Meloidogyne incognita: molecular and biochemical characterisation of a cathepsin L cysteine proteinase and the effect on parasitism following RNAi

Exp Parasitol. 2007 Feb;115(2):114-20. doi: 10.1016/j.exppara.2006.07.008. Epub 2006 Sep 22.

Abstract

RNA interference has been used to investigate the function of a cathepsin L cysteine proteinase Mi-cpl-1, in the plant-parasitic nematode Meloidogyne incognita. A reduction in gene transcript was observed and the number of nematodes infecting plants was reduced by almost 60% as was the number of established females producing eggs at 21 days post-infection. The cysteine proteinase activity of M. incognita, reported by the substrate GLUpNA, was inhibited by the cysteine proteinase inhibitor Oc-IDeltaD86. A reduction in cysteine proteinase activity was also seen following RNAi of Mi-cpl-1 in J2 stage nematodes. In situ hybridization analysis in young and mature female nematodes has shown that Mi-cpl-1 is expressed in the intestine, which suggests that its product is a digestive enzyme. The effects of knocking-out Mi-cpl-1gene function were consistent with a reduction in feeding efficiency. Here, we have shown a correlation between transcript abundance proteinase activity and parasitic success of M. incognita.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cathepsin L
  • Cathepsins / genetics*
  • Cathepsins / metabolism*
  • Chromogenic Compounds / metabolism
  • Cysteine Endopeptidases / genetics*
  • Cysteine Endopeptidases / metabolism*
  • Female
  • Gene Expression Regulation, Enzymologic
  • In Situ Hybridization
  • Lycopersicon esculentum / parasitology
  • Plant Roots / parasitology
  • RNA Interference*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tylenchoidea / enzymology*
  • Tylenchoidea / genetics
  • Tylenchoidea / pathogenicity

Substances

  • Chromogenic Compounds
  • Cathepsins
  • Cysteine Endopeptidases
  • Cathepsin L