The sugarcane defense protein SUGARWIN2 causes cell death in Colletotrichum falcatum but not in non-pathogenic fungi

PLoS One. 2014 Mar 7;9(3):e91159. doi: 10.1371/journal.pone.0091159. eCollection 2014.

Abstract

Plants respond to pathogens and insect attacks by inducing and accumulating a large set of defense-related proteins. Two homologues of a barley wound-inducible protein (BARWIN) have been characterized in sugarcane, SUGARWIN1 and SUGARWIN2 (sugarcane wound-inducible proteins). Induction of SUGARWINs occurs in response to Diatraea saccharalis damage but not to pathogen infection. In addition, the protein itself does not show any effect on insect development; instead, it has antimicrobial activities toward Fusarium verticillioides, an opportunistic fungus that usually occurs after D. saccharalis borer attacks on sugarcane. In this study, we sought to evaluate the specificity of SUGARWIN2 to better understand its mechanism of action against phytopathogens and the associations between fungi and insects that affect plants. We used Colletotrichum falcatum, a fungus that causes red rot disease in sugarcane fields infested by D. saccharalis, and Ceratocystis paradoxa, which causes pineapple disease in sugarcane. We also tested whether SUGARWIN2 is able to cause cell death in Aspergillus nidulans, a fungus that does not infect sugarcane, and in the model yeast Saccharomyces cerevisiae, which is used for bioethanol production. Recombinant SUGARWIN2 altered C. falcatum morphology by increasing vacuolization, points of fractures and a leak of intracellular material, leading to germling apoptosis. In C. paradoxa, SUGARWIN2 showed increased vacuolization in hyphae but did not kill the fungi. Neither the non-pathogenic fungus A. nidulans nor the yeast S. cerevisiae was affected by recombinant SUGARWIN2, suggesting that the protein is specific to sugarcane opportunistic fungal pathogens.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspergillus / cytology
  • Aspergillus / drug effects
  • Cell Death / drug effects
  • Colletotrichum / cytology*
  • Colletotrichum / drug effects
  • Mycelium / cytology
  • Mycelium / drug effects
  • Plant Proteins / pharmacology*
  • Recombinant Proteins / pharmacology
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / drug effects
  • Saccharum / metabolism*
  • Saccharum / microbiology

Substances

  • Plant Proteins
  • Recombinant Proteins

Grants and funding

This work was supported by the Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) grant 08/52067-3, the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) grant 474542/2010-6, and the Instituto Nacional de Ciência e Tecnologia do Bioetanol grant 574002/2008-1 and FAPESP 08/57908-6. M. C. Silva-Filho, G. H. Goldman, F. Henrique-Silva and D. S. Moura are also research fellows of CNPq. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.