| Description: | We are interested in the susceptible interaction between Arabidopsis and the virulent bacterial pathogen Pseudomonas syringe pv. tomato strain DC3000 (Pst). Currently, little is known about the molecular mechanisms by which Pst subverts its plant host, although a number of genes required for bacterial virulence have been identified. The Pst hrp gene cluster is required for pathogenicity in susceptible hosts and encodes the components of a type III protein secretion system responsible for the delivery of virulence proteins to the plant host cell. We propose to utilize the Arabidopsis Functional Genomics Consortium microarray to identify Arabidopsis genes responsive to a single Pst DC3000 type III secreted virulence protein. The Pst delta CEL mutant strain lacks 6 ORFs present in the Conserved Effector Locus (CEL) (Alfano et al., PNAS 97:4856-61). The delta CEL mutant multiplies 200 to 500 fold less than wildtype Pst and fails to produce disease symptoms in Col-0 leaves. Complementation analysis of the delta CEL mutant revealed that orf3 and orf4 of the CEL are responsible for the mutant phenotype, but only Orf3 is secreted into the plant host cell (K. Nomura and S.Y. He, unpublished results). We have developed a heterologous secretion system for the analysis of the function of individual type III secreted effector proteins. We have engineered Pseudomonas fluorescens (Pf), a nonpathogenic saprophyte unable to cause disease on Arabidopsis, to contain the Pst Hrp secretion system. This Pf strain is capable of secreting virulence proteins into the plant host cell. For AFGC microarray analysis, a Pf strain with the Hrp system and a plasmid containing orf3 and orf4 of the CEL will be compared to the control Pf strain with the Hrp system and a plasmid containing only orf4. Arabidopsis leaves inoculated with 1 x 108 bacteria/mL of the treatment (Pf orf3 and orf4) and control (Pf orf4) strains will be harvested at 12 and 24 hours post inoculation and used for RNA isolation. Equal amounts of RNA from the two time-points for each treatment will be pooled and submitted for microarray analysis. Our goal is to identify Arabidopsis genes regulated by the Pst CEL orf3 virulence protein. |
NASCArrays Information at The BAR
Welcome to NASCArrays information at the BAR. This page hosts meta-information from the NASCArrays service (2002-2013). This information was parsed
from text files available on the NASCArrays site. NASCArrays data is on iPlant server. To download experiment data from iPlant, please click on the
experiment number. To download the CEL files, please click on the ftp link.