Transcriptomic analysis reveals the role of abscisic acid and ethylene in regulating starch-source biosynthesis associated with soft nose disorder in ‘Keitt’ mango fruit during postharvest

Abstract

Soft nose is a physiological disorder in the distal flesh of mango fruit during ripening, which results in the decline in its consumer acceptance and salability. In this study, transcriptomic methods were used to compare mesocarp tissue from soft nose and healthy ‘Keitt’ mango fruit at different ripeness stages to identify the genes that are affected by soft nose disorder. The analysis revealed that the occurrence of soft nose affected plant hormone signaling pathways, particularly for abscisic acid (ABA) and ethylene. Also, accelerated starch decomposition and sucrose accumulation were found to be involved in development of soft nose disorder in mango fruit. Thus, soft nose fruit had lower contents of ABA and starch, and higher contents of sucrose, fructose, glucose and β-carotene compared to the healthy fruit. Also, we constructed a network of potential transcription factors and genes related to ABA and starch-sucrose metabolism that might be associated with soft nose disorder, and suggested that ABA might interact with ethylene to collectively regulate changes in downstream metabolic networks, thereby promoting development of soft nose disorder in ‘Keitt’ mango fruit during postharvest.