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Microarray Analysis of the Gene Expression Profile Induced by the Endophytic Plant Growth-Promoting Rhizobacteria, Pseudomonas fluorescens FPT9601-T5 in Arabidopsis

May 2005 , Volume 18 , Number  5
Pages  385 - 396

Yanqing Wang , Yumiko Ohara , Hitoshi Nakayashiki , Yukio Tosa , and Shigeyuki Mayama

Laboratory of Plant Pathology, Graduate School of Science and Technology, Kobe University, Rokkodai, Nada-Ku, Kobe 657-8501, Japan

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Accepted 6 January 2005.

Pseudomonasz fluorescens FPT9601-T5 was originally identified as an endophytic plant growth-promoting rhizobacteria (PGPR) on tomato. To perform a molecular dissecttion of physiological and biochemical changes occurring in the host triggered by P. fluorescens FPT9601-T5 colonization, the model plant Arabidopsis was used in this study. Root colonization of Arabidopsis with P. fluorescens FPT9601-T5 promoted plant growth later than three weeks after inoculation and partially suppressed disease symptoms caused by Pseudomonas syringae pv. tomato DC3000, indicating that P. fluorescens FPT9601-T5 acted as a PGPR on Arabidopsis. To obtain a global view on transcript modification during the Arabidopsis-FPT9601-T5 interaction, we performed microarray analysis using Affymetrix Genechip probe arrays representing approximately 22,800 genes. The results showed that 95 and 105 genes were up- or down-regulated, respectively, more than twofold in FPT9601-T5-treated Arabidopsis plants as compared with control plants. Those up-regulated included genes involved in metabolism, signal transduction, and stress response. Noteworthy, upon FPT9601-T5 colonization, putative auxin-regulated genes and nodulin-like genes were up-regulated, and some ethylene-responsive genes were down-regulated. Our results suggest that P.fluorescens FPT9601-T5 triggered plant responses in a manner similar to known PGPR and, at least in some aspects, to rhizobia.

© 2005 The American Phytopathological Society