关键词: 小麦, 小麦白粉菌, 植物激素, 丝氨酸/苏氨酸激酶, 同源克隆, 表达模式, 响应机制

Abstract: To elucidate the response characteristics of the wheat serine/threonine kinase gene（TaSTK）to Blumeria graminis f.sp.tritici（Bgt）infection and exogenous plant hormone treatments，TaSTK genes were cloned from the susceptible wheat cultivar Yumai 13 and resistant wheat cultivar Hongyoumai，respectively，followed by analyses of their encoded proteins，expression patterns and subcellular localization.The full⁃length sequences of TaSTK from Yumai 13 and Hongyoumai were obtained through homologous cloning，the similarity of the two gene sequences was 98%.Both genes contained complete open reading frames，encoding 476（GenBank accession No.ADP09024.1）and 473（GenBank accession No.ADP09025.1）amino acid residues，respectively.Both proteins possessed typical conserved domains of serine/threonine protein kinases.Protein structural analysis revealed that Yumai 13 TaSTK protein contained one additional β⁃sheet and one additional α⁃helix in its secondary structure compared with Hongyoumai TaSTK protein，resulting in different tertiary structures. Real⁃time quantitative PCR analysis indicated that the expression level of the TaSTK gene in Yumai 13 was significantly decreased at 96 h post inoculation with Bgt.By contrast，TaSTK expression in different Hongyoumai⁃Bgt interaction combinations peaked at 24 h post inoculation，and was higher in the compatible interaction（Hongyoumai/BgtZZ）than the incompatible one（Hongyoumai/BgtGY）.Furthermore，when Hongyoumai was treated with plant hormones，salicylic acid（SA），methyl jasmonate（MeJA），ethylene（ETH），and abscisic acid（ABA），TaSTK expression peaked at 6 h after SA treatment，reaching 2.61⁃fold of 0 h；expression peaked at 0.5 h after MeJA and ETH treatments，reaching 6.16⁃fold and 4.81⁃fold of 0 h，respectively；and showed two peaks at 0.5 h and 24 h after ABA treatment，reaching 7.54⁃fold and 13.29⁃fold of 0 h，respectively.Transient expression analysis revealed that TaSTK protein from Hongyoumai was localized to the plasma membrane.These results demonstrate that TaSTK participates in wheat⁃Bgt interactions and responds to plant hormone signaling pathways.

Key words: Wheat, Blumeria graminis f.sp.tritici, Plant hormone, Serine/threonine kinase, Homologous cloning, Expression pattern, Response mechanism