国内葡萄白粉病菌对戊唑醇的抗药性研究

为明确国内葡萄白粉病菌(Erysiphe necator)对戊唑醇的抗药性,采用实时荧光定量PCR,基于对葡萄白粉病菌CYP51基因第495位点突变A495T的检测,分析国内5个省份分离获得的134株菌株对戊唑醇的抗药性,利用孢子萌发法测定供试菌株对戊唑醇的敏感性,分析2种方法结果的相关性。结果表明,实时荧光定量PCR方法检测到国内葡萄白粉病菌对戊唑醇已出现抗药性,抗性频率为35.07%,不同地区存在差异。孢子萌发法结果显示,供试菌株对戊唑醇的EC_(50)范围为0.085~280.917μg/mL,均值为24.208μg/mL,不同地区菌株对戊唑醇的敏感性差异较大,EC_(50)最大值和最小值之比为2.5~3304。孢子萌发法与实时荧光定量PCR方法间的检测结果趋势一致并显著相关。

葡萄白粉病菌环介导等温扩增检测体系的建立与应用

为了建立高效准确的葡萄白粉病菌(Uncinula necator)环介导等温扩增(LAMP)检测体系,为葡萄白粉病的早期诊断和监测预警提供依据,根据葡萄白粉病菌细胞色素P450全长基因序列设计合成3组LAMP引物并进行筛选,对包括葡萄白粉病菌在内的11种植物病原真菌的DNA进行LAMP扩增,检测体系的特异性,建立并优化葡萄白粉病菌LAMP反应体系,评价体系的灵敏性。使用优化后的检测体系扩增田间发病叶片的总DNA,检测所建立体系的实用性。LAMP最佳反应条件是:以UNITF3-1/UNITB3-1为外引物,以UNITFIP-1/UNITBIP-1为内引物,62℃反应60 min,Bst DNA聚合酶浓度为0.320 U/μL,甜菜碱浓度为0.8 mol/L,dNTPs浓度为2.6 mmol/L,Mg浓度为4.8 mmol/L,内外引物配比为6∶1,能够检测出葡萄白粉病菌DNA,灵敏度为1 pg/μL。应用已建立的检测体系对田间采集的病叶样品进行检测,能够检测到葡萄白粉病菌,准确率达100%。综上,建立的葡萄白粉病菌LAMP检测体系特异性强、灵敏度高,可用于田间葡萄白粉病菌的检测。

Study on the Biology and Epidemiology of Uncinula necator---The Causal Agent of Grape Powdery Mildew Disease

This study was carried out during 2007-2009 in the vineyards of Ardebil province of lran to study the biology and the epidemiology of Uncinula necator--the causal agent of grape powdery mildew disease. The study concentrated on the survival and the initiation of primary inoculum of the fungal causal agent. Results of histopathological experiments indicated that U. necator survived as mycelium in the dormant buds of the grapes during winter season. Results of study on the effect of environmental factors on fungus biology showed that the pathogenic activity of the fungus began when the temperature was between 16-19 ℃ with a relative humidity more than 50%. It was also found that optimum temperature and relative humidity for the sporulation of U.necator was 20-25 ~C and 50%-100% respectively. According to the results, fungal conidia were trapped during formation of 5-6 true leaves and first disease symptoms were observed on the clusters on late June after fruit formation. Fungal cleistothecia were observed abundantly at the end of season on the leaves, petioles and twigs but they were not able to survive during winter. Formation of ascospores on young leaves was proved but their role as the primary inoculum was not supported by the results of this study. Results of this study and the new findings on the biology and epidemiology of U.necator may be of national and international interests for the management of powdery mildew disease which is one of the most destructive diseases around the world including Iran.