核盘菌诱导后向日葵防卫及激素信号传导相关基因差异表达分析

为探讨向日葵抗菌核病分子机制,在已构建的核盘菌诱导向日葵转录组差异表达基因分析基础上,筛选了8个向日葵防卫相关基因和水杨酸（SA）、茉莉（JA）及茉莉酸-乙烯（JA/ET）信号途径中的关键调控基因进行了qRT-PCR诱导表达分析。结果表明,当核盘菌侵染向日葵时,向日葵防御酶基因表达量与对照相比均有显著的变化,超氧化物歧化酶（SOD）、过氧化物酶（POD）和谷胱甘肽-S转移酶（GST）基因在6h表达量分别为对照25.02、22.34和26.25倍;苯丙氨酸解氨酶（PAL）、过氧化氢酶（CAT）和查尔酮合成酶（CHS）基因也上调表达,表达量在12h均达到最高,分别为对照的23.89、24.23和24.89倍;β-1,3-葡聚糖酶（GLU）基因在0～6h下调表达,之后又迅速升高,24h表达量达到最高,为对照的23.66倍;几丁质酶（CHI）基因先是下调表达,12h后开始上调表达,36h时表达量达到最高,为对照的22.13倍。SA、JA及JA/ET信号途径中的调控基因与未经诱导的相比均有明显的转录水平变化,而且JA/ET途径“节”点基因PDF1.2和SA-JA“节”点基因NPR1、MPK4和EDS1也明显上调表达。研究结果表明核盘菌诱导激发了向日葵多种抗病信号传导途径及防御反应,暗示向日葵对核盘菌侵染响应的分子机制受到多基因网络系统的调控。

Analysis of differential expression of genes related to defense and hormone signal transduction in sunflower induced by Sclerotinia sclerotiorum

 In order to explore the molecular mechanism of sunflower resistance to Sclerotinia sclerotiorum, eight defense related genes and the key regulatory genes in SA, JA and JA/ET signal pathway were screened on the basis of the differential expression gene analysis of the transcriptome of Helianthus annuus induced by S. sclerotiorum. qRT-PCR results showed that the genes expression of sunflower defense enzymes had greater increased than that of control when sunflower infected by S.sclerotiorum. The expression of SOD, POD and GST at 6h was 25.02, 22.34 and 26.25 times higher respectively than that of control. The expression of PAL, CAT and CHS at 12h was 23.89, 24.23 and 24.89 times higher respectively than that of control. The expression of GLU and CHI were up-regulated first and then down-regulated, GLU was 23.66 times higher at 24h, and CHI was 22.13 times higher at 36h than that of control. At the same time, the transcriptional levels of regulation genes in signal pathways of sunflower SA, JA and JA/ET had greater variation than that of control. The expression of PDF1.2 gene in JA/ET pathway and NPR1, MPK4 and EDS1 in SA-JA pathway was sharply up-regulated, which showed that many kinds of resistance signal transduction pathways and defense responses of sunflower were induced by S. sclerotiorum, suggesting that the molecular mechanism of sunflower infection on S.sclerotiorum was regulated by multiple gene network system.