Eric W. Triplett

Professor and ChairTriplett

Department of Microbiology and Cell Science University of Florida

B.S. (1976) Rutgers University, Cook College, New Brunswick, NJ
M.S. (1978) University of Maryland, College Park
Ph.D. (1981) University of Missouri, Columbia
Postdoctoral (1981-1982) University of Wisconsin-Madison

Contact Information

352-392-1906
ewt@ufl.edu

Description of Research

Colonization of plants by endophytic bacteria.

Endophytic bacteria are defined as those bacteria that enter plants without causing disease or any organized symbiotic structures.  There are three important reasons to study bacterial endophytes.  First, these bacteria often enhance plant growth under field and greenhouse conditions.  Second, these strain can fix nitrogen and we hope to find ways to improve the nitrogen nutrition with such strains.  And third, some human pathogenic bacteria can colonize the interior of plants.

We have learned that strains within the same bacterial species can differ radically in the their ability to enter plant hosts.  We are seeking to understand the basis of this strain-specificity.  We also know that an endophyte can have a broad-host-range and colonize monocots as well as dicots.  For most of this work, we use a model endophytic bacterium called Klebsiella pneumoniae 342, also referred to as Kp342.  A single cell of Kp342 in the inoculum is sufficient to fully colonize several plant hosts.  This strain fixes nitrogen and can enhance the growth of a number of plant hosts.

Microbial diversity and ecology.

I work with several colleagues at the University of Wisconsin-Madison on an NSF-supported Microbial Observatory of the North Temperate Lakes Long Term Ecological Research site (http://microbes.limnology.wisc.edu).  We have observed tremendous variation in microbial diversity in lakes across time and space.  Different lakes vary greatly in microbial diversity but within lake variability across time is also very significant.  In one of our lakes, changes in microbial diversity appears to be correlated with biological changes that occur in the lake over time rather than changes in water chemistry.  We have developed two new tools for microbial diversity research.  These are Automated Ribosomal Intergenic Spacer Analysis (ARISA) and a web-based tool for T-RFLP analysis.

Currently we are characterizing the taxa found in our study lakes and plan to culture those bacteria that are either unusual or are important in productivity.

Selected Publications

Giongo, A; Crabb, DB; Davis-Richardson, AG; Chauliac, D; Mobberley, JM; Gano, KA; Mukherjee, N; Casella, G; Roesch, LFW; Walts, B; Riva, A; King, G; Triplett, EW. 2010. PANGEA: pipeline for analysis of next generation amplicons. ISME JOURNAL 4 (7): 852-86.

Valladares, R; Sankar, D; Li, N; Williams, E; Lai, KK; Abdelgeliel, AS; Gonzalez, CF; Wasserfall, CH; Larkin, J; Schatz, D; Atkinson, MA; Triplett, EW; Neu, J; Lorca, GL. 2010. Lactobacillus johnsonii N6.2 Mitigates the Development of Type 1 Diabetes in BB-DP Rats. PLOS ONE 5 (5): art. no.-e10507.

Tyler, HL; Roesch, LFW; Gowda, S; Dawson, WO; Triplett, EW. 2009. Confirmation of the Sequence of ‘Candidatus Liberibacter asiaticus’ and Assessment of Microbial Diversity in Huanglongbing-Infected Citrus Phloem Using a Metagenomic Approach. MOLECULAR PLANT-MICROBE INTERACTIONS 22 (12): 1624-1634.

Roesch, LFW; Lorca, GL; Casella, G; Giongo, A; Naranjo, A; Pionzio, AM; Li, N; Mai, V; Wasserfall, CH; Schatz, D; Atkinson, MA; Neu, J; Triplett, EW. 2009. Culture-independent identification of gut bacteria correlated with the onset of diabetes in a rat model. ISME JOURNAL 3 (5): 536-548.

Fouts, DE; Tyler, HL; Deboy, RT; Daugherty, S; Ren, QH; Badger, JH; Durkin, AS; Huot, H; Shrivastava, S; Kothari, S; Dodson, RJ; Mohamoud, Y; Khouri, H; Roesch, LFW; Krogfelt, KA; Struve, C; Triplett, EW; Methe, BA. 2008. Complete Genome Sequence of the N-2-Fixing Broad Host Range Endophyte Klebsiella pneumoniae 342 and Virulence Predictions Verified in Mice. PLOS GENETICS 4 (7): art. no.-e1000141.

