Wu Qingtao, Lin Xianjing, Li Shaoqing, Liang Zhenting, Wang Haihua, Tang Ting
School of Life and Health Sciences, Hunan Key Laboratory of Economic Crops Genetic Improvement and Integrated Utilization, Key Laboratory of Ecological Remediation and Safe Utilization of Heavy Metal Polluted Soils, Hunan University of Science and Technology, Xiangtan 411201, China.
School of Life and Health Sciences, Hunan Key Laboratory of Economic Crops Genetic Improvement and Integrated Utilization, Key Laboratory of Ecological Remediation and Safe Utilization of Heavy Metal Polluted Soils, Hunan University of Science and Technology, Xiangtan 411201, China.
Ecotoxicol Environ Saf. 2023 Jun 22;262:115170. doi: 10.1016/j.ecoenv.2023.115170.
Phytoremediation of heavy metal-polluted soils assisted by plant-associated endophytes, is a suitable method for plant growth and manganese (Mn) removal in contaminated soils. This investigation was conducted to evaluate the Mn-resistant endophytic resources of the Mn hyperaccumulator Arabis paniculata and their functions in the phytoremediation of Mn toxicity. This study isolated an endophytic bacterium with high Mn resistance and indole-3-acetic acid (IAA) production form A. paniculata and identified it as Bacillus sp. AP10 using 16 S rRNA gene sequencing analysis. The effects of Bacillus sp. AP10 on the alleviation of Mn toxicity in Arabidopsis thaliana seedlings and the molecular mechanisms were further investigated using biochemical tests and RNA-seq analysis. Under Mn stress, Bacillus sp. AP10 increased the biomass, chlorophyll content and the translocation factor (TF) values of Mn in the aerial parts, while decreased the malondialdehyde (MDA) content of A. thaliana seedlings compared with that of control plants. The differentially expressed genes (DEGs) and enrichment analysis showed that Bacillus sp. AP10 could significantly increase the expression of key genes involved in cell-wall loosening, which may improve plant growth under Mn stress. Superoxide dismutase (SOD)-encoding genes were detected as DEGs after AP10 treatment. Moreover, AP10 regulated the expression of genes responsible for phenylpropanoid pathway, which may promote antioxidant flavonoids accumulation for reactive oxygen species (ROS) scavenging to improve Mn tolerance. The activation of ATP-binding cassette (ABC) transporter gene expression especially ABCB1 after AP10 stimulation, explained the elevation of metal ion binding or transport related to enhanced Mn accumulation in plants. Futhermore, AP10 might alleviate Mn toxicity through enhancing abscisic acid (ABA) responsive gene expression and ABA biosynthesis. These findings provide new insights into the functions and regulatory mechanism of Bacillus sp. AP10 in promoting plant growth, and tolerance, improving Mn accumulation and alleviating Mn toxicity in plants. The application of Bacillus sp. AP10 as potential phytoremediators may be a promising strategy in Mn contaminated fields. AVAILABILITY OF DATA AND MATERIALS: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
植物相关内生菌辅助的重金属污染土壤植物修复，是一种适用于受污染土壤中植物生长和锰（Mn）去除的方法。本研究旨在评估Mn超富集植物圆锥南芥的耐Mn内生菌资源及其在Mn毒性植物修复中的作用。本研究从圆锥南芥中分离出一株具有高耐Mn能力且能产生吲哚 - 3 - 乙酸（IAA）的内生细菌，并通过16S rRNA基因测序分析将其鉴定为芽孢杆菌属AP10。利用生化试验和RNA测序分析，进一步研究了芽孢杆菌属AP10对拟南芥幼苗Mn毒性缓解的影响及其分子机制。在Mn胁迫下，与对照植株相比，芽孢杆菌属AP10增加了拟南芥幼苗地上部分的生物量、叶绿素含量和Mn的转运因子（TF）值，同时降低了丙二醛（MDA）含量。差异表达基因（DEG）和富集分析表明，芽孢杆菌属AP10可显著增加参与细胞壁松弛的关键基因的表达，这可能改善Mn胁迫下的植物生长。经AP10处理后，检测到超氧化物歧化酶（SOD）编码基因作为DEG。此外，AP10调节了负责苯丙烷途径的基因表达，这可能促进抗氧化黄酮类化合物的积累以清除活性氧（ROS）从而提高对Mn的耐受性。AP10刺激后，ATP结合盒（ABC）转运蛋白基因表达的激活，特别是ABCB1的激活，解释了与植物中Mn积累增强相关的金属离子结合或转运的升高。此外，AP10可能通过增强脱落酸（ABA）响应基因表达和ABA生物合成来缓解Mn毒性。这些发现为芽孢杆菌属AP10在促进植物生长、耐受性、提高Mn积累和缓解植物Mn毒性方面的功能和调控机制提供了新的见解。芽孢杆菌属AP10作为潜在的植物修复剂的应用可能是Mn污染农田中的一种有前景的策略。数据和材料的可用性：在当前研究期间使用和/或分析的数据集可应合理要求从相应作者处获得。
