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Sivaramakrishnan M, Veeraganti Naveen Prakash C, Chandrasekar B. Multifaceted roles of plant glycosyl hydrolases during pathogen infections: more to discover. PLANTA 2024; 259:113. [PMID: 38581452 DOI: 10.1007/s00425-024-04391-5] [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: 08/04/2023] [Accepted: 03/15/2024] [Indexed: 04/08/2024]
Abstract
MAIN CONCLUSION Carbohydrates are hydrolyzed by a family of carbohydrate-active enzymes (CAZymes) called glycosidases or glycosyl hydrolases. Here, we have summarized the roles of various plant defense glycosidases that possess different substrate specificities. We have also highlighted the open questions in this research field. Glycosidases or glycosyl hydrolases (GHs) are a family of carbohydrate-active enzymes (CAZymes) that hydrolyze glycosidic bonds in carbohydrates and glycoconjugates. Compared to those of all other sequenced organisms, plant genomes contain a remarkable diversity of glycosidases. Plant glycosidases exhibit activities on various substrates and have been shown to play important roles during pathogen infections. Plant glycosidases from different GH families have been shown to act upon pathogen components, host cell walls, host apoplastic sugars, host secondary metabolites, and host N-glycans to mediate immunity against invading pathogens. We could classify the activities of these plant defense GHs under eleven different mechanisms through which they operate during pathogen infections. Here, we have provided comprehensive information on the catalytic activities, GH family classification, subcellular localization, domain structure, functional roles, and microbial strategies to regulate the activities of defense-related plant GHs. We have also emphasized the research gaps and potential investigations needed to advance this topic of research.
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Affiliation(s)
| | | | - Balakumaran Chandrasekar
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani (BITS Pilani), Pilani, 333031, India.
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Nguyen TNH, Leclerc L, Manzanares-Dauleux MJ, Gravot A, Vicré M, Morvan-Bertrand A, Prud'homme MP. Fructan exohydrolases (FEHs) are upregulated by salicylic acid together with defense-related genes in non-fructan accumulating plants. PHYSIOLOGIA PLANTARUM 2023; 175:e13975. [PMID: 37616010 DOI: 10.1111/ppl.13975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/05/2023] [Accepted: 07/04/2023] [Indexed: 08/25/2023]
Abstract
The identification of several fructan exohydrolases (FEHs, EC 3.2.1.80) in non-fructan accumulating plants raised the question of their roles. FEHs may be defense-related proteins involved in the interactions with fructan-accumulating microorganisms. Since known defense-related proteins are upregulated by defense-related phytohormones, we tested the hypothesis that FEHs of non-fructan accumulating plants are upregulated by salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) using the model plant Arabidopsis thaliana and the agronomically relevant and genetically related species Brassica napus. By sequence homologies with the two known FEH genes of A. thaliana, At6-FEH, and At6&1-FEH, the genes coding for the putative B. napus FEHs, Bn6-FEH and Bn6&1-FEH, were identified. Plants were treated at root level with SA, methyl jasmonate (MeJA) or 1-aminocyclopropane-1-carboxylic acid (ACC). The transcript levels of defense-related and FEH genes were measured after treatments. MeJA and ACC did not upregulate FEHs, while HEL (HEVEIN-LIKE PREPROTEIN) expression was enhanced by both phytohormones. In both species, the expression of AOS, encoding a JA biosynthesis enzyme, was enhanced by MeJA and that of the defensine PDF1.2 and the ET signaling transcription factor ERF1/2 by ACC. In contrast, SA not only increased the expression of genes encoding antimicrobial proteins (PR1 and HEL) and the defense-related transcription factor WRKY70 but also that of FEH genes, in particular 6&1-FEH genes. This result supports the putative role of FEHs as defense-related proteins. Genotypic variability of SA-mediated FEH regulation (transcript level and activities) was observed among five varieties of B. napus, suggesting different susceptibilities toward fructan-accumulating pathogens.
