Blue mold, caused by Penicillium expansum, is responsible for postharvest losses of apple fruit, and threatens human health through production of the potent mycotoxin patulin. No major gene(s) providing resistance have as yet been identified, but recent studies indicate a quantitative control of the disease. An AryANE chip covering 60K apple transcripts was used to identify possible candidate gene(s) that are differentially regulated between resistant and susceptible cultivars upon P. expansum infection. Induction of cell wall related gene (PGIP1), and three genes involved in the ‘down-stream’ flavonoid biosynthesis pathway (CHS, FLS and LDOX), shows the fundamental role of cell wall as an important barrier, and contents of polyphenolic compounds of fruits as a quantitative components in enhancing disease resistance to blue mold. Moreover, exogenous application of Jasmonic acid hormone enhanced the defense mechanism in fruits. This is the first report linking Jasmonic acid and activation of cell wall and flavonoid pathway genes in apple fruit resistance to blue mold. Results provide an initial categorization of genes that are potentially involved in the resistance mechanism, and should be useful for developing tools for gene marker-assisted breeding of apple cultivars with an improved resistance to blue mold. SUBMITTER_CITATION: Ahmadi-Afzadi, M., Orsel Baldwin, M., Pelletier, S., Cournol, M., Proux-Wéra, E., Nybom, H., Renou, J.-P. (2018). Genome-wide expression analysis suggests a role for jasmonates in the resistance to blue mold in apple. Plant Growth Regulation, 85 (3), 375-387. , DOI : 10.1007/s10725-018-0388-2
Overall design
4 cultivars (2 resistant and 2 susceptible), each in 3 technical replicates, were inoculated with fungal spores, and samples from control and inoculated fruits were taken in 3 time points.