Stellos Tavantzis
Professor of Plant Pathology and Cooperating Professor of Biochemistry and Microbiology
Location: 347 Hitchner Hall
Research Topic:
Molecular genetics of virulence in plant pathogenic fungi; biological control of fungal plant pathogens
Research Program:
Molecular genetics of hypovirulence in plant pathogenic fungi; functional genomics for identification and characterization of genes involved in regulation of virulence in the basidiomycete Rhizoctonia solani.The long-term goal of my work is the biological control of a cosmopolitan, soil-borne plant pathogen, Rhizoctonia solani.Species of Rhizoctonia cause economically important diseases on most of the world’s major field and vegetable crops, fruit and forest trees, turfgrasses, and ornamental plants. Thus, characterization of genetic factors regulating virulence in R. solani could have a significant impact on a wide spectrum of plant related human endeavor.
My research group has shown that particular double-stranded RNA (dsRNA) genetic elements are associated with a dramatically decreased disease-producing capacity (e.g., hypovirulence) in R. solani. Sequencing analysis of these dsRNA’s suggested that they carry an RNA polymerase gene which allows them to replicate in the host cell, but most importantly they carry nucleotide sequences that are genetically related to genes involved in different metabolic pathways. Sequencing analysis of a hypovirulence-associated dsRNA (M2) has enabled me to put forward the following hypothesis: The M2 dsRNA down-regulates the shikimic acid (shikimate) pathway, which is responsible for the synthesis of the aromatic amino acids (AAA). R. solani produces a “toxin” (phenyl acetic acid, PAA) associated with the rhizoctonia disease syndrome in potato. PAA is a derivative of one of the AAA, phenylalanine. Thus, down-regulation of AAA biosynthesis leads to a decreased production of PAA and, in turn, to a diminished degree of pathogenicity (hypovirulence).
It appears that dsRNAs in fungi (and in other organisms) are involved in gene regulation of the host cell. My research program revolves around this hypothesis. Knowledge gained in this area will lead to the development of biocontrol-based strategies of plant disease management that will fulfill the need for sustainable and nonpolluting agricultural practices. Our project is part of a multifaceted, worldwide effort aimed at making agriculture more sustainable, and congruent with the ever-growing societal aspiration to nurture the environment in which we live.
Publications:
Bernard, E., Larkin, R. P., Tavantzis, S. M., Erich, M. S., Alyokhin, A., Sewell, G., Lannan, A., and S. D. Gross. 2012. Compost, rapeseed rotation, and biocontrol agents significantly impact soil microbial communities in organic and conventional potato production systems. Applied Soil Ecology 52: 29 – 41Rioux, R., Manmathan, H., Singh, P., De los Reyes, B. G., Jia, Y., and S. M. Tavantzis. 2011. Comparative analysis of putative pathogenesis-related gene expression in two Rhizoctonia solanipathosystems. Current Genetics 57: 391 – 408.
Charlton, N. D., Carbone, I., Tavantzis, S. M., and M. A. Cubeta. 2008 Phylogenetic relatedness of the M2 doube-stranded RNA in Rhizoctonia fungi. Mycologia 100:555-564.
Tavantzis, S. M. 2008. Partiviruses of Fungi. In “Encyclopedia of Virology” 3rd Edition, Vol. 4, pp. 63-68. B. W. V. Mahy, M. H. V. Van Regenmortel, Eds. Elsevier, Ltd. & Academic Press, San Diego, CA., U.S.A.
Charlton, N. D., Tavantzis, S. M., and Cubeta, M. A. 2007. Detection of Double-stranded RNA Elements in Plant Pathogenic Fungi. In “Plant Pathology Techniques and Procedures”, Chapter 14, pp. 171-182. Burns R., Ed. Humana Press, 2nd Edition, Tocawa, NJ, USA.
Lakshman, D. K, Liu, C., Mishra, P. and Tavantzis, S. M. 2006. Characterization of the arom gene inRhizoctonia solani, and transcription patterns under stable and induced hypovirulence conditions.Current Genetics 49: 166 – 177
Liu C., Lakshman D. K., Tavantzis S. M. 2003. Quinic acid induces hypovirulence, and expression of a hypovirulence-associated double-stranded RNA in Rhizoctonia solani. Current Genetics 43:103-111
Liu C., Lakshman D. K., Tavantzis S. M. 2003. Expression of a hypovirulence-causing double-stranded RNA (dsRNA) is associated with up-regulation of quinic acid pathway, and down-regulation of shikimic acid pathway in Rhizoctonia solani. Current Genetics 42:284-291
Tavantzis, S. M. 2001. dsRNA genetic elements: Concepts and applications in Agriculture, Forestry and Medicine. 304 p. CRC Press LLC, Boca Raton, FL.
