东洞庭湖洲滩水体环境对钉螺体内微生物群落的影响

目的观察东洞庭湖钉螺自然消亡洲滩水体环境对钉螺体内微生物群落的影响,探索钉螺自然消亡与其体内微生物的关系。方法采用笼养观察法,将采集的实验钉螺置于实验螺笼内,分别投放至东洞庭湖有钉螺自然消亡的钱粮湖洲滩(钱粮湖区)和持续有钉螺孳生的君山公园洲滩(君山公园区)水体中,30 d后回收钉螺并观察钉螺死活。对投放前、投放现场后回收钉螺体内的真菌和细菌体进行DNA测序,并进行物种多样性和丰度等分析。结果投放钱粮湖区和君山公园区水淹30d后的钉螺存活率分别为28.0%(70/250)和64.8%(162/250)(χ^2=81.365,P<0.01)。多样性分析显示,投放在钱粮湖区的钉螺体内真菌物种总数和细菌物种多样性指数均高于投放前,且真菌和细菌群落结构有显著差异;生物丰度较其他组有差异的生物群中包括对钉螺有害的黄杆菌科(Flavobacteriaceae)。结论东洞庭湖钉螺自然消亡洲滩的水体环境对钉螺体内微生物群落构成一定影响,但水环境导致的钉螺体内微生物谱变化是否为引起钉螺自然消亡的原因则仍待进一步研究。

Impact of water body environments on the microbial community of Oncomelania hupensis snails in marshlands around the eastern Dongting Lake

Objective To evaluate the effects of water body environments on the microbial community of Oncomelania hupensis snails in marshlands of the eastern Dongting Lake where natural extinction of O.hupensis snails are found,so as to explore the correlation between the natural extinction of O.hupensis snails and the microbial community in snails.Methods Snails were caged water bodies in the Qianliang Lake marshland(Qianliang Lake regions)where natural extinction of snails was found and in the Junshan Park marshland(Junshan Park regions)in the eastern Dongting Lake for 30 days,and then all snails were collected and identified for survival or death.DNA sequencing of the fungi and bacteria was performed in snails before and after immersion in waters,and the biodiversity and abundance were analyzed.Results The survival rates of O.hupensis snails were 28.0%(70/250)and 64.8%(162/250)in Qianliang Lake regions and Junshan Park regions 30 days after immersion in waters,respectively(χ^2=81.365,P<0.01).The number of the fungal community and the biodiversity of the bacterial community were both greater in snails caged in Qianliang Lake regions post-immersion than pre-immersion,and there was a significant difference in the structure of the fungal and bacterial communities.The microbial community with a significant difference included Flavobacteriaceae,whieh was harmful to O.hupensis snails.Conclusion The water body environment affects the composition of the microbial community in O.hupensis snails in marshlands with natural snail distinction around the eastern Dongting Lake;however,further studies are required to investigate whether the natural distinction of snails is caused by water body environments-induced changes of the microbial spectrum in O.hupensis snails.