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Sardar R, Ahmed S, Yasin NA. Seed priming with karrikinolide improves growth and physiochemical features of coriandrum sativum under cadmium stress. ENVIRONMENTAL ADVANCES 2021; 5:100082. [DOI: 10.1016/j.envadv.2021.100082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
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Bursch K, Niemann ET, Nelson DC, Johansson H. Karrikins control seedling photomorphogenesis and anthocyanin biosynthesis through a HY5-BBX transcriptional module. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1346-1362. [PMID: 34160854 DOI: 10.1111/tpj.15383] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 06/18/2021] [Indexed: 05/15/2023]
Abstract
The butenolide molecule, karrikin (KAR), emerging in smoke of burned plant material, enhances light responses such as germination, inhibition of hypocotyl elongation, and anthocyanin accumulation in Arabidopsis. The KAR signaling pathway consists of KARRIKIN INSENSITIVE 2 (KAI2) and MORE AXILLARY GROWTH 2 (MAX2), which, upon activation, act in an SCF E3 ubiquitin ligase complex to target the downstream signaling components SUPPRESSOR OF MAX2 1 (SMAX1) and SMAX1-LIKE 2 (SMXL2) for degradation. How degradation of SMAX1 and SMXL2 is translated into growth responses remains unknown. Although light clearly influences the activity of KAR, the molecular connection between the two pathways is still poorly understood. Here, we demonstrate that the KAR signaling pathway promotes the activity of a transcriptional module consisting of ELONGATED HYPOCOTYL 5 (HY5), B-BOX DOMAIN PROTEIN 20 (BBX20), and BBX21. The bbx20 bbx21 mutant is largely insensitive to treatment with KAR2 , similar to a hy5 mutant, with regards to inhibition of hypocotyl elongation and anthocyanin accumulation. Detailed analysis of higher order mutants in combination with RNA-sequencing analysis revealed that anthocyanin accumulation downstream of SMAX1 and SMXL2 is fully dependent on the HY5-BBX module. However, the promotion of hypocotyl elongation by SMAX1 and SMXL2 is, in contrast to KAR2 treatment, only partially dependent on BBX20, BBX21, and HY5. Taken together, these results suggest that light- and KAR-dependent signaling intersect at the HY5-BBX transcriptional module.
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Affiliation(s)
- Katharina Bursch
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, 14195, Germany
| | - Ella T Niemann
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, 14195, Germany
| | - David C Nelson
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
| | - Henrik Johansson
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, 14195, Germany
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Nelson DC. The mechanism of host-induced germination in root parasitic plants. PLANT PHYSIOLOGY 2021; 185:1353-1373. [PMID: 33793958 PMCID: PMC8133615 DOI: 10.1093/plphys/kiab043] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/25/2021] [Indexed: 05/25/2023]
Abstract
Chemical signals known as strigolactones (SLs) were discovered more than 50 years ago as host-derived germination stimulants of parasitic plants in the Orobanchaceae. Strigolactone-responsive germination is an essential adaptation of obligate parasites in this family, which depend upon a host for survival. Several species of obligate parasites, including witchweeds (Striga, Alectra spp.) and broomrapes (Orobanche, Phelipanche spp.), are highly destructive agricultural weeds that pose a significant threat to global food security. Understanding how parasites sense SLs and other host-derived stimulants will catalyze the development of innovative chemical and biological control methods. This review synthesizes the recent discoveries of strigolactone receptors in parasitic Orobanchaceae, their signaling mechanism, and key steps in their evolution.
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Affiliation(s)
- David C Nelson
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521 USA
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Hrdlička J, Gucký T, van Staden J, Novák O, Doležal K. A stable isotope dilution method for a highly accurate analysis of karrikins. PLANT METHODS 2021; 17:37. [PMID: 33794941 PMCID: PMC8017846 DOI: 10.1186/s13007-021-00738-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Karrikins (KARs) are recently described group of plant growth regulators with stimulatory effects on seed germination, seedling growth and crop productivity. So far, an analytical method for the simultaneous targeted profiling of KARs in plant tissues has not been reported. RESULTS We present a sensitive method for the determination of two highly biologically active karrikins (KAR1 and KAR2) in minute amounts of plant material (< 20 mg fresh weight). The developed protocol combines the optimized extraction and efficient single-step sample purification with ultra-high performance liquid chromatography-tandem mass spectrometry. Newly synthesized deuterium labelled KAR1 was employed as an internal standard for the validation of KAR quantification using a stable isotope dilution method. The application of the matrix-matched calibration series in combination with the internal standard method yields a high level of accuracy and precision in triplicate, on average bias 3.3% and 2.9% RSD, respectively. The applicability of this analytical approach was confirmed by the successful analysis of karrikins in Arabidopsis seedlings grown on media supplemented with different concentrations of KAR1 and KAR2 (0.1, 1.0 and 10.0 µmol/l). CONCLUSIONS Our results demonstrate the usage of methodology for routine analyses and for monitoring KARs in complex biological matrices. The proposed method will lead to better understanding of the roles of KARs in plant growth and development.
