USDA-ARS Temperate Tree Fruit and Vegetable Research Unit, 5230 Konnowac Pass Road, Wapato, WA 98951, USA.
Department of Entomology, Washington State University, 166 FSHN Building, Pullman, WA 99164, USA.
Environ Entomol. 2023 Apr 18;52(2):243-253. doi: 10.1093/ee/nvad015.
Insects often harbor bacterial endosymbionts that provide them with nutritional benefit or with protection against natural enemies, plant defenses, insecticides, and abiotic stresses. Certain endosymbionts may also alter acquisition and transmission of plant pathogens by insect vectors. We identified bacterial endosymbionts from four leafhopper vectors (Hemiptera: Cicadellidae) of 'Candidatus Phytoplasma' species by direct sequencing 16S rDNA and confirmed endosymbiont presence and identity by species-specific conventional PCR. We examined three vectors of Ca. Phytoplasma pruni, causal agent of cherry X-disease [Colladonus geminatus (Van Duzee), Colladonus montanus reductus (Van Duzee), Euscelidius variegatus (Kirschbaum)] - and a vector of Ca. Phytoplasma trifolii, the causal agent of potato purple top disease [Circulifer tenellus (Baker)]. Direct sequencing of 16S identified the two obligate endosymbionts of leafhoppers, 'Ca. Sulcia' and 'Ca. Nasuia', which are known to produce essential amino acids lacking in the leafhoppers' phloem sap diet. About 57% of C. geminatus also harbored endosymbiotic Rickettsia. We identified 'Ca. Yamatotoia cicadellidicola' in Euscelidius variegatus, providing just the second host record for this endosymbiont. Circulifer tenellus harbored the facultative endosymbiont Wolbachia, although the average infection rate was only 13% and all males were Wolbachia-uninfected. A significantly greater percentage of Wolbachia-infected Ci. tenellus adults than uninfected adults carried Ca. P. trifolii, suggesting that Wolbachia may increase this insect's ability to tolerate or acquire this pathogen. Results of our study provide a foundation for continued work on interactions between leafhoppers, bacterial endosymbionts, and phytoplasma.
昆虫通常携带细菌内共生体，这些共生体为它们提供营养益处或保护它们免受天敌、植物防御、杀虫剂和非生物胁迫的侵害。某些内共生体还可能改变昆虫载体对植物病原体的获取和传播。我们通过直接测序 16S rDNA 从四种叶蝉载体（半翅目：叶蝉科）中鉴定出“候选植原体”物种的细菌内共生体，并通过种特异性常规 PCR 确认内共生体的存在和身份。我们检查了三种“候选植原体李树萎缩病”（樱桃 X 病）的叶蝉载体[Colladonus geminatus（Van Duzee），Colladonus montanus reductus（Van Duzee），Euscelidius variegatus（Kirschbaum）]和一种“候选植原体三叶草病”（马铃薯紫顶病）的叶蝉载体[Circulifer tenellus（Baker）]。16S 的直接测序鉴定出两种叶蝉的专性内共生体“Ca. Sulcia”和“Ca. Nasuia”，它们被认为产生叶蝉韧皮部汁液饮食中缺乏的必需氨基酸。约 57%的 C. geminatus 还携带内共生的 Rickettsia。我们在 Euscelidius variegatus 中鉴定出“Ca. Yamatotoia cicadellidicola”，这是该内共生体的第二个宿主记录。Circulifer tenellus 携带兼性内共生菌 Wolbachia，尽管平均感染率仅为 13%，且所有雄性均未感染 Wolbachia。感染 Wolbachia 的 Ci. tenellus 成虫携带 Ca. P. trifolii 的比例明显高于未感染的成虫，这表明 Wolbachia 可能增加了这种昆虫耐受或获取这种病原体的能力。我们的研究结果为进一步研究叶蝉、细菌内共生体和植原体之间的相互作用提供了基础。
