Lai, Erh-Min (賴爾珉)
It is increasingly clear that microbes are essential components for almost all life forms on earth. Thus, understanding how microbes interact with other organisms within microbial community or inside the associated hosts are crucial for improvement of human and plant health. The major research interests in my laboratory are to understand the molecular mechanisms underlying how bacterial pathogens deploy protein secretion systems for survival at its ecological niche and successful infection inside the plant host. My laboratory investigates the mechanistic and biological insights of the two major protein secretion nanomachines, type IV and type VI secretion systems (T4SS and T6SS), in Agrobacterium tumefaciens, the causal agent of crown gall disease and powerful gene transfer tool. By investigating the mechanistic and biological functions of T4SS and T6SS, we hope to understand the underlying mechanisms how A. tumefaciens survive and overcomes several lines of host defense response for successful infection. The knowledge may provide new insights to improve Agrobacterium-mediated plant transformation and translational applications in biomedicine and/or agriculture.
Figure 1. Agrobacterium tumefaciens is a phytopathogenic bacterium that causes crown gall disease by transferring transferred DNA (T-DNA) into the plant genome (Crown gall tumor on an elm tree at UC Davis campus, photo taken by Jer-Ming Hu). We have developed a highly efficient and robust Agrobacterium-mediated transient expression system, named AGROBEST (Agrobacterium-mediated enhanced seedling transformation), for gene functional analyses (Wu et al., 2014. Plant Methods).
Fig. 2. Type VI secretion DNase effectors as weapons for Agrobacterium survival advantage in planta. A. tumefaciens attacks co-existing competitors via injecting T6SS Tde toxins into competitor cells and thereby provides a competitive advantage for Agrobacterium survival inside the plant host (Ma et al., Cell Host Microbe, 2014). The t6ss gene cluster encoded by A. tumefaciens strain C58 is shown.
Fig. 3. T6SS effectors are not just passengers but their loading onto the carriers also activate T6SS sheath assembly. This is potentially a widespread mechanism, which may be deployed by many T6SS-possessing bacteria as a strategy for efficacious T6SS firing to ensure that effectors are loaded onto T6SS prior to completing its assembly(Wu, Lien et al., EMBO Reports, 2019).
Selected publication list
- Yu M, Wang YC, Huang CJ, Ma LS, and Lai EM*. (2020) Agrobacterium tumefaciens Deploys a Versatile Antibacterial Strategy to Increase its Competitiveness. J Bacteriol. 2020 Nov 9:JB.00490-20. doi: 10.1128/JB.00490-20.
- Lin HH, Yu M, Sriramoju MK, Hsu ST, Liu CT*, and Lai EM* (2020) A high-throughput interbacterial competition screen identifies ClpAP in enhancing recipient susceptibility to type VI secretion system-mediated attack by Agrobacterium tumefaciens. Front. Microbiol. doi: 10.3389/fmicb.2019.03077.
- Santos MNM, Cho ST, Wu CF, Chang CJ, Kuo CH, and Lai EM* (2020) Redundancy and specificity of type VI secretion vgrG loci in antibacterial activity of Agrobacterium tumefaciens 1D1609 strain. Front. Microbiol. doi: 10.3389/fmicb.2019.03004.
- Wu CF, Lien YW, Bondage D, Lin JS, Pilhofer M, Shih YL, Chang JH, Lai EM*. (2019) Effector loading onto the VgrG carrier activates type VI secretion system assembly. EMBO Rep. 2019 Dec 5:e47961. doi: 10.15252/embr.201947961.
