Singh Shalini Thakur, Kumar Jitendra, Thomas Asha, Ramamurthy V V, Rajagopal R
Department of Zoology, Gut Biology Laboratory, University of Delhi, Delhi, India.
Environ Entomol. 2013 Aug;42(4):711-6. doi: 10.1603/EN13032.
Mealybug, Phenacoccus solenopsis Tinsley, is a sap-sucking hemipteran insect. It is an agricultural pest that is now widely distributed in India. In this study we report the presence of Rickettsia from P. solenopsis. We constructed a 16S rRNA gene library to study the bacterial diversity associated with this insect and we found that all the clones from the library were only of Candidatus Tremblaya phenacola. This study also highlights that the normal protocol adopted to study the bacterial diversity from environmental sample, by preparation of a 16S rRNA gene library, does not work when the bacterial population is highly skewed in favor of one bacteria (primary endosymbiont in this case). Hence, we used bacterial genus specific polymerase chain reaction primers to test the presence of any of the widely known secondary endosymbionts associated with insects. We tested for the presence of Cardinium, Rickettsia, Wolbachia, and Arsenophonus in P. solenopsis collected from 10 different locations across India. Only Rickettsia was detected from four locations while we were not able to find any other bacteria. We confirmed the presence of these bacteria by localizing Rickettsia and the primary endosmbiont, Candidatus Tremblaya sp. to the bacteriocyte of P. solenopsis using fluorescent in situ hybridization.
粉蚧，即扶桑绵粉蚧（Phenacoccus solenopsis Tinsley），是一种吸食汁液的半翅目昆虫。它是一种农业害虫，目前在印度广泛分布。在本研究中，我们报告了在扶桑绵粉蚧中发现立克次氏体。我们构建了一个16S rRNA基因文库，以研究与这种昆虫相关的细菌多样性，并且我们发现文库中的所有克隆仅属于暂定名为费氏翠蓝菌（Candidatus Tremblaya phenacola）。本研究还强调，当细菌群体高度偏向于一种细菌（在这种情况下是初级内共生菌）时，通过制备16S rRNA基因文库来研究环境样本中细菌多样性所采用的常规方法并不适用。因此，我们使用细菌属特异性聚合酶链反应引物来检测与昆虫相关的任何一种广为人知的次级内共生菌的存在。我们对从印度10个不同地点采集的扶桑绵粉蚧进行了检测，以确定是否存在卡丁氏菌属（Cardinium）、立克次氏体、沃尔巴克氏体（Wolbachia）和嗜菌共生体属（Arsenophonus）。仅在四个地点检测到立克次氏体，而我们未能发现任何其他细菌。我们通过使用荧光原位杂交将立克次氏体和初级内共生菌暂定名为翠蓝菌属（Candidatus Tremblaya sp.）定位到扶桑绵粉蚧的含菌细胞中，从而证实了这些细菌的存在。
