| 杨皓,王常荣,吴赵清华,田耕,王林,黄永春,薛卫杰,孙约兵.根施促生克雷伯菌抑制油菜镉吸收积累的作用机制[J].农业环境科学学报,2025,44(12):3082-3094. |
| 根施促生克雷伯菌抑制油菜镉吸收积累的作用机制 |
| Inhibitory effects of root-applied growth-promoting Klebsiella sp. on cadmium uptake and accumulation in Brassica chinensis L. |
| 投稿时间：2025-01-11 |
| DOI：10.11654/jaes.2025-0035 |
| 中文关键词: 克雷伯菌 油菜 镉 铁 氮 |
| 英文关键词: Klebsiella sp. Brassica chinensis L. cadmium iron nitrogen |
| 基金项目:国家重点研发计划项目（2024YFD1701100）；国家自然科学基金项目（32471707，42077153，42207039）；中国农业科学院创新工程项目（CAAS-CSGLCA-202302） |
| 作者 | 单位 | E-mail | | 杨皓 | 农业农村部产地环境污染防控重点实验室/天津市农业环境与农产品安全重点实验室, 农业农村部环境保护科研监测所, 天津 300191
东北农业大学资源与环境学院, 哈尔滨 150030 | | | 王常荣 | 农业农村部产地环境污染防控重点实验室/天津市农业环境与农产品安全重点实验室, 农业农村部环境保护科研监测所, 天津 300191 | wangchangrong109@163.com | | 吴赵清华 | 农业农村部产地环境污染防控重点实验室/天津市农业环境与农产品安全重点实验室, 农业农村部环境保护科研监测所, 天津 300191 | | | 田耕 | 农业农村部产地环境污染防控重点实验室/天津市农业环境与农产品安全重点实验室, 农业农村部环境保护科研监测所, 天津 300191 | | | 王林 | 农业农村部产地环境污染防控重点实验室/天津市农业环境与农产品安全重点实验室, 农业农村部环境保护科研监测所, 天津 300191 | | | 黄永春 | 农业农村部产地环境污染防控重点实验室/天津市农业环境与农产品安全重点实验室, 农业农村部环境保护科研监测所, 天津 300191 | | | 薛卫杰 | 农业农村部产地环境污染防控重点实验室/天津市农业环境与农产品安全重点实验室, 农业农村部环境保护科研监测所, 天津 300191 | | | 孙约兵 | 农业农村部产地环境污染防控重点实验室/天津市农业环境与农产品安全重点实验室, 农业农村部环境保护科研监测所, 天津 300191 | sunyuebing@caas.cn |
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| 中文摘要: |
| 为探明克雷伯菌对污染土壤中油菜Cd积累特征的影响，以夏绿2号油菜为材料，利用微生物高通量测序、转录组测序、土壤Cd逐级提取等手段，通过盆栽实验研究了根施克雷伯菌对根际微生物群落结构、土壤理化性质和元素形态及油菜不同部位中Cd积累量和功能基因表达的调控作用。结果表明：根施克雷伯菌促进了油菜生长，同时显著降低了油菜根部和地上部Cd含量，与对照处理相比最大降幅分别为44.6%和22.5%。根际微环境中，克雷伯菌处理小幅度提高了土壤pH值，并降低了土壤中Cd的生物可利用性。逐级提取结果显示，施菌后可交换态Cd含量降幅可达6.0%，残渣态Cd增幅可达8.0%。同时，菌株处理促进了土壤氮矿化过程，显著提高了土壤酶活性和无机氮含量，其中，土壤脲酶、蔗糖酶、过氧化氢酶、硝酸还原酶和亚硝酸还原酶的活性增幅分别可达19.5%、20.5%、27.7%、42.9%和27.0%，铵态氮、硝态氮和碱解氮的含量增幅分别可达56.7%、39.6%和54.1%。深入分析根际菌群结构发现，菌株处理提高了 Verrucomicrobiota、铁循环相关菌门 Proteobacteria 和氮循环驱动菌 Arthrobacter、Massilia和Tychonema_CCAP_1459~11B等相对丰度，并降低了Acidobacteriota和Actinobacteriota等相对丰度，进一步分析油菜根系功能基因表达水平发现，施菌可以降低Cd转运相关Nramp和ZIP家族基因水平，降幅分别为17.6%~20.5%和44.8%~77.4%，同时提高铵态氮转运蛋白和氮代谢相关基因 AMT、glnA、nirA的表达，幅度分别为 22.6%~27.8%、57.7%、29.7%~37.7%，从而在抑制 Cd吸收转运的同时促进油菜根系无机氮吸收和利用。研究表明，根施克雷伯菌可以通过调控根际菌群驱动的氮、铁等元素循环，增加营养元素氮的生物可利用性，改变铁氧化物形态并提高其对Cd的固持能力，进而降低土壤中Cd的有效性；同时，微生物代谢能够抑制油菜根系Cd转运基因的表达，促进无机氮吸收和代谢相关基因表达，进一步抑制油菜对Cd的吸收与积累并促进油菜的生长，对于Cd污染耕地中油菜的安全生产具有重要意义。 |
| 英文摘要: |
| This study aimed to explore the impact of Klebsiella on the Cd accumulation characteristics in Brassica chinensis L. within contaminated soil. Utilizing Xialv No.2 Brassica chinensis L. as the experimental material, a combination of high-throughput sequencing of microorganisms, transcriptome sequencing, and step-wise extraction of soil Cd was employed. The research focused on investigating the effects of root-applied Klebsiella on the rhizosphere microbial community structure, soil physical and chemical properties, elemental morphology, as