Veronese, Paola .
Functional genomics of Arabidopsis responses to Verticillium dahliae Klebhan.
Most of our understanding of plant defense mechanisms against pathogens has come from studies with microorganisms causing foliar diseases. Vascular pathogens, which are widespread and very destructive, remain poorly investigated. To elucidate the molecular and genetic bases of host defense responses to vascular wilts, we have developed the genetic resources to study the pathosystem involving Arabidopsis and the soil-borne fungus Verticillium dahliae, causal agent of vascular wilts of herbaceous plants and trees. V. dahliae colonizes the xylem of the host after penetrating the root system. We have found that in Arabidopsis, like in other plant species, V. dahliae infection induces disease symptoms by interfering with the host developmental program. In particular, the pathogen causes early flowering, accelerated senescence and rapid death in the susceptible accession Columbia, whereas, it extends vegetative growth and causes only mild chlorosis in the more tolerant accession C-24 (Veronese et al., 2003). Via forward genetics, we have isolated mutants of C-24 with altered disease phenotype and identified three independent loci, VERTCILLIUM HYPERSENSITIVE (VHS) 1 to 3, able to convey increased tolerance likely functioning as negative regulators of the pathogen-induced transition to flowering and/or senescence syndrome. The vhs3 mutation has been linked to disruption of AtBRAMA, coding a SNF2 chromatin remodeling protein. We will present data characterizing pleiotropic effects of vhs mutations on Arabidopsis defense responses and development. Furthermore, we will discuss results from genome-wide transcriptional analysis of wild type and vhs3 mutant plants upon pathogen challenge, proving insights into signaling pathways controlling Arabidopsis-V. dahliae interaction.
Log in to add this item to your schedule
1 - North Carolina State University, Department of Plant Pathology, Campus Box 7251, Raleigh, NC, 27695-7251, USA
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM