根肿菌侵染油菜抗感病品种早期防御酶活性及转录组分析

Analysis of defense enzyme activities and transcriptome of clubroot-resistant and-susceptible in canola to clubroot pathogen Plasmodiophora brassicae during early infection

为探究抗病和感病2种油菜品种抗病机理及基因表达差异,通过水培法观测油菜抗病品种6M80和感病品种中双11号接种根肿菌后的根毛侵染,利用紫外分光光度法和RNA-Seq技术分别测定根部防御酶的活性及所有的转录序列。结果表明,接菌后3~15 d油菜品种6M80的根毛侵染率显著低于油菜品种中双11号,其根内过氧化氢酶(catalase,CAT)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)活性在接菌后第12天达到峰值,且显著高于油菜品种中双11号,分别为382.50、2 044.44和3 342.22 U·g^(-1)·min^(-1)。与未接菌相比,油菜抗病品种6M80和感病品种中双11号接菌后第3、6、9、12天共分别存在6 607个和2 499个差异表达基因(differentially expressed genes,DEGs)。功能注释结果表明,大多数DEGs参与信号传导、生物代谢、转录过程及防御机制。油菜品种6M80和中双11号中分别存在82个和53个防御酶相关的DEGs。研究表明,根肿菌侵染油菜抗病品种早期防御酶活性较高,其相关差异表达基因参与木质素生物合成和过氧化氢代谢,并在抗根肿病过程中发挥着重要作用。

For the purpose to analyze resistance mechanism and differentially expressed genes（DEGs）of clubroot-resistant（6 M80） and-susceptible（Zhongshuang 11, ZS11） of canola（Brassica napus） by Plasmodiophora brassicae, the incidence of root-hair infected in two varieties was measured after inoculation under solution culture conditions. Furthermore, the activities of defensive enzymes and a global transcriptome profiling of the roots of clubroot-resistant（6 M80） and-susceptible（ZS11） of Canola were performed, respectively, by ultraviolet spectrophotometry and RNA-Seq. The results showed the infected rate on root-hair of 6M80 by P. brassicae was significantly lower than those of ZS11 at 3-15 d after inoculation. The activities of catalase（CAT）, superoxide dismutase（SOD） and peroxidase（POD）in 6M80 reached the peak at 12 d after inoculation and were significantly higher than ZS11, and they were 382.50, 2 044.44, 3 342.22 U · g（-1）· min（-1）, respectively. Compared with uninoculated treatment, the totalof DEGs at three, six, nine and 12 days after inoculated were 6 607 and 2 499 in 6M80 and ZS11. Functional annotation showed that most of the DEGs were involved in signal transduction, metabolism, transportation, and defense. Cultivars 6M80 and ZS11 of canola had 82 and 53 DEGs of defense-related enzymes respectively. The above studies suggested that defensive enzyme activity was higher, and DEGs of defense-related enzymes was involved in lignin biosynthesis and hydrogen peroxide metabolism in clubroot-resistance of canola by P. brassicae during early infection. These metabolism pathways played much important role in clubroot resistance.