Table_1_Bacterial–fungal interactions and response to heavy metal contamination of soil in agricultural areas.DOCX

IntroductionLong-term heavy metal contamination of soil affects the structure and function of microbial communities. The aim of our study was to investigate the effect of soil heavy metal contamination on microorganisms and the impact of different heavy metal pollution levels on the microbial interactions.
MethodsWe collected soil samples and determined soil properties. Microbial diversity was analyzed in two groups of samples using high-throughput sequencing technology. Additionally, we constructed microbial networks to analyze microbial interactions.
ResultsThe pollution load index (PLI) < 1 indicates that the area is not polluted. 1 < PLI < 2 represents moderate pollution. PLI was 1.05 and 0.14 for the heavy metal contaminated area and the uncontaminated area, respectively. Cd, Hg, Pb, Zn, and Cu were identified as the major contaminants in the contaminated area, with the contamination factors were 30.35, 11.26, 5.46, 5.19, and 2.46, respectively. The diversities and compositions of the bacterial community varied significantly between the two groups. Compared to the uncontaminated area, the co-occurrence network between bacterial and fungal species in the contaminated area was more complex. The keystone taxa of the co-occurrence network in the contaminated area were more than those in the uncontaminated area and were completely different from it.
DiscussionHeavy metal concentrations played a crucial role in shaping the difference in microbial community compositions. Microorganisms adapt to long-term and moderate levels of heavy metal contamination through enhanced interactions. Bacteria resistant to heavy metal concentrations may play an important role in soils contaminated with moderate levels of heavy metals over long periods of time.

引言
长期土壤重金属污染会影响微生物群落的结构与功能。本研究旨在探究土壤重金属污染对微生物的作用，以及不同重金属污染水平对微生物互作的影响。
材料与方法
本研究采集土壤样品并测定其基本理化性质；采用高通量测序技术（high-throughput sequencing technology）对两组样品的微生物多样性进行分析；此外，通过构建微生物互作网络解析微生物间的相互作用。
结果
污染负荷指数（pollution load index, PLI）<1表明该区域未受污染；1<PLI<2则代表中度污染。污染区域与未污染区域的PLI分别为1.05和0.14。污染区域的主要重金属污染物为镉（Cd）、汞（Hg）、铅（Pb）、锌（Zn）和铜（Cu），其污染因子分别为30.35、11.26、5.46、5.19和2.46。两组样品的细菌群落多样性与组成均存在显著差异。与未污染区域相比，污染区域内细菌与真菌物种间的共现互作网络更为复杂；该区域共现网络的关键类群（keystone taxa）数量多于未污染区域，且类群组成完全不同。
讨论
重金属浓度是塑造微生物群落组成差异的核心驱动因素。微生物可通过强化物种间互作来适应长期中度重金属污染环境；长期暴露于中度重金属污染的土壤中，耐重金属细菌可能发挥着关键作用。