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N ‐acetylchitooligosaccharides elicit expression of a single (1→3)‐β‐glucanase gene in suspension‐cultured cells from barley ( Hordeum vulgare )
Author(s) -
Kaku Hanae,
Shibuya Naoto,
Xu Peilin,
Aryan Arun P.,
Fincher Geoffrey B.
Publication year - 1997
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1997.tb03460.x
Subject(s) - glucanase , hordeum vulgare , isozyme , biology , gene expression , gene isoform , gene , elicitor , pathogenesis related protein , biochemistry , microbiology and biotechnology , xyloglucan , enzyme , gene family , enzyme assay , glucan , poaceae , botany
N ‐acetylchitooligosaccharides of degree of polymerization 6 to 8 elicit the synthesis of (1→3)‐β‐glucan endohydrolase (EC 3.2.1.39) activity in suspension‐cultured cells derived from immature barley ( Hordeum vulgare ) embryos. Corresponding de‐acety‐lated chitooligosaccharides have no effect. Concentrations of N ‐acetylchitoheptaose in the 200 n M range are sufficient to elicit the response. A 2‐ to 3‐fold increase in (1→3)‐β‐glucanase activity is detected 24 h after the addition of the oligosaccharide. Non‐denaturing gel electrophoresis, coupled with the in situ detection of (1→3)‐β‐glucanase activity in the gels, has enabled the separation of specific isoforms of the enzyme. The increase in (1→3)‐β‐glucanase activity following N ‐acetylchitoheptaose induction is attributable predominantly to enhanced levels of isoenzyme GII, although the barley (1→3)‐β‐glucanase gene family encodes at least seven different isoforms of the enzyme. Northern hybridization analyses with gene‐specific probes confirmed the presence of mRNA encoding isoenzyme GII as the major mRNA in cells treated with the oligosaccharide elicitor. The results therefore demonstrate a specific induction of the (1→3)‐β‐glucanase isoenzyme GII gene following stimulation of barley cells with oligosaccharides of fungal cell wall origin, and further suggest that a plant's response to microbial attack involves transcription of quite specific members of the gene families that encode pathogenesis‐related proteins.