BioProject

The pathogen Agrobacterium tumefaciens infects a broad range of plants, introducing the T-DNA into their genome. More...

The pathogen Agrobacterium tumefaciens infects a broad range of plants, introducing the T-DNA into their genome. Contrary to all known bacterial phyto-pathogens, Agrobacterium lacks the hypersensitive response-inducing HRP genes although it introduces numerous proteins into the plant cell through a type IV secretion system. To understand the timing and extent of the plant transcriptional response to this unusual pathogen, we used an Arabidopsis 26-thousand gene oligonucleotide microarray. We inoculated Arabidopsis cell cultures with an oncogenic strain of Agrobacterium and analyzed four biological replicates to identify two robust sets of regulated genes, one induced and the other suppressed. In both cases, the response was distinct at 48 hours after infection, but not at 24 hours or earlier. The induced set includes genes encoding known defense proteins, the repressed set is enriched with genes characteristic of cell proliferation even though a growth arrest was not visible in the inoculated cultures. The analysis of the repressed genes revealed that the conserved upstream regulatory elements Frankiebox (a.k.a. “site II”) and Telobox are associated with the suppression of gene expression. The regulated gene sets should be useful in dissecting the signaling pathways in this plant-pathogen interaction. Keywords: Time-course of Agrobacterium infection Overall design: Time-course of Agrobacterium-inoculated Arabidopsis cell cultures. Four biological replicates of mock- and Agrobacterium-inoculated samples collected at 4h, 12h, 24h and 48h after inoculation were compared to a reference RNA in a oligonucleotide array. Less...