Lois M. Banta

Lois Banta

Halvorsen Professor for Distinguished Teaching and Research of Biology

Thompson Biology Lab Rm 213
At Williams since 2000


B.A. Johns Hopkins University (1983)
Ph.D. California Institute of Technology, Biology (1990)

Areas of Expertise

Microbiology, Genomics, Molecular/Cell Biology


Scholarship/Creative Work

For all publications, search “Banta LM” on PubMed.

  • Dean DM, Deitcher DL, Loehlin DW, Banta LM. 2020. Mapping a mutation to its gene: The “fly lab” as a modern research experience. CourseSource. https://doi.org/10.24918/cs.2020.51
  • Hwang EE (Williams College ’13), Wang MB (Williams College ’14), Bravo JE, Banta LM. Front Plant Sci. 2015 Mar 31;6:200. doi: 10.3389/fpls.2015.00200. Unmasking host and microbial strategies in the Agrobacterium-plant defense tango. eCollection 2015. Review. PMID: 25873923
  • Rundell E.A., Banta L.M., Ward D.V., Watts C.D. (Williams College ’10), Birren B., Esteban D.J. PLoS One. 2014 Aug 7;9(8):e104134. doi: 10.1371/journal.pone.0104134. 16S rNA Gene Survey of Microbial Communities in Winogradsky Columns. eCollection 2014.
  • Barnhart, D.M., S. Su, B. E. Baccaro (Williams College ’09), L. M. Banta, and S. K. Farrand.  2013. CelR, an ortholog of the diguanylate cyclase PleD of Caulobacter, regulates cellulose synthesis in Agrobacterium tumefaciens.  Appl. Environ. Microbiol. 79:7188-7202.
  • Banta, L. M., J. Kerr, E. Cascales, M. Giuliano (Williams’05), M. E. Bailey (Williams ’08), C. McKay*, V. Chandran, G. Waksman, and P.J. Christie. 2011. An Agrobacterium tumefaciens VirB10 mutation conferring a type IV secretion system gating defect. J. Bacteriol. 193:2566-2574.
  • L. M. Banta, E. J. Crespi, R. H. Nehm, J. A. Schwarz, S. Singer, C. A. Manduca, E. C. Bush, E. Collins, C. M. Constance, D. Dean, D. Esteban, S. Fox, J. McDaris, C. A. Paul, G. Quinan, K. M. Raley-Susman, M. L. Smith, C. S. Wallace, G. S. Withers and L. Caporale. 2012. Integrating genomics research throughout the undergraduate curriculum: A collection of inquiry-based genomics lab modules. Cell Biology Education-Life Science Education 11:203-208
  • Baumler, D. J., L. M. Banta, K. F. Hung, J. A. Schwarz, E. L. Cabot, J. D. Glasner, and N. Perna. 2012. Using comparative genomics for inquiry-based learning to dissect virulence of Escherichia coli O157:H7 and Yersinia pestis. Cell Biology Education-Life Science Education 11:81-93.
  • SlaterS., B. Goldman, B. Goodner, J. C. Setubal, S. K. Farrand, E. W. Nester, T. Burr, L. Banta, A. W. Dickerman, I. Paulsen, L. Otten, G. Suen, R. Welch, N. Almeida Jr., F. Arnold,O. T. Burton (Williams ’06), Z. Du, A. Ewing, E. Godsy, S. Heisel, K. L. Houmiel, J. Jhaveri, J. Lu, N. M. Miller, S. Norton, Q. Chen, W. Phoolcharoen, V. Ohlin, D. Ondrusek, N. Pride, S. L. Stricklin, J. Sun, C. Wheeler, L. Wilson, H. Zhu and D. W. Wood.  2009.  Genome sequences of three Agrobacterium biovars help elucidate the evolution of multi-chromosome genomes in the Rhizobiales. J. Bacteriol. 191:2501-2511.
  • Dangl, J., L. Banta, R. Boerma, J. Carrington, J. Chory, S. Kay, S. Lewis, T. Mitchell-Olds, N. Sinha, M. Snyder, S. Strauss, and E. Ward.  2008.  Achievements of the National Plant Genome Initiative and New Horizons in Plant Biology.  National Research Council.  Washington, DC: The National Academies Press (166 pages).  Available at http://dels.nas.edu/plant_genome/background.shtml
  • Badri, D., V.M. Loyola-Vargas, C.D. Broekling, C. De-la-Pena, M. Jasinski, D. Santelia, E. Martinoia, L.W. Sumner, L.M. Banta, F. Stermitz, and J.M. Vivanco.  2008.  Altered profile of secondary metabolites in the root exudates of Arabidopsis ATP-binding cassette transporter mutants.  Plant Physiol 146: 762-771
