Research Interests:

Sensing and defending against microbial infections is essential to the survival of multicellular organisms. In plants, recognition of pathogen effectors or PAMPs (pathogen-associated molecular patterns) by plant immune receptors leads to local activation of downstream signaling cascades and resistance to pathogens. Local defense responses also activate a secondary resistance response in the distal parts of plants termed systemic acquired resistance (SAR). Our research is focused on the following two areas.

1. Signal Transduction Pathways downstream of Plant Immune Receptors
There are three main classes of immune receptors in plants. The largest class encodes intracellular NB-LRR type Resistance (R) proteins. The other two classes belong to the transmembrane receptor-like kinase (RLK) and receptor-like protein (RLP) families. We have obtained a series of mutants such as snc2-1D, snc4-1D, bir1-1, and mkk1 mkk2 that constitutively activate immunity mediated by these three classes of immune receptors. To identify components downstream of the receptors, suppressor screens have been performed in these mutant backgrounds. Cloning the suppressor genes and analyzing biochemical functions of proteins encoded by them will help us build the signal transduction network of plant immunity.

2. Systemic Acquired Resistance
Genetic analysis of SAR has been hampered by lack of good assays for studying SAR in Arabidopsis. We developed an SAR assay in which we inoculated the local leaves with the bacterial pathogen P.s.m. ES4326 and assayed the distal leaves for induced resistance against the virulent oomycete pathogen H. a. Noco2. We found that this new assay is sensitive and reproducible and it can be used to screen a large number of plants. Using this assay, we have carried out both forward and reverse genetic screens to look for mutants with defects in SAR. Identification and characterization of genes required for SAR will help us better understand the underlining mechanisms of SAR.

Xu, S., Zhang, Z., Jing, B., Gannon, P., Ding, J., Xu, F., Li, X. and Zhang, Y. 2011. Transportin-SR is required for proper splicing of resistance genes and plant immunity.  PLoS Genetics, 7(6): e1002159.

Jing, B., Xu, S., Xu, M., Li, Y., Li, S., Ding, J. and Zhang, Y. 2011. Brush and Spray: A high throughput systemic acquired resistance assay suitable for large-scale genetic screening. Plant Physiology, 157(3):973-80.

Germain, H., Qu, N., Cheng, Y.T., Lee, E.K., Huang, H., Dong, O.X., Gannon, P., Huang, S., Ding, P., Li, Y., Sack, F. and Zhang, Y. (co-corresponding), and Li X. 2010. MOS11: a new component in the mRNA export pathway. PLoS Genetics, 6(12): e1001250.

Zhang, Y., Xu, S., Ding, P., Wang, D., Cheng, Y., He, J., Gao, M., Xu, F., Li, Y., Zhu, Z., Li, X., and Zhang, Y. 2010. Control of salicylic acid synthesis and systemic acquired resistance by two members of a plant-specific family of transcription factors. Proceedings of the National Academy of Sciences (track II). 107(42):18220-18225.

Li, Y., Li, S., Bi, D., Cheng, Y., Li, X. and Zhang, Y. 2010. SRFR1 negatively regulates plant NB-LRR Resistance protein accumulation to prevent autoimmunity. PLoS Pathogens, 6 (9), e1001111.

Zhang, Y., Yang, Y., Fang, B., Gannon, P., Ding, P., Li, X., and Zhang, Y. 2010. snc2-1D activates receptor like protein-mediated immunity transduced through WRKY70. Plant Cell, 22(9):3153-3163.

Zhu, Z., Xu, F., Zhang, Y., Cheng, Y., Wiermer, M., Li, X., and Zhang, Y. 2010. Arabidopsis Resistance protein SNC1 activates immune responses through association with a transcriptional co-repressor. Proceedings of the National Academy of Sciences(track II). 107(31):13960-13965.

Bi, D., Cheng, Y., Li, X., and Zhang, Y. 2010. Activation of plant immune responses by a gain-of-function mutation in an atypical receptor-like kinase. Plant Physiology, 153(4):1771-1779.

Li, Y., Tessaro, M., Li, X., and Zhang, Y. 2010. Regulation of the expression of plant Resistance gene SNC1 by a Protein with a Conserved BAT2 Domain. Plant Physiology, 153(3):1425-1434.

Gao, M., Wang, X., Wang, D., Xu, F., Ding, X., Zhang, Z., Bi, D., Cheng, Y.T., Chen, S., Li, X., and Zhang, Y. 2009. Regulation of cell death and innate immunity by two receptor-like kinases in Arabidopsis. Cell Host & Microbe 6:34-44.

Gao, M., Liu, J., Bi, D., Zhang, Z., Cheng, F., Chen, S., and Zhang, Y. 2008. MEKK1, MKK1/MKK2 and MPK4 function together in a mitogen-activated protein kinase cascade to regulate innate immunity in plants. Cell Research 18:1190-1198. (Cover story)