Integrated Transcriptome and Metabolome Analysis of Fruit Flavor between Endospermic and Mutated Genotype Without Endosperm in ‘Guifei’ Mango

To explore the metabolic basis of amino acids, organic acids, terpenoids, esters and carotenoid in endospermic and mutated genotype without endosperm mango fruit, targeted transcriptomic and metabonomic analyses were conducted in two cultivars (cv. ‘Guifei’ mango with small and big size fruit) with different flavor metabolites contents. A total of 88 different metabolites were separately identified in mango pulps with different sizes, including organic acids, amino acids, phenolic acids and saccharides. There were 73 types of volatile organic compounds (VOCs) were identified in different sizes mango pulps through metabolomics of volatiles. The major volatile compounds found were terpenoids, ester and aromatics. p-Mentha-1(7),2-dien-8-ol, Selina-6-en-4-ol and 1,3-Dimethyl-5-(propen-1-yl) adamantane as major terpenes play an important role in the aroma of ‘Guifei’ mango fruits. In addition, p-Mentha-1(7), 2-dien-8-ol was found in mutated genotype without endosperm mango fruit for the first time and has a relatively high concentration of the glycosidically-bound form in ‘Guifei’ mango. 12 types of carotenes were identified in mango pulp with different fruit size. In SF and LF, the carotenoid contents of the two cultivars were significantly different, and β-cryptoxanthin and zeaxanthin were the key metabolites that caused the difference in the total carotenoid content between the examined cultivars. The integrated analysis of carotenoid metabolism data and transcriptome data showed that GGPS, Z-ISO and NCED were the key genes leading to the great differences in fruit flavor and carotenoid content on mango pulps. This study provides new insights into the effects of mutated genotype on changes in the appearance and intrinsic quality of fruits.