Extended mutualism between termites and gut microbes: nutritional symbionts contribute to nest hygiene
Extended mutualism between termites and gut microbes: nutritional symbionts contribute to nest hygiene
复制标题
DOI：
10.1007/s00114-018-1580-y
复制
发表时间：
2018-10-01
影响因子：
1.8
通讯作者：
Matsuura, Kenji
中科院分区：
文献类型：
--
作者：
Inagaki, Tatsuya;Matsuura, Kenji
所有高等真核生物都与不同的微生物建立了共生关系。最具特点的共生系统之一是白蚁及其肠道微生物的共生系统，它们消化纤维素。近年来，肠道微生物与包括人类在内的宿主微生物之间的多种类型的共生，因其除营养之外的复杂相互作用的各种特征而受到越来越多的关注。在白蚁中，研究人员开始探索肠道共生菌的这种功能，但仅在少数物种中已知对昆虫病原的内部免疫贡献。在这里，我们报告了湿木白蚁Zooteropsis nevendsis的肠道共生体保护巢不受具有致病潜力的共生细菌粘质沙雷氏菌的传播。未驯化的白蚁通过捕食细菌来驱散周围环境中的粘质葡萄球菌，然后细菌通过它们的消化道存活下来，而未驯化的白蚁则不能。肠道共生菌的丧失导致肠道醋酸盐的显著减少，而肠道醋酸盐是白蚁的重要碳源。培养实验表明，醋酸盐在低至12 mM的浓度下对粘质葡萄球菌有明显的抑制作用，说明未脱毒白蚁(40-130 mM)的肠道醋酸酯对粘质葡萄球菌有抑制作用。这些结果表明，肠道共生菌产生的消化衍生物除了对白蚁具有营养作用外，还在巢卫生中发挥着重要作用。我们的研究更好地理解了不同生物体中除营养以外的共生关系的多功能性。
All higher eukaryotes have established symbiotic relationships with diverse microorganisms. One of the most well-characterized symbiotic systems is that of termites and their intestinal microorganisms, which digest cellulose. Recently, diverse types of symbioses between gut microbes and host organisms including humans have received growing attention for various features of their complex interactions beyond nutrition. In termites, researchers are beginning to explore such function of gut symbionts, but only the contribution to internal immunity against entomopathogen is known in a few species. Here, we report that gut symbionts of the dampwood termite Zootermopsis nevadensis protect nests from the spread of the commensal bacterium Serratia marcescens, which has pathogenic potential. Defaunated termites dispersed S. marcescens in the surrounding environment by feeding on the bacteria, which then survived passage through their alimentary tracts, while non-defaunated termites did not. Loss of gut symbionts caused a significant reduction in intestinal acetate, which is an important carbon source for termites. Culture experiments showed that acetate had significant inhibitory effects on S. marcescens at a concentration as low as 12mM, which indicated that the intestinal acetate of non-defaunated termites (40-130mM) was capable of suppressing this bacterium. These results suggest that digestive derivatives produced by intestinal symbionts play an essential role in nest hygiene in addition to their nutritional function for termites. Our study provides a better understanding of the multifunctionality of symbiotic relationships in diverse organisms beyond nutrition.