【摘要】 为探究CmDREBa-2基因的抗性功能,了解CmDREBa-2调控菊花参与高、低温防御反应及响应白色锈病的分子机制,构建了过表达载体pBI121-CmDREBa-2,利用农杆菌介导法转化菊花’C029’。对转基因植株进行45℃高温、-4℃低温及接菌处理后,观察表型并分析下游基因表达量。结果表明:PCR检测共获得2个阳性植株,半定量与qRT-PCR表明CmDREBa-2成功高表达。在45℃的高温胁迫处理下,转基因株系存活率显著高于野生型,并显著提高了热胁迫基因CmHsp90、CmHsfA2、活性氧清除基因SOD的表达。低温胁迫处理下,转基因株系OE-5,OE-8的存活率分别为90%和85%,而野生型仅为10%,同时,抗寒相关基因COR413、COR6.6和抗逆基因rd29a的表达较处理前升高,且高于野生型。接种白色锈病病原菌32h时,转基因株系中CmDREBa-2的表达量激增,同时CmDREBa-2的过表达也不同程度地促进了病程相关基因PR1和PDF1.2的表达。其中,PR1基因的表达更为明显。综上,CmDREBa-2可能直接或间接调控胁迫相关基因增强菊花对高温胁迫和低温胁迫的耐受性。CmDREBa-2通过SA介导的抗病信号途径,参与菊花抵抗白色锈病反应。更多还原

【Abstract】 In oorder to verify the function of CmDREBa-2 in Chrysanthemum morifolium and understanding the molecular mechanism of CmDREBa-2 regulating response to high, low temperature and white rust stress, an overexpression vector pBI121-CmDREBa-2 was constructed and transformed into Chrysanthemum morifolium ’C029’ by Agrobacterium-mediated transformation.We carried out phenotype observation and downstream gene expression analysis of transgenic plants under stress treatments at45℃,-4℃ and inoculation. The results showed that we obtained two positive plants by PCR, CmDREBa-2 was highly expressed successfully by semi-quantitative and qRT-PCR. The survival rate of two transgenic lines were significantly higher than wild type under high temperature stress at 45℃. The expression of heat stress genes CmHsp 90, CmHsfA2 and reactive oxygen scavenging gene SOD was significantly increased. Under low temperature stress, the survival rate of two transgenic lines were as high as90% and 85%, respectively, while the wild type was only 10%. Meanwhile, the expressions of COR413, COR6.6 and rd29 A were higher than those of wild plants. The expression of CmDREBa-2 in transgenic line that had been inoculated with white rust pathogen increased sharply at 32 hours. The overexpression of CmDREBa-2 also promoted the expression of PR1 and PDF1.2 in different degrees, the expression of PR1 was more obvious than PDF1.2. In conclusion, CmDREBa-2 in Chrysanthemum may directly or indirectly regulate stress-related genes to enhance its tolerance to high and low temperature stress.CmDREBa-2 participates in Chrysanthemum resistance to white rust through SA-mediated resistance signaling pathway.更多还原