Each year, the University of Kentucky College of Agriculture, Food and Environment honors one outstanding faculty researcher through its Thomas Poe Cooper awards. The awards were endowed by Cooper, who was dean of the college from 1917 to 1951.

Hongyan Zhu, a professor in the Department of Plant and Soil Sciences, is the recipient of the 2019 Thomas Poe Cooper Research Award. The award is presented to recognize outstanding career research achievement by a member of the College of Agriculture, Food and Environment faculty. Designed to recognize and encourage research excellence, the award is the college’s premier award for distinguished scientific accomplishment.

His research interests focus on pathogenic and symbiotic plant-microbe interactions, with a special focus on legumes. His lab has engineered alfalfa for resistance to anthracnose disease using the gene cloned from the model legume Medicago truncatula. Research projects involving root symbioses include 1) functional analysis of non-legume orthologs of legume genes required for nodulation and mycorrhizal symbioses, 2) cloning and characterization of soybean and Medicago genes that control nodulation specificity, and 3) identification and cloning of Medicago genes that govern strain-specific nitrogen fixation and regulate natural variation in nitrogen fixation efficiency. He and his colleagues (as well as others) have shown that non-legumes, such as rice and maize, possess the orthologs of all cloned genes required for root nodule symbiosis in legumes, and these non-legume genes have equivalent functions to their legume counterparts. Zhu also led the isolation of two soybean genes Rj2 and Rfg1 that control cultivar-specific nodulation, and showed that legume plants use disease resistance (R) genes to choose their symbiotic partners. This latter finding reveals a common recognition mechanism underlying symbiotic and pathogenic host-bacteria interactions and indicates that establishment of a root nodule nitrogen fixing symbiosis requires the evasion of plant immune responses triggered by rhizobial effectors or microbe-associated molecular patterns (MAMPs). Despite recent advances in our understanding of the signaling pathways leading to root nodule development, the molecular mechanisms underlying natural variation in nitrogen fixation efficiency/specificity are completely unknown. Thus, the Zhu lab also attempts to elucidate the complexity of this important, but currently overlooked, aspect of the legume-rhizobia symbiosis using genetic, genomic, and molecular approaches, with an ultimate goal of developing novel strategies to enhance the agronomic potential of biological nitrogen fixation.