Global gene expression in rice blast pathogen Magnaporthe oryzae treated with a natural rice soil isolate

Carla A. Spence, Vidhyavathi Raman, Nicole M. Donofrio, Harsh P. Bais

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

The rhizospheric microbiome is comprised of many microbes, some of which reduce the virulence of their phytopathogenic neighbors; however, the mechanisms underlying these interactions are largely unknown. Rice soil isolate Pseudomonas chlororaphis EA105 strongly inhibits Magnaporthe oryzae's in vitro growth by restricting fungal diameter as well as inhibiting the formation of the appressorium, required for penetration. We were interested in elucidating M. oryzae's response to EA105 treatment, and utilized a microarray approach to obtain a global perspective of EA105 elicited changes in this pathogen. Based on this analysis, three genes of interest were knocked out in M. oryzae 70-15, and their sensitivity to EA105 treatment as well as their ability to infect rice was determined. Priming rice plants with EA105 prior to M. oryzae infection decreased lesion size, and the mutants were tested to see if this effect was retained. A null 70-15 mutant in a trichothecene biosynthesis gene showed less susceptibility to bacterial treatment, forming more appressoria than the parental type 70-15. A similar pattern was seen in a null mutant for a stress-inducible protein, MGG_03098. In addition, when this mutant was inoculated onto the leaves of EA105-primed rice plants, lesions were reduced to a greater extent than in 70-15, implicating the lack of this gene with an increased ISR response in rice. Understanding the global effect of biocontrol bacteria on phytopathogens is a key for developing successful and lasting solutions to crop loss caused by plant diseases and has the potential to greatly increase food supply.

Original languageEnglish (US)
Pages (from-to)171-185
Number of pages15
JournalPlanta
Volume239
Issue number1
DOIs
StatePublished - Jan 2014
Externally publishedYes

Bibliographical note

Funding Information:
Acknowledgements H.P.B. acknowledges the support from National Science Foundation Award PGPR-0923806. We would like to thank Dr. Venkatesan Sundaresan and his lab for the M-104 seeds and for the soil and root samples from which we obtained our isolates. We would also like to thank Dr. Sandra Mathioni for her advice on microarray analysis.

Keywords

  • Biocontrol
  • ISR
  • Magnaporthe oryzae
  • Microarray
  • Pseudomonas chlororaphis

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