灰飞虱胁迫下水稻防卫相关基因的表达

Expression of Rice Defence Genes under Small Brown Planthopper Stress

运用荧光定量PCR方法及特异性引物,对不同时间(12、24、36、48和72h)灰飞虱胁迫下抗虫和感虫水稻品种中主要防卫途径的相关基因进行转录水平上定量分析。灰飞虱取食后,与水杨酸合成途径相关的基因PAL、NPR1、EDS1和PAD4在抗灰飞虱品种Mudgo中的表达水平均高于在感虫水稻Kittake中。接虫12h后,PAL基因表达量达到未接虫时的6.914倍;在Mudgo中,PAL基因相对表达量上升更快,在24、48和72h分别是Kittake中的42.848、70.743和69.193倍。NPR1基因在灰飞虱为害12、36和72h后,在Mudgo中的表达量分别是Kittake中的4.690、6.231和4.112倍。与茉莉酸合成相关的基因LOX和AOS2,在灰飞虱为害36h后,在Kittake中的表达水平显著高于Mudgo中。乙烯信号途径中的受体基因EIN2在Kittake中的表达量也高于Mudgo中。结果表明,灰飞虱取食激活了抗虫水稻Mudgo中依赖水杨酸介导的抗性途径,同时诱导感虫水稻Kittake产生了依赖茉莉酸/乙烯途径的防卫反应,PAL和NPR1基因的表达在调节Mudgo抗灰飞虱中具有重要作用。

The small brown planthopper （SBPH）, Laodelphax striatellus Fallen （Homoptera： Delphacide）, is an economically important pest in rice （Oryza sativa L.） production in China. Real-time PCR was used to determine transcriptional level of rice defence genes after SBPH infestation using specific primers. The expression levels of SA synthesis-related genes PAL, NPR1, EDS1, and PAD4 were higher in the resistant variety ＂Mudgo＂ than in the susceptible variety ＂Kittake＂ after SBPH feeding. The expression level of gene PAL in 12 h-infestation rice was 6.914 times of that in untreated flee. The expression amount of PAL in Mudgo increased more rapidly and in higher levels, which were 42.848, 70.743, and 69.193 times over the expression amounts of Kittake at 24, 48, and 72 h after SBPH infestation, respectively. The expression levels of NPR1 in Mudgo were 4.690, 6.231, and 4.112 times over those in Kittake after SBPH infestation for 12, 36, and 72 h, respectively. There were significant differences in transcriptional levels of the jasmonate （JA） synthesis-related genes LOX and AOS2 after 36 h-infestation between Mudgo and Kittake. The expression level was substantially lower in Mudgo than in Kittake at subsequent time points. In addition, the expres- sion level of receptor gene EIN2 in ethylene signaling pathway was higher in Kittake than in Mudgo after SBPH feeding. The above results indicated that SBPH feeding activated the salicylic acid signaling pathway in resistant Mudgo and induced the de- fenses in susceptible Kittake associated with a JA/ethylene-dependent pathway. Genes PAL and NPR1 play a considerable role in the regulation of Mudgo expressing resistance to SBPH.