赤子爱胜蚓(Eisenia fetida)肠道细菌群落的肠段分异特征及对饥饿-牛粪培养的响应

doi:10.19741/j.issn.1673-4831.2022.0802

摘要/Abstract

摘要： 通过在初始-饥饿-牛粪连续培养条件下采集赤子爱胜蚓（Eisenia fetida）的前肠、中肠和后肠3个肠段内容物进行细菌16S rRNA基因测序分析，研究蚯蚓肠道细菌群落的肠段分异特征及对饥饿和食物培养的响应。结果显示：细菌群落多样性和组成在相邻肠段间相似，中肠和后肠的相似程度高于前肠和中肠，在相隔肠段间差异较大。厚壁菌门（14%~55%）、放线菌门（16%~39%）和变形菌门（15%~37%）是所有蚯蚓肠段的主要优势菌群。在不同培养状态下的肠道传递（前肠-中肠-后肠）过程中，优势菌门丰度变化趋势不同。前肠、中肠和后肠的核心扩增序列变体（ASVs）主要属于厚壁菌门（35%~48%）、放线菌门（20%~26%）和γ变形菌纲（14%~16%），前肠和后肠具有独有的核心ASVs，分别属于δ变形菌纲（7%）和纤维杆菌门（6%）。从初始状态到饥饿状态，肠道菌群Shannon多样性显著降低（P<0.05），Sobs丰富度降低，但未达显著水平（P>0.05）；肠道中α/δ变形菌纲和放线菌门等类群相对丰度显著降低（P<0.05），γ变形菌纲、厚壁菌门和拟杆菌门相对丰度显著提高（P<0.05）。从饥饿状态到牛粪培养状态，肠道菌群Shannon多样性和Sobs丰富度进一步显著降低（P<0.05）；肠道中δ变形菌纲和厚壁菌门等类群相对丰度显著提高（P<0.05），γ/α变形菌纲和放线菌门等类群相对丰度显著降低（P<0.05），拟杆菌门相对丰度无显著变化（P>0.05）。聚类分析结果表明，蚯蚓肠道菌群具有一定的稳定性。结合菌群结构和差异ASVs分析结果表明，饥饿-牛粪处理显著改变了蚯蚓肠道细菌群落，其中，饥饿处理主要改变菌群丰度，而牛粪处理同时改变菌群丰度和组成。综上所述，蚯蚓肠道微生物群落存在明显的肠段分异，且在一定程度上具有抵抗干扰以保持稳态的能力。蚯蚓肠道微生物群落对饥饿和食物均有明显响应，其中对食物的响应程度更强。

关键词: 蚯蚓, 肠道微生物, 肠段, 饥饿, 牛粪, 细菌群落

Abstract: The intestinal contents from the foregut, midgut and hindgut of earthworms (Eisenia fetida) were collected under initial-starvation-cow dung continuous culture conditions, and the 16S rRNA gene amplicon sequencing was consequently conducted to investigate the segmental differentiation of gut bacterial communities and their responses to starvation and feeding. The results show that the bacterial community diversity and composition were similar between adjacent intestinal segments; the community similarity between midgut and hindgut segments was higher than that between foregut and midgut segments, and the differences were greater between separated gut segments (foregut vs. hindgut). The dominant bacterial phyla across all earthworm gut segments were Firmicutes (14%-55%), Actinobacteria (16%-39%), and Proteobacteria (15%-37%). The changing trends of dominant bacteria along with the gut transmission (foregut-midgut-hindgut) were inconsistent under different culture conditions. The core ASVs of the foregut, midgut and hindgut segments mainly belonged to Firmicutes (35%-48%), Actinobacteria (20%-26%), and gamma-Proteobacteria (14%-16%). The foregut and hindgut segments had unique core ASVs, which mainly belonged to delta-Proteobacteria (7%) and Fibrobacteres (6%), respectively. From initial state to starvation state, the Shannon diversity index of gut microbiota decreased significantly (P<0.05), while the Sobs richness index decreased insignificantly (P>0.05); the relative abundances of alpha-/delta-Proteobacteria and Actinobacteria decreased significantly (P<0.05), while that of gamma-Proteobacteria, Firmicutes and Bacteroidetes increased significantly (P<0.05). From starvation state to cow dung culture state, the Shannon diversity index and Sobs richness index further significantly decreased (P<0.05). The relative abundance of delta-Proteobacteria and Firmicutes increased significantly (P<0.05), while that of gamma-/alpha-Proteobacteria and Actinobacteria significantly decreased (P<0.05), and that of Bacteroidetes had no significant change (P>0.05). The cluster analysis results show that the gut microbiota of earthworms was stable to a certain extent. Combining the results of bacterial community structure and differential ASVs analysis, it was shown that starvation-cow dung culture changed the gut bacterial community of earthworms, with starvation mainly changing the bacterial community abundance, while cow dung culture changing both the bacterial community abundance and composition. Taken together, the intestinal microbial community of earthworms had obvious intestinal segment differentiation, which can resist disturbance and maintain stability to a certain extent. The earthworm gut microbial community displayed a clear response to both starvation and feeding, with a stronger response to feeding.

Key words: earthworm, gut microorganism, gut segment, starvation, cow dung, bacterial community

中图分类号:

S154.1

王宁, 刘洋, 代威, 姚丹丹, 王辉. 赤子爱胜蚓(Eisenia fetida)肠道细菌群落的肠段分异特征及对饥饿-牛粪培养的响应[J]. 生态与农村环境学报, 2023, 39(7): 954-962.

WANG Ning, LIU Yang, DAI Wei, YAO Dan-dan, WANG Hui. Intestinal Segmental Differentiation Characteristics of Earthworm (Eisenia fetida) Gut Bacterial Communities and Their Responses to Starvation-cow Dung Culture[J]. Journal of Ecology and Rural Environment, 2023, 39(7): 954-962.

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