Deciphering fruit flesh colour in melon

Resumen del póster presentado al XIIth Eucarpia Meeting on Cucurbit Genetics and Breeding, celebrado on-line del 24 al 28 de mayo de 2021.

Fruit flesh colour in melon (Cucumis melo) is a major attribute of fruit quality related to the accumulation of carotenoids and chlorophylls. This character is determined by two loci, green-flesh (Gf) and white flesh (Wf), Gf being epistatic over Wf. Gf is located in chromosome 9 and has already been identified as CmOr, a gene that induces an orange phenotype associated to beta-carotene accumulation. Wf is in chromosome 8, being responsible of white and green fruit flesh phenotypes. A major quantitative trait locus (QTL) for fruit flesh colour corresponding to Wf (LUMQU8.1) was previously mapped in chromosome 8 using a Recombinant Inbred Line (RIL) population derived from the melon cultivars “Védrantais” (cantalupensis, highly climacteric, orange flesh) and “Piel de Sapo” (inodorous, non-climacteric, white flesh). The QTL interval contained 32 annotated genes. To identify the Wf gene in this interval, we searched for candidates with a high and predominant expression in fruit flesh and a functional link to chloroplasts (e.g. presence of a chloroplast transport peptide of predicted role in a chloroplast-associated processes). Gene expression was confirmed by qPCR analyses of melon fruit samples at different developmental stages, whereas chloroplast localization and function was tested by transient expression of “Védrantais” and “Piel de Sapo” alleles in Nicotiana benthamiana leaves followed by analysis of chlorophyll and carotenoid content and in photosynthetic activity. The results with some of the candidate genes, including some previously proposed in the literature to be Wf, will be presented.

Peer reviewed