Chitosan coating to delay the ripening process in banana: a transcriptomics study

Banana fruit has the characteristic of ripening via respiration-affected metabolism and fruit-borne ethylene production. Without proper handling, the fruit’s shelf life during the distribution process may be shortened. Chitosan is recommended as a cost-effective substance that can postpone the ripening process through coating application. This study was focused on the total transcriptomics analysis of chitosan-coated bananas versus untreated, which served as a control to understand the molecular impact of chitosan-coating on banana ripening. The banana fruit samples’ total RNA has been extracted and sequenced. Changes in some genes were seen in the transcriptomic analysis, based on the KEGG Pathway Enrichment Analysis and log₂-fold change values. It was also identified in the current focus that chitosan coating might affect glycolysis, starch and sucrose metabolism, and the ethylene synthesis pathway. Fruit coating with chitosan was considered to suspend the biosynthesis of ethylene at the step of 1-aminocyclopropane-1-carboxylic acid (ACC) conversion to ethylene through permeability adjustment of surrounding O₂ and inhibition of ACC oxidase or ACO gene expression. As a result, the fruit’s glycolysis and the ripening processes were delayed. Additionally, starch degradation and sucrose metabolism were also affected, as shown by the changes in β-amylase (BAM) gene expression. Furthermore, chitosan also plays a role in maintaining the expression of genes involved in the glycolysis process, which has implications for inhibiting fruit ripening.