Characterisation of four LIM protein-encoding genes involved in infection-related development and pathogenicity by the rice blast fungus Magnaporthe oryzae

PLoS One. 2014 Feb 5;9(2):e88246. doi: 10.1371/journal.pone.0088246. eCollection 2014.

Abstract

LIM domain proteins contain contiguous double-zinc finger domains and play important roles in cytoskeletal re-organisation and organ development in multi-cellular eukaryotes. Here, we report the characterization of four genes encoding LIM proteins in the rice blast fungus Magnaporthe oryzae. Targeted gene replacement of either the paxillin-encoding gene, PAX1, or LRG1 resulted in a significant reduction in hyphal growth and loss of pathogenicity, while deletion of RGA1 caused defects in conidiogenesis and appressorium development. A fourth LIM domain gene, LDP1, was not required for infection-associated development by M. oryzae. Live cell imaging revealed that Lrg1-GFP and Rga1-GFP both localize to septal pores, while Pax1-GFP is present in the cytoplasm. To explore the function of individual LIM domains, we carried out systematic deletion of each LIM domain, which revealed the importance of the Lrg1-LIM2 and Lrg1-RhoGAP domains for Lrg1 function and overlapping functions of the three LIM domains of Pax1. Interestingly, deletion of either PAX1 or LRG1 led to decreased sensitivity to cell wall-perturbing agents, such as Congo Red and SDS (sodium dodecyl sulfate). qRT-PCR analysis demonstrated the importance of both Lrg1 and Pax1 to regulation of genes associated with cell wall biogenesis. When considered together, our results indicate that LIM domain proteins are key regulators of infection-associated morphogenesis by the rice blast fungus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fungal Proteins / genetics*
  • Gene Deletion
  • Gene Expression Regulation, Fungal
  • Magnaporthe / genetics*
  • Magnaporthe / pathogenicity*
  • Oryza / microbiology*
  • Plant Diseases / microbiology*
  • Spores, Fungal / genetics
  • Spores, Fungal / pathogenicity

Substances

  • Fungal Proteins

Grants and funding

This work was supported by National Key Basic Research and Development Program of China (2012CB114002), by Program for Changjiang Scholars and Innovative Research Team in University (IRT0943), by the Natural Science Foundation of China (Grant No. 31071648 and 30970129) and the Doctoral Fund of Ministry of Education of China (20100101110097) to ZW. NJT is supported by an ERC Advanced Investigator Award GENBLAST. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.