| Name: |
| Fangming Xiao |
| Title: |
| Assistant Professor |
| Degree: |
| Ph.D., 2002, Kansas State University |
| Phone: |
| (208) 885-0120 |
| Fax: |
| (208) 885-6518 |
| Email: |
| fxiao@uidaho.edu |
| Lab/Office Location: |
| LSS 140 |
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| Research Interests: |
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My lab studies the molecular basis of plant-pathogen interactions, focusing on the defense signal recognition and transduction in
plants. Unlike animals, which have the circulating immune system that produces specialized mobile cells, plants have evolved two
branches of the immune system to defend themselves against pathogens. The first, usually occurring at the cell surface, is mediated
by perception of pathogen-associated molecular patterns (PAMPs) by plasma membrane-associated pattern recognition receptors (PRRs)
in plants. The PAMP-trigged immunity (PTI) is a basal level defense and is relatively weak but effective to limit pathogen invasion.
The second, largely taking place inside the cell, is determined by recognition of effector proteins from pathogens by plant
resistance (R) proteins. The R-mediated resistance is a strong defense response, usually coupled with a localized cell death, termed
hypersensitive response (HR). Despite the distinct signaling pathways for PAMP-triggered immunity and R protein-mediated resistance,
there is considerable evidence suggesting that signaling cross-talk exists between two branches of plant immune system.
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In tomato plants, resistance to bacterial speck disease is initiated by a physical interaction of the host Pto kinase with either of
the sequence dissimilar Pseudomonas effector proteins AvrPto or AvrPtoB that are delivered into the host cell cytoplasm via
bacterial type III secretion system. Pto-mediated immunity requires Prf, a host resistance protein with a nucleotide-binding site
and a region of leucine-rich repeats. Pto and Prf form a recognition complex in the plant cell and function coordinately in defense
signaling. However, how the recognition signal is transduced into downstream cellular responses is largely unknown. We are currently
using a combination of molecular, genetic, biochemical and cellular approaches to identify host factors involved in the
Pto/Prf-mediated defense signaling in tomato. We are particularly interested in proteins associated with Pto/Prf complex in the
plant cell and their role in R-mediated or/and PAMP-triggered defense signalings.
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| Selected Publications: |
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Xiao, F., Giavalisco, P. and Martin G. B. (2007) Pseudomonas syringae type III effector AvrPtoB is phosphorylated in plant cells on serine 258 promoting its virulence activity. J Biol Chem (282) 30737-30744.
Xiao, F., He, P., Abramovitch, R. B., Dawson, J. E., Nicholson, L. K., Sheen, J. and Martin G. B. (2007) The N-terminal region of Pseudomonas type III effector AvrPtoB elicits Pto-dependent immunity and has two distinct virulence determinants. The Plant Journal, (52) 595-614.
Rosebrock, T. R., Zeng, L., Brady, J. J., Abramovitch, R. B., Xiao, F., and Martin, G. B. (2007) A bacterial E3 ligase targets a host protein kinase to promote plant disease. Nature (448) 370-374.
Anderson, J. C., Pascuzzi, P. E., Xiao, F., Sessa, G., and Martin, G. B. (2006) Host-mediated phosphorylation of type III effector AvrPto promotes Pseudomonas virulence in tomato. The Plant Cell (18) 502-514.
Xiao, F., Goodwin, M. S., Xiao, Y., Sun, Z., Baker, D., Tang, X., Jenks M. A. and Zhou J.-M. (2004) Arabidopsis CYP86A2 represses Pseudomonas syringae type III genes and is required for cuticle development. EMBO J. (23) 2903-2913.
Xiao, F., Lu, M., Li, J., Zhao, T., Yi, S. Y., Thara, V. K, Tang, X., and Zhou J.-M. (2003) Pto mutants differentially activate Prf-dependent, avrPto-independent resistance and Gene-for-Gene resistance. Plant Physiology (131) 1239-1249.
Kang, K., Li, J., Zhao, T., Xiao, F., Tang, X., Thilmony, R., He, S. Y., and Zhou, J.-M. (2003) Interplay of the Arabidopsis nonhost resistance gene NHO1 with bacterial virulence. Proc. Natl. Acad. Sci. USA (100) 3519-3524.
Xiao, F., Tang, X., and Zhou J.-M. (2001) Expression of 35S::Pto globally activates defense-related genes in tomato plants. Plant Physiology (126) 1637-1645.
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