Fungi belonging to the Magnaporthe grisea species-complex infect a wide range of cereals and grasses, including economically important crops such as rice, barley, wheat, and millet. Magnaporthe oryzae is a member of this species-complex and causes rice-blast disease which is responsible for the loss of 10-30% of the annual rice harvest worldwide. M. grisea has been regarded as a typical foliar pathogen, but recently it has been shown that it can also infect cereal roots, undergoing developmental steps typical for root-infecting pathogens. A forward-genetics screen using in vitro tests on hydrophilic and hydrophobic surfaces as well as in planta assays on roots and leaves has enabled the identification of additional tissue-specific and general determinants involved in pathogenicity of M. grisea. A transformant of the fungus identified during the in vitro screen on polystyrene hydrophilic surfaces has been found to be compromised in root and leaf pathogenesis. The disrupted gene was identified by recovery of the sequence flanking the T-DNA insertion site and encodes a putative transcription factor (rfeG), previously identified in Aspergillus terreus. Targeted gene replacement mutants of this gene have been generated, via Agrobacterium tumefaciens-mediated transformation. The DNA-binding function of the rfeG protein has been shown by yeast-one-hybrid experiments. The coding sequences of other two putative transcription factors, related to rfeG, have also been selected and disruption mutants are being generated.
Full conference title:
9th EUROPEAN CONFERENCE ON FUNGAL GENETICS
- ECFG 9th (2008)