College of Biological Sciences and Technology, Taiyuan Normal University, Taiyuan, China.
Shanxi Key Laboratory of Earth Surface Processes and Resource Ecology Security in Fenhe River Basin, Taiyuan Normal University, Taiyuan, China.
PeerJ. 2024 Jun 28;12:e17461. doi: 10.7717/peerj.17461. eCollection 2024.
Agricultural soils contaminated with heavy metals poison crops and disturb the normal functioning of rhizosphere microbial communities. Different crops and rhizosphere microbial communities exhibit different heavy metal resistance mechanisms. Here, indoor pot studies were used to assess the mechanisms of grain and soil rhizosphere microbial communities on chromium (Cr) stress. Millet grain variety 'Jingu 21' () and soil samples were collected prior to control (CK), 6 hours after (Cr_6h), and 6 days following (Cr_6d) Cr stress. Transcriptomic analysis, high-throughput sequencing and quantitative polymerase chain reaction (qPCR) were used for sample determination and data analysis. Cr stress inhibited the expression of genes related to cell division, and photosynthesis in grain plants while stimulating the expression of genes related to DNA replication and repair, in addition to plant defense systems resist Cr stress. In response to chromium stress, rhizosphere soil bacterial and fungal community compositions and diversity changed significantly ( < 0.05). Both bacterial and fungal co-occurrence networks primarily comprised positively correlated edges that would serve to increase community stability. However, bacterial community networks were larger than fungal community networks and were more tightly connected and less modular than fungal networks. The abundances of C/N functional genes exhibited increasing trends with increased Cr exposure. Overall, these results suggest that Cr stress primarily prevented cereal seedlings from completing photosynthesis, cell division, and proliferation while simultaneously triggering plant defense mechanisms to resist the toxic effects of Cr. Soil bacterial and fungal populations exhibited diverse response traits, community-assembly mechanisms, and increased expression of functional genes related to carbon and nitrogen cycling, all of which are likely related to microbial survival during Cr stress. This study provides new insights into resistance mechanisms, microbial community structures, and mechanisms of C/N functional genes responses in cereal plants to heavy metal contaminated agricultural soils. Portions of this text were previously published as part of a preprint (https://www.researchsquare.com/article/rs-2891904/v1).
受重金属污染的农业土壤会毒害作物并扰乱根际微生物群落的正常功能。不同的作物和根际微生物群落表现出不同的重金属抗性机制。在这里，室内盆栽研究用于评估谷物和土壤根际微生物群落对铬（Cr）胁迫的机制。谷子品种“金谷 21”（）和土壤样本在对照（CK）、Cr 胁迫后 6 小时（Cr_6h）和 6 天后（Cr_6d）采集。转录组分析、高通量测序和实时定量聚合酶链反应（qPCR）用于样品测定和数据分析。Cr 胁迫抑制了谷物植物中与细胞分裂和光合作用相关的基因表达，同时刺激了与 DNA 复制和修复以及植物防御系统相关的基因表达，以抵抗 Cr 胁迫。对铬胁迫的响应，根际土壤细菌和真菌群落组成和多样性发生了显著变化（<0.05）。细菌和真菌共同发生网络主要由正相关的边缘组成，这将有助于增加群落稳定性。然而，细菌群落网络大于真菌网络，与真菌网络相比，细菌网络更紧密连接且模块性更小。C/N 功能基因的丰度随着 Cr 暴露的增加呈上升趋势。总体而言，这些结果表明，Cr 胁迫主要阻止谷类幼苗完成光合作用、细胞分裂和增殖，同时触发植物防御机制以抵抗 Cr 的毒性作用。土壤细菌和真菌种群表现出不同的响应特征、群落组装机制以及与碳氮循环相关功能基因的表达增加，这可能与 Cr 胁迫期间微生物的生存有关。本研究为了解受重金属污染的农业土壤中谷类植物对重金属的抗性机制、微生物群落结构以及 C/N 功能基因响应机制提供了新的见解。本文部分内容已作为预印本的一部分（https://www.researchsquare.com/article/rs-2891904/v1）发表。
