Dissection of QTL linked to grain yield and identification of candidate genes involved in grain yield formation using comparative SNP sequences analysis

Abstract

Durum wheat (Triticum turgidum L. var durum) is among the most important crop in the word. Obtaining high and stable yield under different environments constitute the major aim in durum breeding. This character is mainly linked to quantitative trait loci (QTL). The crucial steps to identify the QTL linked to the grain yield is the construction of a genomic map with high markers density. The aims of this study were to dissect detected QTL linked to the grain yield and identify candidate genes co-located with these QTL. We have used the map population of Lahn/Chaml to identify and annotate QTLs linked to grain yield under contrasting environments. 583 SNPs markers were selected from detected QTL regions and their sequences were analyzed through bioinformatic approaches. 122 sequences are annoted of which 53% candidate genes were found to be nvolved in tolerance to stresses, with 44.6% of them to biotic stresses, 32.3% to abiotic stresses, and 23.1% to both biotic and abiotic stresses. Also, 29.5% were linked to plant growth and reproduction. 3.3% to cell transport. In addition, 1.6% are retro/transposant and 2.4% were with unknown function. It was also found that 9.8% are involved in others cellular processes. The results showed that 66.7% of candidate genes harbored on 4B chromosome and are involved in tolerance to stresses. The remaining candidate genes are involved in plant growth and reproduction, with 77.8% of candidate genes also located on the short arm of 4B chromosome. These result show clearly the importance of the 4B short arm in durum breeding programs for abiotic stresses. The current study provides informations on the use of SNPs as a powerful tool to identify candidate genes involved in grain yield trait in durum wheat.