well as the regulation of Cd accumulation and functional gene expression in different organs of Brassica chinensis L. The results showed that the application of Klebsiella at the root promoted the growth of Brassica chinensis L. and significantly reduced the Cd content in the roots and shoots of Brassica chinensis L.. Compared with the CK treatment, the maximum reduction in the Cd content of the roots and shoots of Brassica chinensis L. was 44.6% and 22.5%, respectively. In the rhizosphere micro-environment, the Klebsiella treatment caused a slight elevation in soil pH and a decline in the bioavailability of Cd in the soil. Specifically, the content of the exchangeable fraction of Cd reduced by 6.0%, while the residual fraction of Cd rose by 8.0%. Meanwhile, Klebsiella accelerated the soil nitrogen mineralization process and significantly enhanced soil enzyme activity and inorganic nitrogen content. To be specific, the activities of soil urease, sucrase, catalase, nitrate reductase, and nitrite reductase increased by 19.5%, 20.5%, 27.7%, 42.9%, and 27.0%, respectively, and the contents of ammonium nitrogen, nitrate nitrogen, and alkali-hydrolyzed nitrogen increased by 56.7%, 39.6%, and 54.1%, respectively. Further, Klebsiella augmented the relative abundance of Verrucomicrobiota, Proteobacteria, Arthrobacter, Massilia, and Tychonema_CCAP_1459_11B, while reducing the relative abundance of Acidobacteriota and Actinobacteriota. The application of Klebsiella could lower the levels of Nramp and ZIP family genes associated with Cd transport by 17.6% - 20.5% and 44.8% - 77.4%, respectively. Additionally, the expression of ammonium nitrogen transporter and nitrogen - metabolism - related genes AMT, glnA, and nirA increased by 22.6% - 27.8%, 57.7%, and 29.7% - 37.7%, respectively. This promoted the absorption and utilization of inorganic nitrogen in Brassica chinensis L. roots and concurrently inhibited the absorption and transport of Cd. Klebsiella can boost the bioavailability of the nutrient element nitrogen, transform the form of iron oxide, and enhance its Cd-fixing capacity by regulating the cycles of nitrogen, iron, and other elements driven by the rhizosphere flora, thus reducing the availability of Cd in the soil. Moreover, microbial metabolism can suppress the expression of Cd-transport genes in Brassica chinensis L. roots and promote the expression of genes related to inorganic nitrogen absorption and metabolism. This is further beneficial for inhibiting the absorption and accumulation of Cd by Brassica chinensis L. and promoting its growth, which is of great significance for the safe production of Brassica chinensis L. in cadmium - contaminated farmland. |
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