低剂量杀线虫剂对马铃薯腐烂茎线虫三个热激蛋白70 mRNA表达的影响

为了解马铃薯腐烂茎线虫Ditylenchus destructor对低剂量杀线虫剂胁迫的适应机制,采用RTPCR和RACE技术克隆了3个热激蛋白70基因Dd-hsp70-A(KF792307)、Dd-hsp70-C(JQ422276)和Dd-hsp70-F(JQ422277),并利用实时荧光定量PCR分别检测了33℃热激及低剂量(10、1、0.1、0.01和0.001μg/m L)杀线虫剂阿维菌素、丙溴磷和涕灭威处理对3个Dd-hsp70基因mRNA表达量的影响。结果表明,3个Dd-hsp70基因在翻译区均含有内含子,编码的氨基酸序列均包含了完整的保守结构域和3段保守的HSP70家族签名序列,且在氨基酸C末端具有保守的亚细胞定位基序。33℃热激3、6 h及0.1μg/m L涕灭威浸渍处理24 h,马铃薯腐烂茎线虫Dd-hsp70-A基因mRNA表达量分别比对照显著上调1.865、4.127和1.634倍;其它处理的mRNA表达量与对照差异均不显著。证实了Dd-hsp70-A、Dd-hsp70-C和Dd-hsp70-F基因均为组成型,其中Dd-hsp70-A基因的响应在植物线虫应对低剂量杀线虫剂胁迫过程中具有重要作用。     

SGT1 and HSP90 are essential for age-related non-host resistance of Nicotiana benthamiana against the oomycete pathogen Phytophthora infestans

The oomycete pathogen, Phytophthora infestans, is the causal agent of potato late blight, which is one of the most destructive and economically important plant diseases. We investigated the interaction between P. infestans and Solanaceous model plant Nicotiana benthamiana. Mature N. benthamiana plants were resistant to 8 isolates of P. infestans, whereas relatively young plants were susceptible to all isolates. Analysis with virus-induced gene silencing (VIGS) indicated that NbSGT1 and NbHSP90, genes essential for the function of R proteins, are required for the resistance of N. benthamiana to P. infestans. NbSGT1 was also required for the production of reactive oxygen species (ROS), hypersensitive cell death and expression of NbEAS, a gene for phytoalexin biosynthesis, induced by INF1, a secretory protein derived from P. infestans. These results suggested that N. benthamiana possibly possesses a broad-spectrum R protein against P. infestans, which requires an SGT1/HSP90-dependent mechanism, for the recognition of a conserved molecular pattern of P. infestans.     

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.     

Flufenoxuron, an acylurea insect growth regulator, alters development of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) by modulating levels of chitin, soluble protein content, and HSP70 and p34 in the larval tissues

The effect of sublethal concentrations, 0.00141% (LC₂₀), 0.00251% (LC₃₀), and 0.0036% (LC₄₀) of a dispersible formulation of an acylurea insect growth regulator, flufenoxuron (Cascade) on certain biochemical parameters in the larvae of Tribolium castaneum was investigated. When neonates were fed on diet treated with sublethal concentrations for 24 h, it was observed that at all concentrations tested, there was a significant reduction in chitin content on the 15th day of development. Total soluble protein content at LC₂₀ and LC₃₀ decreased with increasing age of the larvae. At LC₂₀ and LC₄₀ concentrations there was a progressive increase in the protein: chitin ratio as a function of increase in age of the larvae. SDS-PAGE analysis of the larval tissue extracts indicated gross quantitative changes in some of the protein bands (MW 50-97 kDa). Western blot analysis revealed significant increase in the level of HSP70 in the extracts of larvae fed on LC₃₀ treated diet, on the 7th and 10th day of development in the decreasing order. Conversely, a significant decrease in the hyper-phosphorylated form of p34^cdc2 kinase due to flufenoxuron treatment indicating modulation of cell cycle regulation was observed. Thus, sublethal concentrations of flufenoxuron alter expression of developmentally regulated proteins, HSP70 and p34^cdc2 and chitin formation in a stage-specific manner thereby resulting developmental abnormalities in T. castaneum.