玉米大斑病菌CaM基因的克隆及三氟拉嗪的抑菌作用

 以玉米大斑病菌为材料,根据同源序列法分别进行了3'端和5'端的RACE扩增,获得了玉米大斑病菌钙调素基因cDNA全长。利用genomic walking技术获得了CaM基因启动子序列,该序列含有多个与转录调控有关的保守序列(如TATA-box、Spl、AP-2和TFⅡD)。Southem杂交结果表明,玉米大斑病菌CaM基因在基因组中以单拷贝形式存在。用CaM特异性抑制剂三氟拉嗪(trifluoperazine)处理玉米大斑病菌,发现其对孢子萌发和附着胞形成的抑制作用与浓度呈正相关,同一浓度下,抑制剂对附着胞形成的抑制作用大于对孢子萌发的抑制。推测CaM基因在玉米大斑病菌的致病过程中起着至关重要的作用。

Cloning of CaM (Calmodulin) gene and inhibitory effect of trifluoperazine on Setosphaeria turcica

The full-length cDNA sequence of CaM encoding calrnodulin was obtained by 3' and 5' RACE amplification from Setosphaeria turcica. The promoter of CaM was isolated with genomic walking strategy. Analysis of CaM promoter using the Proscan software showed that it contained several regulatory elements, such as TATA box, Spl, AP2 and TFⅡD. The result of Southern-blot showed that CaM was single copy in the genome of S. turcica. Furthermore, the CaM inhibitor trifluoperazine (TFP)was able to inhibit conidial germination and appressorium formation of S. turcica. This inhibtion was positively related to TFP concention. However, appressorium formation was more sensitive than conidium germination to the inhibitor at the same concentration. It was suggested that CaM might play an important role in Ca²⁺ signal transduction pathway and pathogenicity of S. turcica.