Cloning and characterization of a wheat β-1,3-glucanase gene induced by the stripe rust pathogen Puccinia striiformis f. sp tritici

beta-1,3-Glucanases are a group of pathogenesis-related proteins that have been reported to be involved in plant defense against pathogens in many other plant-pathogen systems. However, it was not clear if these genes play similar role in wheat (Triticum aestivum L.) against Puccinia striiformis f. sp. tritici (Pst), the stripe rust pathogen. To investigate the role of beta-1,3-glucanase (EC 3.2.1.39) in the resistance response of wheat (cv. Suwon 11) to stripe rust, a wheat beta-1,3-glucanase gene induced by Pst, designated as TaGlu, was cloned and characterized. TaGlu was predicted to encode a basic protein of 334 amino acids. Quantitative real-time PCR analyses revealed that the transcription of TaGlu was induced during both compatible and incompatible interactions with Pst, but the transcription level was much higher in the incompatible interaction than that in the compatible interaction. TaGlu also showed noticeable induction of gene expression in young green leaf tissues treated with salicylic acid, methyl jasmonate or ethylene. Immunogold labeling assays showed that the enzyme were localized mainly in the host cell wall and over the extrahaustorial matrix, and the labeling densities were found significantly higher in the incompatible interaction than those in the compatible interaction.