Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 30, 2005
Publication Date: July 30, 2005
Citation: Wechter, W.P., Kluepfel, D.A. 2005. Global gene expression of Pseudomonas Putida KT2440 during growth in the rhizosphere of Arabidopsis Thaliana [abstract]. Phytopathology 95 (6):S110. Technical Abstract: Identification of the bacterial genes involved, and the functions they provide, in colonization of the rhizosphere is crucial to a comprehensive understanding of the interaction of plants with both beneficial and pathogenic microorganisms. Here we report on the utilization of full-genome microarrays to perform gene expression studies of Pseudomonas putida KT2440 in the rhizosphere of Arabidopsis thaliana Columbia. The Arabidopsis rhizosphere, which was supported on a minimal medium agar, was inoculated with KT2440 and then sampled at 48 hr and 120 hr post-inoculation. RNA was extracted from bacteria growing in the rhizosphere as well as from bacteria growing in the absence of plant roots and used to hybridized to P. putida KT2440 microarrays. At 48 hr post-inoculation we identified 26 bacterial genes that were induced and 149 genes that were repressed in the rhizosphere at a level of 2-fold or greater. In addition, 195 bacterial genes were modulated as a function of growth in the rhizosphere 120 hr post-inoculation. Thirty-one percent of the genes up-regulated after 48 hr returned to basel expression levels 72 hr later while 85 unique genes were up-regulated only at the 120 hr sample time. The identity of these rhizosphere-modulated bacterial genes and their potential involvement in root colonization will be discussed.