论文部分内容阅读
利用RT-PCR技术,从条锈菌诱导的小麦叶片中分离出一个编码CaM基因的cDNA序列,经氨基酸序列分析确定其为一个新的小麦CaM亚型,暂被命名为TaCaM5。TaCaM5包含一个完整450bp的开放阅读框,编码149个氨基酸;编码的蛋白不含跨膜区、无信号肽、定位在胞内,具有4个EF-hand保守结构域。在目前已知的CaM基因中,TaCaM5与玉米CaM基因的亲缘关系最近,相似性高达97%。该基因在根、茎、叶等组织中均有不同程度的表达;并且受条锈菌诱导表达,在非亲和组合与亲和组合中,分别在接种后6h和24h表达量最高。外源植物激素脱落酸、茉莉酸甲酯和乙烯诱导TaCaM5上调表达,水杨酸诱导其下调表达。TaCaM5在机械伤害、干旱和低温条件下表达量上升,在高盐环境下表达量降低。表明TaCaM5可能通过茉莉酸和乙烯等信号途径参与小麦对条锈菌的防御反应,同时参与机械伤害、低温和干旱环境下的Ca2+-CaM信号转导途径。
A cDNA encoding CaM gene was isolated from wheat leaves induced by stripe rust by RT-PCR and identified as a new CaM subtype of wheat by amino acid sequence analysis. It was temporarily named TaCaM5. TaCaM5 contains a complete 450bp open reading frame encoding 149 amino acids. The encoded protein contains no transmembrane region, no signal peptide and is localized intracellularly with 4 EF-hand conserved domains. Among the CaM genes known to date, TaCaM5 has the closest genetic relationship with maize CaM gene, with a similarity of 97%. The gene was expressed in different degrees in root, stem, leaf and other tissues, and was induced by stripe rust. The highest expression level was found at 6h and 24h after inoculation in non-affinity combination and affinity combination, respectively. Exogenous plant hormone abscisic acid, methyl jasmonate and ethylene induced TaCaM5 up-regulated expression, and salicylic acid induced its down-regulated expression. TaCaM5 expression increased under mechanical injury, drought and low temperature, and decreased in high salt environment. The results indicated that TaCaM5 could participate in the defensive reaction of wheat stripe rust via signal pathways such as jasmonic acid and ethylene, and participate in Ca2 + -CaM signal transduction pathways under mechanical injury, hypothermia and drought.