a naturally associated rhizobacterium of arabidopsis thaliana induces a starvation-like transcriptional response while promoting growth自然相关的拟南芥rhizobacterium诱发starvation-like转录反应而促进经济增长.pdfVIP

A Naturally Associated Rhizobacterium of Arabidopsis thaliana Induces a Starvation-Like Transcriptional Response while Promoting Growth . . ¨ ¤a ¤b Jens Schwachtje* , Silke Karojet , Ina Thormahlen , Carolin Bernholz, Sabine Kunz , Stephan ¨ Brouwer, Melanie Schwochow, Karin Kohl, Joost T. van Dongen* Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany Abstract Plant growth promotion by rhizobacteria is a known phenomenon but the underlying mechanisms are poorly understood. We searched for plant growth-promoting rhizobacteria that are naturally associated with Arabidopsis thaliana to investigate the molecular mechanisms that are involved in plant growth-promotion. We isolated a Pseudomonas bacterium (Pseudomonas sp. G62) from roots of field-grown Arabidopsis plants that has not been described previously and analyzed its effect on plant growth, gene expression and the level of sugars and amino acids in the host plant. Inoculation with Pseudomonas sp. G62 promoted plant growth under various growth conditions. Microarray analysis revealed rapid changes in transcript levels of genes annotated to energy-, sugar- and cell wall metabolism in plants 6 h after root inoculation with P. sp. G62. The expression of several of these genes remained stable over weeks, but appeared differentially regulated in roots and shoots. The global gene expression profile observed after inoculation with P. sp. G62 showed a striking resemblance with previously described carbohydrate starvation experiments, although plants were not depleted from soluble sugars, and even showed