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Affiliation(s)
- Jakub Hrdlička
- Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences and Faculty of Science, Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic
- Department of Chemical Biology, Faculty of Science, Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Tomáš Gucký
- Department of Experimental Biology, Faculty of Science, Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Johannes van Staden
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville, 3209, South Africa
| | - Ondřej Novák
- Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences and Faculty of Science, Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic.
| | - Karel Doležal
- Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences and Faculty of Science, Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic
- Department of Chemical Biology, Faculty of Science, Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic
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Carbonnel S, Torabi S, Griesmann M, Bleek E, Tang Y, Buchka S, Basso V, Shindo M, Boyer FD, Wang TL, Udvardi M, Waters MT, Gutjahr C. Lotus japonicus karrikin receptors display divergent ligand-binding specificities and organ-dependent redundancy. PLoS Genet 2020; 16:e1009249. [PMID: 33370251 PMCID: PMC7808659 DOI: 10.1371/journal.pgen.1009249] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/14/2021] [Accepted: 11/03/2020] [Indexed: 12/15/2022] Open
Abstract
Karrikins (KARs), smoke-derived butenolides, are perceived by the α/β-fold hydrolase KARRIKIN INSENSITIVE2 (KAI2) and thought to mimic endogenous, yet elusive plant hormones tentatively called KAI2-ligands (KLs). The sensitivity to different karrikin types as well as the number of KAI2 paralogs varies among plant species, suggesting diversification and co-evolution of ligand-receptor relationships. We found that the genomes of legumes, comprising a number of important crops with protein-rich, nutritious seed, contain two or more KAI2 copies. We uncover sub-functionalization of the two KAI2 versions in the model legume Lotus japonicus and demonstrate differences in their ability to bind the synthetic ligand GR24ent-5DS in vitro and in genetic assays with Lotus japonicus and the heterologous Arabidopsis thaliana background. These differences can be explained by the exchange of a widely conserved phenylalanine in the binding pocket of KAI2a with a tryptophan in KAI2b, which arose independently in KAI2 proteins of several unrelated angiosperms. Furthermore, two polymorphic residues in the binding pocket are conserved across a number of legumes and may contribute to ligand binding preferences. The diversification of KAI2 binding pockets suggests the occurrence of several different KLs acting in non-fire following plants, or an escape from possible antagonistic exogenous molecules. Unexpectedly, L. japonicus responds to diverse synthetic KAI2-ligands in an organ-specific manner. Hypocotyl growth responds to KAR1, KAR2 and rac-GR24, while root system development responds only to KAR1. This differential responsiveness cannot be explained by receptor-ligand preferences alone, because LjKAI2a is sufficient for karrikin responses in the hypocotyl, while LjKAI2a and LjKAI2b operate redundantly in roots. Instead, it likely reflects differences between plant organs in their ability to transport or metabolise the synthetic KLs. Our findings provide new insights into the evolution and diversity of butenolide ligand-receptor relationships, and open novel research avenues into their ecological significance and the mechanisms controlling developmental responses to divergent KLs.
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Affiliation(s)
- Samy Carbonnel
- LMU Munich, Faculty of Biology, Genetics, Biocenter Martinsried, Martinsried, Germany
- Technical University of Munich (TUM), TUM School of Life Sciences, Plant Genetics, Freising, Germany
| | - Salar Torabi
- LMU Munich, Faculty of Biology, Genetics, Biocenter Martinsried, Martinsried, Germany
- Technical University of Munich (TUM), TUM School of Life Sciences, Plant Genetics, Freising, Germany
| | - Maximilian Griesmann
- LMU Munich, Faculty of Biology, Genetics, Biocenter Martinsried, Martinsried, Germany
| | - Elias Bleek
- LMU Munich, Faculty of Biology, Genetics, Biocenter Martinsried, Martinsried, Germany
| | - Yuhong Tang
- Noble Research Institute, Ardmore, Oklahoma, United States of America
| | - Stefan Buchka
- LMU Munich, Faculty of Biology, Genetics, Biocenter Martinsried, Martinsried, Germany
| | - Veronica Basso
- LMU Munich, Faculty of Biology, Genetics, Biocenter Martinsried, Martinsried, Germany
| | - Mitsuru Shindo
- Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga, Fukuoka, Japan
| | - François-Didier Boyer
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France
| | - Trevor L. Wang
- John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Michael Udvardi
- Noble Research Institute, Ardmore, Oklahoma, United States of America
| | - Mark T. Waters
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, Australia
| | - Caroline Gutjahr
- LMU Munich, Faculty of Biology, Genetics, Biocenter Martinsried, Martinsried, Germany
- Technical University of Munich (TUM), TUM School of Life Sciences, Plant Genetics, Freising, Germany