Tavantzis, S. M., Lakshman, D. K. and Liu, C. 2001. Double-stranded RNA Elements Modulating Virulence in Rhizoctonia solani in DsRNA Genetic Elements: Concepts and Applications in Agriculture, Forestry, and Medicine, pp. 191-201. Ed. S. M. Tavantzis, 304 p.CRC Press LLC.
Strauss, E. E., Lakshman, D. K., and Tavantzis, S. M. 2000. Molecular characterization of the genome of a partitivirus from the basidiomycete Rhizoctonia solani. Journal of General Virology 81:549-555.
Jian, J., Lakshman, D. K., and S. M. Tavantzis. 1998. A virulence-associated 6.4-kb dsRNA fromRhizoctonia solani is phylogenetically related to plant bromoviruses and electron transport enzymes.Molecular Plant-Microbe Interactions 11:601-609.
Lakshman, D. K., Jian, J., and Tavantzis, S. M. 1998. A novel mitochondrial double-stranded RNA found in a hypovirulent strain of Rhizoctonia solani occurs in DNA form, and is phylogenetically related to the pentafunctional AROM protein of the shikimate pathway. Proceedings of the National Academy of Sciences (USA) 95:6425-6429 .
Jian, J., Lakshman D. K., and Tavantzis, S. M. 1997. Association of distinct double-stranded RNAs with enhanced or diminished virulence in Rhizoctonia solani infecting potato. Molecular Plant-Microbe Interactions 10:1002-1009.
Rubio, V., Tavantzis, S. M., and Lakshman, D. K. 1996. Extrachromosomal elements and degree of pathogenicity in Rhizoctonia solani. In “Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control”, pp.127-138. B. Sneh, S. Jabaji-Hare, S. Neate and G. Dijst, Eds., 578 p. Kluwer Academic Publishers, Dordrecht, The Netherlands.
Tavantzis, S. M., and D. K. Lakshman. 1995. Virus-like double-stranded RNA elements and hypovirulence in phytopathogenic fungi. Vol. III, Chapter 17, pp. 249-267. In Pathogenesis and Host-Parasite Specificity in plant Diseases: Histopathological, Biochemical, Genetic and Molecular Bases, Vol. III: Viruses and Viroids. K. Kohmoto, R. P. Singh, and U. S. Singh Eds. Elsevier (Pergamon) Press, Oxford, UK.
Castello, J. D., D. K. Lakshman, S. M. Tavantzis, S. O. Rogers, G. D. Bachand, R. Jagels, and J. Carlisle. 1995. Detection of infectious tomato mosaic virus in fog and clouds. Phytopathology 85: 1409-1411.
Tavantzis, S. M., and D. K. Lakshman. 1995. Virus-like double-stranded RNA elements and hypovirulence in phytopathogenic fungi. Vol. III, Chapter 17, pp. 249-267. In “Pathogenesis and Host-Parasite Specificity in plant Diseases: Histopathological, Biochemical, Genetic and Molecular Bases, Vol. III: Viruses and Viroids”. K. Kohmoto, R. P. Singh, and U. S. Singh Eds. Elsevier (Pergamon) Press, Oxford, UK.
Lakshman, D. K. and S. M. Tavantzis. Spontaneous appearance of genetically distinct dsRNA elements in Rhizoctonia solani. 1994. Phytopathology 84: 633-639.
Singh, R. P., A. Boucher, D. K. Lakshman, and S. M. Tavantzis. 1994. Multimeric non-radioactive cRNA probes improve detection of potato spindle tuber viroid (PSTV). Journal of Virological Methods 49: 221-234.
Tavantzis, S. M. 1994. Double-stranded RNA-associated cytoplasmic hypovirulence in Rhizoctonia solani: Prospects for developing a reliable, target-specific biocontrol system. pp. 565-579. In “Advances in Potato Pest Biology and Management. G. W. Zehnder, M. L. Powelson, R. K. Jansson, and K. V. Raman, Eds. APS Press, St. Paul, MN.
Lakshman, K. D. and Tavantzis, S. M.. 1993. Primary and secondary structure of a 360-nucleotide isolate of potato spindle tuber viroid. Archives of Virology 128: 319-332.
Singh, R. P., Lakshman, D. K., Boucher, A., and Tavantzis, S. M. 1992. A viroid from Nemantanthus wettsteineii plants closely related to Columnea latent viroid. J. Gen. Virology 73: 2769-2774.
Lakshman, D., Tavantzis, S. M., Boucher, A., and Singh, R. P. 1992. A rapid and versatile method for cloning viroids or other circular plant pathogenic RNA’s. Analytical Biochemistry 203: 269-273.
