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

PELUFFO L.; LIA V.V.; TROGLIA C.; MARINGOLO C.; PANIEGO N.; ESCANDE A.; HOPP H.E.; FERNIE A.R.; HEINZ R.A.; CARRARI F.

Rosario, Santa Fé, Argentina

Simposio; VII Simposio Argentino de Biotecnología REDBIO 2009.; 2009

REDBIO ARGENTINA

We report here a comprehensive metabolic profiling of sunflower (Helianthus annuus) genotypes showing contrasting behavior against Sclerotinia sclerotiorum infection. Applying a GC-MS-based metabolite profiling approach we were able to identify 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 capitulum, the main target organ of pathogen attack. Metabolic changes of the two contrasting genotypes were determined along the infection period of main disease incidence (R5.2 to R6) concomitant to the timing of the determination of main yield components. 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 suggest that metabolic changes are synchronized in a time course dependent manner in response to the pathogen. Concerted differential metabolic changes were detected to a higher extent in the susceptible genotype rather than in the resistant one allowing differentiation of modules composed by intermediates of the same pathway which are highly connected between each other in the susceptible line while they are not in the resistant counterpart. Results also evidenced genotype specific regulation of distinct metabolic pathways, suggesting that some specific metabolites could lead to candidate markers for molecular breeding. 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 pathogens causing great detrimental impact on the crop yield.