Journal of Integrative Agriculture ›› 2026, Vol. 25 ›› Issue (3): 1209-1222.DOI: 10.1016/j.jia.2025.05.005

• • 上一篇    下一篇

共现网络中的机会型关键固氮菌驱动花生/棉花间作系统中的生物固氮过程

  

  • 收稿日期:2025-01-13 修回日期:2025-05-14 接受日期:2025-04-21 出版日期:2026-03-20 发布日期:2026-02-06

Opportunistic keystone diazotrophs from co-occurrence networks drive biological nitrogen fixation in peanut/cotton intercropping systems 

Shijie Zhang1, 3, Yingchun Han2, Guoping Wang2, Lu Feng1, 2, Yaping Lei2, Shiwu Xiong2, Beifang Yang2, Xiaoyu Zhi2, Minghua Xin2, Yahui Jiao2, Xiaofei Li2#, Yabing Li1, 2#, Zhen Jiao1, 3#   

  1. 1 Zhengzhou Research Base, State Key Laboratory of Cotton Bio-breeding and Integrated Utilization/School of Agriculture and Biomanufacturing, Zhengzhou University, Zhengzhou 450001, China

    2 State Key Laboratory of Cotton Bio-breeding and Integrated Utilization/Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China

    3 Henan Key Laboratory of Ion-Beam Green Agriculture Bioengineering, Zhengzhou University, Zhengzhou 450001, China

  • Received:2025-01-13 Revised:2025-05-14 Accepted:2025-04-21 Online:2026-03-20 Published:2026-02-06
  • About author:Shijie Zhang, E-mail: sjzhang@zzu.edu.cn; #Correspondence Xiaofei Li, E-mail: lixiaofei01@caas.cn; Yabing Li, E-mail: criliyabing1@163.com; Zhen Jiao, E-mail: jiaozhen@zzu.edu.cn
  • Supported by:

    This work was financially supported by the National Natural Science Foundation of China (32301962 and 31901127), the China Postdoctoral Science Foundation (2024M752947), the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation (GZC20232437), the State Key Laboratory of Cotton Bio-breeding and Integrated Utilization Open Fund, China (CB2023C02), and the Natural Science Foundation of Henan Province, China (252300420222).

PDF

摘要：

豆科作物间作可增强非共生生物固氮（BNF）作用，但其潜在机制，尤其是不同生态位宽度的土壤关键固氮菌类群在其中发挥的作用仍不明确。本研究通过田间试验，评估了花生/棉花间作与各自单作条件下根际与非根际土壤中BNF活性的变化。通过固氮速率、固氮酶活性以及nifH基因丰度，结合微生物系统发育零模型、共现网络及生态位宽度分析，探讨关键固氮类群及其生态功能与BNF的关系。结果显示，与非根际土壤相比，根际土壤的BNF潜力提高了7.8%–125.5%；与单作相比，花生/棉花间作系统中固氮速率、固氮酶活性和nifH基因丰度提升了11.6%–323.0%（P<0.05）。固氮菌群落组成与多样性存在显著差异：间作系统与根际土壤中增加了大部分变形菌门（α-变形菌外）、降低了蓝藻门和厚壁菌门的相对丰度。固氮菌的群落构建主要受确定性过程驱动，尤其是异质性选择过程，在根际（91.9%）和间作土壤（86.3%）中占主导地位。此外，间作系统与根际土壤中的固氮菌共现网络更复杂、连接性更强，其中，优势类群为机会型固氮菌（78.8%–85.9%），其次为特化型（10.2%–18.5%）和泛化型（1.38%–3.80%）。网络关键类群（机会型的Azoarcus、Azohydromonas 和Steroidobacter，泛化型的Pseudomonas 和 Azotobacter），以及土壤微生物量碳和硝态氮，与间作系统和根际土壤BNF活性的增强显著相关。花生/棉花间作通过选择性招募生态功能不同的关键固氮类群，尤其是机会型固氮菌，从而提升农田BNF潜力，促进农业可持续发展。

Abstract:

Legume-based intercropping enhances asymbiotic biological nitrogen fixation (BNF); however, the underlying mechanisms remain unclear, including the roles of soil keystone diazotroph taxa with varying niche breadths.  A field experiment was conducted to evaluate soil BNF variations between rhizosphere and bulk soils in peanut/cotton intercropping systems and monocultures.  BNF activities were measured by nitrogen fixation rates, nitrogenase activity, and nifH gene abundance.  Phylogenetic null models, co-occurrence networks, and niche breadth analysis were applied to investigate the roles of diazotrophic keystone taxa and their ecological niches.  Rhizosphere soils exhibited 7.8–125.5% higher BNF potentials than bulk soils, whereas intercropping systems showed 11.6–323.0% increases over monocultures for nitrogen fixation rate, nitrogenase activity, and nifH gene abundance (all P<0.05).  Diazotrophic community composition and diversity differed significantly, with Proteobacteria (excluding Alphaproteobacteria) enriched in intercropping and rhizosphere soils, while Cyanobacteria and Firmicutes were less abundant.  Deterministic processes, particularly heterogeneous selection, dominated community assembly in the rhizosphere (91.9%) and intercropping soils (86.3%).  The co-occurrence networks consistently revealed more complex and interconnected communities in intercropping and rhizosphere soils that were dominated by opportunistic diazotrophs (78.8–85.9%), followed by specialists (10.2–18.5%) and generalists (1.38–3.80%).  Keystone taxa, including opportunists such as Azoarcus, Azohydromonas, and Steroidobacter, and generalists like Pseudomonas and Azotobacter, correlated positively with microbial biomass carbon and nitrate nitrogen, contributing to enhanced BNF.  Peanut/cotton intercropping enhances BNF by selectively enriching the keystone diazotrophic taxa with varying ecological roles, particularly opportunists and generalists.  Such targeted intercropping strategies can optimize BNF, improve soil fertility, and promote sustainable agricultural production.

Key words: biological nitrogen fixation , community assembly , habitat ecotypes , keystone diazotroph taxa