Integrated Transcriptomic and Volatile Metabolome Provide Insights into the Flavor Formation of Kiwifruit （Actinidia Deliciosa）During Storage

Abstract

'Cuixiang' (Actinidia deliciosa) is an economically important fruit with unique flavor due to its distinct volatile compounds. However, the flavor of 'Cuixiang' changes significantly during storage. In this study, we performed metabolome and transcriptome analysis on samples during storage to analyze the changes in volatiles. A total of 63 volatiles were detected by HS-SPME-GC-MS. Among them, sixteen volatiles were identified as characteristic aroma compounds by PLS-DA. Ethyl acetate, methyl butanoate, ethyl butanoate, methyl hexanoate, ethyl hexanoate, and 3-Hydroxy-2-butanone contributed a characteristic fruity and sweet aroma of 'Cuixiang', while 1-pentanol, (z)-3-hexenol, and nonanal produced a fresh green aroma. Besides, a total of 13,922 differentially expressed genes in fruits were identified and used to identify key candidate genes that may regulate volatile during storage. The results of KEGG analysis showed that Achn072171, Achn270621, and Achn012241 were involved in the synthesis of key aroma compounds. Weighted gene co-expression network analysis (WGCNA) showed that NAC and BHLH transcription factors were positively correlated with the expression of these genes. Our results elucidate the fundamental aroma regulation metabolism of 'Cuixiang', which could be helpful for flavor regulation during 'Cuixiang' storage in the future.

Keywords: Kiwifruit, Aroma formation, Volatiles metabolome, Transcriptome