  • Banta, L.M. and M. Montenegro (Williams College ’02).  2008.  Agrobacterium and plant biotechnology in Agrobacterium, From Biology to Biotechnology, Springer (New York NY) pp. 73-147
  • Yuan, Z., M. Edlind (Williams College ’07), L. Pu, A. Weiss, P. Saenkham, L. Banta, A. Binns, K. Kerr, and E. Nester. 2007. Salicylic acid, important in regulating plant defense, directly shuts down expression of the vir regulon and activates quormone-quenching gene in Agrobacterium. Proc. Natl. Acad. Sci. USA 104:11790-11795.
  • Atmakuri, K., E. Cascales, O.T. Burton (Williams College ’06), L.M. Banta, and P.J. Christie. 2007. Agrobacterium ParA/MinD-like VirC1 spatially coordinates early conjugative DNA transfer reactions. EMBO J. 26:2540-2551.
  • Peng, W.-T., L. M. Banta, T.C. Charles, and E.W. Nester. 2001. The chvH locus of Agrobacterium tumefaciens encodes a homolog of the elongation factor P. J. Bacteriol. 183:36-45.
  • Lai, E.-M., O. Chesnokova, L. M. Banta, and C. I. Kado. 2000. Genetic and environmental factors affecting T-pilin export and T-pilus biogenesis in relation to flagellation of Agrobacterium tumefaciens.J. Bacteriol. 182:3705-3716
  • Banta, L. M., J. Bohne, S. D. Lovejoy, and K. Dostal. 1998. Stability of the Agrobacterium tumefaciens VirB10 protein is modulated by growth temperature and periplasmic osmoadaption. J.Bacteriol. 180:6597-6606.
  • Babst, M., T. K. Sato, L. M. Banta, and S. D. Emr. 1997. Endosomal transport function in yeast requires a novel AAA-type ATPase, Vps4p. EMBO J. 16:1820-1831.
  • Rieder, S. E., L. M. Banta, K. Koehrer, J. M. McCaffery, and S. D. Emr. 1996. Multilamellar endosome-like compartment accumulates in the yeast vps28 vacuolar protein sorting mutant. Mol. Biol. Cell 7:985-999.
  • Finberg, K. E., *T. R. Muth, *S. P. Young, *J. B. Maken, *S. M. Heitritter, A. N. Binns, and L. M. Banta. 1995. Interactions of VirB9, VirB10, and VirB11 with the membrane fraction of Agrobacterium tumefaciens: Solubility studies provide evidence for tight associations. J. Bacteriol.177:4881-4889.
  • Banta, L. M., R. D. Joerger, V. R. Howitz, A. M. Campbell, and A. N. Binns. 1994. Glu-255 outside the predicted ChvE binding site in VirA is crucial for sugar enhancement of acetosyringone perception by Agrobacterium tumefaciens. J.Bacteriol.176:3242-3249.
  • Binns, A. N. , R. D. Joerger, L. M. Banta, K. Lee, and D. G. Lynn. 1992. Molecular and chemical analysis of signal perception by agrobacterium. In: Molecular Genetics of Plant-Microbe Interactions, Kluwer Academic Publishers, Dordrecht, Netherlands, pp. 51-61.
  • Banta, L. M., T. A. Vida, P. K. Herman and S. D. Emr. 1990. Characterization of the yeast Vps33p, a protein required for vacuolar protein sorting and vacuole biogenesis. Mol. Cell. Biol. 10:4638-4649.
  • Banta, L. M., J. S. Robinson, D. J. Klionsky and S. D. Emr. 1988. Organelle assembly in yeast: Characterization of yeast mutants defective in vacuolar biogenesis and protein sorting. J. Cell. Biol. 107:1369-1383.
  • Robinson, J. S., Klionsky, D. J., L. M. Banta and S. D. Emr. 1988. Protein sorting in Saccharomyces cerevisiae: Isolation of mutants defective in the delivery and processing of multiple vacuolar hydrolases. Mol. Cell. Biol. 8:4936-4948.
  • Klionsky, D. J., L. M. Banta, J. S. Robinson and S. D. Emr. 1988. Genetics of protein sorting to the yeast lysosome-like vacuole. In: Yeast Cell Biology: “UCLA Symposium on Molecular and Cellular Biology”, Alan R. Liss, New York, NY, pp. 173-186.
  • Klionsky, D. J., L. M. Banta and S. D. Emr. 1988. Intracellular sorting and processing of a yeast vacuolar hydrolase: The proteinase A propeptide contains vacuolar targeting information. Mol. Cell. Biol. 8:2105-2116.
  • Banta, L. M., F. R. Bühler and E. Bürgisser. 1985. Inhibition of [3H]Gpp(NH)p release from human platelet membranes by GDP. J. Cyclic Nuc. Prot. Phos.Res. 10:511-523.

