All Articles by Hana Lee

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All Articles by Hana Lee

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All Articles by Hana Lee

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All Articles by Hana Lee

I am broadly interested in the evolution and structure of host-associated microbial communities. Of the numerous taxa that compose the Arabidopsis microbiome, fungi make up a substantial portion, but studies to date have tended to focus on the bacterial portion. With the help of my labmate Manon Guilberteau, I have cultured over thirty unique fungal species from natural populations of Arabidopsis. By infecting sterile Arabidopsis with specific microbial taxa under tightly controlled environmental conditions, I will investigate the role of fungi in formation of the non-mycorrhizal plant microbiome.

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All Articles by Hana Lee

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All Articles by Hana Lee

I am a phytopathologist in Sichuan Agricultural University, China. My research is mainly focused on the interaction mechanisms between rice fungal pathogens and hosts. I have worked on the cytology, morphology, histologic pathology, genomics and epidemiology of rice sheath blight and kernel smut disease pathogens, and illustrated the effectors and evolution mechanism against hosts. A second line of research deals with defenses against Lepidoptera, Homoptera and nematode pests. We clone plant defensive genes, do functional verification, create transgenic crops but we are also interested in the genomics of Bacillus thuringiensis, a Gram-positive bacteria that often is used as a biological pesticide. In the Bergelson lab, I am investigating the fitness of Pseudomonas syringae among different crops. Pseudomonas syringae is multi host generalist pathogen, it can infect more than 100 families plants. It has a complex life history, including pathogenic, epiphytic and saprophytic phases. The mechanisms of pathogen virulence and host resistance have been well characterized in several model systems. But knowledge about genetic dynamics in ecology is limited. Tn-seq high-throughput parallel sequencing will be used to elucidate the fitness mechanism of Pseudomonas syringae in crops. One can find me in the following website: https://www.researchgate.net/profile/Aiping_Zheng2 http://scholar.google.com/citations?hl=en&user=98cgrigAAAAJ&sortby=pubdate&view_op=list_works and http://wiki.pestinfo.org/wiki/Aiping_Zheng. Selected Publications Lei D, Lin R, Yin C, Li P, Zheng A. Global protein-protein interaction network of rice sheath blight pathogen. J Proteome Res. 2014 Jul 3;13(7):3277-93. doi: 10.1021/pr500069r. Aiping Zheng, Runmao Lin, Danhua Zhang, etc. The evolution and pathogenic mechanisms of the rice sheath blight pathogen. Nature Communications. 2013, 4: 1424 doi:10.1038/ncomms2427. Li S, Li W, Huang B, Cao X, Deng Q, Wang S, Zheng A, Zhu J, Liu H, Wang L, Li P. Natural variation in PTB1 regulates rice seed setting rate by controlling pollen tube growth. Nature Communications. 2013, 4:2793. doi: 10.1038/ncomms3793. Guan P, Ai P, Dai X, Zhang J, Xu L, Deng Q, Li S, Wang S, Liu H, Wang L, Li P, Zheng A. Complete genome sequence of Bacillus thuringiensis serovar Sichuansis strain MC28. J Bacteriol. 2012 Dec;194(24):6975. doi: 10.1128/JB.01861-12.

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All Articles by Hana Lee

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All Articles by Hana Lee

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All Articles by Hana Lee

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All Articles by Hana Lee

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Evolution of pathogenicity and intraspecific interactions in Pseudomonas syringae

The high selective pressures involved in the “arms race” between plants and their pathogens drives rapid evolution of genes involved in immunity on the host side and virulence on the pathogen side (Alcázar et al., 2011). However, plants are not typically infected by individual pathogens: they interact with a community of inter- and intraspecifically diverse microbes that also experience competitive pressures from one another. How these interactions among microbes affect their ability to cause disease and how the host plant influences the microbial community it harbors remain open questions for investigation.

Researchers have observed that P. syringae is a common natural pathogen of A. thaliana and that resistance to P. syringae infection varies among different A. thaliana accessions (Jakob et al., 2002). Recent work has shown that  P. syringae strains isolated from A. thaliana leaf tissue are not only genetically diverse but also differ in their degree of virulence: many isolates harbor a polymorphism in the type three secretion system (T3SS), losing the ability to cause disease (Barrett et al., 2011; Kniskern et al., 2011). Such strains show increased growth in plant tissue when co-inoculated with other P. syringae isolates harboring an intact T3SS. This result suggests a model where non-pathogenic strains engage in “cheating” through taking advantage of the nutrients released from host cells infected by pathogenic strains (Barrett et al., 2011).

Works cited

Alcázar, R., Reymond, M., Schmitz, G., and de Meaux, J. (2011). Genetic and evolutionary perspectives on the interplay between plant immunity and development. Curr. Opin. Plant Biol. 14, 378–384.

Barrett, L.G., Bell, T., Dwyer, G., and Bergelson, J. (2011). Cheating, trade-offs and the evolution of aggressiveness in a natural pathogen population. Ecol. Lett. 14, 1149–1157.

Jakob, K., Goss, E.M., Araki, H., Van, T., Kreitman, M., and Bergelson, J. (2002). Pseudomonas viridiflava and P. syringae–natural pathogens of Arabidopsis thaliana. Mol. Plant Microbe Interact. 15, 1195–1203.

Kniskern, J.M., Barrett, L.G., and Bergelson, J. (2011). Maladaptation in wild populations of the generalist plant pathogen Pseudomonas syringae. Evolution 65, 818–830.