辣椒疫病抗病性分子鉴定技术研究

Study on Molecular Identification Technology of Pepper Resistance to Phytophthora Blight

根据辣椒疫霉菌(Phytophora capsiciLeonian)核糖体(Ribosome)基因及其转录间隔区(Internal transcribed spacer,ITS)序列设计两对引物,确定其中一对用于辣椒疫病抗病性的分子检测。用不同的辣椒品种进行接种,并设置不同的采样时间和部位,提取辣椒基因组和侵染到植株中疫霉菌的DNA,扩增后者的rDNA及其ITS序列。试验表明,在接种后24 h和48 h不能从辣椒叶片中检测到疫霉菌,而接种后24 h可从感病辣椒品种茎中检测到。接种后48 h均能从感病、抗病辣椒品种的茎中检测到疫霉菌,并且感病品种中疫霉菌的DNA的扩增量为100 ng,抗病品种中的为20 ng,前者是后者的5倍;辣椒品种N3中疫霉菌的DNA扩增量为77 ng,介于感病和抗病品种之间,更接近前者,因此该品种是感病的。

Primers were designed according to Phytophora capsici sequence of ribosomal gene and its internal transcribed spacer（ITS）.A pair of them was used for molecular detection of pepper resistance to P.capsici.Three pepper cultivars were inoculated by P.capsici.The genomic DNA of pepper and P.capsici in inoculated plants were extracted together from different plant tissues at 24 and 48 hours post-inoculation.The DNA of P.capsici was amplified by polymerase chain reaction（PCR）.Nothing was detected in all leaves,whereas P.capsici can be detected in stems of susceptible pepper cultivar at 24 hours post-inoculation and all pepper cultivars at 48 hours post-inoculation.The DNA amplification of P.capsici in the susceptible cultivar is 100ng which is 5 times of the one in resistant cultivar.The DNA amplification of P.capsici in the cv.N3 is 77ng between the one in the resistant cultivar and susceptible cultivar,which is close to the susceptible one.Therefore the cv.N3 is susceptible to P.capsici.