Analysis of aroma-related volatile compounds affected by "Ginsen Makuwa" genomic regions introgressed in 'Vedrantais' melon background

Abstract

[EN] Volatile profile of melon fruit from 25 introgression lines (ILs), developed by introgressing specific genomic regions from the Japanese cultivar `Ginsen makuwa¿ (MAK) into the `Charentais¿ recurrent genetic background of the cultivar `Vedrantais¿ (VED), was characterized in two environments. Fifty-seven VOCs were identified by purge and trap extraction followed by chromatography-mass spectrometry. IL population was also genotyped by GBS with 2,146 SNP distributed throughout the melon genome to tag MAK introgressions. The aromatic profiles of both parents and their hybrid suggested the dominance of MAK alleles. MAK introgressions in the VED background in general reduced the accumulation of VOCs in fruit, mainly alkyl esters and apocarotenoids. The environmental effect was remarkable, although some ILs showed a volatile profile stability in both environments. Some ILs with specific MAK introgressions displayed specific VOC profiles. The joint analysis of VOC profiles and GBS genotypes allowed for the identification of candidate genes, such as MELO3C024886, a 4-coumarate:CoA ligase which can be involved in the eugenol pathway, and other genes previously reported to be involved in melon VOCs production from fatty acids, aminoacids or carotenoids (CmLOX18, CmAAT, CmBAMT, CmCRTISO1), whose MAK alleles introgressed on VED genetic background might change the Charentais VOC profile. Additionally, some ILs showed changes in VOC profiles due to pleiotropic effects of changes in other traits, such as the low levels of apocarotenoids in the two green fleshed ILs (CmOrCmOr genotype), associated to the lack of carotenoid precursors, and the new ester profile of the ILs with altered ripening pattern (likely due to the introgression of the MAK NAC factor MELO3C012215). The information generated about the candidate regions and genes will be of interest for further genetic studies, to optimize the use of MAK genetic resources in melon breeding, and also to develop new lines with Charentais background and novel aroma profiles.