B.Sc. (Biology), Henan University, P. R. China 1992
M. Sc (Microbiology) McMaster University, Canada 2000
Ph.D. (Microbiology) McMaster University, Canada 2005
Postdoctoral (Microbiology), University of Washington at Seattle, 2005-2009
Major research interests:
Molecular Plant-Bacteria Interactions; Bacterial Genetics; Signal Transduction; Biotic and Abiotic Stress Responses (both plant host and bacteria); Metagenomics. I obtained my M.Sc and Ph.D from Dr. Turlough M. Finan’s lab at McMaster University, Canada, where I studied how Sinorhizobium meliloti, a soil dwelling alpha-proteobacterium best known for its ability to form nitrogen-fixing nodules on legume plants, perceives, responds to and survives under phosphate-limiting conditions. I did my postdoctoral research with Dr. Eugene W. Nester at the University of Washington (Seattle), where I studied Agrobacterium pathogenesis. As a well known plant pathogen, Agrobacterium tumefaciens infects and causes tumors on many plants with agricultural importance including cherry, apple, pear, peach, grape, rose, and walnut. Agrobacterium has the unique ability to transfer and integrate its oncogenic T-DNA (Transferring DNA) from its tumor-inducing plasmid (pathogenicity plasmid, also called Ti plasmid) into plant chromosome, and the expression of T-DNA genes in the infected plant cells leads to uncontrolled synthesis of plant hormones indole-3-acetic acid (IAA) and cytokinin, resulting in abnormal tissue proliferation and the formation of plant tumors (also called Crown Gall disease), which is a chronic and resurgent worldwide problem. During my postdoctoral work, I used multidisciplinary approaches to elucidate how environmental signal and plant-derived chemicals/signals affect Agrobacterium pathogenicity, biofilm formation, cell-to-cell communication (also called quorum sensing), and how Agrobacterium perceives and transduces these environmental and host signals.
Current researches in the Yuan laboratory continues focus on understanding the complex signalling and interaction, either beneficial or detrimental, between plant host and plant-associated bacteria. We currently are investigating the mutual perception and response between bacterial pathogen and plant host: what genes are involved (functional genomics) and how signalling pathways integrated and orchestrated at the systems-level, using Agrobacterium as a model. In addition, we are: 1) exploring the molecular mechanism by which salicylic acid and Aspirin (acetylsalicylic acid) interferes with (blocks) bacterial quorum-sensing; 2) identifying and characterizing biological control agents, plant- or microbe-derived chemicals that suppress or eliminate bacterial pathogens; 3) studying plant responses to biotic, abiotic stresses, using Brachypodium distachyon as a new monocot model plant system, especially how Brachypodium responds to microbial pathogens; 4) metagenomic analysis and chromosome engineering of plant epiphytic and endophytic bacteria that participate in nutrient cycling, bioremediation, suppressing/eliminating microbial pathogens, promoting plant growth, health and productivity and tolerance to biotic and abiotic stresses, converting biomass to biofuel, or producing novel compounds with antimicrobial activities.
Current lab members
Naeem Nathoo (UWO project student)
Megan Smith-Uffen (UWO project student)
Mi Zhou (Fanshawe College project student)
Selected recent publications:
Yuan ZC, Haudecoeur E, Faure D, Kerr KD and Nester EW. Comparative transcriptome
analysis of Agrobacterium tumefaciens in response to plant signals salicylic acid, indole-3-acetic acid, and Gamma-amino butyric acid reveals signaling crosstalk and
Agrobacterium-plant co-evolution. 2008. Cellular Microbiology. 10: 2339-2354.
Yuan ZC, Liu P, Saenkham P, Kerr KD and Nester EW. Transcriptome profiling and
functional analysis of Agrobacterium tumefaciens reveals a general conserved response
to acidic condition (pH5.5) and a complex acid-mediated signaling involved in
Agrobacterium-plant interactions. 2008. Journal of Bacteriology. 190: 494-507.
Yuan ZC, Edlind MP, Liu P, Saenkham P, Banta L, Wise AA, Ronzone E, Binns AN,
Nester EW. The plant signal salicylic acid shuts down expression of the vir regulon and
activates quormone-quenching genes in Agrobacterium. 2007. Proceedings of the National
Academy of Sciences. 104: 11790-11795.
Yuan ZC, Zaheer R, Morton R, Finan TM. Genome prediction of PhoB regulated
promoters in Sinorhizobium meliloti and twelve proteobacteria. 2006. Nucleic Acids Research. 34: 2686-2697.
Yuan ZC, Zaheer R, Finan TM. Regulation and properties of PstSCAB, a highaffinity,
high-velocity phosphate transport system of Sinorhizobium meliloti. 2006. Journal of Bacteriology. 188: 1089-1102.
Yuan ZC, Zaheer R, Finan TM. Phosphate limitation induces catalase expression in
Sinorhizobium meliloti, Pseudomonas aeruginosa and Agrobacterium tumefaciens.
2005. Molecular Microbiology. 58: 877-894.