Molecular basis of ergosterol-induced protection of grape against botrytis cinerea: induction of type I LTP promoter activity, WRKY, and stilbene synthase gene expression.

Laboratoire de Physiologie et Biochimie Végétales, UMR CNRS 6161, Université de Poitiers, Bâtiment Botanique, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France.

Type I lipid transfer proteins (LTPs) are basic, 9-kDa cystein-rich proteins believed to be involved in plant defense mechanisms. A 2,100-bp fragment containing the coding region of Vitis vinifera lipid transfer protein 1 (VvLTP1) and 1,420-bp of its promoter region was isolated by screening a grape genomic library. In silico analysis revealed several putative, defense-related, cis-regulatory elements such as W- and MYB-boxes, involved in the binding of WRKY and MYB transcription factors, respectively. The 5'-truncated versions of the VvLTP1 promoter were generated, cloned in front of the beta-glucuronidase (GUS) reporter gene, and introduced in tobacco plants and grapevine cell suspensions using Agrobacterium spp. Single MYB- and the W-boxes identified on the 0.250-kbp fragment were sufficient to induce GUS activity in transgenic tobacco plants after transient expression of MYB and WRKY. Ergosterol, a nonspecific fungal elicitor, induced GUS activity in transgenic grapevine cell suspensions transformed with the 1,420- and 750-bp promoter containing a palindromic arrangement of two W-boxes but not the 650- or 250-bp fragment, where only one W-box was present. Moreover, ergosterol triggered WRKY, VvLTP1, and stilbene synthase gene expression in grape plantlets and enhanced protection against Botrytis cinerea. The molecular basis of ergosterol-induced protection is discussed.

PMID: 17022174 [PubMed - indexed for MEDLINE]