Physiological and Metabolic Basis of Aphid Resistance in Wild Emmer Wheat

Currently, 10-16% of worldwide crop production is lost to pests and pathogens. Cereal aphids are among the foremost vital biological constraints limiting yield potential of bread wheat which provides 20% of the world’s calorie and protein consumption. In response to aphids attack, plants modify specialized metabolites to reduce damage and preserve their fitness. Benzoxazinoids are the most relevant group of plant specialized metabolites which are associated with biochemical defense against a variety of biotic stresses. The biosynthetic pathways for benzoxazinoid are well studied in maize, yet it is still at the beginning towards a full understanding in hexaploid bread wheat. Cultivated wheat was bred for higher yield, however, might have lost traits related to aphid resistance. While wild relatives, particularly tetraploid wild emmer wheat have been adapted to a wider range of biotic conditions and contain greater resistance diversity, the cultivated bred wheat is more susceptible to aphids. The genetic basis of natural defense mechanisms of tetraploid wheat during plant-insect interaction is largely unknown; thus, in the present study, we systematically characterize the phenotypes and physiologic variation as well as the primary and specialized metabolic profiles by using analytical tools in response to aphid feeding. We screen a large collection of wild emmer, including 200 accessions to reveal their diversity in defense mechanisms against aphids. The knowledge gained from studying wild emmer wheat can be used for pre-breeding and marker-assisted selection to improve aphid-resistance in cultivated wheat and facilitate improved crop resistance and scale back our current reliance on harmful pesticides.