广东省稻区越冬代大螟种群动态监测及遗传多态性差异分析

Dynamics monitoring and analysis of genetic polymorphism of overwintering generation of Asiatic pink stem borer Sesamia inferens populations in Guangdong rice area

为制订行之有效的大螟Sesamia inferens区域综合防治策略,2018—2022年对广东省珠三角稻区、粤东稻区、粤西稻区和粤北稻区9个市的越冬代大螟进行调查和采样,于室内对样品进行DNA提取、扩增和序列分析,采用线粒体COI、COII等分子标记技术对越冬代大螟进行单倍型分析、系统发育树分析和遗传多态性分析。结果显示,2018—2022年广东省稻区越冬代大螟虫量很高,粤东稻区和珠三角稻区平均虫量均大于大发生量。在越冬代大螟幼虫线粒体COI基因样本中共检测出20个单倍型,89个多态位点,总群体单倍型多样度为0.840,固定系数为0.473,基因流为0.56,总群体的Tajima’s D值为-1.965,Fu’s Fs值为-2.454。在越冬代大螟幼虫线粒体COII基因样本中共检测出19个单倍型,372个多态位点,总群体单倍型多样度为0.790,固定系数为0.816,基因流为0.11,总群体的Tajima’s D值为3.224,Fu’s Fs值为54.260。表明广东省不同稻区越冬代大螟种群间的遗传多态性较高,亲缘关系近,但存在着遗传分化现象,种群间遗传分化现象主要原因为遗传漂变,种群未经历明显扩张。

In order to formulate effective regional comprehensive control strategies for overwintering generation of Asiatic pink stem borer Sesamia inferens,surveys and sampling were conducted in nine cities in the Pearl River Delta rice area,Guangdong east rice area,Guangdong west rice area,and Guangdong north rice area from 2018 to 2022.DNA extraction,amplification,and sequence analysis were performed on samples in the laboratory,utilizing molecular markers such as mitochondrial COI and COⅡfor single-nucleotide polymorphism(SNP)analysis,phylogenetic tree analysis,and genetic diversity analysis on overwintering generation of S.inferens larvae.The results showed that the population density of overwintering generation of S.inferens larvae in the rice-growing regions of Guangdong Province was very high,with an average of more than 7500 heads/hm2 in the East and Pearl River Delta rice areas.A total of 20 SNPs and 89 polymorphic loci were identified in the mitochondrial COI gene samples of overwintering generation of S.inferens larvae,with an overall population diversity of 0.840,a fixation index of 0.473,and gene flow value of 0.56.The Tajima’s D value for the total population was-1.965,and the Fu’s Fs value was-2.454.In the mitochondrial COⅡgene samples of overwintering generation of S.inferens larvae,a total of 19 SNPs and 372 polymorphic loci were identified,with an overall population diversity of 0.790,a fixation index of 0.816,and gene flow value of 0.11.The Tajima’s D value for the total population was 3.224,and the Fu’s Fs value was 54.260.These results indicated that the genetic polymorphisms of overwintering generation of S.inferens populations in Guangdong were relatively high,and the relatedness among populations was relatively close.However,there were genetic differentiations among these populations,which were mainly due to genetic drift.The population did not experience significant expansion.