不同菌核病抗性甘蓝型油菜中BnVRN2基因的克隆与表达

Cloning and transcription of Bn VRN2 gene from Sclerotinia resistant and susceptible lines of Brassica napus

为了探索甘蓝型油菜开花期与菌核病抗性的关系,以甘蓝型油菜M083(抗病、晚花)和888-5(感病、早花)品系为材料对开花相关基因Bn VRN2进行克隆;对2个品系中Bn VRN2序列差异及核盘菌诱导前后的表达水平差异进行分析。结果显示,在甘蓝型油菜中Bn VRN2基因存在2个拷贝,分别命名为Bn VRN2a(位于A8染色体)和Bn VRN2b(位于C8染色体),Bn VRN2a在抗/感品系中存在序列差异,而Bn VRN2b则不存在。Bn VRN2a在M083和888-5中的CDS全长分别为1 278bp、1 284bp,分别编码425、427个氨基酸残基;2个品系中Bn VRN2a基因的CDS序列存在着12个SNP变异位点以及一个6bp的插入/缺失片段;核苷酸序列的差异导致了蛋白质序列7个氨基酸的改变,且第100位氨基酸变异存在于两者的锌指结构域中。Bn VRN2a基因在菌核病诱导前后,在M083和888-5中的表达水平都存在差异,初步推测该基因在甘蓝型油菜开花相关途径和菌核病防御反应中都起到一定的作用。

To better understand the relationship between flowering time and Sclerotinia sclertiorum resistance of rapeseed,related gene Bn VRN2 was cloned and explored in resistant and suspective B. napus bred lines M083（ resistant,bloomed late） and 888- 5（ susceptible,bloomed earlier）. Expression levels in both M083 and 888- 5 after S. sclertiorum inoculation were also tested. Results showed that Bn VRN2 gene had 2 copies in B. napus,respectively named Bn VRN2a（ located on A8 chromosome） and Bn VRN2b（ located on C8 chromosome）. Bn VRN2 a sequences were found different between the 2 lines（ which named Bn VRN2a- M and Bn VRN2a- 8 respectively）,while Bn VRN2 b sequences were the same. The size of coding sequence（ CDS） of Bn VRN2 a was 1 278 bp（ encoding 425 amino acids） in M083 and 1 284 bp（ encoding 427 amino acids） in 888- 5. 12 SNP mutations and 6 bp insertion / deletion fragments were found among the 2 lines. Nucleotide sequence variation resulted in 7 amino acid changes,and the 100 th amino acid variation existed in zinc finger motifs of Bn VRN2 a. Bn VRN2 a expression in M083 and 888- 5 were different before and after S. sclertiorum inoculation. Results suggested that Bn VRN2 a was not only involved in flowering related pathway,but also participated in plant resistance against S. sclertiorum.