What are the roles of SSPs in regulating ECM symbiosis in response to biotic and abiotic nutritional signals in trees? - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2022

What are the roles of SSPs in regulating ECM symbiosis in response to biotic and abiotic nutritional signals in trees?

Résumé

To improve their mineral nutrition, plants form symbiotic associations with microorganisms. Occurring between 6,000 tree species and 20,000 ascomycetes and basidiomycetes, ectomycorrhizal (ECM) symbioses dominate boreal and temperate forests. Providing mineral nutrients in exchange for organic carbon, they have an energetic cost for the tree. To use their resources efficiently, trees must integrate environmental and metabolic nutritional cues to regulate adequately their ECM interactions. The signalling pathways leading to the regulation of ECM symbiosis in response to nutrient signals are unknown. In herbaceous plants, Small Secreted Peptides (SSPs) transduce local and long-distance signals regulating their symbiotic associations in response to abiotic and biotic nutrient cues. For example, in nitrate deficiency the secretion of C-TERMINALLY ENCODED PEPTIDEs (CEP) in the xylem sap drives a root-to-shoot starvation signal promoting nodulation in nitrate rich zones, while associations with arbuscular mycorrhizal (AM) fungi represses the expression of CEP genes. Similarly, the secretion of CLAVATA3/ESR related (CLE) peptides transduces root-to-shoot signals repressing symbiotic associations with nitrogen (N)-fixing bacteria and AM fungi in response nitrate, inorganic phosphate or to prior associations with AM fungi and N-fixing bacteria. SSPs are small peptides (<100 amino acids) produced from short open reading frames or by proteolytic cleavage of pre-proteins 11. More than 4,000 SSP families exist in herbaceous, most remain to be functionally characterized 12. Several of these families were found in trees. To investigate their role in the regulation of ECM symbiosis in response to nutrient cues, we scanned the genomes of poplar and oak with an iterative method of HMM and blast to identify members of 21 SSP families known to regulate plant-microorganism interactions or induced during nutrient stresses in herbaceous. Using a transcriptomic approach, we selected a set of poplar SSPs transcriptionally regulated by ECM associations and/or nitrate stresses and tested their effects on ECM symbiosis through exogeneous application of synthetic peptides. We found that several CLEs and CEPs enhance the ECM association between poplar and the fungus Laccaria bicolor. This suggests that SSPs participate to the formation/regulation of ECM symbiosis in poplar. Further functional characterization of these peptides is required to understand their functions.
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Dates et versions

hal-04186873 , version 1 (24-08-2023)

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  • HAL Id : hal-04186873 , version 1

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C. Bonnot, Him K. Shrestha, Alexis Chartoire, Alexandra Hénocq, Cécile Gaumétou, et al.. What are the roles of SSPs in regulating ECM symbiosis in response to biotic and abiotic nutritional signals in trees?. JOURNÉES 2022 SYMBIPHYT, Nov 2022, Dijon, France. ⟨hal-04186873⟩
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