Defensive Bacteriome Symbiont with a Drastically Reduced Genome
Defensive Bacteriome Symbiont with a Drastically Reduced Genome
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DOI：
10.1016/j.cub.2013.06.027
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发表时间：
2013-08-05
期刊：
影响因子：
9.2
通讯作者：
Fukatsu, Takema
中科院分区：
文献类型：
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作者：
Nakabachi, Atsushi;Ueoka, Reiko;Fukatsu, Takema
不同的昆虫物种都有共生细菌，它们在提供营养和防御天敌等方面发挥着重要作用[1-6]。而营养共生往往是不可或缺的双方的合作伙伴，防御共生往往是一个兼性的性质[1-12]。柑橘木虱Diaphorina citri是一种臭名昭著的农业害虫，传播Liberibacter spp。（Alphaproteobacteria），引起毁灭性的柑橘绿化病或黄龙病[13，14]。在一个叫做细菌组的共生器官中，D.柑橘含有两种不同的细胞内共生体：一种假定的营养提供者Carsonella_DC（γ-变形菌门），和一种功能未知的未命名的β-变形菌[15]，我们建议将其命名为“Armatura Profftella armatura”。“在这里，我们报告说，Profftella是一种防御性共生体，可能具有一种绝对的性质，具有极其精简的基因组。Profftella和Carsonella_DC的基因组分别为464，857 bp和174，014 bp，表明它们与宿主的古老和相互不可或缺的联系。引人注目的是，15%的小Profftella基因组编码水平获得的基因合成一种新的聚酮毒素。对该毒素进行了提取、鉴定和结构表征，并命名为黄递素。Profftella及其黄递素生物合成基因在世界D. Citri populations.
Diverse insect species harbor symbiotic bacteria, which play important roles such as provisioning nutrients and providing defense against natural enemies [1-6]. Whereas nutritional symbioses are often indispensable for both partners, defensive symbioses tend to be of a facultative nature [1-12]. The Asian citrus psyllid Diaphorina citri is a notorious agricultural pest that transmits Liberibacter spp. (Alphaproteobacteria), causing the devastating citrus greening disease or Huanglongbing [13, 14]. In a symbiotic organ called the bacteriome, D. citri harbors two distinct intracellular symbionts: a putative nutrition provider, Carsonella_DC (Gammaproteobacteria), and an unnamed betaproteobacterium with unknown function [15], for which we propose the name "Candidatus Profftella armatura." Here we report that Profftella is a defensive symbiont presumably of an obligate nature with an extremely streamlined genome. The genomes of Profftella and Carsonella_DC were drastically reduced to 464,857 bp and 174,014 bp, respectively, suggesting their ancient and mutually indispensible association with the host. Strikingly, 15% of the small Profftella genome encoded horizontally acquired genes for synthesizing a novel polyketide toxin. The toxin was extracted, pharmacologically and structurally characterized, and designated diaphorin. The presence of Profftella and its diaphorin-biosynthetic genes was perfectly conserved in the world's D. citri populations.