Rice is one of the world’s most important crops and provides staple food for two thirds of the world population. With its completely sequenced genome, rich genetic and molecular resources, powerful genomics and molecular tools, and syntenic to other cereal crop species, rice has become increasingly popular as a model system to study plant biology in general and crop in particular. Rice bacterial blight is one of most devastating rice diseases, and also a model pathosystem to understand the molecular mechanism of plant disease. The causal pathogen, Xanthomonas oryzae pv. oryzae (Xoo) primarily infect rice leaves and spread along vascular tissue. The disease is the complex outcome of molecular interaction between factors in both host and pathogen bridged by a bacterial protein secretion system, which is revolutionarily similar to the type III secretion system (T3SS) in some bacterial animal and human pathogens. The T3SS of Xoo delivers and injects a group of substrate proteins, called type III effectors, into host cells to induce a state of disease. The effector serves as either virulence factor intrinsically to promote bacterial growth and disease development or elicitor to trigger host resistance responses through the recognition of specific host resistance R gene leading to the pathogen its own demise. Working with Dr. Frank White at Kansas State University, I have cloned and characterized in Xoo several members of a type III effector family with other members also been found in a wide range of Xanthomonas species and pathovars. Four members (AvrXa27, PthXo1, PthXo6 and AvrXa7) of this eukaryotic transcription activation like (TAL) effector family each specifically activates the corresponding host gene expression. The activation of R gene (Xa27 by AvrXa27) resulted in the host disease resistance, while elevation in expression of S gene (Os8N3 induced by PthXo1 and TFX1 by PthXo6) lead to disease susceptibility in host. Os8N3 is a member of MtN3/Saliva family with unknown molecular function and TFX1 is a bzip transcription factor; we call them S genes because of their association with disease susceptibility of host. My research interests at ISU will focus on revealing the nature of interaction between the effector protein and the promoter of the corresponding responsive gene in rice. My lab will also be interested in understanding the molecular and biochemical basis of the S genes for disease susceptibility. Since field isolates of Xoo depend on different but closely related TAL effector genes for virulence, another research project will be to investigate how many adaptive ways in which this pathogen to explore the host plants for virulence. The long term goal of research in my laboratory is to better understand the plant disease, and gain knowledge to aid the design of more intelligent breeding strategies for disease control by blocking the host disease susceptibility pathway in addition to deployment of genetic disease resistance genes in crop plants.
Dr. Bing Yang
Area of Expertise:
genetic disease resistance
B.S., Southwest Forestry College, China, 1986
M.S., Southwest Forestry College, China, 1989
Ph.D., Kansas State University, 2000