CAREER: Deciphering sorghum resistance mechanisms to phloem-feeding aphids

University Of Nebraska-Lincoln, Lincoln NE

Investigators

Abstract

Approximately 20 percent of global annual crop loss is attributable to insect infestation, creating major economic concerns about decreases in the food supply for a growing global population expected to exceed nine billion by 2050. Sorghum, one of the world's most important monocot crops grown for food, feed, and fuel, suffers severe yield losses due to attack by phloem-feeding insects, including aphids. However, little is known about the extent of genetic variation that contributes to sorghum resistance or susceptibility to these insects. The goal of this project is to elucidate previously unknown sorghum resistance mechanisms to aphids in order to help design novel targets for pest control and reduce dependence on costly and harmful insecticides. The knowledge gained from this project identifies key genes, signaling networks, pathways, and/or regulatory mechanisms that underlie sorghum resistance to phloem-feeding insect pests. The broader impacts of the project include an innovative and comprehensive outreach/education program to understand plant resistance to insects by involving middle and secondary school teachers and middle school and undergraduate students, particularly those from underserved and underrepresented groups, as they explore solutions to real-world situations involving concepts of plant resistance to insect pests. In addition, this project will provide multidisciplinary training to undergraduate and graduate students and post-doctoral research associates in the areas of plant biology, genomics, and entomology. The defense signaling networks underlying monocot crop resistance to aphids remain largely unknown, and this is especially true for sorghum. This project fills an important gap in current research by utilizing genomic resources to gain insight into the underlying genetic networks and phenotypic traits that contribute to sorghum resistance to aphids. Natural variation in a panel of sorghum inbred lines is used to elucidate the novel sources of sorghum resistance to sugarcane aphids. A combination of molecular, biochemical, and electrophysiological approaches enable a better understanding of the genetic basis of sorghum resistance to aphids. Four objectives are proposed: 1) characterization of SCA feeding behavior and the early physiological defense responses involved in sorghum resistance to aphids, 2) discovery of novel genes and the underlying transcriptional networks that contribute to sorghum resistance/susceptibility to SCA, 3) determination of key defense metabolites in sorghum resistance/susceptibility to SCA, and 4) development and delivery of outreach and educational programs in plant insect interactions and plant defense for middle and secondary school teachers and middle students. The results from this project provide improved insight into how endogenous defenses and manipulation of defense signaling networks contribute to the development of more efficient and durable insect pest-resistant varieties of sorghum. Although the project focuses on sorghum, the knowledge gained has broader applications to other significant cereal crops such as maize, wheat, rice and barley. This project is jointly funded by the Division of Integrative Organismal Systems (IOS) in the Biological Sciences Directorate (BIO) and the Established Program to Stimulate Competitive Research (EPSCoR). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.