Das Biswadeep, Satapathy Truptimayee, Kar Santanu K, Hazra Rupenangshu K
Department of Medical Entomology, Regional Medical Research Centre, Bhubaneswar, Odisha, India.
PLoS One. 2014 Apr 8;9(4):e94094. doi: 10.1371/journal.pone.0094094. eCollection 2014.
Aedes albopictus has recently been implicated as a major vector in the emergence of dengue and chikungunya in several parts of India, like Orissa, which is gradually gaining endemicity for arboviral diseases. Ae. albopictus is further known to be naturally infected with Wolbachia (maternally inherited bacterium), which causes cytoplasmic incompatibility (CI) in mosquitoes leading to sperm-egg incompatibility inducing the death of embryo. Knowledge of genetic diversity of Ae. albopictus, along with revealing the type of Wolbachia infection in Ae. albopictus is important to explore the genetic and biological characteristics of Ae. albopictus, prior to exploring the uses of CI-based vector control strategies. In this study, we assessed the population genetic structure and the pattern of Wolbachia infection in Ae. albopictus mosquitoes of Orissa.
Ae. albopictus mosquitoes were collected from 15 districts representing the four physiographical regions of Orissa from 2010-2012, analyzed for genetic variability at seven microsatellite loci and genotyped for Wolbachia strain detection using wsp gene primers. Most microsatellite markers were successfully amplified and were polymorphic, showing moderate genetic structure among all geographic populations (FST = 0.088). Genetic diversity was high (FST = 0.168) in Coastal Plains populations when compared with other populations, which was also evident from cluster analyses that showed most Coastal Plains populations consisted of a separate genetic cluster. Genotyping analyses revealed that Wolbachia-infected Ae. albopictus field populations of Orissa were mostly superinfected with wAlbA and wAlbB strains. Wolbachia superinfection was more pronounced in the Coastal Plain populations.
High genetic structure and Wolbachia superinfection, observed in the Coastal Plain populations of Orissa suggested it to be genetically and biologically more unique than other populations, and hence could influence their vectorial attributes. Such high genetic diversity observed among Coastal Plains populations could be attributed to multiple introductions of Ae. albopictus in this region.
白纹伊蚊最近被认为是印度几个地区（如奥里萨邦）登革热和基孔肯雅热出现的主要传播媒介，该地区虫媒病毒病的地方流行性正在逐渐增加。此外，已知白纹伊蚊自然感染沃尔巴克氏体（一种母系遗传细菌），这种细菌会导致蚊子出现细胞质不亲和（CI），导致精卵不亲和，从而致使胚胎死亡。了解白纹伊蚊的遗传多样性以及揭示其体内沃尔巴克氏体感染类型，对于在探索基于细胞质不亲和的病媒控制策略的用途之前，探究白纹伊蚊的遗传和生物学特性至关重要。在本研究中，我们评估了奥里萨邦白纹伊蚊的种群遗传结构和沃尔巴克氏体感染模式。
2010年至2012年期间，从代表奥里萨邦四个自然地理区域的15个地区收集白纹伊蚊，分析其在七个微卫星位点的遗传变异性，并使用 wsp 基因引物对沃尔巴克氏体菌株检测进行基因分型。大多数微卫星标记成功扩增且具有多态性，显示出所有地理种群之间存在中等程度的遗传结构（FST = 0.088）。与其他种群相比，沿海平原种群的遗传多样性较高（FST = 0.168），聚类分析也表明这一点，即大多数沿海平原种群构成一个单独的遗传簇。基因分型分析显示，奥里萨邦受沃尔巴克氏体感染的白纹伊蚊野外种群大多同时感染 wAlbA 和 wAlbB 菌株。沃尔巴克氏体双重感染在沿海平原种群中更为明显。
在奥里萨邦沿海平原种群中观察到的高遗传结构和沃尔巴克氏体双重感染表明该种群在遗传和生物学上比其他种群更为独特，因此可能会影响其病媒属性。在沿海平原种群中观察到的如此高的遗传多样性可能归因于该地区白纹伊蚊的多次引入。
