Scholarlink

<p>Carbon fixation by soil autotrophic microbes is an overlooked process in organic carbon anabolism, which is potentially affected by biochar. In this study, we quantified the abundance of functional genes <i>cbbL</i> and <i>cbbM</i>, key components of the widely distributed Calvin cycle, and combined this with Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) enzyme activity assays and high-throughput sequencing of <i>cbbL</i>- and <i>cbbM</i>-harboring microbial communities to investigate the carbon fixation potential, activity, and community structure under biochar application in paddy and upland soils. Results showed that <i>cbbL</i> consistently dominated over <i>cbbM</i> in both paddy and upland soils, with higher abundances in paddy soils, driven by biochar amendment, rice growth stage, and rhizosphere effects. The rhizosphere acted as a hotspot for <i>cbbL</i> and <i>cbbM</i> genes and RubisCO activity in paddy soil. In upland soils, nitrogen availability (NH₄⁺, dissolved organic nitrogen- DON), microbial biomass carbon, and labile carbon and nitrogen pools (dissolved organic carbon, N-acetyl-β-D-glucosaminidase) were consistently associated with <i>cbbL</i> abundance, underscoring their ecological role in soil CO₂ fixation. In paddy soils, inorganic nitrogen (NH₄⁺, NO₃⁻, NO₂⁻), redox potential (Eh), and urease activity were the main predictors of <i>cbbL</i> abundance and the <i>cbbL</i>/16S ratio, while pH and nitrogen availability (NO₂⁻, DON) was mostly associated with <i>cbbM</i>/16S ratio. Biochar was the primary driver reshaping the structure of autotrophic microbial communities harboring <i>cbbL</i> and <i>cbbM</i> genes across different soil compartments, including surface soil, rhizosphere, and bulk soil. <i>Pseudomonadota</i>, <i>Cyanobacteriota</i>, <i>Actinomycetota</i> and <i>Chloroflexota</i> were dominant <i>cbbL</i> carriers, while <i>Pseudomonadota</i>, <i>Actinomycetota</i> and <i>Myxococcota</i> predominated in <i>cbbM</i> assemblages across soils. Biochar induced functional differentiation of facultative autotrophic taxa under different RubisCO forms by enhancing the abundance of <i>Rhodopseudomonas</i> in <i>cbbM</i>-bearing communities while decreasing it in <i>cbbL</i>-bearing ones. Furthermore, Calvin cycle-mediated CO₂ fixation was found to couple with pathways including methylotrophy, methanotrophy, iron oxidation and respiration, nitrogen fixation and reduction, and arsenate reduction and detoxification. Collectively, the results of this study emphasize the importance of soil type, micro-environmental conditions, nitrogen status and the impact of biochar in shaping microbial carbon assimilation via the Calvin cycle pathway and the <i>cbbL</i> and <i>cbbM</i>-harboring microbial community.</p> Graphical Abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Calvin cycle driven autotrophic CO2-fixation traits and autotrophic microbial communities in paddy (Anthrosol) and upland (Vertisol) soils: rhizosphere effects and impacts of biochar

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年11月18日

查看全文
  • Huimei Jiang,
  • Shuyue Han,
  • Haojun Zhang,
  • Tianchu Liu,
  • Shihao Huang,
  • Xiaoyu Zhu,
  • Jingwan Fang,
  • Jing Mu,
  • Xiaomin Zhu

摘要

Carbon fixation by soil autotrophic microbes is an overlooked process in organic carbon anabolism, which is potentially affected by biochar. In this study, we quantified the abundance of functional genes cbbL and cbbM, key components of the widely distributed Calvin cycle, and combined this with Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) enzyme activity assays and high-throughput sequencing of cbbL- and cbbM-harboring microbial communities to investigate the carbon fixation potential, activity, and community structure under biochar application in paddy and upland soils. Results showed that cbbL consistently dominated over cbbM in both paddy and upland soils, with higher abundances in paddy soils, driven by biochar amendment, rice growth stage, and rhizosphere effects. The rhizosphere acted as a hotspot for cbbL and cbbM genes and RubisCO activity in paddy soil. In upland soils, nitrogen availability (NH₄⁺, dissolved organic nitrogen- DON), microbial biomass carbon, and labile carbon and nitrogen pools (dissolved organic carbon, N-acetyl-β-D-glucosaminidase) were consistently associated with cbbL abundance, underscoring their ecological role in soil CO₂ fixation. In paddy soils, inorganic nitrogen (NH₄⁺, NO₃⁻, NO₂⁻), redox potential (Eh), and urease activity were the main predictors of cbbL abundance and the cbbL/16S ratio, while pH and nitrogen availability (NO₂⁻, DON) was mostly associated with cbbM/16S ratio. Biochar was the primary driver reshaping the structure of autotrophic microbial communities harboring cbbL and cbbM genes across different soil compartments, including surface soil, rhizosphere, and bulk soil. Pseudomonadota, Cyanobacteriota, Actinomycetota and Chloroflexota were dominant cbbL carriers, while Pseudomonadota, Actinomycetota and Myxococcota predominated in cbbM assemblages across soils. Biochar induced functional differentiation of facultative autotrophic taxa under different RubisCO forms by enhancing the abundance of Rhodopseudomonas in cbbM-bearing communities while decreasing it in cbbL-bearing ones. Furthermore, Calvin cycle-mediated CO₂ fixation was found to couple with pathways including methylotrophy, methanotrophy, iron oxidation and respiration, nitrogen fixation and reduction, and arsenate reduction and detoxification. Collectively, the results of this study emphasize the importance of soil type, micro-environmental conditions, nitrogen status and the impact of biochar in shaping microbial carbon assimilation via the Calvin cycle pathway and the cbbL and cbbM-harboring microbial community.

Graphical Abstract