内蒙古典型草原和荒漠草原土壤固碳微生物组成及其固碳途径差异分析

doi:10.11686/cyxb2024476

草业学报 ›› 2025, Vol. 34 ›› Issue (8): 123-131.DOI: 10.11686/cyxb2024476

• 研究论文 • 上一篇

内蒙古典型草原和荒漠草原土壤固碳微生物组成及其固碳途径差异分析

彭浩¹^,²(), 董宝珠³, 马利娟⁴, 于晓东³, 张艺帆¹, 李晓芳¹

^1.内蒙古财经大学资源与环境经济学院，内蒙古呼和浩特 010070
^2.内蒙古财经大学祖国北疆资源利用与环境保护协调发展院士专家工作站，内蒙古呼和浩特 010070
^3.内蒙古大学生命科学学院，内蒙古呼和浩特 010020
^4.内蒙古农业大学资源与环境学院，内蒙古呼和浩特 010040

收稿日期:2024-11-26 修回日期:2024-12-30 出版日期:2025-08-20 发布日期:2025-06-16
通讯作者: 彭浩
作者简介:彭浩（1976-），女，湖南湘潭人，副教授，博士。E-mail： pengden@163.com
彭浩（1976-），女，湖南湘潭人，副教授，博士。E-mail： pengden@163.com
基金资助:
国家自然科学基金(3206140110);教育部人文社会科学研究规划基金(20YJA790058);内蒙古自治区直属高校基本科研业务费项目(NCYWT25063)

Composition and carbon-fixation pathways of carbon-fixing microorganisms in soils of a typical steppe and desert steppe in Inner Mongolia

Hao PENG¹^,²(), Bao-zhu DONG³, Li-juan MA⁴, Xiao-dong YU³, Yi-fan ZHANG¹, Xiao-fang LI¹

^1.College of Resources and Environmental Economics，Inner Mongolia University of Finance and Economics，Hohhot 010070，China
^2.Resource Utilization and Environmental Protection Coordinated Development Academician Expert Workstation in the North of China，Inner Mongolia University of Finance and Economics，Hohhot 010070，China
^3.School of Life Sciences，Inner Mongolia University，Hohhot 010020，China
^4.College of Resources and Environmental Sciences，Inner Mongolia Agricultural University，Hohhot 010040，China

Received:2024-11-26 Revised:2024-12-30 Online:2025-08-20 Published:2025-06-16
Contact: Hao PENG

摘要/Abstract

摘要：

土壤中自养微生物可以同化大气CO₂并将碳固定于土壤中。与湿润区生态系统相比，干旱区土壤微生物固碳的相对贡献更大。但当前碳评估模型主要研究植物固碳，往往忽略了土壤微生物的固碳代谢，这不利于全面了解干旱区生态系统碳汇特征。本研究以内蒙古典型草原和荒漠草原的土壤微生物为对象，剖析了土壤中固碳微生物群落组成和固碳途径的差异。研究结果显示：1）两种类型草原土壤中共有14个固碳微生物类群（纲），其中酸微菌纲、γ‐变形菌纲和绿弯菌纲在荒漠草原土壤中的丰度显著高于典型草原；2）还原柠檬酸循环（rTCA）和3-羟基丙酸循环（3-HP）相对丰度在荒漠草原土壤中显著高于典型草原；3）rTCA途径关键酶EC（1.2.7.1）和EC（1.2.7.3）、3-HP途径关键酶EC（6.4.1.2）和EC（6.4.1.3）的编码基因丰度在荒漠草原土壤中高于典型草原。显然，内蒙古荒漠草原土壤固碳微生物（纲）、固碳途径及其编码关键酶基因丰度都高于典型草原，由此表明荒漠草原土壤固碳微生物具有更强的大气CO₂固定潜力。

关键词: 草原土壤, 固碳微生物, 固碳途径, 宏基因组, 相对丰度

Abstract:

Autotrophic soil microbes can assimilate atmospheric CO₂ and fix carbon into the soil. The relative contributions of soil microorganisms to carbon fixation are greater in arid regions than in humid ecosystems. However， current carbon-fixation models mainly focus on plant functions and often neglect the roles of soil autotrophs. Therefore， such models cannot accurately predict carbon sequestration in the soil of arid ecosystems. In this study， we focused on the soil microorganisms of the typical steppe and desert steppe in Inner Mongolia， and analyzed differences in the composition and metabolic pathways of carbon-fixing microbial communities in those soils. The main results were as follows： 1） There were 14 carbon-fixing microbial groups （classes） in soils of both categories of steppe， among which Acidimicrobiia， γ-Proteobacteria， and Chloroflexi showed significantly higher abundance in the desert steppe soil than in the typical steppe soil； 2） The relative abundance of genes related to the reductive citric acid （rTCA） cycle and the 3-hydroxypropionate （3-HP） cycle was significantly higher in the desert steppe soil than in the typical steppe soil； 3） The abundance of genes encoding key enzymes in the rTCA pathway ［EC （1.2.7.1） and EC （1.2.7.3）］ and the 3-HP pathway ［EC （6.4.1.2） and EC （6.4.1.3）］ was higher in the desert steppe soil than in the typical steppe soil. Clearly， the abundance of carbon-fixing microorganism classes， carbon-fixation pathways， and genes encoding their key enzymes was higher in the desert steppe soil of Inner Mongolia than in the typical steppe soil， indicating that the desert steppe soil microorganisms have stronger potential for atmospheric CO₂ fixation.

Key words: grassland soil, carbon-fixing microorganisms, carbon-fixation pathways, metagenomics, relative abundance

彭浩, 董宝珠, 马利娟, 于晓东, 张艺帆, 李晓芳. 内蒙古典型草原和荒漠草原土壤固碳微生物组成及其固碳途径差异分析[J]. 草业学报, 2025, 34(8): 123-131.

Hao PENG, Bao-zhu DONG, Li-juan MA, Xiao-dong YU, Yi-fan ZHANG, Xiao-fang LI. Composition and carbon-fixation pathways of carbon-fixing microorganisms in soils of a typical steppe and desert steppe in Inner Mongolia[J]. Acta Prataculturae Sinica, 2025, 34(8): 123-131.

图/表 5

表1 采样点位置信息

Table 1 Locations of sampling points

采样点Sampling points	荒漠草原 Desert steppe	典型草原 Typical steppe
1	110°36'34.4'' E，41°52'18.1'' N	117°41'16.5'' E，44°54'17.2'' N
2	111°5'16.4'' E，41°47'8.5'' N	118°34'32.1'' E，45°5'26.9'' N
3	111°37'0.5'' E，41°41'58.4'' N	117°29'7.9'' E，45°30'57.5'' N
4	111°52'44.3'' E，41°52'18.1'' N	118°29'0.9'' E，45°47'13.1'' N
5	110°50'5.7'' E，41°20'5.5'' N	119°10'24.6'' E，46°9'55.3'' N
6	112°10'40.5'' E，42°26'17.1'' N	119°37'35.3'' E，45°47'34.4'' N

表2 典型草原和荒漠草原土壤固碳微生物（纲）相对丰度

Table 2 Relative abundance of carbon-fixing microorganisms （class） in soils of typical steppe and desert steppe （%）

固碳微生物分类（纲） Carbon-fixing microorganisms （class）	典型草原 Typical steppe	荒漠草原 Desert steppe
古细菌Archaea
亚硝化球菌纲Nitrososphaeria	0.389±0.203	0.571±0.284
热原体纲Thermoplasmata	0.003±0.000	0.003±0.001
深古菌纲Candidatus_Bathyarchaeota	0.003±0.002	0.003±0.001
热变形菌纲Thermoprotei	n.d.	n.d.
古丸菌纲Archaeoglobi	n.d.	n.d.
洛基古菌纲Lokiarchaeia	n.d.	n.d.
细菌Bacteria
α-变形菌纲α-Proteobacteria	13.837±3.349	10.524±2.115
酸微菌纲Acidimicrobiia	1.050±0.301*	1.397±0.184*
芽单胞菌纲Gemmatimonadetes	0.728±0.170	1.174±0.477
γ-变形菌纲γ-Proteobacteria	0.557±0.167*	0.906±0.335*
蓝藻纲Cyanophyceae	0.254±0.065	0.370±0.246
厌氧绳菌纲Anaerolineae	0.250±0.144	0.373±0.100
硝化螺旋菌纲Nitrospiria	0.165±0.104	0.270±0.096
绿弯菌纲Chloroflexi	0.080±0.028*	0.129±0.030*
迷踪菌纲Unclassified_Elusimicrobia	0.007±0.003	0.008±0.002
ζ-变形菌纲ζ-Proteobacteria	0.001±0.001	0.001±0.000
绿菌纲Chlorobiia	0.001±0.000	0.001±0.000
脱硫杆菌纲Desulfurobacteriia	n.d.	n.d.
弯曲杆菌纲Campylobacteria	n.d.	n.d.
热脱硫杆菌纲Thermodesulfovibrionia	n.d.	n.d.
δ-变形菌纲δ-Proteobacteria （SAR324）	n.d.	n.d.
放线菌纲Actinobacteria	n.d.	n.d.
螺旋体纲Leptospirae	n.d.	n.d.