Lakshman, K. D. and S. M. Tavantzis. 1992. RNA progeny of an infectious two-base deletion cDNA mutant of the potato spindle tuber viroid acquire two nucleotides in planta. Virology 187: 565-572.
Tavantzis, S. M. 1991. In vitro translation of potato carlavirus M RNA: coat protein and protease activity as translation products of virion-associated RNA. Archives of Virology 120: 241-252.
Bharathan, N. and Tavantzis, S. M. 1991. Assessment of genetic relatedness among double-stranded RNA components from Rhizoctonia solani isolates of diverse geographic origin. Phytopathology 81: 411-415.
Tavantzis, S. M. 1990. Outlook on the molecular biology of virus resistance in potato, p.113-135. In “The Molecular Biology of Potato”, M. E. Vayda & W. D. Park, eds. C.A.B. International, Wallingford, U.K.
Bharathan, N., and Tavantzis, S. M. 1990. Genetic diversity of double-stranded RNAs in Rhizoctonia solani. Phytopathology 80: 631-635.
Tavantzis, S. M. 1990. Outlook on the molecular biology of virus resistance in potato, p.113-135. In “The Molecular Biology of Potato”, M. E. Vayda & W. D. Park, eds. C.A.B. International, Wallingford, U.K.
Frey, M., Tavantzis, S. M. and Saedler, H. 1989. The maize En/Spm element transposes in potato.Molecular and General Genetics 217: 172-177.
Tavantzis, S. M. 1988. Biological control of Rhizoctonia disease and increased growth response of potato effected by hypovirulent R. solani. pp. 44-46, in “Innovations in Pest Management” ed. by S. Engelstad, W.M. Coli, & J. L. Carlson. 75 p., U. Mass. Press.
Tavantzis, S. M. and B. P. Bandy. 1988. Properties of a mycovirus from Rhizoctonia solani and its virion-associated RNA polymerase. Journal of General Virology 69: 1465-1477.
Tavantzis, S. M. 1988. Biological control of Rhizoctonia disease and increased growth response of potato effected by hypovirulent R. solani. pp. 44-46, in “Innovations in Pest Management” ed. by S. Engelstad, W.M. Coli, & J. L. Carlson. 75 p., U. Mass. Press.
Hoch, J. G., Tavantzis, S. M., Campana, R. J., and Anagnostakis, S. L. 1985. Evaluation of the presence of double-stranded RNA in Ceratocystis ulmi. Can. J. Botany 63:297-300.
Tavantzis, S. M. 1984. Physicochemical properties of potato virus M. Virology 133:427-430.
Bandy, B. P., Zanzinger, D. H., and Tavantzis, S. M. 1984. Anastomosis group 5 of Rhizoctonia solani Kuhn isolated from potato-cultivated soils in Maine. Phytopathology 74:1220-1224.
Zanzinger, D. H., Bandy, B. P., and Tavantzis, S. M. 1984. High frequency of finding double-stranded RNA in naturally occurring isolates of Rhizoctonia solani. J. Gen. Virol. 65:1601-1605.
Tavantzis, S. M. 1983. State of development of leaf and tuber tissue in potato influences the titer of potato virus M. Am. Potato J. 69:99-108.
Tavantzis, S. M. 1983. Improved purification of two potato carlaviruses. Phytopathology 73:190-194.
Tavantzis, S. M., Romaine, C. P. and Smith, S. H. 1983. Mechanism of genome expression in a single-stranded RNA virus from the cultivated mushroom [Agaricus bisporus (Lange) Imbach.]. Phytopath. Z. 106:45-50.
Tavantzis, S. M. and Southard, S. G. 1983. Incidence of potato virus X in seed potatoes of seven cultivars. Plant Disease 67:959-961.
Tavantzis, S. M. and Smith, S. H.. 1982. Isolation and evaluation of a plant-virus-inhibition quinone from sporophores of Agaricus bisporus. Phytopathology 72:619-621.
Tavantzis, S. M., Romaine, C. P., and Smith, S. H. 1980. Purification and partial characterization of a bacilliform virus from Agaricus bisporus: A single-stranded RNA mycovirus. Virology 105:94-102.
Tavantzis, S. M., Smith, S. H. and Witham, F. H. 1979. The influence of kinetin on tobacco ringspot virus infectivity and the effect of virus infection on the cytokinin activity in intact leaves ofNicotiana glutinosa L. Physiological Plant Pathology. 14:227-233.
Tavantzis, S. M. and Smith, S. H. 1979. Virus-like particles transmitted by and detected in spawn ofAgaricus bisporus. Phytopathology 69:104-107.