domain and present a pyrrolo-quinoline-dione compound that inhibits AtDLK2's enzymatic activity.
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Affiliation(s)
- Marco Bürger
- Plant Biology LaboratorySalk Institute for Biological StudiesLa JollaCaliforniaUSA
| | - Kaori Honda
- Chemical Biology Research GroupRIKEN Centre for Sustainable Resource ScienceWakoSaitamaJapan
| | - Yasumitsu Kondoh
- Chemical Biology Research GroupRIKEN Centre for Sustainable Resource ScienceWakoSaitamaJapan
| | - Sharon Hong
- Plant Biology LaboratorySalk Institute for Biological StudiesLa JollaCaliforniaUSA
| | - Nobumoto Watanabe
- Bioprobe Application Research UnitRIKEN Centre for Sustainable Resource ScienceWakoSaitamaJapan
| | - Hiroyuki Osada
- Chemical Biology Research GroupRIKEN Centre for Sustainable Resource ScienceWakoSaitamaJapan
| | - Joanne Chory
- Plant Biology LaboratorySalk Institute for Biological StudiesLa JollaCaliforniaUSA
- Howard Hughes Medical InstituteSalk Institute for Biological StudiesLa JollaCaliforniaUSA
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15
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An Interplay of Light and Smoke Compounds in Photoblastic Seeds. PLANTS 2022; 11:plants11131773. [PMID: 35807725 PMCID: PMC9269607 DOI: 10.3390/plants11131773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 11/17/2022]
Abstract
Light increases the germinability of positively photoblastic seeds and inhibits the germination of negative ones. In an area where plant-generated smoke from fire is a periodically occurring environmental factor, smoke chemicals can affect the germination of seeds, including those that are photoblastically sensitive. Moreover, as smoke and its compounds, mostly karrikin 1, KAR1, have been used for priming the seeds of many species, including photoblastic ones, a systematic review of papers dealing with the phenomenon was conducted. The review indicates that the unification of experimental treatments (light spectrum, intensity and photoperiod, and KAR1 concentration within the species) could improve the quality of global research on the impact of smoke chemicals on photoblastic seeds, also at the molecular level. The review also reveals that the physiologically active concentration of KAR1 varies in different species. Moreover, the physiological window of KAR’s impact on germination can be narrow due to different depths of primary seed dormancy. Another concern is the mode of action of different smoke sources and formulations (aerosol smoke, smoke-saturated water), or pure smoke chemicals. The reason for this concern is the additive or synergetic effect of KARs, cyanohydrins, nitrates and other compounds, and the presence of a germination inhibitor, trimethylbutenolide (TMB) in smoke and its formulations. Obviously, environmental factors that are characteristic of the local environment need to be considered. From a practical perspective, seeds germinating faster in response to smoke chemicals can outcompete other seeds. Hence, a thorough understanding of this phenomenon can be useful in the restoration of plant habitats and the protection of rare species, as well as yielding an improvement in plants that are sown directly to the field. On the other hand, the application of smoke compounds can induce “suicidal germination” in the photoblastic seeds that are buried in the soil and deplete the soil seed bank of the local population of unwanted species.
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