Abstract: 【Objective】β-1, 3-glucanase, a kind of pathogenesis-related protein, plays an important role in signal transduction in plants. The objective of this study is to understand the expression patterns of β-1, 3-glucanase gene in the interaction between Puccinia triticina and wheat TcLr35, identify the relativity between the aim gene and resistance to leaf rust pathogen attack, and explore the molecular mechanism of PRs mediated resistance in adult wheat to P. triticina.【Method】Based on the previous studies, the structure characteristics of β-1, 3-glucanase gene (TaLr35PR2) were analyzed using bioinformatics methods. In the meanwhile, the gene expression profiles of TaLr35PR2 induced by P. triticina and chemical molecule at different time points were analyzed by semi-quantitative RT-PCR method combining genetools and SPSS software. In addition, the similar analysis was also conducted on the different tissues of wheat including roots, stems and leaves, and different growth stages of wheat.【Result】TaLr35PR2 coded an alkaline protein positioned in the vacuole contained a signal peptide. The protein sequence of TaLr35PR2 had high homology with other plants, and had the closest relationship with pathogenesis-related protein 2 gene in Triticum aestivum, but farthest relationship with the PR protein in rice. The expression profile analysis of TaLr35PR2 at the adult stage in wheat at different time points after P. triticina inoculation indicated that the transcription level changed little in the compatible interaction (Thatcher), but changed much in the incompatible interaction (TcLr35). The transcription level was much earlier and higher in the incompatible interaction than that in the compatible interaction at different points. Different tissues of the adult wheat TcLr35 detection results showed that the gene expression in leaves increased significantly with the extension of inoculation time, the expression level reached a peak at 48 hpi, but the gene was not expressed in roots at different time points, and there was a little expression level at 48 hpi in stems and changed a little at the later period, so its expression abundance was leaf＞stem＞root. In different periods of wheat growth and development, the TaLr35PR2 expressed at certain levels without inoculation both in TcLr35 and Thatcher except at one-leaf stage, and the expression levels were much higher both in the incompatible and compatible interactions than that in the Mock reaction, then expressed stably at the adult stage. In addition, the expression level of the TaLr35PR2 increased significantly after pre-treatments with chemical molecule such as salicylic acid (SA) and abscisic acid (ABA).【Conclusion】The expression of TaLr35PR2 was induced by P. triticina. TaLr35PR2 may be involved in the defense response against rust pathogen and participate in SA, ABA mediated signaling pathway and take part in defense reaction to P. triticina of wheat TcLr35 adult stage.

Key words: wheat , pathogenesis-related protein (PRP) , signal molecule , Puccinia triticina , expression and analysis