图1 典型草原和荒漠草原土壤固碳微生物优势种相对丰度变化

Fig.1 Relative abundance of dominant species of carbon-fixing microorganisms in soils of typical steppe and desert steppe

图2 典型草原和荒漠草原土壤不同固碳途径的相对丰度*： P<0.05； CBB：卡尔文循环Calvin-Benson-Bassham cycle； rTCA：还原柠檬酸循环Reductive citric acid cycle； DC/4-HB： 2-羧酸/4-羟基丁酸循环Dicarboxylate/4-hydroxybutyrate cycle； 3-HP/4-HB： 3-羟基丙酸/4-羟基丁酸循环3-hydroxypropionate/4-hydroxybutyrate cycle； 3-HP： 3-羟基丙酸循环3-hydroxypropionate cycle； WLP：还原性乙酰辅酶A途径Reductive acetyl-CoA pathway.

Fig.2 Relative abundance of different carbon-fixing pathways in soils of typical steppe and desert steppe

图3 两类草原土壤中调控还原柠檬酸循环和3-羟基丙酸循环的酶编码基因相对丰度的变化A：调控还原柠檬酸循环的酶编码基因相对丰度变化； B：调控3-羟基丙酸循环的酶编码基因相对丰度变化；方框内编号表示固碳途径的调控酶，红色方框表示酶编码基因的相对丰度典型草原显著高于荒漠草原（P<0.05），浅红色方框表示酶编码基因的相对丰度典型草原高于荒漠草原，但无显著性差异（P>0.05）；绿色方框表示酶编码基因的相对丰度典型草原显著低于荒漠草原（P<0.05），浅绿色方框表示酶编码基因的相对丰度典型草原低于荒漠草原，但无显著性差异（P>0.05）；白色方框代表在本次宏基因组测序分析中未注释到该酶的编码基因； *表示还原柠檬酸循环或者3-羟基丙酸循环的关键酶。A： Comparing the relative abundance of enzyme coding genes regulating the reductive citric acid cycle （rTCA）； B： Comparing the relative abundance of enzyme coding genes regulating the 3-hydroxypropionate cycle （3-HP）. The number inside the box indicates the regulatory enzyme of the carbon sequestration pathway， and the red boxes indicate that the relative abundance of enzyme coding genes is significantly higher in typical steppe than in desert steppe （P<0.05）. The light red boxes indicate that the relative abundance of enzyme coding genes is higher in typical steppe than in desert steppe， but there is no significant difference （P>0.05）. The green boxes indicate that the relative abundance of enzyme coding genes is significantly lower in typical steppe than in desert steppe （P<0.05）， while the light green boxes indicates that the relative abundance of enzyme coding genes is lower in typical steppe than in desert steppe， but there is no significant difference （P>0.05）. The white boxes indicate the genes encoding the enzyme that was not annotated in metagenomic sequencing analysis. “*” marks the key enzyme of rTCA or 3-HP.

Fig.3 Comparing the relative abundances of enzyme coding genes regulating reductive citric acid cycle （rTCA） and 3-hydroxypropionate cycle （3-HP） in two types of grassland soils

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内蒙古典型草原和荒漠草原土壤固碳微生物组成及其固碳途径差异分析

Composition and carbon-fixation pathways of carbon-fixing microorganisms in soils of a typical steppe and desert steppe in Inner Mongolia

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