Ma, Lay-Sun (馬麗珊)

Assistant Research Fellow

  • 2018- Assistant Research Fellow, IPMB, Academia Sinica, Taiwan
  • 2014 PDF, Max Planck Institute for Terrestrial Microbiology, Germany
  • 2012 PDF, IPMB, Academia Sinica, Taiwan
  • 2011 Ph.D., Academia Sinica and National Chung Hsing University
  • +886-2-2787-1146(Lab)
  • +886-2-2787-1145(Office)
  • laysunma@gate.sinica.edu.tw
  • Molecular mechanisms of plant-fungi interactions

Ustilago maydis-maize pathosystem

The biotrophic fungi U. maydis cause smut disease on maize plants with prominent symptoms-tumor formation and anthocyanin induction. It completes its sexual reproduction in living plants by initiating pathogenic dikaryotic hyphal formation, plant surface attachment, appressorial formation, penetration, proliferation, and spore formation. To colonize a plant successfully and cause disease, U. maydis is predicted to secrete several hundred effector proteins in consecutive waves during the biotrophic interaction. Most effectors are novel molecules without any known motifs. They either function in the interface between the plant and pathogen cells (apoplastic effectors) or translocate inside plant cells (cytoplasmic effectors). They can act by shielding the pathogen, inactivate plant defense molecules or toxic harmful compounds, suppress plant immune response or change the physiology of the infected plant to benefit fungal needs. Up to date, only seven effectors have been functionally characterized in U. maydis and most of the secreted proteins are functional unknown. It significantly hampers our understanding of plant-microbe interactions. Since effectors contribute to fungal accommodation in the host tissue and allow disease progression, it is important to investigate their biochemical function. Studying effectors will provide insights to the underlying mechanisms of effectors and the defense mechanisms of target molecules in plant.

The research interest

The focus of our research is to understand the underlying mechanisms in governing disease and disease resistance in plant-microbe interaction. Using Ustilago maydis-maize as our model system and effectors as molecular probes, we aim to unravel the biological function of effectors in disease progression and discover the role of effector targets in plant immunity. Exploring the effector function will provide insights to plant-microbe interactions and allow to exploit the knowledge in seeking plant resistance genes used in disease control and prevention.

● Investigating how effectors facilitate host colonization
● Exploring how plant takes defensive action against microbial invaders

Selected publication list

  • Lay-Sun Ma, Lei Wang, Christine Trippel, Artemio Mendoza-Mendoza, Steffen Ullmann, Marino Moretti, Alexander Carsten, Jörg Kahnt, Stefanie Reissmann, Bernd Zechmann, Gert Bange, and Regine Kahmann. (2018) The Ustilago maydis repetitive effector Rsp3 blocks the antifungal activity of mannose-binding maize proteins. Nat. Commun. 2018 Apr 27;9(1):1711.
  • Lay-Sun Ma*, Clément Pellegrin*, and Regine Kahmann. (2018) Repeat-containing effectors of filamentous pathogens and symbionts. Curr. Opin. Microbiol. https://doi.org/10.1016/j.mib.2018.01.007 (*Equal contribution).
  • Daniel Lanver, Marie Tollot, Gabriel Schweizer, Libera Lo Presti, Stefanie Reissmann, Lay-Sun Ma, Mariana Schuster, Shigeyuki Tanaka, Liang Liang, Nicole Ludwig, and Regine Kahmann. (2017) Ustilago maydis effectors and their impact on virulence. Nature Rev. Microbiol. doi:10.1038/nrmicro.2017.33.
  • Devanand Bondage, Jer-Sheng Lin, Lay-Sun Ma, Chih-Horng Kuo, and Erh-Min Lai. (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 USA Jul 5; 113(27): E3931-40.
  • Lay-Sun Ma, Abderrahman Hachani, Jer-Sheng Lin, Alain Filloux, and Erh-Min Lai. (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.
  • Jer-Sheng Lin, Hsin-Hui Wu, Pang-Hung Hsu, Lay-Sun Ma, Yin-Yuin Pang, Ming-Daw Tsai, and Erh-Min Lai. (2014) Fha interaction with phosphothreonine of TssL activates type VI secretion in Agrobacterium tumefaciens. PLoS Pathogen. March 10 (3): e1003991.
  • Jer-Sheng Lin, Lay-Sun Ma, and Erh-Min Lai. (2013) Systematic dissection of the Agrobacterium type VI secretion system reveals machinery and secreted components for subcomplex formation. PLoS One. Jul 5; 8(7): e67647.
  • Lay-Sun Ma, Franz Narberhaus, and Erh-Min Lai. (2012) IcmF family protein TssM exhibits ATPase activity and energizes type VI secretion. J. Biol Chem. 287(19):15610-15621.
  • Lay-Sun Ma, Jer-Sheng Lin, and Erh-Min Lai. (2009) An IcmF family protein, ImpLM, is an integral inner membrane protein interacting with ImpKL, and its walker A motif is required for Type VI secretion system-mediated Hcp secretion in Agrobacterium tumefaciens. J. Bacteriol, 191, 4316-4329.

Li, Hui-Chun (Lab manager)

Xu, Meng-Yun(Research technician)

Raviraj M. Kalunke (Postdoctoral research fellow)

Chibbhi K B (Ph.D. student, TIGP-MBAS program)

Cuong Hoang Van (Ph.D. student, TIGP-MBAS program)