School of Geography and Oceanography, Nanjing University, Nanjing 210008, China.
State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 138 Haping Road, Harbin 150081, China.
Sci Total Environ. 2023 May 15;873:162321. doi: 10.1016/j.scitotenv.2023.162321. Epub 2023 Feb 18.
Anthropogenic climate change threatens ecosystem multifunctionality. Arbuscular mycorrhizal (AM) fungi are important symbionts that participate in mediating many ecosystem processes, and thus being potentially essential link in the chain of responses to climate change. Yet, how climate change affect the abundance and community structure of AM fungi associated with different crops remains elusive. Here, we investigated the changes in rhizosphere AM fungal communities and growth performance of maize and wheat grown in Mollisols under experimentally elevated CO (eCO, +300 ppm), temperature (eT, +2 °C) and both in-combination (eCT) with open-top chambers, representing a scenario likely to occur by this century's end. The results showed that eCT significantly shifted AM fungal communities in both rhizospheres compared with control, but with no remarkable variation of the overall communities in maize rhizosphere, suggesting their greater resistance to climate change. Both eCO and eT increased rhizosphere AM fungal diversity, and conversely they reduced mycorrhizal colonization of both crops, probably since AM fungi had distinct adaptive strategies to climate change in rhizospheres (i.e., r-strategy) and roots (K-strategy), while the colonization intensity positively correlated with a decreased phosphorus (P)-uptake in two crops. Furthermore, co-occurrence network analysis showed that eCO strongly decreased the modularity and betweenness centrality of network structure than that of eT and eCT in both rhizospheres, along with the reduced network robustness, implied their destabilized communities under eCO, while root stoichiometry (C:N and C:P ratio) was the most important factor associating with taxa in networks regardless of climate change. Overall, those findings suggest that rhizosphere AM fungal communities in wheat appear to be more sensitive to climate change than that in maize, further highlighting the importance of effective monitoring and managing AM fungi, which may allow crops to maintain critical levels of mineral nutrients (at least P) under future global change.
人为引起的气候变化威胁着生态系统的多功能性。丛枝菌根（AM）真菌是重要的共生体，它们参与调节许多生态系统过程，因此是对气候变化做出反应的链条中潜在的关键环节。然而，气候变化如何影响与不同作物相关的 AM 真菌的丰度和群落结构仍然难以捉摸。在这里，我们研究了在开放顶篷室中，实验性地升高 CO（eCO，+300ppm）、温度（eT，+2°C）以及两者同时升高（eCT）条件下，在黑钙土中生长的玉米和小麦的根际 AM 真菌群落的变化以及它们的生长表现。结果表明，与对照相比，eCT 显著改变了两个根际中的 AM 真菌群落，但玉米根际中总体群落没有明显变化，表明它们对气候变化的抵抗力更强。eCO 和 eT 均增加了根际 AM 真菌的多样性，而相反，它们降低了两种作物的菌根定殖，这可能是因为 AM 真菌在根际（即 r 策略）和根部（K 策略）对气候变化有不同的适应策略，而定殖强度与两种作物磷（P）吸收的减少呈正相关。此外，共生网络分析表明，与 eT 和 eCT 相比，eCO 强烈降低了两个根际中网络结构的模块性和介数中心性，同时降低了网络稳定性，表明它们在 eCO 下的群落不稳定，而根系化学计量（C:N 和 C:P 比）是与网络中分类群相关的最重要因素，无论气候变化如何。总体而言，这些发现表明，与玉米相比，小麦的根际 AM 真菌群落似乎对气候变化更为敏感，进一步强调了有效监测和管理 AM 真菌的重要性，这可能使作物在未来的全球变化下保持关键的矿物质营养水平（至少 P）。