- Wu CF, Santos Santos MNM, Cho ST, Chang HH, Tsai YM, Smith DA, Kuo CH*, Chang JH*, Lai EM* (2019) Plant pathogenic Agrobacterium tumefaciens strains have diverse type VI effector-immunity pairs and vary in in planta competitiveness. Mol Plant-Microbe Interact. Mar 4. doi: 10.1094/MPMI-01-19-0021-R.(Editor's pick)
- Wang YC, Yu M, Shih PY, Wu HY, Lai EM* (2018) Stable pH Suppresses Defense Signaling and is the Key to Enhance Agrobacterium-Mediated Transient Expression in Arabidopsis Seedlings. Sci Rep 8(1):17071. doi: 10.1038/s41598-018-34949-9.
- Lin JS, P Panayiota, Wu HH, Tsai MD, Filloux A, and Lai EM* (2018) TagF-mediated repression of bacterial type VI secretion systems involves a direct interaction with the cytoplasmic protein Fha. J Biol Chem. 2018 293(23) 8829–8842. pii: jbc.RA117.001618. doi: 10.1074/jbc.RA117.001618.
- Shih PY, Chou SJ, Mueller C, Halkier BA, Deeken R, and Lai EM* (2018) Differential Roles of Glucosinolates and Camalexin at Different Stages of Agrobacterium-Mediated Transformation. Mol Plant Pathol. 19 (8), 1956–1970 DOI: 10.1111/mpp.12672. (recommended by Faculty 1000)
- Bondage D, Lin JS, Ma LS, Kuo CH, and Lai EM* (2016) VgrG C-terminus confers the type VI effector transport specificity and is required for binding with PAAR and adaptor-effector complex. Proc Natl Acad Sci U S A Jul 5;113(27):E3931-40. doi: 10.1073/pnas.1600428113. (recommended by Faculty 1000)
- Ma LS, Hachani A, Lin JS, Filloux A*, and Lai EM.* (2014) Agrobacterium tumefaciens deploys a superfamily of type VI secretion DNase effectors as weapons for interbacterial competition in planta. Cell Host & Microbe. Jul 9;16(1):94-104. doi: 10.1016/j.chom.2014.06.002. (recommended by Faculty 1000)
- Wu HY, Liu KH, Wang YC, Wu JF, Chiu WL, Chen CY, Wu SH, Sheen J, and Lai EM.* (2014) AGROBEST: an efficient Agrobacterium-mediated transient expression method for versatile gene function analysis in Arabidopsis seedlings. Plant Methods. Jun 18;10:19. doi: 10.1186/1746-4811-10-19. (recommended by Faculty 1000)
- Lin, J. S., Wu, H. H., Hsu, P. H., Ma, L. S., Pang, Y. Y., Tsai, M. D., and Lai, E. M.* (2014) Fha interaction with phosphothreonine of TssL activates type VI secretion in Agrobacterium tumefaciens. PLoS Pathog. Mar 13;10(3):e1003991. doi: 10.1371/journal.ppat.1003991.
Reviews or commentaries
- Lin HH, Filloux A, and Lai EM* Role of Recipient Susceptibility Factors During Contact-Dependent Interbacterial Competition. (2020) Front. Microbiol. 11:603652. doi: 10.3389/fmicb.2020.603652.
- Wu HY and Lai EM* (2019) AGROBEST: a highly efficient Agrobacterium-mediated transient expression system in Arabidopsis seedlings. Methods Mol Biol Plant Synthetic Biology: Methods and Protocols. New York, NY: Springer. In press (Invited book chapter)
- Hwang HH*, Yu M, and Lai EM*. (2017) Agrobacterium-mediated plant transformation: biology and applications. The Arabidopsis Book 15: e0186. USA: American Society of Plant Biologists.: e0186. doi: 10.1199/tab.0186.
- Lien YW and Lai EM* (2017) Type VI secretion effectors: methodologies and Biology. Front Cell Infect Microbiol Jun 15;7:254. doi: 10.3389/fcimb.2017.00254.
- Yu M and Lai EM* (2017) Warfare between Host Immunity and Bacterial Weapons. Cell Host & Microbe Jan 11;21(1):3-4. doi: 10.1016/j.chom.2016.12.012.
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