Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/4/2002
Publication Date: 8/4/2002
Citation: Keates, S.E., Kostman, T.A., Anderson, J.D., Bailey, B.A. 2002. Cellular damage and wound responsive gene induction in weeds treated with nep1, a necrosis inducing peptide [abstract]. American Society of Plant Biologists Annual Meeting.
Technical Abstract: The necrosis and ethylene inducing protein (Nep1) isolated from Fusarium oxysporum f. sp. erythroxyli causes cell death in many dicot plant species including weed species. Although many of the plant responses to Nep1 are similar to elicited responses leading to induction of plant defense responses, it has not been demonstrated that Nep1 induces resistance to disease: in contrast, Nep1 appears to enhance susceptibility to disease. At the transmission electron microscopy level, application of Nep1 caused a visible reduction in the thickness of the cuticle and a breakdown of chloroplast membrane within 1 h of treatment. Membrane breakdown was most severe in cells closest to the epidermal surface. When stomata were present on the application side of the leaf, guard cell membranes were disrupted. Differential display techniques were used to identify an initial set of genes induced by Nep1. Individual genes identified in Arabadopsis thaliana L., Centaurea maculosa Lam., or Taraxacum officinale L., showed homology to protein kinases, senescence-related proteins, phospholipase D, SA/wound-induced genes, serpin, calmodulin-like proteins, b-glucosidase, translation initiation factor IF-1, protein phosphatase, and cytochrome P450. Typically, transcripts observed in the 15 min control declined with time whereas transcripts were maintained or accumulated in Nep1 treated tissues up to 4 h after treatment. Increasing Nep1 concentration from 1 mg/ml to 5 mg/ml enhanced accumulation of some transcripts but did not significantly alter accumulation of others, suggesting differential expression of Nep1 responsive genes. Transcripts identified in this study provide strong evidence that Nep1 induces genes associated with wound responses in plants.