Genomic characterization of a fructophilic bee symbiont Lactobacillus kunkeei reveals its niche-specific adaptation
Genomic characterization of a fructophilic bee symbiont Lactobacillus kunkeei reveals its niche-specific adaptation
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DOI：
10.1016/j.syapm.2016.09.006
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发表时间：
2016-12-01
影响因子：
3.4
通讯作者：
Endo, Akihito
中科院分区：
文献类型：
--
作者：
Maeno, Shintaro;Tanizawa, Yasuhiro;Endo, Akihito
昆基乳杆菌被归类为唯一的专性嗜果乳酸菌，存在于富含果糖的生态位中，包括蜜蜂的内脏。该菌种与其他乳酸杆菌的区别在于其在葡萄糖下生长不良，在氧气和其他电子受体存在下生长增强，并且通过葡萄糖代谢产生高浓度的乙酸盐。这些特征与系统发育上遥远的果杆菌属相似。在本研究中，利用16个不同菌株对Kunkeei乳杆菌的基因组结构进行了表征，与其他乳杆菌相比，其基因明显更少，基因组更小。功能基因分类显示，L. kunkeei 丢失了专门参与碳水化合物运输和代谢的基因。该物种还缺乏大部分呼吸基因，尽管在氧气存在的情况下生长会增强。 L. kunkeei编码双功能乙醇脱氢酶(ADH)/乙醛脱氢酶(ALDH)蛋白的adhE基因缺乏编码ADH结构域的部分，这是首次在乳酸菌中报道。该缺失导致 ADH 活性缺失，这意味着葡萄糖同化需要电子受体。这些结果清楚地表明，L kunkeei 为了适应富含果糖的环境，经历了特定的还原进化。其还原特性与果杆菌属相似，但与其他基因组较小的乳杆菌（例如格氏乳杆菌和阴道乳杆菌）不同。因此，富含果糖会导致系统发育较远的微生物中环境特异性基因减少。 (C) 2016 爱思唯尔有限公司。版权所有。
Lactobacillus kunkeei is classified as a sole obligate fructophilic lactic acid bacterium that is found in fructose-rich niches, including the guts of honeybees. The species is differentiated from other lactobacilli based on its poor growth with glucose, enhanced growth in the presence of oxygen and other electron acceptors, and production of high concentrations of acetate from the metabolism of glucose. These characteristics are similar to phylogenetically distant Fructobacillus spp. In the present study, the genomic structure of L. kunkeei was characterized by using 16 different strains, and it had significantly less genes and smaller genomes when compared with other lactobacilli. Functional gene classification revealed that L. kunkeei had lost genes specifically involved in carbohydrate transport and metabolism. The species also lacked most of the genes for respiration, although growth was enhanced in the presence of oxygen. The adhE gene of L. kunkeei, encoding a bifunctional alcohol dehydrogenase (ADH)/aldehyde dehydrogenase (ALDH) protein, lacked the part encoding the ADH domain, which is reported here for the first time in lactic acid bacteria. The deletion resulted in the lack of ADH activity, implying a requirement for electron acceptors in glucose assimilation. These results clearly indicated that L kunkeei had undergone a specific reductive evolution in order to adapt to fructose-rich environments. The reduction characteristics were similar to those of Fructobacillus spp., but distinct from other lactobacilli with small genomes, such as Lactobacillus gasseri and Lactobacillus vaginalis. Fructose-richness thus induced an environment-specific gene reduction in phylogenetically distant microorganisms. (C) 2016 Elsevier GmbH. All rights reserved.