西瓜花叶病毒诱导对不同抗性美洲南瓜防卫基因表达的影响

为了明确防卫基因PAL与美洲南瓜抗西瓜花叶病毒(watermelon mosaic virus,WMV)之间的关系,通过室内接种和实时荧光定量PCR技术,测定了WMV侵染对不同抗性美洲南瓜体内防卫基因PAL表达的影响。结果表明:(1)室内测定显示,抗病品种GBRV-8发病率和病情指数(15.6%和14.2)显著低于感病品种‘光板’(91.1%和65.9)。(2)实时荧光定量PCR表明,接种WMV后不同抗感品种不同组织部位PAL基因相对表达量随着接种时间增加,整体呈现出先增加后降低的趋势,而且不同组织部位PAL基因相对表达量总体呈现出叶片较高,叶柄和茎秆次之。(3)接种后5个品种不同组织部位PAL基因相对表达量与对照相比均存在显著差异,且抗病和中抗品种不同组织部位PAL基因相对表达量显著高于感病品种,尤其抗病品种GBRV-8不同组织部位PAL基因相对表达量最高,感病品种光板最低。研究认为,防卫基因PAL表达量与美洲南瓜品种抗病毒病强弱密切相关。

Induction Expression of Defense Gene in Different Varieties of Cucurbita pepo by Watermelon Mosaic Virus Infection

In order to determine the relationship between the defense gene of PAL and resistance of Cucurbita pepo to watermelon mosaic virus (WMV),we determined and analyzed changes of PAL gene expression in different resistant varieties of C.pepo tissue by the methods of indoor inoculation and real-time PCR after inoculated with the pathogen of WMV.(1)In vitro,the results showed that the incidence and disease index of disease-resistant variety of GBRV-8 (15.6% and 14.2) were significantly lower than that of the susceptible variety of Guangban (91.1% and 65.9).(2)Real-time PCR results showed that the relative expression of PAL gene was increased after inoculated with the pathogen of WMV in different tissues and different resistant varieties of C.pepo at initial stage,but decreased later.Also,the relative expression of PAL gene in the leaves of different disease-resistant varieties of C.pepo was significantly higher than that in petioles and stems after inoculated with WMV.(3)The relative expression of PAL gene in five different varieties was significantly different from the control after determined at different days,and the relative expression of PAL gene in resistant varieties and middle-resistant varieties were higher than that in susceptible varieties.The relative expression of PAL gene in resistant varieties of GBRV-8 was the highest and susceptible varieties of Guangban was the lowest.Therefore,the relative expression of PAL gene had a positive correlation to the disease resistance of varieties.