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Affiliation(s)
- Thi Ngoc Hanh Nguyen
- Normandie Université, UNICAEN, UMR 950 INRAE, EVA Ecophysiologie Végétale Agronomie et Nutritions N.C.S, SFR Normandie Végétale FED4277, Caen, France
- Normandie Université, Univ Rouen Normandie, Laboratoire Glyco-MEV EA 4358, SFR Normandie Végétale FED4277, Rouen, France
| | - Laëtitia Leclerc
- Normandie Université, UNICAEN, UMR 950 INRAE, EVA Ecophysiologie Végétale Agronomie et Nutritions N.C.S, SFR Normandie Végétale FED4277, Caen, France
| | | | - Antoine Gravot
- Institut Agro, Université Rennes, INRAE, IGEPP, Le Rheu, France
| | - Maïté Vicré
- Normandie Université, Univ Rouen Normandie, Laboratoire Glyco-MEV EA 4358, SFR Normandie Végétale FED4277, Rouen, France
| | - Annette Morvan-Bertrand
- Normandie Université, UNICAEN, UMR 950 INRAE, EVA Ecophysiologie Végétale Agronomie et Nutritions N.C.S, SFR Normandie Végétale FED4277, Caen, France
| | - Marie-Pascale Prud'homme
- Normandie Université, UNICAEN, UMR 950 INRAE, EVA Ecophysiologie Végétale Agronomie et Nutritions N.C.S, SFR Normandie Végétale FED4277, Caen, France
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New Insights into the Mechanism of Trichoderma virens-Induced Developmental Effects on Agrostis stolonifera Disease Resistance against Dollar Spot Infection. J Fungi (Basel) 2022; 8:jof8111186. [DOI: 10.3390/jof8111186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/12/2022] Open
Abstract
Trichoderma is internationally recognized as a biocontrol fungus for its broad-spectrum antimicrobial activity. Intriguingly, the crosstalk mechanism between the plant and Trichoderma is dynamic, depending on the Trichoderma strains and the plant species. In our previous study, the Trichoderma virens 192-45 strain showed better pathogen inhibition through the secretive non-volatile and volatile substrates. Therefore, we studied transcriptional and metabolic responses altered in creeping bentgrass (Agrostis stolonifera L.) with T. virens colonization prior to a challenge with Clarireedia homoeocarpa. This fungal pathogen causes dollar spot on various turfgrasses. When the pathogen is deficient, the importance of T. virens to the enhancement of plant growth can be seen in hormonal production and microbe signaling, such as indole-3-acrylic acid. Therefore, these substrates secreted by T. virens and induced genes related to plant growth can be the ‘pre-defense’ for ensuing pathogen attacks. During C. homoeocarpa infection, the Trichoderma–plant interaction activates defense responses through the SA- and/or JA-dependent pathway, induced by T. virens and its respective exudates, such as oleic, citric, and stearic acid. Thus, we will anticipate a combination of genetic engineering and exogenous application targeting these genes and metabolites, which could make creeping bentgrass more resistant to dollar spot and other pathogens.
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Versluys M, Toksoy Öner E, Van den Ende W. Fructan oligosaccharide priming alters apoplastic sugar dynamics and improves resistance against Botrytis cinerea in chicory. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4214-4235. [PMID: 35383363 DOI: 10.1093/jxb/erac140] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 04/01/2022] [Indexed: 06/14/2023]
Abstract
Carbohydrates such as fructans can be involved in priming or defence stimulation, and hence potentially provide new strategies for crop protection against biotic stress. Chicory (Cichorium intybus) is a model plant for fructan research and is a crop with many known health benefits. Using the chicory-Botrytis cinerea pathosystem, we tested the effectiveness of fructan-induced immunity, focussing on different plant and microbial fructans. Sugar dynamics were followed after priming and subsequent pathogen infection. Our results indicated that many higher plants might detect extracellular levan oligosaccharides (LOS) of microbial origin, while chicory also detects extracellular small inulin-type fructooligosaccharides (FOS) of endogenous origin, thus differing from the findings of previous fructan priming studies. No clear positive effects were observed for inulin or mixed-type fructans. An elicitor-specific burst of reactive oxygen species was observed for sulfated LOS, while FOS and LOS both behaved as genuine priming agents. In addition, a direct antifungal effect was observed for sulfated LOS. Intriguingly, LOS priming led to a temporary increase in apoplastic sugar concentrations, mainly glucose, which could trigger downstream responses. Total sugar and starch contents in total extracts of LOS-primed leaves were higher after leaf detachment, indicating they could maintain their metabolic activity. Our results indicate the importance of balancing intra- and extracellular sugar levels (osmotic balance) in the context of 'sweet immunity' pathways.
