BACKGROUND High-altitude ecosystems are extreme environments that generate specific physiological, morphological, and behavioral adaptations in ectotherms. The shifts in gut microbiota of the ectothermic hosts as an adaptation to environmental changes are still largely unknown. We investigated the food ingested and the bacterial, fungal, and protistan communities in feces of the lizard Sceloporus grammicus inhabiting an altitudinal range using metabarcoding approaches. RESULTS The bacterial phyla Bacteroidetes and Firmicutes, and the genera Bacteroides and Parabacteroides dominated the core fecal bacteriome, while Zygomycota and Ascomycota, and the species Basidiobolus ranarum and Basidiobolus magnus dominated the core fecal mycobiome. The diet of S. grammicus included 29 invertebrate families belonging to Arachnida, Chilopoda, and Insecta. The diversity and abundance of its diet decreased sharply at high altitudes, while the abundance of plant material and Agaricomycetes was significantly higher at the highest site. The composition of the fecal microbiota of S. grammicus was different at the three altitudes, but not between females and males. Dietary restriction in S. grammicus at 4150 m might explain the high fecal abundance of Akkermansia and Oscillopira, bacteria characteristic of long fasting periods, while low temperature favored B. magnus. A high proportion of bacterial functions were digestive in S. grammicus at 2600 and 3100, while metabolism of aminoacids, vitamins, and key intermediates of metabolic pathways were higher at 4150 m. Different assemblages of fungal species in the lizard reflect differences in the environments at different elevations. Pathogens were more prevalent at high elevations than at the low ones. CONCLUSIONS Limiting food resources at high elevations might oblige S. grammicus to exploit other food resources and its intestinal microbiota have degradative and detoxifying capacities. Sceloporus grammicus might have acquired B. ranarum from the insects infected by the fungus, but its commensal relationship might be established by the quitinolytic capacities of B. ranarum. The mycobiome participate mainly in digestive and degradative functions while the bacteriome in digestive and metabolic functions.

中文翻译：

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饮食对豆科蜥蜴Sceloporus grammicus（Wiegmann，1828）在不同高度的肠道菌群的影响。

背景技术高海拔生态系统是极端环境，会在等温线中产生特定的生理，形态和行为适应。对于环境变化的适应性，吸热宿主肠道菌群的变化仍然未知。我们使用metabarcoding方法调查了居住在海拔高度范围内的蜥蜴Seloporus grammicus粪便中的食物摄入以及细菌，真菌和protistan群落。结果细菌菌门菌和纤毛虫，以及细菌杆菌和副细菌属占主导的粪便细菌群，而合子菌和子囊菌，以及Basidiobolus ranarum和Basidiobolus magnus菌种占主导的粪便菌群。语法链球菌的饮食包括29个无脊椎动物科，分别属于蛛形纲，千足纲和昆虫纲。在高海拔地区，其饮食的多样性和丰度急剧下降，而最高部位的植物材料和姬松茸的丰度则明显更高。在三个高度上，革兰氏链球菌的粪便微生物群的组成是不同的，但雌雄之间没有差异。语法链球菌在4150 m处的饮食限制可能解释了Akkermansia和Oscillopira的高粪便含量，这是禁食期长的细菌特征，而低温则有利于B. magnus。在2600和3100时，语法链霉菌消化的细菌功能比例很高，而在4150 m处，氨基酸，维生素和代谢途径的关键中间体的代谢较高。蜥蜴中不同种类的真菌物种反映了不同海拔环境的差异。高海拔地区的病原体比低海拔地区的病原体更为普遍。结论在高海拔地区限制食物资源可能会迫使语法链球菌开发其他食物资源，其肠道菌群具有降解和解毒的能力。革螺假单胞菌可能是从真菌感染的昆虫中获得了枝状芽孢杆菌，但其共鸣关系可能是由枝状芽孢杆菌的分解蛋白酶能力建立的。细菌组主要参与消化和降解功能，而细菌组主要参与消化和代谢功能。由真菌感染的昆虫产生的雷纳姆菌，但其共鸣关系可能是由雷纳特菌的分解蛋白酶能力建立的。细菌组主要参与消化和降解功能，而细菌组主要参与消化和代谢功能。由真菌感染的昆虫产生的雷纳姆菌，但其共鸣关系可能是由雷纳特菌的分解蛋白酶能力建立的。细菌组主要参与消化和降解功能，而细菌组主要参与消化和代谢功能。