Molecular Analysis of Fruit Ripening in Banana

Abstract

Banana is a climacteric fruit and has a very short postharvest life. Many varieties of banana fruits are ripened artificially by treating them with hydrocarbons. The current methods of postharvest management practices used for fruits are not enough to control the ripening in banana. Recent advances in recombinant DNA technology and genetic engineering have resulted in the modification of fruit ripening in banana. Towards this, many genes involved in ripening have been cloned and characterized. Ripening in banana is characterized by a biphasic ethylene production with a sharp early peak and a post climacteric small peak. During banana fruit ripening, ethylene production induces a developmental cascade which results in the conversion of starch into sugars, an associated burst of respiratory activity, and an increase in the protein synthesis. Other changes include fruit softening, flavor and aroma development, change in pigmentation, and increased susceptibility to pathogens; also, banana fruit softening is attributed to activities of various cell wall hydrolases. The participation of various cell wall hydrolases in banana softening during ripening has also been reported recently. The enhancing and suppressive effects of ABA and IAA on activities of different cell wall hydrolases have been noticed during ethylene-induced ripening in banana. Simultaneously, decrease in polyphenols, higher alcohol acetyl transferase activity, chlorophyll degradation etc., have been earlier reported during ripening in banana. Recently efforts are made to delay the ripening by antisense suppression of a transcription factor-related ripening. This review summarizes the various advances made in the field of fruit ripening in banana.