*Denotes Haverford College undergraduate

Research and Honors Students

  • Erin Troy ’01 (Independent Study 2000-2001)
  • Dave Lewis ’03 (Winter Study 2001)
  • Aidan Finlay ’04 (Winter Study, Summer 2001)
  • Maywa Montenegro ’02 (Honors Thesis 2001-2002)
  • Susan Levin ’02 (Honors Thesis 2001-2002)
  • Jessica Bauman ’02 (Honors Thesis 2001-2002)
  • Ken-ichi Ueda ’03 (Summer 2002, Honors Thesis 2002-2003)
  • Emily Hatch ’03 (Summer 2002, Honors Thesis 2002-2003)
  • Caty Sumner ’03 (Summer 2002)
  • Alice Hensley ’05 (Summer 2003)
  • Jackie Hom ’04 (Honors Thesis 2003-2004)
  • Virginia Newman ’04 (Honors Thesis 2003-2004)
  • Jeff Dougherty ’05 (Independent Study Spring 2004)
  • Anne Newcomer ’04 (Independent Study Spring 2004)
  • Kate Roberts ’04 (Summer 2002, Winter Study 2003, Independendent Study Spring 2004)
  • Jessica Davis ’06 (Summer 2003, 2004, Academic year 2004-2005: Honors Thesis 2005-2006)
  • Meghan Giuliano ’05 (Summer 2003, 2004, Honors Thesis 2004-2005)
  • Molly Sharlach ’05 (Summer 2004, Honors Thesis 2004-2005)
  • Ian Buchanan ’07 (Summer 2004, Academic Year 2004-2005)
  • Ashleigh Theberge ’06 (Winter Study 2003, 2004)
  • Didem Ilter ’08 (Winter Study 2005)
  • Eric Bautista ’08 (Winter Study 2005)
  • James Kim ’08 (Winter Study 2005)
  • Shannon Chiu ’08 (Summer 2005)
  • Danai Musarurwa (Bennett College ’05; Summer 2005)
  • Oliver Burton ’06 (Summer 2005, 2006, Honors Thesis 2005-2006)
  • Esa Seegulam ’06 (Summer 2005, Honors Thesis 2005-2006)
  • Ruby Dale-Brown ’09 (Academic Year 2005-2006)
  • Matt Toy ’08 (Summer 2006)
  • Rachael Williams ’08 (Bennett College; Summer 2006)
  • Gape Machao ’06 (Research Assistant)
  • James Lowe ’09 (Summer 2006, 2007, Academic Year 2005-2007)
  • Ian Buchanan ’07 (Summer 2006, Honors Thesis 2006-2007)
  • Merritt Edlind ’07 (Honors Thesis 2006-2007)
  • Maggie Lowenstein ’07 (Honors Thesis 2006-2007, Summer 2007)
  • Alex Kopynec ’09 (Summer 2007, Academic Year 2006-2007, 2007-2008)
  • Megan Bailey ’08 (Winter 2007, Summer 2007)
  • Jason Fan ’08 (Summer 2007, Honors Thesis 2007-2008)
  • Didem Ilter ’08 (Honors Thesis 2007-2008)
  • David Rogawski ’08 (Honors Thesis 2007-2008)
  • Cat Hoover ’09 (Summer 2008, Honors thesis 2008-2009)
  • Hannah Ratcliffe ’09 (Summer 2008, Honors thesis 2008-2009)
  • Brenna Baccaro ’09 (Summer 2008, Honors thesis 2008-2009)
  • Ang Li ’11 (Academic years 2007-2009, Summer 2008)
  • Jose Ruiz ’10 (Academic year 2007-2008)
  • Tarjinder Singh ’12 (Winter study 2009)
  • Amulya Iyer ’10 (Summer 2009, Honors thesis 2009-2010)
  • Lauren Sinnenberg ’10 (Honors thesis 2009-2010)
  • Annie Park ’10 (Honors thesis 2009-2010)
  • Corey Watts ’10 (Summer 2009, Honors thesis 2009-2010)
  • Emily Porter ’10 (Summer 2009, Honors thesis 2009-2010)
  • Maddy Haff ’11 (Summer 2010, Academic year 2010-2011)
