Synergistic rhizosphere degradation of γ-hexachlorocyclohexane (lindane) through the combinatorial plant-fungal action

Abstract

Fungi are usually involved in degradation/deterioration of many anthropogenic wastes due to their verse enzyme secretions and adaptive capabilities. In this study, five dominant fungal strains were isolated from an aged lindane polluted site, they were all mixed (100 mg each) together with pent mushroom compost (SMC) and applied to lindane polluted soil (5 kg) at 10, 20, 30, 40% and control 0% (soil with no treatment), these were used to grow M. maximus Jacq for 3 months. To establish lindane degradation, deductions such as Degradation rate (K1), Half-life (t1/2) and Degradation efficiency (DE) were made based on the analyzed lindane concentrations before and after the experiment. We also tested the presence and expressions of phosphoesterases (mpd and opd-A) and catechol 1,2-dioxygenases (efk2 and efk4) genes in the strains. The stains were identified as Aspergillus niger (KY693970); Talaromyces atroroseus (KY488464), Talaromyces purpurogenus (KY488468), Yarrowia lipolytica (KY488469) and Aspergillus flavus (KY693973) through morphological and molecular methods. Combined rhizospheric action of M. maximus and fungi speed up lindane degradation rate, initially detected lindane concentration of 45 mg/kg was reduced to 11.26, 9.34 and 11.23 mg/kg in 20, 30 and 40% treatments respectively making 79.76, 85.93 and 88.67% degradation efficiencies. K1 of 1.29 was recorded in control while higher K1 of 1.60, 1.96 and 2.18 /day were recorded in 20, 30 and 40% treatments respectively. The best t1/2 of 0.32 and 0.35 /day were recorded in 40 and 30% compared to control (0.54 /day). All the strains were also affirmed to possess the tested genes; opd was overexpressed in all the strains except KY693973 while mpd was overexpressed in KY693970, KY488464 but moderately expressed in KY488468, KY488469 and KY693973. However, efk genes were under-expressed in most of the strains except KY488469 and KY693973 which showed moderate expression of efk4. This work suggests that the synergistic association of the identified rhizospheric fungi and M. maximus roots could be used to remove lindane in soil at a limited time period and this combination could be used at large scale.

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

“…The bacteria isolated belong to Mameliella phaeodactyli, Pseudovibrio ascidiaceicola, Oceanicaulis stylophorae, Ruegeria atlantica, and other uncharacterized genera (Loredana et al, 2017). For lindane bioremediation in samples collected from different polluted sites, researchers applied novel techniques (Asemoloye et al, 2017;Salam et al, 2017;Wang et al, 2019). Pure cultures, microbial consortium, nanobiotechnology, and plantmicrobe interactions are discussed below along with their successful outcomes.…”

“…Plants also possess a remarkable ability to remove or immobilize various environmental pollutants (Asemoloye et al, 2017). A unique chemical communication occurs between plants and their rhizospheric microbes that can be used to repair the polluted environment.…”

“…The results showed that the inoculation of C. striatus with a combination of bacterial strains is a promising approach for the remediation of lindane-contaminated sites. Asemoloye et al (2017) isolated five dominant fungal strains from an aged lindane polluted site. Lindane degradation in polluted soil was reported to be more effective in response to the combined actions of plant roots and fungi.…”

Exploration of microbial stimulants for induction of systemic resistance in plant disease management

“…Also observed was the suppression of both early and late defence responses through the activation of JA signalling pathway by a plant‐growth‐promoting fungi (PGPF) called Piriformospora indica (Zuccaro et al, 2011). Transcriptome analysis has also revealed the expressions of genes encoding proteins by many PGPF which may play roles as immune suppressive effectors during root colonisation (Asemoloye, Ahmad, & Jonathan, 2017a, 2017b; Asemoloye et al, 2017; Brotman et al, 2013; Verhagen et al, 2004) both the PGPF and ISR‐inducing genes have been described in down regulation of root immune responses (Hoffland et al, 1995; Pieterse et al, 2000).…”

Identification and degradation characteristics of Bacillus cereus strain WD-2 isolated from prochloraz-manganese-contaminated soils

“…The source of pesticide residue in the environment is mainly agricultural practices through a few routes such as spray drift, surface runoff and field drainage[9]. The fate of residual pesticides was determined by various mechanisms including volatilization, chemical degradation, photodegradation, absorption, hydrolysis, enzymatic degradation and bacterial/fungal degradation[10,11]. The use of microorganisms to degrade pesticides or even macromolecular substances was dependent on their high metabolic diversity and adaptability[12].…”