小麦白粉菌HSP70基因的克隆及高温胁迫对其表达的影响

小麦白粉病是由专性寄生菌Blumeria graminisf.sp.tritici引起的一种重要的气传真菌病害,该病曾于1990-1991年两年在我国发生大流行,近年来其发生面积也一直维持在500万公顷以上,给我国小麦生产造成了严重的损失.已有的研究结果表明,温度不但影响小麦白粉病的发生和流行,而且温度胁迫作用还会对白粉病菌群体产生影响,从而使病菌群体对温度的敏感性降低.目前已发现在我国白粉病菌群体中存在抗高温或耐高温的菌株,而且这些菌株在较高的温度下其寄生适合度要高于对温度高敏感性的菌株[1].由于病菌群体对温度敏感性的变化有可能影响病害越夏和越冬的范围,进而影响病害的发生和流行程度,因此,有必要对其耐高温的分子机制进行研究,这对于了解小麦白粉菌对温度的适应性以及气候变暖对此病害发生和流行的长期影响具有重要的意义.

Cloning of heat shock protein gene, HSP70, in Blumeria graminis f. sp. tritici and its expression under high temperature stress

The objective of this study was to detect the effect of high temperature stress on the expression of HSP70 gene in Blumeria graminis f. sp. tritici. The cDNA sequence of HSP70 gene was cloned using RT-PCR and RACE. The obtained cDNA sequence contained a 1 947 bp open reading frame (ORF) and encoded a sequence of 648 amino acids residues. The molecular mass was estimated as 70.5 kDa and isoelectric point (pI) 4.84. The gene contained the signature sequences of HSP70 family. Real-time quantitative PCR was used to analyze the expression of HSP70 gene of B. graminis f. sp. tritici after the treatments of heat shock (28℃) in different time. The results showed that the mRNA expression of HSP70 gene of B. graminis f. sp. tritici was significantly up-regulated after heat shock at 28℃. The expression level of HSP70 gene reached the maximum (11.6 times of the control) after 60 minutes, and then decreased. It was inferred that HSP70 gene might play an important role in B. graminis f. sp. tritici to high temperature.