Expression analysis of a set of genes related to the ripening of bananas and mangoes

During ripening many important physic-chemical changes contribute to fruit quality, and they are precisely determined by gene expression. Specific genes are essential to normal ripening; however, information on gene expression about the majority of tropical fruit, such as bananas and mangoes is limited. In this way, the present study was undertaken with the objective to provide preliminary access to the changes in expression of some genes potentially relevant to banana and mango ripening. To simultaneously evaluate the changes in gene expression, a small collection of genes related to ethylene biosynthesis, starch mobilization, cell wall disassembly, pigment synthesis and ascorbate metabolism was assembled in nylon membranes and probed with cDNA from unripe and ripe fruit. Some interesting differences were observed between gene expression in bananas and mangoes. In relation to starch metabolism, banana a-amylase was induced during ripening while phosphorylase was more induced in mangoes. Similarly, expression of cell wall-related genes for polygalacturonase and expansin were also different in those fruits. Fructanfructosyltransferase, chalcone synthase, and ascorbate oxidase genes were also induced in ripening mangoes, but not in bananas. Although the number of sequences involved was relatively small, this simple and feasible approach provided interesting preliminary data that can be starting points for more in depth studies