Agriculture: An international study reveals the complete set of eggplant genes and traits

A team of 24 international researchers from 7 countries, including Italian representatives from ENEA, CNR, CREA and the University of Turin, has produced a comprehensive catalogue of eggplant genes (the pan-genome) and agronomic traits (the pan-phenome). The study, published in the journal Nature Communications, makes it possible to reconstruct the history of this crop and opens up new prospects for its future breeding.

“This work is a cornerstone for the sector. It rewrites the history of eggplant domestication and genetic improvement,and paves the way for further crop improvement for future generations”, says Giovanni Giuliano, who coordinated the project for ENEA in collaboration with researchers Giuseppe Aprea, Paola Ferrante and Maria Sulli from the GREEN Biotechnology Laboratory.

Starting from a large global collection of 3,400 eggplant varieties and their wild progenitors, the team reconstructed the history of the crop’s domestication in India and Southeast Asia, as well as its subsequent spread to the Middle East, Europe and the Far East (China and Japan), most likely via Arab and Chinese trade routes ^[1]. The researchers then analysed the traits selected by both humans and the environment in the centers of domestication and diversification. For instance, many varieties from India and Southeast Asia have retained the non-purple skin colour and spiny leaves, characteristic of their wild ancestors, whereas these traits have been lost in other geographical regions ^[2].

Finally, the team focused on 368 varieties representative of the global phenotypic and genetic diversity of eggplant, including their wild ancestors, Solanum incanum and Solanum insanum. Using advanced bioinformatic techniques to analyse data collected from three field trials in Montanaso Lombardo (Lodi, Italy), Valencia (Spain) and Antalya (Turkey), the researchers found that the eggplant core genome consists of around 16,300 gene families present in all varieties, while approximately 4,000 gene families are found in only a few. Similarly, some traits were detected in all locations (stable traits), while others were observed in only one or two locations, indicating a strong environmental influence.

"We discovered over 3,000 associations between traits and genomic regions, and identified the exact DNA mutation underlying many of these traits. In the article, we provide three examples: spine formation, resistance to Fusarium — a serious fungal disease that affects productivity — and antioxidant compound content, which is also associated with flesh browning”, the researchers add.

All genomic data are publicly available, as are the varieties, which will be distributed according to FAO rules ^[3],

to ensure that all stakeholders share the benefits of the new varieties developed through this scientific work.

“This win–win solution will allow all interested parties — seed custodians, researchers, seed companies, growers and consumers — to reap the benefits of this publicly funded research ^[4]”, the researchers conclude.