文献类型： 外文期刊

作者： Zheng, Jiaoli ¹ ; Zhang, Dengcheng ³ ; Li, Hua ¹ ; Peng, Chengrong ¹ ; Liu, Yongding ¹ ; Li, Dunhai ¹ ;

作者机构： 1.Chinese Acad Sci, Inst Hydrobiol, CAS Key Lab Algal Biol, Wuhan 430072, Peoples R China

2.Hubei Acad Agr Sci, Hubei Biopesticide Engn Res Ctr, Wuhan 430064, Peoples R China

3.Changjiang Water Resources Protect Inst, Wuhan 430051, Peoples R China

4.South Donghu Rd 7, Wuhan 430072, Hubei, Peoples R China

关键词： Biological crusts; Nitrogen fixation; Cyanobacteria; Moss rhizoids; Desert crust restoration

期刊名称：RHIZOSPHERE （ 影响因子：3.7； 五年影响因子：3.8 ）

ISSN：

年卷期： 2023 年 28 卷

页码：

收录情况： SCI

摘要： Biological soil crusts (biocrusts) are associations of highly specialized communities and topsoil particles and play important ecosystem functions in drylands. Biotic interactions affected the assemblage of biocrust communities and thus their ecological function and adaption abilities. As the dominant organism in the moss crust, moss plays a significant role in modifying the microenvironment and releasing carbon, and this may affect the distribution and metabolic activity of diazotrophic cyanobacteria, which are the dominant diazotrophs. In this study, we examined the contribution of diazotrophic cyanobacteria to nitrogenase activity (NA) by investigating the NA under different light conditions and estimated the proportion of diazotrophic cyanobacteria from total diazo-trophs. We tested the spatial distribution of cyanobacteria using laser confocal fluorescence microscopy (CLSM). Additionally, we separated diazotrophs in moss crust into free-living and moss-associated diazotrophs and compared the NA, nifH gene abundances and their transcripts, and the community composition of free-living and moss-associated diazotrophs. The light-dependent characteristic of NA and dominance of heterocystous cyano-bacteria (accounting for over 90% of total nifH sequences at both the DNA and transcript levels) suggested a significant contribution of heterocystous cyanobacteria to NA. Cyanobacteria were mainly distributed in a few millimeters of subsoil in which abundant cyanobacteria were associated with moss rhizoids. The NA rates of moss-associated diazotrophs were comparable to those of moss crust and approximately 4-8 times higher than those of free-living diazotrophs, indicating the major role of moss-associated diazotrophs in nitrogen fixation. The community composition of moss-associated diazotrophs was similar to that of free-living diazotrophs. Moss -associated diazotrophs have a higher NA per copy of the nifH gene and transcript than free-living diazotrophs, proving the synergistic association of moss and cyanobacteria with NA.