Biodegradation of 2,4-dichlorophenol by lichen-originated endophytic bacteria and their potential to alleviate its phytotoxic effects on wheat seedlings

The objective of this study was to assess the potential of endophytic bacteria isolated from lichens consortium on the biodegrade of 2,4-Dichlorophenol (2,4-DCP), alleviate its detrimental impacts on crop growth. Additionally, the study evaluated the influence of byproducts formed during the degradation process through the isolates crop growth. After finding that these bacteria could use 2,4-DCP as the sole carbon source and tolerate its concentrations up to 2000 ppm, they were applied to wheat seedlings exposed to 500 ppm 2,4-DCP under hydroponic conditions. LC-MS analysis findings revealed that all these isolates were able to degrade 2,4-DCP at impressive rate of approximately 99 % by predominantly producing the same degradation byproducts. Following this, the seedlings were also subjected to testing for the effects of degradation byproducts of 2,4-DCP by the same isolates. 2,4-DCP alone had negative impact on photosynthesis, plant growth, but the bacterial isolates reduced these adverse effects. Degradation byproducts of 2,4-DCP also improved the same parameters compared to both control and 2,4-DCP alone. 2,4-DCP induced oxidative stress by increasing the production of reactive oxygen species, decreasing antioxidant enzyme activities leading to damage to cell membranes through lipid peroxidation. Both isolates and the degradation products of 2,4-DCP significantly modulated the activities of antioxidant enzymes, thus alleviating oxidative stress in the seedlings exposed to 2,4-DCP. These results suggest that the endophytic bacteria isolated from the lichen consortium have promising potential for the biodegradation of 2,4-DCP and amelioration of its detrimental effects on crop growth, indicating their potential applications in sustainable agricultural practices