A point mutation in the ethylene-inducing xylanase elicitor inhibits the β-1-4-endoxylanase activity but not the elicitation activity

Noa Furman-Matarasso, Eitan Cohen, Quansheng Du, Nor Chejanovsky, Uri Hanania, Adi Avni

Research output: Contribution to journalArticlepeer-review

56 Scopus citations

Abstract

Ethylene-inducing xylanase (EIX) elicits plant defense responses in certain tobacco (Nicotiana tabacum) and tomato cultivars in addition to its xylan degradation activity. It is not clear, however, whether elicitation occurs by cell wall fragments released by the enzymatic activity or by the xylanase protein interacting directly with the plant cells. We cloned the gene encoding EIX protein and overexpressed it in insect cells. To determine the relationship between the two activities, substitution of amino acids in the xylanase active site was performed. Substitution at glutamic acid-86 or -177 with glutamine (Gln), aspartic acid (Asp), or glycine (Gly) inhibited the β-1-4-endoxylanase activity. Mutants having Asp-86 or Gln-177 also lost the ability to induce the hypersensitive response and ethylene biosynthesis. However, mutants having Gln-86, Gly-86, Asp-177, or Gly-177 retained ability to induce ethylene biosynthesis and the hypersensitive response. Our data show that the xylanase activity of EIX elicitor can be separated from the elicitation process, as some of the mutants lack the former but retain the latter.

Original languageEnglish (US)
Pages (from-to)345-351
Number of pages7
JournalPlant Physiology
Volume121
Issue number2
DOIs
StatePublished - Oct 1999

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

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