Zhang Zhiming, Han Xiaozeng, Pan Fengjuan, Liu Hang, Yan Jun, Zou Wenxiu, McLaughlin Neil B, Hao Xiangxiang
Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, China.
University of Chinese Academy of Sciences, Beijing, China.
Front Microbiol. 2022 Jul 15;13:941170. doi: 10.3389/fmicb.2022.941170. eCollection 2022.
Changes in land use can generate environmental pressures that influence soil biodiversity, and numerous studies have examined the influences of land use on the soil microbial communities. However, little is known about the effects of land use on ecological interactions of soil microbes and their predators. Diazotrophs are key soil microbes that play important functional roles in fixing atmospheric nitrogen. In this study, we investigated the co-association of diazotroph community members and patterns of diazotroph and bacterivore networks under different long-term land uses including cropland, grassland, and bare land. Diazotroph community was characterized by high-throughput sequencing. The results indicated that land use type influenced the dominant genera of diazotrophs and shaped the occurrence of specific indicator diazotroph taxa. Co-existing pattern analysis of diazotrophs and bacterivores indicated that grassland converted from cropland increased the complexity of diazotroph and bacterivore network structure. The number of nodes for diazotrophs and bacterivores was higher in grassland than in cropland and bare land. Random forest analysis revealed that six bacterivore genera , and had significant effects on diazotrophs. Bacterivores were found to have predominantly negative effects in bare land. Different bacterivores had differing effects with respect to driving changes in diazotroph community structure. Structural equation model showed that land use could control diazotroph community composition by altering soil properties and regulating abundance of bacterivores. These findings accordingly enhance our current understanding of mechanisms underlying the influence of land use patterns on diazotrophs from the perspective of soil food webs.
土地利用变化会产生影响土壤生物多样性的环境压力，许多研究已经探讨了土地利用对土壤微生物群落的影响。然而，关于土地利用对土壤微生物及其捕食者生态相互作用的影响却知之甚少。固氮菌是在固定大气氮方面发挥重要功能作用的关键土壤微生物。在本研究中，我们调查了不同长期土地利用方式（包括农田、草地和裸地）下固氮菌群落成员的共关联以及固氮菌和食细菌者网络的模式。通过高通量测序对固氮菌群落进行了表征。结果表明，土地利用类型影响了固氮菌的优势属，并塑造了特定指示固氮菌类群的出现。固氮菌和食细菌者的共存模式分析表明，由农田转变而来的草地增加了固氮菌和食细菌者网络结构的复杂性。草地中固氮菌和食细菌者的节点数量高于农田和裸地。随机森林分析显示，六个食细菌属对固氮菌有显著影响。在裸地中发现食细菌者主要具有负面影响。不同的食细菌者在驱动固氮菌群落结构变化方面具有不同的影响。结构方程模型表明，土地利用可以通过改变土壤性质和调节食细菌者的丰度来控制固氮菌群落组成。因此，这些发现从土壤食物网的角度增强了我们目前对土地利用模式影响固氮菌潜在机制的理解。
