Benzoxazinoids (BXDs), a class of specialized metabolites, are abundant in many species of the Poaceae, especially in economically important crops such as wheat. The amount and composition of BXDs provide different resistances against pests. However, the source of genetic variation between different genotypes has not been fully addressed. Tetraploid wheat genomes encode larger allelic variation, which could facilitate breeding of elite wheat cultivars with increased pest resistance. The BXD levels of two tetraploid wheat accessions, the domesticated durum ‘Svevo’, and a wild emmer wheat ‘Zavitan’, had shown contrasting amounts of these molecules. Thus, these two wheat accessions were selected as potential genetic sources for identifying pest resistance quantitative trait loci (QTL) and associated genes. Using a population of Svevo × Zavitan recombinant inbred lines (RILs), we carried out QTL mapping for BXDs. The results show three significant marker-trait associations (MTAs) located on chromosomes 2B, 4B, and 5B. We generated a list of candidate genes found in the MTA regions and identified specific introgression lines (ILs) which are homozygous in Svevo or Zavitan. Our next step is to establish the difference in BXDs among these ILs and to check the effect of their genetic variation on plant resistance to caterpillars. We will also probe the list and select several candidate genes that might be related to BXD biosynthesis and regulation, and/or pest resistance. The outcome of this study could be deployed to increase natural resistance against pests, thereby contributing to global food security and sustainability.
Ms. Toluwanimi Ade-Ajayi
Exploring the Genetic Variation of Tetraploid Wheat to Uncover Benzoxazinoid Resistance Genes to Pests
Ben Gurion University of the Negev, Israel