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Affiliation(s)
- Maxime Versluys
- Laboratory of Molecular Plant Biology and KU Leuven Plant Institute, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven, Belgium
| | - Ebru Toksoy Öner
- IBSB-Industrial Biotechnology and Systems Biology Research Group, Department of Bioengineering, Marmara University, Istanbul, Turkey
| | - Wim Van den Ende
- Laboratory of Molecular Plant Biology and KU Leuven Plant Institute, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven, Belgium
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Versluys M, Porras-Domínguez JR, De Coninck T, Van Damme EJM, Van den Ende W. A novel chicory fructanase can degrade common microbial fructan product profiles and displays positive cooperativity. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1602-1622. [PMID: 34750605 DOI: 10.1093/jxb/erab488] [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: 09/15/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
Fructan metabolism in bacteria and plants relies on fructosyltransferases and fructanases. Plant fructanases (fructan exohydrolase, FEH) only hydrolyse terminal fructose residues. Levan (β-2,6 linkages) is the most abundant fructan type in bacteria. Dicot fructan accumulators, such as chicory (Cichorium intybus), accumulate inulin (β-2,1 linkages), harbouring several 1-FEH isoforms for their degradation. Here, a novel chicory fructanase with high affinity for levan was characterized, providing evidence that such enzymes widely occur in higher plants. It is adapted to common microbial fructan profiles, but has low affinity towards chicory inulin, in line with a function in trimming of microbial fructans in the extracellular environment. Docking experiments indicate the importance of an N-glycosylation site close to the active site for substrate specificity. Optimal pH and temperature for levan hydrolysis are 5.0 and 43.7 °C, respectively. Docking experiments suggested multiple substrate binding sites and levan-mediated enzyme dimerization, explaining the observed positive cooperativity. Alignments show a single amino acid shift in the position of a conserved DXX(R/K) couple, typical for sucrose binding in cell wall invertases. A possible involvement of plant fructanases in levan trimming is discussed, in line with the emerging 'fructan detour' concepts, suggesting that levan oligosaccharides act as signalling entities during plant-microbial interactions.
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Affiliation(s)
- Maxime Versluys
- Laboratory of Molecular Plant Biology, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven, Belgium
| | | | - Tibo De Coninck
- Laboratory of Biochemistry and Glycobiology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Els J M Van Damme
- Laboratory of Biochemistry and Glycobiology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Wim Van den Ende
- Laboratory of Molecular Plant Biology, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven, Belgium
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Versluys M, Van den Ende W. Sweet Immunity Aspects during Levan Oligosaccharide-Mediated Priming in Rocket against Botrytis cinerea. Biomolecules 2022; 12:370. [PMID: 35327562 PMCID: PMC8945012 DOI: 10.3390/biom12030370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 02/04/2023] Open
Abstract
New strategies are required for crop protection against biotic stress. Naturally derived molecules, including carbohydrates such as fructans, can be used in priming or defense stimulation. Rocket (Eruca sativa) is an important leafy vegetable and a good source of antioxidants. Here, we tested the efficacy of fructan-induced immunity in the Botrytis cinerea pathosystem. Different fructan types of plant and microbial origin were considered and changes in sugar dynamics were analyzed. Immune resistance increased significantly after priming with natural and sulfated levan oligosaccharides (LOS). No clear positive effects were observed for fructo-oligosaccharides (FOS), inulin or branched-type fructans. Only sulfated LOS induced a direct ROS burst, typical for elicitors, while LOS behaved as a genuine priming compound. Total leaf sugar levels increased significantly both after LOS priming and subsequent infection. Intriguingly, apoplastic sugar levels temporarily increased after LOS priming but not after infection. We followed LOS and small soluble sugar dynamics in the apoplast as a function of time and found a temporal peak in small soluble sugar levels. Although similar dynamics were also found with inulin-type FOS, increased Glc and FOS levels may benefit B. cinerea. During LOS priming, LOS- and/or Glc-dependent signaling may induce downstream sweet immunity responses.