  • Josh Blanco ’11 (Summer 2010, Honors thesis 2010-2011)
  • Helen Cha ’11 (Honors thesis 2010-2011)
  • Kate Dusenbury ’13 (Academic year 2010-2011)
  • Nicole Lou ’13 (Academic year 2010-2011, Summer 2011)
  • Lauren Goldstein-Kral ’12 (Winter study 2011, Honors thesis 2011-2012)
  • Connor Dempsey ’13 (Winter study 2011, Summer 2011, Honors thesis 2012-2013)
  • Chalita Washington ’13 (Summer 2010)
  • Audrey Kwon ’13 (Summer 2011)
  • Greg McElroy ’12 (Summer 2011, Honors thesis 2011-2012)
  • Grace LaPier ’13 (Academic year 2011-2012)
  • Hannah Wilson ’12 (Independent study 2011-2012)
  • Naomi Patterson ’15 (Academic year 2011-2012, Summer 2012)
  • Abbi Davies ’13 (Summer 2012, Honors thesis 2012-2013)
  • Elizabeth Hwang ’13 (Honors thesis 2012-2013)
  • Sam Lewis ’15 (Academic year 2012-2013)
  • Tendai Chisowa ‘16 (Summer 2013, Academic Year 2013-2015)
  • Darcy Mishkind (Carleton College ’16) (Summer 2013)
  • Betsy Hart ’14 (Summer 2013, Honors Thesis 2013-2014)
  • Melinda Wang ’14 (Summer 2013, Honors Thesis 2013-2014)
  • Chiara del Piccolo ’14 (Summer 2013, Academic year 2013-2014)
  • Zihan Su ’17 (Summer 2014)
  • Raza Currimjee ’16 (Summer 2014)
  • Isaiah Clarke ’15 (Summer 2014, Independent study 2014-2015)
  • Achala Chittor ’15 (Summer 2014, Honors thesis 2014-2015)
  • Adrienne Strait ’15 (Honors thesis 2014-2015)
  • Alison Smith ’15 (Winter Study 2015)
  • Jacob Kim ’16 (Summer 2015, Honors thesis 2015-2016)
  • Aubrey Kenefick ’16 (Summer 2015, Honors thesis 2015-2016)
  • Breanna Nguyen ’16 (Summer 2015, Honors thesis 2015-2016)
  • Adam Resnick ’17 (Summer 2015, Academic year 2015-2016, Summer 2016, Honors thesis 2016-2017)
  • Ruby Froom ’17 (Academic year 2015-2016, Honors thesis 2016-2017)
  • Rebecca Gorelov ’18 (Winter-study 2016, Summer 2017, Honors thesis 2017-2018)
  • Michelle Buncke ’17 (Summer 2016, Honors thesis 2016-2017)
  • Nicole Tanna ’18 (Summer 2016, Academic year 2016-2017)
  • Alonso Villasmil ’18 (Academic year 2016-2017, Independent study 2017-2018)
  • Abby Brustad ’20 (Academic year 2016-2017, 2017-2018)
  • Will Doyle ’19 (Winter Study 2018, Summer 2018, Honors thesis 2018-2019)
  • Joelle Troiano ’20 (Academic year 2017-2018, 2018-2019)
  • Matthew Long ’22 (Summer 2019)
  • Sonya Lee ’22 (Summer 2019)
  • David Gorestki ’20 (Honors thesis 2019-2020)
  • Rachel Cross ’21 (Summer 2020, Honors thesis 2020-2021)
  • Surabhi Iyer ’21 (Summer 2020, Honors thesis 2020-2021)
  • Georgia McClain ’22 (Summer 2020, Independent Study 2020-21)
  • Irfa Qureshi ’22 (Summer 2021, Honors thesis 2021-22)
  • Derrick Spencer ’20 (Independent study 2019-2020)
  • Sofia Neaher ’22 (Winter study and summer 2020, Academic year 2020-2021, Honors thesis 2021-2022)
  • Amy Wang ’24 (Winter study and summer 2020, Academic year 2021-2022)
  • Cooper Desmond ’24 (Academic year 2021-22)

