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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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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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