Colonization on Cucumber Root and Enhancement of Chlorimuron-ethyl Degradation in the Rhizosphere by Hansschlegelia zhihuaiae S113 and Root Exudates

Abstract

The colonization of Hansschlegelia zhihuaiae S113 and its degradation of the herbicide chlorimuron-ethyl in the cucumber rhizosphere was investigated. The results reveal that S113 colonized the cucumber roots (2.14 × 10cells per gram of roots) and were able to survive in the rhizosphere (maintained for 20 d). The root exudates promoted colonization on roots and increased the degradation of chlorimuron-ethyl by S113. Five organic acids in cucumber-root exudates were detected and identified by HPLC. Citric acid and fumaric acid significantly stimulated S113 colonization on cucumber roots, with 18.4 and 15.5% increases, respectively, compared with the control. After irrigation with an S113 solution for 10 days, chlorimuron-ethyl could not be detected in the roots, seedlings, or rhizosphere soil, which allowed for improved cucumber growth. Therefore, the degradation mechanism of chlorimuron-ethyl residues by S113 in the rhizosphere could be applied in situ for the bioremediation of chlorimuron-ethyl contaminated soil to ensure crop safety.

Insights Into the Biodegradation of Lindane (γ-Hexachlorocyclohexane) Using a Microbial System

“…The bacterial degradation of lindane and other xenobiotics are widely reported (Chen et al, 2012(Chen et al, , 2013Yang et al, 2018;Zhang H. et al, 2018;Bhatt et al, 2020c). Bacterial cells use organic pollutants as a sole source of carbon and nitrogen (Chen et al, 2011(Chen et al, , 2014Zhan et al, 2018b;Lin et al, 2020).…”

“…They also generate highly toxic compounds during the degradation process (Manickam et al, 2006;Usman et al, 2014;Dominguez et al, 2018a,b;Jung et al, 2018;Huang et al, 2019). However, the microbial degradation of lindane contamination is attracting increasing attention as a less expensive and more environmentally friendly alternative to conventional treatment methods Arora et al, 2017;Bajaj et al, 2017;Cycoń et al, 2017;Zhang H. et al, 2018;Bhatt et al, 2019a). The first report regarding the microbial degradation of lindane was published in 1967.…”

Combined Bioremediation of Bensulfuron-Methyl Contaminated Soils With Arbuscular Mycorrhizal Fungus and Hansschlegelia zhihuaiae S113

“…The water-swollen seeds were transferred to a glass culture dish covered with two layers of sterile, wet gauze at the bottom, and then left to germinate in the dark for three days. Maize seedlings with nearly equal lengths of root and stem were selected for further study ( Zhang et al, 2018 ).…”

The Prevention of Bio-Organic Fertilizer Fermented from Cow Manure Compost by Bacillus sp. XG-1 on Watermelon Continuous Cropping Barrier

“…Therefore, it is necessary to study the effect of the watermelon root exudates on the growth of strain XG-1 and the chemotactic response of strain XG-1 towards the root exudates and root colonization. The root exudates of watermelon planted in soil S1 applied with novel bio-organic fertilizer were collected to investigate the effect on the growth of XG-1 [32]. We inoculated a XG-1 bacterial suspension to 100 mL MSM medium to a final concentration of 10 7 CFU/mL with the addition of 2 mL watermelon root exudates, cultured at 30 • C, 180 rpm for 120 h. Each sample was collected every 24 h for OD 600 determination.…”

“…We inoculated a XG-1 bacterial suspension to 100 mL MSM medium to a final concentration of 10 7 CFU/mL with the addition of 2 mL watermelon root exudates, cultured at 30 • C, 180 rpm for 120 h. Each sample was collected every 24 h for OD 600 determination. Root colonization of XG-1 was observed qualitatively using a confocal laser-scanning microscope (CLSM, LeicaTCSSP3, Leica Microsystems Trading Co., Ltd., Shanghai, China) [32]. A qualitative detection of the chemotactic response of XG-1 towards the root exudates was also performed with minor amendments [33].…”