The Nicotiana sylvestris extensin gene, Ext 1.2A, is expressed in the root transition zone and upon wounding

Abstract

The Ext 1.2A gene of Nicotiana sylvestris L. encoding an extensin, a cell wall structural protein, was characterized. Ext 1.2A encodes a polypeptide of 311 amino acids having a highly repetitive structure and showing extensin features such as Ser-(Pro)(4) repeats and a high content of Tyr and Lys. The expression profile of the gene was demonstrated using the reporter GUS (beta-glucuronidase) fused to its promoter region (-630/+124, relative to the transcription start site) and by RNA gel blots. The results show that the (-630/+124) Ext 1.2A/GUS gene fusion is expressed in the root transition zone, where cells undergo an isodiametric growth but have not yet reached the rapid elongation phase, in stem inner and outer phloems and in cortical cells at the stem/petiole junction. The Ext 1.2A gene is also induced after wounding of stems, ribs, leaves or roots. The gene fusion is expressed in stem cortical cells, in ribs and at leaf edges upon wounding. These data suggest that the (-630/+124) promoter region contains regulatory elements responsible for expression in roots and stems, as well as for response to wounding in stems and leaves.

Role of the Extensin Superfamily in Primary Cell Wall Architecture

“…Furthermore, the identification of gene regulatory elements (Guzzardi et al, 2004) is consistent with the suggestion that "selective activation of genes encoding specific structural proteins provides a mechanism for precise morphogenetic control of cell wall architecture during cellular differentiation" (Keller and Lamb, 1989). The known roles of extensins in cell wall assembly, cell shape and size, disease resistance, and quite possibly in reproductive isolation and speciation (Lee et al, 2007) raise the question of mechanism for each extensin molecule.…”

Deciphering the Responses of Root Border-Like Cells of Arabidopsis and Flax to Pathogen-Derived Elicitors

“…The accumulation of extensin in cell walls is known to occur as a response to biotic stress (Brisson et al, 1994;Guzzardi et al, 2004;Deepak et al, 2007;Xie et al, 2011). To investigate the impact of the MAMPs on extensin, we examined the distribution of extensin epitopes in border-like cells of Arabidopsis and flax using the mAb LM1 (Smallwood et al, 1995) and immunofluorescence microscopy.…”

Accumulation of Defence Response‐related and Unique Expressed Sequence Tags during the Incompatible Interaction in theOryza sativa–Magnaporthe oryzaePathosystem

“…The induction of hydroxyproline‐rich glycoprotein mRNA accumulation by elicitor extracted from Fusarium moniliforme has been studied in detail (Garcia‐Muniz et al., 1998). A gene of Nicotiana sylvestris encoding an extensin, a cell wall structural protein, was characterized and shown to express in response to wounding in stems and leaves (Guzzardi et al., 2004). Extensin gene has also been shown to be induced by the Brassica pathogen Xanthomonas campestris pv.…”