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Khosla A, Morffy N, Li Q, Faure L, Chang SH, Yao J, Zheng J, Cai ML, Stanga J, Flematti GR, Waters MT, Nelson DC. Structure-Function Analysis of SMAX1 Reveals Domains That Mediate Its Karrikin-Induced Proteolysis and Interaction with the Receptor KAI2. THE PLANT CELL 2020; 32:2639-2659. [PMID: 32434855 PMCID: PMC7401016 DOI: 10.1105/tpc.19.00752] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 04/13/2020] [Accepted: 05/14/2020] [Indexed: 05/18/2023]
Abstract
Karrikins (KARs) are butenolides found in smoke that can influence germination and seedling development of many plants. The KAR signaling mechanism is hypothesized to be very similar to that of the plant hormone strigolactone (SL). Both pathways require the F-box protein MORE AXILLARY GROWTH2 (MAX2), and other core signaling components have shared ancestry. Putatively, KAR activates the receptor KARRIKIN INSENSITIVE2 (KAI2), triggering its association with the E3 ubiquitin ligase complex SCFMAX2 and downstream targets SUPPRESSOR OF MAX2 1 (SMAX1) and SMAX1-LIKE2 (SMXL2). Polyubiquitination and proteolysis of SMAX1 and SMXL2 then enable growth responses to KAR. However, many of the assumptions of this model have not been demonstrated. Therefore, we investigated the posttranslational regulation of SMAX1 from the model plant Arabidopsis (Arabidopsis thaliana). We find evidence that SMAX1 is degraded by KAI2-SCFMAX2 but is also subject to MAX2-independent turnover. We identify SMAX1 domains that are responsible for its nuclear localization, KAR-induced degradation, association with KAI2, and ability to interact with other SMXL proteins. KAI2 undergoes MAX2-independent degradation after KAR treatment, which we propose results from its association with SMAX1 and SMXL2. Finally, we discover an SMXL domain that mediates receptor-target interaction preferences in KAR and SL signaling, laying the foundation for understanding how these highly similar pathways evolved to fulfill different roles.
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Affiliation(s)
- Aashima Khosla
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521
| | - Nicholas Morffy
- Department of Genetics, University of Georgia, Athens, Georgia 30602
| | - Qingtian Li
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521
| | - Lionel Faure
- Department of Genetics, University of Georgia, Athens, Georgia 30602
- Department of Biology, Texas Woman's University, Denton, Texas 76204
| | - Sun Hyun Chang
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521
| | - Jiaren Yao
- School of Molecular Sciences, University of Western Australia Perth, Crawley, Western Australia 6009, Australia
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia Perth, Crawley, Western Australia 6009, Australia
| | - Jiameng Zheng
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521
| | - Mei L Cai
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521
| | - John Stanga
- Department of Genetics, University of Georgia, Athens, Georgia 30602
- Department of Biology, Mercer University, Macon, Georgia 31207
| | - Gavin R Flematti
- School of Molecular Sciences, University of Western Australia Perth, Crawley, Western Australia 6009, Australia
| | - Mark T Waters
- School of Molecular Sciences, University of Western Australia Perth, Crawley, Western Australia 6009, Australia
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia Perth, Crawley, Western Australia 6009, Australia
| | - David C Nelson
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521
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Divergent receptor proteins confer responses to different karrikins in two ephemeral weeds. Nat Commun 2020; 11:1264. [PMID: 32152287 PMCID: PMC7062792 DOI: 10.1038/s41467-020-14991-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 02/12/2020] [Indexed: 11/08/2022] Open
Abstract
Wildfires can encourage the establishment of invasive plants by releasing potent germination stimulants, such as karrikins. Seed germination of Brassica tournefortii, a noxious weed of Mediterranean climates, is strongly stimulated by KAR1, the archetypal karrikin produced from burning vegetation. In contrast, the closely-related yet non-fire-associated ephemeral Arabidopsisthaliana is unusual because it responds preferentially to KAR2. The α/β-hydrolase KARRIKIN INSENSITIVE 2 (KAI2) is the putative karrikin receptor identified in Arabidopsis. Here we show that B. tournefortii expresses three KAI2 homologues, and the most highly-expressed homologue is sufficient to confer enhanced responses to KAR1 relative to KAR2 when expressed in Arabidopsis. We identify two amino acid residues near the KAI2 active site that explain the ligand selectivity, and show that this combination has arisen independently multiple times within dicots. Our results suggest that duplication and diversification of KAI2 proteins could confer differential responses to chemical cues produced by environmental disturbance, including fire. Karrikins are germination stimulants perceived by KAI2 in Arabidopsis. Here the authors show that Brassica tournefortii, a close relative to Arabidopsis, has multiple copies of KAI2 with amino acid substitutions that confer responsiveness to the specific karrikin compounds found in wildfire smoke.
