Characterization of tolerance to Fusarium oxysporum f.sp., cubense infection in banana using suppression subtractive hybridization and gene expression analysis

Identification of defense response genes in the host is one of the most essential steps in understanding disease resistance mechanisms in plants. In this study, suppression subtractive hybridization (SSH) library was constructed to study the genes involved in response to fusarium wilt disease in banana. Here cDNAs from a tolerant genotype Musa acuminata spp. burmannicoides ‘Calcutta-4’ infected by Fusarium oxysporum f.sp., cubense were used as tester and cDNAs from uninfected ‘Calcutta-4’ as driver population. After hybridization and cloning, EST library of 83 non-redundant clones were obtained. Based on sequence analysis and homology search in NCBI database the clones were assigned to different functional categories. The expression pattern of selected eight defense related genes namely peroxidase, glutaredoxin, polyphenol oxidase, glutamate synthase, S-adenosyl methionine synthetase, 14-3-3, heat shock protein, mannose binding lectin were analyzed through real-time PCR in contrasting genotypes. It was observed that the expression of these genes during initial progression of disease was found to be higher in tolerant genotype ‘Calcutta-4’ than in susceptible genotype ‘Kadali’.

► Eighty three ESTs induced against Fusarium wilt in banana were identified.
► Seventeen percent of ESTs comprises stress and cell defense.
► Early expression of defense related genes was observed intolerant genotype.
► Higher expression of antioxidant enzymes supports its role against Fusarium wilt.