Early regulation of primary metabolism, antioxidant, methyl cycle and phenylpropanoid pathways during the Mycosphaerella fijiensis-Musa spp. interaction

Black leaf streak disease (BLSD) caused by Mycosphaerella fijiensis is considered the most destructive and costly foliar disease that affects bananas and plantains. In spite of some recent progress regarding the study of M. fijiensis-Musa spp. interaction, there is still limited information for this pathosystem. To gain insights into the molecular mechanisms behind the M. fijiensis-Musa spp. interaction, gene expression and biochemical analysis related with primary metabolism, methyl cycle, antioxidant and phenylpropanoid pathways were conducted. Early screening of the resistant cultivar (cv.) ‘Calcutta 4’ (Musa AA) and the susceptible cv. ‘Grande naine’ (Musa AAA) plants infected with M. fijiensis was effective at looking for defense-related genes. Quantitative PCR experiments showed up-regulation of Photosystem I reaction center subunit N chloroplastic-like (primary metabolism) and S-adenosyl- L-methionine synthetaste (methyl cycle) genes in the incompatible interaction, as well as down-regulation of the phenylpropanoid pathway genes in the susceptible cv. ‘Grande naine’ as main finding of this study. Improved knowledge concerning the M. fijiensis-Musa spp. interaction could help to establish innovative approaches for plant breeding programs against BLSD.