Insights on the Structural and Metabolic Resistance of Potato (Solanum tuberosum) Cultivars to Tuber Black Dot (Colletotrichum coccodes)

Article Article scientifique Article Insights on the Structural and Metabolic Resistance of Potato (Solanum tuberosum) Cultivars to Tuber Black Dot (Colletotrichum coccodes) eng 2020 author Massana Codina Josep 858059 author Schnee Sylvain author Allard Pierre-Marie 812151 author Rutz Adriano 0000-0003-0443-9902 747246 author Boccard Julien 0000-0001-5913-9566 507373 author Michellod Emilie author Cléroux Marilyn author Schürch Stéphanie author Gindro Katia author Wolfender Jean-Luc 135649 10.3389/fpls.2020.01287 32973846 1664-462X https://www.frontiersin.org/article/10.3389/fpls.2020.01287/full Black dot is a blemish disease of potato tubers caused by the phytopathogenic fungus Colletotrichum coccodes. Qualitative resistance (monogenic) that leads to the hypersensitive response has not been reported against black dot, but commercial potato cultivars show different susceptibility levels to the disease, indicating that quantitative resistance (polygenic) mechanisms against this pathogen exist. Cytological studies are essential to decipher pathogen colonization of the plant tissue, and untargeted metabolomics has been shown effective in highlighting resistance-related metabolites in quantitative resistance. In this study, we used five commercial potato cultivars with different susceptibility levels to black dot, and studied the structural and biochemical aspects that correlate with resistance to black dot using cytological and untargeted metabolomics methods. The cytological approach using semithin sections of potato tuber periderm revealed that C. coccodes colonizes the tuber periderm, but does not penetrate in cortical cells. Furthermore, skin thickness did not correlate with disease susceptibility, indicating that other factors influence quantitative resistance to black dot. Furthermore, suberin amounts did not correlate with black dot severity, and suberin composition was similar between the five potato cultivars studied. On the other hand, the untargeted metabolomics approach allowed highlighting biomarkers of infection, as well as constitutive and induced resistance-related metabolites. Hydroxycinnamic acids, hydroxycinnamic acid amides and steroidal saponins were found to be biomarkers of resistance under control conditions, while hydroxycoumarins were found to be specifically induced in the resistant cultivars. Notably, some of these biomarkers showed antifungal activity in vitro against C. coccodes. Altogether, our results show that quantitative resistance of potatoes to black dot involves structural and biochemical mechanisms, including the production of specialized metabolites with antifungal properties. Solanum tuberosum Black dot (Colletotrichum coccodes) Hydroxycinnamic acid amide Metabolomics Phellem Quantitative resistance Steroid derivative. Dewey 615 31 Section des sciences pharmaceutiques 17 false 881 Sciences analytiques Frontiers in Plant Science 11 1287 1fad2b6f-4e6d-4206-9e24-b81d65bef210 Article (Published version) Public MassanaCodina2020.pdf 5148115 application/pdf CC BY openAccess Faculté des sciences / Section des sciences pharmaceutiques

Title	Published in	Year	Views	Downloads

Epidemiological insights, cultivar resistance and natural products to control black dot (Colletotrichum coccodes) and silver scurf (Helminthosporium solani) on potato (Solanum tuberosum) tubers		2020	581	2,520
Insights on the Structural and Metabolic Resistance of Potato (Solanum tuberosum) Cultivars to Tuber Black Dot (Colletotrichum coccodes)	Frontiers in Plant Science	2020	426	401

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Massana Codina, Josep