Molecular cloning of a soybean class III beta-1,3-glucanase gene that is regulated both developmentally and in response to pathogen infection

We isolated and characterized a soybean gene (SGN1) encoding a basic beta-1 ,3-glucanase that is a plant class III isoform of beta-1,3-glucanase. The d educed amino acid sequence of the SGN1 gene is similar to that of the PR-Q' b gene, the basic class III beta-1,3-glucanase of tomato. Based on RNA blot hybridization, SGN1 gene expression was detected in all tissues of 4-day o ld seedlings, but it was present only in root tissue of 30-day old plants. GUS expression analysis carried out in transgenic tobacco plants harboring a SGN1::GUS reporter gene revealed the same expression pattern. Furthermore , the expression of SGN1 was strongly induced by a variety of defense-relat ed signals, such as treatment with H2O2, wounding, or treatment with fungal elicitor prepared from Phytophthora spp as well as inoculation with Pseudo monas syringae. However, the expression level of SGN1 was hardly induced wi th jasmonate, ethephon and salicylate. Overall the results suggest that the SGN1 may play a role in both plant development and plant defense against p athogen attack. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.