A consortium of new public and private research centres have completed the melon genome sequence, one of the most interesting species in the world in economic terms. The study –in which researchers from the National Centre for Genomic Analysis (CNAG), based at the Barcelona Science Park (PCB), have taking part– has been published in the journal Proceedings of the National Academy of Sciences (PNAS).This marks the first time a public-private Spanish initiative completes the genome sequence of a superior plant species and, what's more, it was done using new cheaper and more efficient mass sequencing technologies.

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The projecte –known as Melonomics– was launched by the Genoma España Foundation and was led by Pere Puigdomènech of the Spanish National Research Council (CSIC), and Jordi Garcia Mas, of the Institute of Agro Food Research and Technology (IRTA), ), who develop their work at the Centre for Research in Agricultural Genomics (CRAG). The project also enjoyed the outstanding collaboration of the CNAG researcher, Tyler Alioto and the team lead by Roderic Guigó, at the Centre for Genomic Regulation (CRG).

Results have shown that the melon genome has 450 millions of base pairs and 27.427 genes. It is much bigger than the genome of its nearest “relative”, the cucumber that has 360 million base pairs.

Another question of interest is that related to the ripening of the fruit, a process which determines fruit characteristics such as taste and flavor. Scientists have identified up to 89 genes related with some aspects of this process: 26 genes related to the carotenoid accumulation -which gives the color to the melon flesh- and 63 related to the sugar accumulation and the taste of melon. Twenty-one of these have never been described before.

The CNAG researcher, Tyler Alioto, in collaboration with the CRG, led the effort to identify and assign functions to the complete set of protein-coding genes in the melon genome. More specifically he created a reference gene set (27.427 genes in total) from a combination of gene predictions and gene expression evidence. This repertoire of annotated genes, which includes disease resistance genes and the aforementioned genes affecting fruit quality, can be used as a new tool to improve melon varieties through breeding, as well as aid our understanding of the evolution of the family of cucurbits.

The CNAG also resequenced other melon varieties, including the parental genomes, that will help to identify genetic variation among different melon varieties.