Comparative transcriptomic study of matured fruit and post-fruit developmental stages in Malaysian durian varieties

Durian (Durio zibethinus Murr.) is a famous tropical fruit in Malaysia and well-known for its sweet and creamy taste and unique strong aroma. Despite the differences, durian fruit undergo similar fruit developmental stages upon maturity. However, not much information related to metabolic changes at molecular level are available for fruit development in durian. Hence, the aim of this study was to identify and analyze fruit development transcriptomic changes on six commercial durian varieties (D24, D99, D160, D168, D197, and D200). The transcriptome analysis via RNA-seq assays generated 67 to 234 million raw reads, which are assembled into 49,601 genes with protein coding genes as the largest gene biotype, with a total of 35,832 genes (72.2%). All genes were annotated against Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). GO analysis revealed genes were highly linked to biological process, cellular components and molecular function, with the highest representation in cell wall, while the most common pathways identified by KEGG were carotenoid biosynthesis, fatty acid biosynthesis, starch and sucrose metabolism, phenylpropanoid biosynthesis and galactose metabolism. Important changes were found in abscisic acid and lignin accumulation, which associated with post-harvest response and concurrent colour change. Moreover, significant increase in butyric acid, palmitoyl-CoA and different forms of sugars were associated with buttery smell, creamy texture, and sweetness respectively. Thus, mass sequence data and expression profiling provide an insight into molecular mechanisms for durian fruit developmental process. This study aims to enhance comprehension of durian fruit development stages, including physiological, genetic, and molecular processes, to inform breeding, crop enhancement, and post-harvest strategies to meet consumer and agro-biotechnology demands.