Plant Pathology Graduate Program

Ansel Hsiao


Ansel Hsiao
Office: 951-827-2525
Fax: 951-827-4294
3263 Webber Hall
Office Hours: , not specified - not specified
Email: ansel.hsiao@ucr.edu

Ansel Hsiao

Assistant Professor, Department of Plant Pathology and Microbiology

  • B.A. in Biology and B.A. in History, University of Pennsylvania, Philadelphia, PA, 2004
  • Ph.D. Department of Microbiology, University of Pennsylvania, Philadelphia, PA, 2008
  • Postdoctoral Fellow, Center for Genome Sciences and Systems Biology, Washington University in Saint Louis, 2015

Biography & Research Interests

Humans share their bodies with many trillions of commensal microbes, collectively known as the microbiota. The gut is site of the densest microbial colonization, and the bacteria resident there have been demonstrated to play a role in a variety of physiological processes ranging from immune development to resistance to pathogens.

Research in my laboratory focuses on identifying the mechanisms by which the gut microbiota can confer susceptibility or resistance to enteropathogenic bacteria. Recently, my work has identified that interspecies bacterial communication, a process known as quorum sensing, is employed by the gut microbiota to inhibit virulence gene production by the important human diarrheal pathogen Vibrio cholerae.

My future research focuses on

1) Elucidating the role played by quorum sensing in modulating the structure and function of the gut microbiota and virulence gene regulation in V. cholerae

2) Identifying mechanisms underlying gut microbiota-mediated colonization resistance against pathogens of the gut

3) Developing methods for manipulating the structure of the gut microbiota with a view to providing prophylaxis against bacterial enteropathogenesis

Participating graduate programs

1)      Microbiology
2)      Cell, Molecular & Developmental Biology
3)      Genetics, Genomics & Bioinformatics




  1. Hsiao, A., A.M. Shamsir Ahmed, S. Subramanian, N.W. Griffin, L.L. Drewry, W.A. Petri, R. Haque, T. Ahmed, and J.I. Gordon. 2014. Members of the human gut microbiota involved in recovery from Vibrio cholerae infection. Nature advance online publication, doi:10.1038/nature13738.
  2. Stern, A. M., A. Hsiao, and J. Zhu. 2013. Regulation of Bacterial Virulence Ch. 26, 528-544 (2013).
  3. McNulty, N.M.*,T. Yatsunenko*, A. Hsiao*, J. Faith, B. Muegge, A. Goodman, B. Henrissat, R. Oozeer, S. Cools-Portier, G. Gobert, C. Chervaux, C. Lozupone, R. Knight, A. Duncan, A.H. Heath, and J.I. Gordon. 2013. The Impact of a consortium of yogurt strains on the human gut microbiome: a translational medicine study involving monozygotic twins and humanized gnotobiotic mice. Science Translational Medicine 3:106ra106. *equal contribution.
  4. Tsou, A.M., E. Frey, A. Hsiao, Z. Liu, and J. Zhu. 2008. Coordinated regulation of virulence by quorum sensing and motility pathways during the initial stages of Vibrio cholerae infection. Communicative and Integrative Biology 1:42-44.
  5. Hsiao, A. and J. Zhu. 2009. Genetic tools to study gene expression during bacterial pathogen infection. Advances in Applied Microbiology 67:297-314.
  6. Hsiao, A., X. Xu, B. Kan, R.V. Kulkarni, and J. Zhu. 2009. Direct Regulation by the Vibrio cholerae regulator ToxT to modulate colonization and anti-colonization pilus expression. Infection & Immunity 77:1383-8.
  7. Liu, Z., T. Miyashiro, A. Tsou, A. Hsiao, M. Goulian, and J. Zhu. 2008. Mucosal penetration primes Vibrio cholerae for host colonization by repressing quorum sensing. Proceedings of the National Academy of Sciences 105:9769-74.
  8. Hsiao, A., K. Toscano, and J. Zhu. 2008. Post-transcriptional cross-talk between pro- and anti-colonization pili biosynthesis systems in Vibrio cholerae. Molecular Microbiology 67:849-860.
  9. Hsiao, A., Z. Liu, A. Joelsson, and J. Zhu. 2006. Vibrio cholerae virulence regulator-coordinated evasion of host immunity. Proceedings of the National Academy of Sciences 103: 14542-14547.
  10. Liu, Z., A. Hsiao, A. Joelsson, and J. Zhu. 2006. The Transcriptional Regulator VqmA Increases Expression of the Quorum-Sensing Activator HapR in Vibrio cholerae. Journal of Bacteriology 188:2446-2453.

More Information

General Campus Information

University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

Career OpportunitiesUCR Libraries
Campus StatusDirections to UCR

Contact Information

Graduate Program in Plant Pathology
1140 Batchelor Hall

Tel: (800) 735-0717 or (951) 827-5688
Fax: (951) 827-5517
E-mail: laura.mcgeehan@ucr.edu

Department of Plant Pathology and Microbiology
Boyce Hall 1463

Tel: (951) 827-3598
Fax: (951) 827-4294
E-mail: margarita.flores@ucr.edu