Dr. Zhao characterizes the molecular mechanisms driving disease resistance in crop plants, in order to increase food and bioenergy production and improve the agriculture sustainability.
Dr. Zhao's current research involves three plant pathogens: (1) Acidovorax avenae pv. citrulli (Aac), the causal agent of watermelon fruit blotch disease; (2) Xanthomonas oryzae pv. orizyicola (Xoc), which causes rice bacterial leaf streak disease; and (3) Puccinia emaculata (Pe) that causes switchgrass rust disease.
By collaboration with Ron Walcott (University of Georgia), Saul Burdman (The Hebrew University), an Gregory E. Welbaum (Virginia Tech), Dr. Zhao's research team is trying to characterize the genetic diversity of Aac, identify virulence effectors, and develop novel resistance resources that can effectively control watermelon fruit blotch disease. The project is currently supported by BARD-USDA.
Dr. Zhao is also collaborating with Dr. Jan Leach at Colorado State University and Dr. Jianyong Li at Virginia Tech working on the rice bacterial pathogen Xanthomonas oryzae pv. oryzicola. Dr. Zhao's group employed Arabidopsis, tobacco and rice plants as models to study the biological funcations of a bacterial type III effector AvrRxo1, and the molecular interactions with the cognate plant resistance gene Rxo1. The project is currently supported by NSF.
Dr. Zhao teamed with Drs. Brett Tyler (VBI), Stephen Marek (OSU), Carla Garzon (OSU), and Bing Yang (ISU), working on switchgrass rust disease resistance. Switchgrass (Panicum virgatum L.) is considered a prime candidate for large-scale biomass production for lingo-cellulose derived bio-energy. However, switchgrass rust disease could severely threaten biomass production and feed stock quality. The research team is trying to identify switchgrass rust resistance genes from natural germplasm and develop novel rust resistance through genetic engineering, which may control the switchgrass rust disease. This project is currently funded by NIFA.
Dr. Zhao's research team is also interested in modifying switchgrass for improved biomass yield, abiotic stresses, and feedstock quality. They recently identified switchgrass 4-coumarate: coenzyme A ligase (4CL) gene that is a key enzyme involved in lignin biosynthesis pathway. Lignin plays a critical role in the recalcitrant of biomass conversion to ethanol and other biofuels through the biological processing. Dr. Zhao's group generated transgenic switchgrass plants that suppressed the switchgrass 4CLgene. The transgenic biomass has lower lignin content, which is more efficient to be converted to biofuels.