Stanton B. Gelvin
Professor; Ph.D., California, San Diego, 1977

Crown gall is a neoplastic disease caused by the infection of dicotyledonous plants by virulent strains of the Gram-negative soil bacterium Agrobacterium tumefaciens. During the process of infection, part of a bacterial plasmid, called the tumor inducing (Ti) plasmid, is transferred from the bacterium to the plant, where it stably integrates into the nuclear DNA. This transferred, or T-DNA, can be expressed as mRNAs which are translated. Tumorous lesions result, as well as the production of rare compounds called opines which the bacterium can utilize as an energy source.

In our laboratory we have been interested in the molecular mechanism of Ti-plasmid transfer, integration, and expression. Projects related to these areas include molecular and genetic analyses of the T-DNA transfer machinery in A. tumefaciens, regulation of the vir genes of A. tumefaciens that direct this transfer, and a molecular analysis of the form of T-DNA that is transferred. We have recently initiated experiments to examine the process of T-DNA transfer to plant cells, including the targeting of the T-DNA to the plant nucleus and the very early events of T-DNA expression and integration. After the T-DNA integrates into plant chromosomal DNA, T-DNA genes are transcribed. We are investigating promoters and transcriptional activators of T-DNA genes, and have made recombinant promoters with a very high level of transcriptional activity. These promoters will be useful for the genetic engineering of plants. Other projects in the lab involve an investigation, using various ecotypes of Arabidopsis thaliana that are susceptible or resistant to crown gall tumorigenesis, of molecular aspects of plant defense responses to pathogen attack. We have cloned several Arabidopsis genes necessary for susceptibility to Agrobacterium-mediated transformation.

crown gall


Three types of tobacco tumors grown in tissue culture. Left, an unorganized crown gall tumor; center, a shooty crown gall teratoma; right, a hairy root tumor.

SELECTED PUBLICATIONS

Mysore, K. S., C. T. R. Kumar, and S. B. Gelvin. 2000. Arabidopsis ecotypes and mutants that are recalcitrant to Agrobacterium root transformation are susceptible to germ-line transformation. Plant J. 21:9-16.

Mysore, K. S., J. Nam, and S. B. Gelvin. 2000. An Arabidopsis histone H2A mutant is deficient in Agrobacterium T-DNA integration. Proc. Natl. Acad. Sci. 97:948-953.

Gelvin, S. B. 2000. Agrobacterium and plant proteins involved in T-DNA transfer and integration. Ann. Rev. Plant Physiol. Plant Mol. Biol. 51:223-256.

Gelvin, S. B., J. Nam, K. Mysore, R. C. T. Kumar, A. G. Matthysse, Y. Tao, and P. Rao. 2000. Plant genes involved in Agrobacterium-mediated transformation, p. 153-158. In P. J. G. M. de Wit, T. Bisseling, and W. Stiekema, (eds.), Biology of Plant-Microbe Interactions, Vol. 2. IS-MPMI, St. Paul, Minnesota.

Karcher, S. J. and S. B. Gelvin. 2000. Transgenic plants and the GUS reporter gene in the teaching lab, p. 80-87. In G. Madrazo and S.E. Dyche (eds.), Exciting Plant Science Activities for the Secondary Classroom. UNC Mathematics and Science Education Network, Chapel Hill, North Carolina.

EDITORIAL BOARD MEMBERSHIPS

Associate Editor: Plant Molecular Biology 1985-1994
Senior Editor: Molecular Plant/Microbe Interactions 1992-1994
Editor-in-Chief: Molecular Plant/Microbe Interactions 1995-1998

Identification of Plant Genes Involved in Agrobacterium-Mediated Transformation