Genes, Proteins and Metabolites in the Interaction of Strawberry and Fungal Pathogen

Colletrotrichum acutatum and Botrytis cinerea are among the major fungal pathogens of Fragaria spp. Both pathogens could infect strawberry fruits during the fruit’s early developing stage and remain quiescent until ripening. In strawberry, a fruit ontogenic resistance to pathogen infection was described and correlated with fungal quiescence during the unripe stages of the fruit. Due to the period of fungal quiescence, the management of anthracnose and gray mould diseases becomes more complex as symptoms only manifest in ripe fruits. To identify the underlying component in the ontogenic resistance of strawberry fruits, transcriptomic and metabolomic approaches were used. White and red fruits of strawberry were artificially inoculated with C. acutatum and B. cinerea. Transcriptome profile of B. cinerea infected fruits exhibited a general up-regulation of defense-related genes in white fruits after 24 h of infection. Meanwhile, accumulation of phenolic compounds such as proanthocyanidins, catechins and the ellagitannin casuarictin was also observed in white fruits after 48 h of interacting with C. acutatum and B. cinerea. The acquisition of these findings could provide a benchmark to further investigate the interaction of strawberry against pathogens with latent infection. Hence, a strawberry transformation was performed to study the mechanism of a gene encoding for a mannose-binding lectin protein which was previously identified to be correlated with the resistance of white strawberry fruits to C. acutatum. The regeneration system utilized in the transformation is also discussed.