Title: Genome-wide association study of drought tolerance and gene cloning in maize seedlings
Speaker: Prof. Qin Feng，College of Biological Sciences, China Agricultural University
Date: March 24th, 2017 (Thursday)
Host PI: Prof. Mingguang Lei
Venue: PSC Auditorium
Maize production is frequently threatened by drought stress on a global-scale. Identification of the genetic components underlying the drought tolerance in maize is of great importance. Here, we report a genome-wide association study (GWAS) of maize drought tolerance at the seedling stage that identified 83 genetic variations which were resolved to 42 candidate genes. Firstly, a Miniature Inverted-repeat Transposable Element (MITE) inserted in the promoter of a NAC gene (ZmNAC111) was found to be significantly associated with the natural variation in maize drought tolerance. We discovered that the 82-bp MITE represses ZmNAC111 expression via RNA-directed DNA methylation and H3K9 dimethylation. Increasing ZmNAC111 expression in transgenic maize conferred enhanced drought tolerance by improving water use efficiency and upregulation of drought-responsive genes under water stress. Secondly, the peak signal of GWAS uncovered that the natural variation in ZmVPP1, encoding a vacuolar-type H+-pyrophosphatase, most significantly contributes to maize drought tolerance. Further analysis found that a 366-bp insertion in the promoter, containing three MYB cis-elements, confers drought-inducible expression of ZmVPP1 in drought-tolerant genotypes. Transgenic maize with enhanced ZmVPP1 expression exhibits improved drought tolerance, probably due to enhanced photosynthetic efficiency and root development. Taken together, this research provides important genetic insights into the natural variation of maize drought tolerance at seedling stage. The identified loci/genes can serve as direct targets for both genetic engineering and selection for the trait improvement of maize.
This presentation will be delivered in English.