Fulthorpe, RR; Roesch, LFW; Riva, A; Triplett, EW. 2008. Distantly sampled soils carry few species in common. ISME JOURNAL 2 (9): 901-910.

Tyler, HL; Triplett, EW. 2008. Plants as a habitat for beneficial and/or human pathogenic bacteria. ANNUAL REVIEW OF PHYTOPATHOLOGY 46: 53-73.

Roesch, LFW; Passaglia, LMP; Bento, FM; Triplett, EW; Camargo, FAO. 2007. Diversity of diazotrophic endophytic bacteria associated with maize plants. REVISTA BRASILEIRA DE CIENCIA DO SOLO 31 (6): 1367-1380.. Roesch, LFW; Camargo, FAO; Bento, FM; Triplett, EW. 2008. Biodiversity of diazotrophic bacteria within the soil, root and stem of field-grown maize. PLANT AND SOIL 302 (1-2): 91-104.

Roesch, LFW; de Quadros, PD; Camargo, FAO; Triplett, EW. 2007. Screening of diazotrophic bacteria Azopirillum spp. for nitrogen fixation and auxin production in multiple field sites in southern Brazil. WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY 23 (10): 1377-1383.

Roesch, LF; Fulthorpe, RR; Riva, A; Casella, G; Hadwin, AKM; Kent, AD; Daroub, SH; Camargo, FAO; Farmerie, WG; Triplett, EW. 2007. Pyrosequencing enumerates and contrasts soil microbial diversity. ISME JOURNAL 1 (4): 283-290.

Shade, A; Kent, AD; Jones, SE; Newton, RJ; Triplett, EW; McMahon, KD. 2007. Interannual dynamics and phenology of bacterial communities in a eutrophic lake. LIMNOLOGY AND OCEANOGRAPHY 52 (2): 487-494.

Newton, RJ; Kent, AD; Triplett, EW; McMahon, KD. 2006. Microbial community dynamics in a humic lake: differential persistence of common freshwater phylotypes. ENVIRONMENTAL MICROBIOLOGY 8 (6): 956-970.

Lau, HT; Faryna, J; Triplett, EW. 2006. Aquitalea magnusonii gen. nov., sp nov., a novel Gram-negative bacterium isolated from a humic lake. INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 56: 867-871, Part 4.

Scupham, AJ; Triplett, EW. 2006. Determination of the amino acid residues required for the activity of the anti-rhizobial peptide antibiotic trifolitoxin. JOURNAL OF APPLIED MICROBIOLOGY 100 (3): 500-507.

Pongslip, N., E.W. Triplett, and M.J. Sadowsky.  2005. Detection of homoserine lactone-like quorum sensing molecules in Bradyrhizobium strains.  Current Microbiol. 51:250-254.

Iniguez, A.L., Y. Dong., H.D. Carter, B.M.M. Ahmer, J.M. Stone, and E.W. Triplett.  2005. Regulation of enteric endophytic bacterial colonization by plant defenses.  Molecular Plant-Microbe Interactions 18:169-178.

Yannarell, A.C. and E.W. Triplett.  2005.  Geographic and environmental sources of variation in lake bacterial community composition.  Appl. Environ. Microbiol. 71:227-239.

Iniguez, A.L., Y. Dong, and E.W. Triplett.  2004.   Nitrogen fixation in wheat provided by Klebsiella pneumoniae 342.  Molec. Plant-Microbe Interact. 17:1078-1085.

Graham, J.M., A.D. Kent, G.H. Lauster, A.C. Yannarell, L.E. Graham, T.K. Kratz, and E.W. Triplett.  2004.  Seasonal dynamics of phytoplankton and protoplankton communities in a northern temperate humic lake: diversity in a dinoflagellate dominated system. Microbial Ecology (in press).

Kent, A.D, S.E. Jones, A.C. Yannarell, J.M. Graham, G.H. Lauster, T.K. Kratz, and E.W. Triplett.  2004.  Annual patterns in bacterioplankton community variability in humic lake. Microbial Ecology (in press).

Iniguez, A.L., E.A. Robleto, A.D. Kent, and E.W. Triplett.  2004.  Significant yield increase in Phaseolus vulgaris obtained by inoculation with a trifolitoxin-producing, Hup+ strain of Rhizobium leguminosarum bv. phaseoli.  Crop Management (on line only: http://www.plantmanagementnetwork.org/pub/cm/

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