Location: Crop Production and Pest Control Research
2019 Annual Report
Accomplishments
1. Brachypodium distachyon identified as potential surrogate model for functional characterization of Hessian fly-responsive defense genes in wheat. ARS researchers in West Lafayette, Indiana, have characterized the molecular response of Brachypodium distachyon (Bd) plants, a model grass genome and nonhost to Hessian fly, following larval attack. The study clearly documented that Bd plants exhibit responses intermediate between resistant and susceptible host wheat. Resembling the resistant wheat host, Bd plants produce insecticidal defense proteins that does not allow the larvae to complete their development. Resembling the susceptible wheat host Bd plants also showed increase in expression of susceptibility-associated genes thus allowing the larvae to survive up to 41 days longer than the dying larvae feeding on resistant host wheat. The scientists have prepared a model depicting the molecular mechanism during interaction of Bd with Hessian fly and documented the work in a high-impact peer reviewed journal. This work confirms the suitability of utilizing this nonhost genome to study and characterize the function of candidate Hessian fly-responsive genes that will allow for efficient management of this insect pest and thereby prolong the durability of wheat cultivars. The same approach can also be used by other researchers to manage other devastating insect pests of wheat, and other important cereal crops that are of economic importance to the farmers.
2. Development of novel targeted population sequencing in Hessian fly. Hessian fly is a gall midge that historically has been a devastating pest of wheat. Hessian fly larvae do not move after they have begun to feed, and their feeding on wheat seedlings reprograms the shoot apex to stop normal development. Instead, the wheat tissues at the feeding site become abnormally permeable, and the larvae lap up exuded nutrients. Since secreted salivary proteins are the first intimate molecular contact between the larvae and the wheat host, researchers in West Lafayette, Indiana, looked at proteins from salivary glands in Hessian fly to find possible candidates that reprogram the wheat allowing for the fly to overcome the wheat defenses. We also developed a for surveying populations allowing for the assessment of 52 different proteins in 48 individuals at one time. This accomplishment provides cheaper and more efficient methods for surveying HF populations and will be valuable to wheat breeders and researchers by allowing a rapid assessment of extant fly populations for potential hazards for new wheat deployment.
