Sharma Anjney, Song Xiu-Peng, Singh Rajesh Kumar, Vaishnav Anukool, Gupta Saurabh, Singh Pratiksha, Guo Dao-Jun, Verma Krishan K, Li Yang-Rui
Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Academy of Agricultural Sciences (GXAAS), Nanning, Guangxi, China.
Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences (GXAAS), Nanning, Guangxi, China.
Front Microbiol. 2022 Dec 20;13:1005942. doi: 10.3389/fmicb.2022.1005942. eCollection 2022.
Agrochemicals are consistently used in agricultural practices to protect plants from pathogens and ensure high crop production. However, their overconsumption and irregular use cause adverse impacts on soil flora and non-target beneficial microorganisms, ultimately causing a hazard to the ecosystem. Taking this into account, the present study was conducted to determine the high dosage of fungicide (carbendazim: CBZM) effects on the rhizobacteria survival, plant growth promoting trait and reactive oxygen species (ROS) scavenging antioxidant enzyme system. Thus, a multifarious plant growth promoting rhizobacteria (PGPR) isolate, ANCB-12, was obtained from the sugarcane rhizosphere through an enrichment technique. The taxonomic position of the isolated rhizobacteria was confirmed through 16S rRNA gene sequencing analysis as ANCB-12 (accession no. ON878101). Results showed that increasing concentrations of fungicide showed adverse effects on rhizobacterial cell growth and survival. In addition, cell visualization under a confocal laser scanning microscope (CLSM) revealed more oxidative stress damage in the form of ROS generation and cell membrane permeability. Furthermore, the increasing dose of CBZM gradually decreased the plant growth promoting activities of the rhizobacteria ANCB-12. For example, CBZM at a maximum 3,000 μg/ml concentration decreases the indole acetic acid (IAA) production by 91.6%, ACC deaminase by 92.3%, and siderophore production by 94.1%, respectively. Similarly, higher dose of fungicide enhanced the ROS toxicity by significantly ( < 0.05) modulating the stress-related antioxidant enzymatic biomarkers in ANCB-12. At a maximum 3,000 μg/ml CBZM concentration, the activity of superoxide dismutase (SOD) declined by 82.3%, catalase (CAT) by 61.4%, glutathione peroxidase (GPX) by 76.1%, and glutathione reductase (GR) by 84.8%, respectively. The results of this study showed that higher doses of the fungicide carbendazim are toxic to the cells of plant-beneficial rhizobacteria. This suggests that a recommended dose of fungicide should be made to lessen its harmful effects.
农用化学品在农业生产中持续被用于保护植物免受病原体侵害并确保作物高产。然而，其过度使用和不当使用会对土壤微生物群落和非靶标有益微生物产生不利影响，最终对生态系统造成危害。考虑到这一点，本研究旨在确定高剂量杀菌剂（多菌灵：CBZM）对根际细菌存活、促进植物生长特性以及活性氧（ROS）清除抗氧化酶系统的影响。因此，通过富集技术从甘蔗根际获得了一种具有多种促进植物生长功能的根际细菌（PGPR）分离株ANCB - 12。通过16S rRNA基因测序分析确定分离出的根际细菌分类地位为ANCB - 12（登录号ON878101）。结果表明，杀菌剂浓度增加对根际细菌细胞生长和存活产生不利影响。此外，共聚焦激光扫描显微镜（CLSM）下的细胞可视化显示，以ROS产生和细胞膜通透性形式存在更多氧化应激损伤。此外，CBZM剂量增加逐渐降低根际细菌ANCB - 12的植物生长促进活性。例如，最高浓度为3000μg/ml的CBZM分别使吲哚乙酸（IAA）产量降低91.6%，ACC脱氨酶降低92.3%，铁载体产量降低94.1%。同样，较高剂量的杀菌剂通过显著（<0.05）调节ANCB - 12中与应激相关的抗氧化酶生物标志物增强了ROS毒性。在最高3000μg/ml的CBZM浓度下，超氧化物歧化酶（SOD）活性分别下降82.3%，过氧化氢酶（CAT）下降61.4%，谷胱甘肽过氧化物酶（GPX）下降76.1%，谷胱甘肽还原酶（GR）下降84.8%。本研究结果表明，高剂量的杀菌剂多菌灵对植物有益根际细菌细胞有毒性。这表明应制定推荐的杀菌剂剂量以减轻其有害影响。
