A Seed Dormancy Gene Undergoes Parallel Selection in Multiple Crops

 

Domestication is one of the most important technological innovations in human history. Domesticated species often exhibit convergent phenotypic evolution, termed the ‘domestication syndrome’. An intriguing question is whether the genes responsible for the domestication syndrome were parallel selected among species. To date, genes undergoing parallel selection during the domestication of crops from multiple families have not been identified. Loss of seed dormancy is a typical ‘domestication syndrome’ related agricultural trait and one of the most difficult evaluate trait which result in slow progress in gene identification.

 

Recently, a team led by Prof. TIAN Zhixi and Prof. CHU Chengcai at Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, collaborating with Prof. Scott Jackson from University of Georgia, identified a gene responsible for seed dormancy that has been subjected to parallel selection in multiple crop families.

 

Initially, the researchers cloned the gene G responsible for soybean green seed coat color using genome-wide associate analysis. Surprisingly, they found G was a domestication gene involved in soybean seed dormancy.

 

The following analysis showed orthologs of G in rice and tomato were undergone selection during domestication. Moreover, the domestication of G ortholog in rice was related to seed dormancy. In Arabidopsis, the ortholog of G was also responsible for dormancy.

 

Based on dormancy data from dozens of accessions, researchers found that different haplotypes of this gene showed significantly different levels of dormancy. They also revealed that G might regulate seed dormancy by physically interacting with NCED3 and PSY and in turn modulated ABA synthesis.

 

This is the first report that to identify a domestication gene that has been subjected parallel selection in multiple crop families. This may help facilitate the domestication of new crops.

 

The research entitled "Parallel selection on a dormancy gene during domestication of crops from multiple families" was published in Nature Genetics on September 24, 2018.