cyanogenic pseudomonads influence multitrophic interactions in the rhizosphere生氰假单胞菌根际中的multitrophic交互影响.pdfVIP

Cyanogenic Pseudomonads Influence Multitrophic Interactions in the Rhizosphere Thimmaraju Rudrappa1,2, Robert E. Splaine1,2, Meredith L. Biedrzycki1,2, Harsh P. Bais1,2* 1 Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware, United States of America, 2 Delaware Biotechnology Institute, Newark, Delaware, United States of America Abstract In the rhizosphere, plant roots cope with both pathogenic and beneficial bacterial interactions. The exometabolite production in certain bacterial species may regulate root growth and other root-microbe interactions in the rhizosphere. Here, we elucidated the role of cyanide production in pseudomonad virulence affecting plant root growth and other rhizospheric processes. Exposure of Arabidopsis thaliana Col-0 seedlings to both direct (with KCN) and indirect forms of cyanide from different pseudomonad strains caused significant inhibition of primary root growth. Further, we report that this growth inhibition was caused by the suppression of an auxin responsive gene, specifically at the root tip region by pseudomonad cyanogenesis. Additionally, pseudomonad cyanogenesis also affected other beneficial rhizospheric processes such as Bacillus subtilis colonization by biofilm formation on A. thaliana Col-0 roots. The effect of cyanogenesis on B. subtilis biofilm formation was further established by the down regulation of important B. subtilis biofilm operons epsA and yqxM . Our results show, the functional significance of pseudomonad cyanogenesis in regulating multitrophic rhizospheric interactions. Citation: Rudrappa T, Splaine RE, Biedrzycki ML, Bais HP (2008) Cyanogenic Pseudomonads Influence Multitrophic Interactions in the Rhizosphere. PLoS ONE 3(4): e2073. doi:10.1371/jou