An article describing the complete catalogue of genes (pan-genome) and agricultural traits (pan-phenome) of eggplant has just appeared in Nature Communications. The team behind this tour de force comprised 24 researchers from seven countries and was led by Lorenzo Barchi (University of Turin, Italy), Björn Usadel (Research Centre Jülich, Germany) and Giovanni Giuliano (Italian National Agency of New Technologies, Italy).
The team started from a large worldwide collection of 3,400 varieties of eggplant and its wild progenitors, and used it to reconstruct its domestication history in India and South-East Asia, and its expansion to the Middle East, Europe and Far East (China and Japan), probably through Arab and Chinese trading routes. Then it went on to analyze the characteristics selected both by humans and the environment in the domestication and diversification centres: for instance, the varieties coming from India and South-East Asia have retained the non-purple skin colour and the spiny leaves characteristic of their wild ancestors, while these traits were progressively lost in the other geographical areas.
Finally, the team focused on 368 varieties, representative of the worldwide phenotypic and genetic diversity of eggplant and comprising its wild progenitors, Solanum incanum and Solanum insanum. The genome sequences of these accessions were determined and 218 traits (agronomic, resistance to biotic and abiotic stresses, fruit metabolic composition) were scored in three field trials, in Valencia (Spain), Montanaso Lombardo (Italy) and Antalya (Türkiye). This enormous dataset was analyzed using advanced bioinformatic techniques. The ‘core’ genome of eggplant was found to consist of around 16,300 gene families (present in all varieties) while around 4,000 gene families were ‘dispensable’ (i.e. they were present in only one or few varieties). Similarly, some traits gave similar scores in all locations (stable traits) while others were scored only in one or two, implying they are under strong environmental influence.
“This work is a cornerstone: It not only rewrites the breeding history of this delicious vegetable but empowers its breeding for future generations”, says Giovanni Giuliano, one of the project coordinators. “We have discovered over 3,000 associations between traits and genomic regions, and for many of them we have discovered the exact DNA mutation at the basis of the trait. In the present paper we give three examples: the formation of prickles, the resistance to Fusarium, a serious fungal disease affecting eggplant productivity, and the content of fruit isochlorogenic acids, potent antioxidants that are also associated with flesh browning. The remaining 215 traits will be published in a follow-up paper. Importantly, all the genomic data and the varieties are publicly available. The latter will be distributed under a Standard Material Transfer Agreement, to ensure that the revenues arising from new varieties stemming from our work will be shared with the original custodians of these varieties, as stipulated by the FAO International Treaty on Plant Genetic Resources for Food and Agriculture. We think that this will establish a win-win situation, where all stakeholders (custodians, researchers, seed companies and consumers) will reap the benefits of this publicly funded research”.
Read the paper: https://rdcu.be/ePm4
This work was supported by the European Commission through projects G2P-SOL (www.g2p-sol.eu) and PRO-GRACE (www.grace-ri.eu)