晒烟品种塘蓬烟抗白粉病基因的等位性测定和序列分析

Allelic test and sequence analysis of the powdery mildew resistance genes of sun-cured tobacco variety Tangpeng

【背景和目的】广东连江县晒烟品种“塘蓬烟”是我国特有的烟草隐性遗传白粉病抗性种质资源,但到目前为止对其抗病机制未见深入报道。【方法】利用塘蓬烟花粉与抗白粉病烟草品种Kutsaga E1及感病品种K326杂交进行抗病基因的等位性检测;利用等位基因分子标记检测塘蓬烟中感白粉病基因NtMLO1/2的突变情况;利用PCR克隆技术获得塘蓬烟NtMLO1/2基因的cDNA和gDNA序列信息,明确基因突变类型。【结果】(1)根据等位性测验结果推断塘蓬烟白粉病抗性由NtMLO1/2隐性突变基因控制。(2)等位基因分子标记检测和PCR克隆测序结果发现塘蓬烟NtMLO2基因的转录本发生外显子重复突变,形成一个新的可变剪接变异体。【结论】本研究从分子水平阐述了地方烟草品种塘蓬烟的抗白粉病机制,其结果不仅丰富了烟草抗白粉病基因资源信息,而且为日后抗性基因资源的深入研究和合理利用提供了参考依据。

[Background]Tangpeng,a sun-cured tobacco variety in Lianjiang,is a unique recessive powdery mildew resistant germplasm resource of tobacco in China.However,there have been few reports on the mechanism of disease resistance.[Methods]Tangpeng was crossed with the powdery mildew resistant variety kutsaga E1 and the susceptible variety K326 to test the allelism of the resistance genes.The mutations of powdery mildew susceptibility genes NtMLO1 and NtMLO2 of Tangpeng were detected by allele-specific amplification.The NtMLO1 and NtMLO2 genes of Tangpeng were amplified by polymerase chain reaction(PCR)and sequenced after T-A cloning for the identification of mutation types.[Results]1)In an allelic test,it was preliminarily inferred that the Tangpeng’s resistance to powdery mildew was controlled by the recessive mutant genes of NtMLO1 and NtMLO2;2)The results of allele molecular marker detection and PCR cloning and sequencing showed that an exon duplication mutation occurred in the NtMLO2 transcripts from Tangpeng,resulting in a new alternative splicing variant.[Conclusion]In this study,the mechanism of powdery mildew resistance of Tangpeng,a local tobacco variety,was elucidated at the molecular level,which not only enriched the information on the tobacco gene resources resistant to powdery mildew,but also provided a reference for the further research and rational utilization of the resistance gene resource.