College of Forestry, Guangxi University, Nanning, Guangxi, China.
Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China.
PLoS One. 2021 Oct 14;16(10):e0258610. doi: 10.1371/journal.pone.0258610. eCollection 2021.
Leptocybe invasa Fisher et LaSalle is a global invasive pest that seriously damages Eucalyptus plants. Studying the genetic diversity, genetic structure and introgression hybridization of L. invasa in China is of great significance for clarifying the breeding strategy, future invasion and diffusion trends of L. invasa in China and developing scientific prevention and control measures. Genetic diversity and phylogenetic analyses of 320 L. invasa female adults from 14 geographic populations in China were conducted using 10 polymorphic microsatellite loci (SSRs) and mitochondrial DNA cytochrome oxidase I gene sequences (COIs). (1) The Bayesian phylogenetic tree and haplotype network diagram showed that only haplotype Hap3 existed in L. invasa lineage B in China, while haplotypes Hap1 and Hap2 existed in lineage A, among which haplotype Hap2 was found for the first time. The nucleotide and haplotype diversities of lineage A were higher than those of lineage B. (2) The SSR genetic diversity of the Wuzhou Guangxi, Ganzhou Jiangxi and Panzhihua Sichuan populations was higher than that of the other 11 populations, and the SSR genetic diversity of lineage A was higher than that of lineage B. (3) The AMOVA analysis of mitochondrial COI data showed that 75.55% of the variation was among populations, and 99.86% of the variation was between lineages, while the AMOVA analysis of nuclear SSR data showed that 35.26% of the variation was among populations, and 47.04% of the variation was between lineages. There were obvious differences in the sources of variation between the COI and SSR data. (4) The optimal K value of COI and SSR data in structure analysis was 2, and PCoA analysis also divided the dataset into two obvious categories. The UPMGA phylogenetic tree based on SSR data clustered 14 geographic species into two groups. The results of genetic structure analysis supported the existence of two lineages, A and B, in China. (5) Structural analysis showed that there was obvious introgressive hybridization in Wuzhou Guangxi, Ganzhou Jiangxi, Panzhihua Sichuan and other populations. These results suggest that lineage introgressive hybridization has occurred in the L. invasa population in China. The introgressive hybridization degree and genetic diversity of lineage A are obviously higher than those of lineage B. Lineage introgressive hybridization may be the driving force for further L. invasa invasion and diffusion in China in the future.
入侵红火蚁（Leptocybe invasa Fisher et LaSalle）是一种全球性的入侵害虫，严重危害桉树植物。研究中国入侵红火蚁的遗传多样性、遗传结构和渐渗杂交，对于阐明中国入侵红火蚁的育种策略、未来入侵和扩散趋势以及制定科学的防控措施具有重要意义。本研究采用 10 个多态性微卫星标记（SSR）和线粒体 DNA 细胞色素氧化酶 I 基因序列（COI）对来自中国 14 个地理种群的 320 只入侵红火蚁雌性成虫进行了遗传多样性和系统发育分析。（1）贝叶斯系统发育树和单倍型网络图显示，中国 B 谱系中仅存在单倍型 Hap3，而 A 谱系中存在单倍型 Hap1 和 Hap2，其中 Hap2 为首次发现。A 谱系的核苷酸和单倍型多样性均高于 B 谱系。（2）广西梧州、江西赣州和四川攀枝花种群的 SSR 遗传多样性高于其他 11 个种群，A 谱系的 SSR 遗传多样性高于 B 谱系。（3）线粒体 COI 数据分析的 AMOVA 显示，种群间的变异为 75.55%，谱系间的变异为 99.86%，而核 SSR 数据分析的 AMOVA 显示，种群间的变异为 35.26%，谱系间的变异为 47.04%。COI 和 SSR 数据的 AMOVA 分析显示，变异来源存在明显差异。（4）结构分析中 COI 和 SSR 数据的最佳 K 值为 2，PCoA 分析也将数据集分为两个明显的类别。基于 SSR 数据的 UPMGA 系统发育树将 14 个地理种聚为两类。遗传结构分析结果支持中国存在 A、B 两个谱系。（5）结构分析表明，广西梧州、江西赣州、四川攀枝花等种群存在明显的渐渗杂交。这些结果表明，中国入侵红火蚁种群中存在谱系渐渗杂交。A 谱系的渐渗杂交程度和遗传多样性明显高于 B 谱系。谱系渐渗杂交可能是未来入侵红火蚁在中国进一步入侵和扩散的驱动力。