Post-doctoral fellows and Research Associates:

  • Bronwyn Butcher (Ph.D., Stellenbosch University, South Africa) 2001-2003
  • Mardi Crane (Ph.D., Dartmouth) 2005-2006
  • Gape Machao (B.A., Williams ’06) 2006-2007
  • Annie Knox (M.S., UC Davis) 2009-2010
  • Janis Bravo (Ph.D., Rutgers) 2010-2017

Awards, Fellowships & Grants

Nelson Bushnell ’20 Teaching Award, 2017


  • National Science Foundation Research in Undergraduate Institutions, “Characterization of Arabidopsis Defense Responses to the Agrobacterium tumefaciens Type VI Secretion System”-$452,196 (August 2013-August 2017)
  • National Science Foundation, “Modulation of host defense responses by Agrobacterium tumefaciens Type VI secretion system”-$415,330 (September 2009-August, 2012)
  • Teagle Foundation Genomics Curriculum Development, “Big Science for Small Colleges”-$97,000 (April 2007-August 2009)-Project Director
  • Instrumentation/Development Grant for Interdisciplinary Program in Genomics, Bioinformatics, and Proteomics-$500,000 (December 2004-December, 2009) (Co-authored with Charles Lovett, Professor of Chemistry)
  • National Science Foundation, “Role of VirC1 and VirC2 in Regulation of Substrate Delivery by the VirB/D4 Secretion Apparatus of Agrobacterium tumefaciens“-$330,000 (July, 2004-June, 2008)
  • National Science Foundation, “Protein-Protein Interactions Mediating Substrate Recognition by the VirB Complex of Agrobacterium tumefaciens“-$180,000 (September, 1999-August, 2003)
  • National Institutes of Health Senior International Fellowship, “Substrate Recognition by Agrobacterium VirB Transporter”-$22,500 (January-June, 2000)
  • Fulbright Senior Research/Lecturing Award-University of Leiden, The Netherlands-$12,000 (January-April, 2000)
  • Pediatric AIDS Foundation Student Intern Award to Marguerite Cadwallader (Student at Haverford College) for project “The Use of Agrobacterium as a New Mechanism for the Delivery of DNA into Mammalian Cells”-$2000 (September-December 1996)
  • National Science Foundation, “Biochemical and Genetic Characterization of Membrane-Associated VirB-Protein Complexes in Agrobacterium tumefaciens“-$300,000 (July, 1995-December, 1998) Funded extension (January, 1999-December, 1999)
  • GTE Lectureship Program on Technology and Ethics, Presidential Symposium on “The Ethical, Legal and Social Implications of Recent Advances in Human Genetics”- $5000 (October, 1994)
  • National Science Foundation Research Planning Grant, “Role of Agrobacterium VirB Proteins in T-DNA Transfer”-$18,000 (September, 1993-August, 1995)