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Potential of Karrikins as Novel Plant Growth Regulators in Agriculture. PLANTS 2019; 9:plants9010043. [PMID: 31888087 PMCID: PMC7020145 DOI: 10.3390/plants9010043] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/19/2019] [Accepted: 12/24/2019] [Indexed: 01/30/2023]
Abstract
Karrikins (KARs) have been identified as molecules derived from plant material smoke, which have the capacity to enhance seed germination for a wide range of plant species. However, KARs were observed to not only impact seed germination but also observed to influence several biological processes. The plants defected in the KARs signaling pathway were observed to grow differently with several morphological changes. The observation of KARs as a growth regulator in plants leads to the search for an endogenous KAR-like molecule. Due to its simple genomic structure, Arabidopsis (Arabidopsis thaliana L.) helps to understand the signaling mechanism of KARs and phenotypic responses caused by them. However, different species have a different phenotypic response to KARs treatment. Therefore, in the current work, updated information about the KARs effect is presented. Results of research on agricultural and horticultural crops are summarized and compared with the findings of Arabidopsis studies. In this article, we suggested that KARs may be more important in coping with modern problems than one could imagine.
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Aremu AO, Masondo NA, Gruz J, Doležal K, Van Staden J. Potential of Smoke-Water and One of Its Active Compounds (karrikinolide, KAR 1) on the Phytochemical and Antioxidant Activity of Eucomis autumnalis. Antioxidants (Basel) 2019; 8:antiox8120611. [PMID: 31816895 PMCID: PMC6943415 DOI: 10.3390/antiox8120611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/21/2019] [Accepted: 11/25/2019] [Indexed: 11/28/2022] Open
Abstract
Eucomis autumnalis (Mill.) Chitt. subspecies autumnalis is a popular African plant that is susceptible to population decline because the bulbs are widely utilized for diverse medicinal purposes. As a result, approaches to ensure the sustainability of the plants are essential. In the current study, the influence of smoke-water (SW) and karrikinolide (KAR1 isolated from SW extract) on the phytochemicals and antioxidant activity of in vitro and greenhouse-acclimatized Eucomis autumnalis subspecies autumnalis were evaluated. Leaf explants were cultured on Murashige and Skoog (MS) media supplemented with SW (1:500, 1:1000 and 1:1500 v/v dilutions) or KAR1 (10−7, 10−8 and 10−9 M) and grown for ten weeks. In vitro regenerants were subsequently acclimatized in the greenhouse for four months. Bioactive phytochemicals in different treatments were analyzed using ultra-high performance liquid chromatography (UHPLC-MS/MS), while antioxidant potential was evaluated using two chemical tests namely: DPPH and the β-carotene model. Smoke-water and KAR1 generally influenced the quantity and types of phytochemicals in in vitro regenerants and acclimatized plants. In addition to eucomic acid, 15 phenolic acids and flavonoids were quantified; however, some were specific to either the in vitro regenerants or greenhouse-acclimatized plants. The majority of the phenolic acids and flavonoids were generally higher in in vitro regenerants than in acclimatized plants. Evidence from the chemical tests indicated an increase in antioxidant activity of SW and KAR1-treated regenerants and acclimatized plants. Overall, these findings unravel the value of SW and KAR1 as potential elicitors for bioactive phytochemicals with therapeutic activity in plants facilitated via in vitro culture systems. In addition, it affords an efficient means to ensure the sustainability of the investigated plant. Nevertheless, further studies focusing on the use of other types of antioxidant test systems (including in vivo model) and the carry-over effect of the application of SW and KAR1 for a longer duration will be pertinent. In addition, the safety of the resultant plant extracts and their pharmacological efficacy in clinical relevance systems is required.
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Affiliation(s)
- Adeyemi Oladapo Aremu
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa;
- Indigenous Knowledge Systems (IKS) Centre, Faculty of Natural and Agricultural Sciences, North West University, Private Bag X2046, Mmabatho 2735, South Africa
- Correspondence: (A.O.A.); (J.V.S.); Tel.: +27-18-389-2573 (A.O.A.); +27-33-260-5130 (J.V.S.)
| | - Nqobile Andile Masondo
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa;
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, Private Bag X1, Matieland 7602, South Africa
| | - Jiri Gruz
- Laboratory of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic; (J.G.); (K.D.)
| | - Karel Doležal
- Laboratory of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic; (J.G.); (K.D.)
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic
| | - Johannes Van Staden
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa;
- Correspondence: (A.O.A.); (J.V.S.); Tel.: +27-18-389-2573 (A.O.A.); +27-33-260-5130 (J.V.S.)
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