Metabolic profiles of sunflower genotypes with contrasting response to Sclerotinia sclerotiorum infection

PELUFFO L, LIA V, TROGLIA C, MARINGOLO C, PANIEGO N, ESCANDE A, HOPP HE, LYTOVCHENKO A, FERNIE AR, HEINZ R, CARRARI F.

PHYTOCHEMISTRY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2010 vol. 71 p. 70 - 80

0031-9422

We report a comprehensive primary metabolite profiling of sunflower (Helianthus annuus) genotypes displaying contrasting behavior to Sclerotinia sclerotiorum infection. Applying a GC-MS-based metabolite profiling approach we were able to identify differential patterns involving a total of 63 metabolites including major and minor sugars and sugar alcohols, organic acids, amino acids, fatty acids and few soluble secondary metabolites in the sunflower capitulum, the main target organ of pathogen attack. Metabolic changes and disease incidence of the two contrasting genotypes were determined throughout the main infection period (R5.2 to R6). Both point-by-point and non-parametric statistical analyses revealed metabolic differences between genotypes as well as interaction effects between genotype and time after inoculation. Network correlation analyses suggested that these metabolic changes were synchronized in a time-dependent manner in response to the pathogen. Concerted differential metabolic changes were detected to a higher extent in the susceptible, than the resistant genotype allowing differentiation of modules composed by intermediates of the same pathway which are highly interconnected in the susceptible line but not in the resistant one. Evaluation of these data also revealed genotype specific regulation of distinct metabolic pathways, suggesting the importance of the detection of metabolic patterns rather than specific metabolite changes when looking for metabolic markers differentially responding to pathogen infection. In summary, the GC-MS strategy developed in this study proved suitable for the detection of differences in carbon primary metabolism in sunflower capitulum, a tissue which is the main entry point for this and other pathogens causing great detrimental impact on the crop yield.