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Affiliation(s)
| | - Wim Van den Ende
- Laboratory of Molecular Plant Biology and KU Leuven Plant Institute, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven, Belgium;
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Wu S, Greiner S, Ma C, Zhong J, Huang X, Rausch T, Zhao H. A Fructan Exohydrolase from Maize Degrades Both Inulin and Levan and Co-Exists with 1-Kestotriose in Maize. Int J Mol Sci 2021; 22:5149. [PMID: 34068004 PMCID: PMC8152283 DOI: 10.3390/ijms22105149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 12/03/2022] Open
Abstract
Enzymes with fructan exohydrolase (FEH) activity are present not only in fructan-synthesizing species but also in non-fructan plants. This has led to speculation about their functions in non-fructan species. Here, a cell wall invertase-related Zm-6&1-FEH2 with no "classical" invertase motif was identified in maize. Following heterologous expression in Pichia pastoris and in Nicotiana benthamiana leaves, the enzyme activity of recombinant Zm-6&1-FEH2 displays substrate specificity with respect to inulin and levan. Subcellular localization showed Zm-6&1-FEH2 exclusively localized in the apoplast, and its expression profile was strongly dependent on plant development and in response to drought and abscisic acid. Furthermore, formation of 1-kestotriose, an oligofructan, was detected in vivo and in vitro and could be hydrolyzed by Zm-6&1-FEH2. In summary, these results support that Zm-6&1-FEH2 enzyme from maize can degrade both inulin-type and levan-type fructans, and the implications of the co-existence of Zm-6&1-FEH2 and 1-kestotriose are discussed.
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Affiliation(s)
- Silin Wu
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, College of Horticulture, South China Agricultural University, Ministry of Agriculture and Rural Affairs, Guangzhou 510642, China; (S.W.); (X.H.)
| | - Steffen Greiner
- Centre for Organismal Studies Heidelberg, Department of Plant Molecular Physiology, University of Heidelberg, 69120 Heidelberg, Germany; (S.G.); (J.Z.); (T.R.)
| | - Chongjian Ma
- Department of Horticulture, Henry Fok College of Biology and Agricultural Science, Shaoguan University, Shaoguan 512005, China;
| | - Jiaxin Zhong
- Centre for Organismal Studies Heidelberg, Department of Plant Molecular Physiology, University of Heidelberg, 69120 Heidelberg, Germany; (S.G.); (J.Z.); (T.R.)
| | - Xiaojia Huang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, College of Horticulture, South China Agricultural University, Ministry of Agriculture and Rural Affairs, Guangzhou 510642, China; (S.W.); (X.H.)
| | - Thomas Rausch
- Centre for Organismal Studies Heidelberg, Department of Plant Molecular Physiology, University of Heidelberg, 69120 Heidelberg, Germany; (S.G.); (J.Z.); (T.R.)
| | - Hongbo Zhao
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, College of Horticulture, South China Agricultural University, Ministry of Agriculture and Rural Affairs, Guangzhou 510642, China; (S.W.); (X.H.)
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Yoshida M. Fructan Structure and Metabolism in Overwintering Plants. PLANTS 2021; 10:plants10050933. [PMID: 34067059 PMCID: PMC8151721 DOI: 10.3390/plants10050933] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 12/27/2022]
Abstract
In northern regions, annual and perennial overwintering plants such as wheat and temperate grasses accumulate fructan in vegetative tissues as an energy source. This is necessary for the survival of wintering tissues and degrading fructan for regeneration in spring. Other types of wintering plants, including chicory and asparagus, store fructan as a reserve carbohydrate in their roots during winter for shoot- and spear-sprouting in spring. In this review, fructan metabolism in plants during winter is discussed, with a focus on the fructan-degrading enzyme, fructan exohydrolase (FEH). Plant fructan synthase genes were isolated in the 2000s, and FEH genes have been isolated since the cloning of synthase genes. There are many types of FEH in plants with complex-structured fructan, and these FEHs control various kinds of fructan metabolism in growth and survival by different physiological responses. The results of recent studies on the fructan metabolism of plants in winter have shown that changes in fructan contents in wintering plants that are involved in freezing tolerance and snow mold resistance might be largely controlled by regulation of the expressions of genes for fructan synthesis, whereas fructan degradation by FEHs is related to constant energy consumption for survival during winter and rapid sugar supply for regeneration or sprouting of tissues in spring.
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Affiliation(s)
- Midori Yoshida
- NARO Hokkaido National Agricultural Research Center, Sapporo 062-8555, Japan
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