Professional Affiliations

  • Visiting Senior Fulbright Fellow, Leiden University, Netherlands, 2000
  • University of Pennsylvania: Postdoctoral fellow

Current Committees

  • Global Studies

Bioinformatics, Genomics, and Proteomics
Secretary/Treasurer, Williams Chapter of Sigma Xi

Research Interests

In the Banta lab, we study the interactions between the soil bacterium Agrobacterium tumefaciens and its host plants.  In particular, we are interested in the transport of a large fragment of DNA across the membrane system surrounding the bacterium, and in the plant defense responses elicited by the bacterium.  Infection of susceptible plants by A. tumefaciens results in crown gall tumor formation.  The disease mechanism involves the transfer and integration into the plant genome of a specific DNA molecule (T-DNA) from a bacterial tumor-inducing (Ti) plasmid.  Sequences on the T-DNA encode enzymes responsible for the biosynthesis of plant growth hormones; expression of these genes in the host plant leads to uncontrolled hormone production and hence unregulated plant cell division (“plant cancer”).  This naturally occurring process of DNA transfer to plants is widely used to introduce new genes into plants, but its utility is limited by the fact that some plants, including the agriculturally important grains rice, wheat, corn and barley, are poor hosts.  Thus, advances in our understanding of the mechanism of DNA delivery, and in particular the contributions made by bacterial proteins that are required for infection of some but not all hosts, may further the work of those scientists engaged in efforts to increase global food productivity.

More On Research

Many bacteria including A. tumefaciens form biofilms, complex aggregates of bacteria, held together by polysaccharides, that are resistant to antibiotics and immune attack. Dental plaque and slime on rocks or metal in water are examples of biofilms; in the lungs of cystic fibrosis patients, biofilms serve as a clinically significant reservoir of bacteria.  David Rogawski ‘08 discovered that a newly identified “Type VI Secretion System” (T6SS), implicated in virulence in several other human pathogens, plays a key role in regulating Agrobacterium’s ability to form biofilms. More recently, students in my lab have shown that bacteria deficient in the T6SS also exhibit enhanced attachment to host plant surfaces.

We also discovered that this T6SS mutant is less able than its wild-type parent to infect host plants efficiently, and we believe this is because substrates secreted by the T6SS are needed to dampen host defenses.   Additional data from our lab have led us to hypothesize further, however, that those same substrates can also trigger defense responses through a previously unknown mechanism.  Current students are comparing the defenses mounted by Arabidopsis plants against T6SS mutant versus wild-type bacteria.  The goal of our research is to characterize this novel pathogen-recognition pathway, using protein biochemistry, plant genetics, and molecular biology approaches.

I am also involved in genomics curriculum development.  Please see the links below for two modules suitable for undergraduate courses at a variety of levels.

http://serc.carleton.edu/genomics/units/19163.html: Comparison of a Highly Polymorphic Olfactory Receptor Gene Subfamily in Genetically Diverse Dog Breeds

http://serc.carleton.edu/genomics/units/33047.html: Using Metagenomics to Investigate Microbial Diversity