Project description:Arthrobacter chlorophenolicus A6 is a 4-chlorophenol degrading soil bacterium with high phyllosphere colonization capacity. Till now the genetic basis for the phyllosphere competency of Arthrobacter or other pollutant-degrading bacteria is uncertain. We investigated global gene expression profile of A. chlorophenolicus grown in the phyllosphere of common bean (Phaseolus vulgaris) compared to growth on agar surfaces.
Project description:Arthrobacter chlorophenolicus A6 is a 4-chlorophenol degrading soil bacterium with high phyllosphere colonization capacity. Till now the genetic basis for the phyllosphere competency of Arthrobacter or other pollutant-degrading bacteria is uncertain. We investigated global gene expression profile of A. chlorophenolicus grown in the phyllosphere of common bean (Phaseolus vulgaris) compared to growth on agar surfaces. We designed transcriptome arrays and investigated which genes had different transcript levels in the phyllosphere of common bean (Phaseolus vulgaris) as compared to agar surfaces. Since water availability is considered an important factor in phyllosphere survival and activity, we included both high and low relative humidity treatments for the phyllosphere-grown cells. In addition, we determined the expression profile under pollutant exposure by the inclusion of two agar surface treatments, i.e. with and without 4-chlorophenol.
Project description:Plants are colonized by a variety of microorganisms, the plant microbiota. In the phyllosphere, the above-ground parts of plants, bacteria are the most abundant inhabitants. Most of these microorganisms are not pathogenic and the plant responses to commensals or to pathogen infection in the presence of commensals are not well understood. We report the Arabidopsis leaf transcriptome after 3 to 4 weeks of colonization by Methylobacterium extorquens PA1 and Sphingomonas melonis Fr1, representatives of two abundant genera in the phyllosphere, compared to axenic plants. In addition, we also sequenced the transcriptome of Arabidopsis 2 and 7 days after spray-infection with a low dose of P. syringae DC3000 and in combination with the commensals.
Project description:As the phyllosphere is a resource-limited niche, microbes have evolved different survival strategies by collaborating or competing with other organisms. This leads to the establishment of network structures which are stabilised by so-called microbial hub organisms. An already identified hub in the Arabidopsis thaliana phyllosphere is the oomycete pathogen Albugo laibachii. From wild Arabidopsis plants with white rust symptoms we isolated the basidiomycete yeast Moesziomyces albugensis, which is closely related to plant pathogenic smut fungi. It suppresses the infection of A. laibachii in lab experiments and inhibits growth of several bacterial phyllosphere members. The transcriptomic response of M. albugensis to presence of A. laibachii and bacterial SynCom members was investigated by using RNA sequencing. Interestingly, several genes encoding secretory proteins, mostly glycoside hydrolases and peptidases, are particularly induced upon interaction with A. laibachii.