Amelioration of Chlorpyrifos-Induced Toxicity in Brassica juncea L. by Combination of 24-Epibrassinolide and Plant-Growth-Promoting Rhizobacteria

Abstract

Pervasive use of chlorpyrifos (CP), an organophosphorus pesticide, has been proven to be fatal for plant growth, especially at higher concentrations. CP poisoning leads to growth inhibition, chlorosis, browning of roots and lipid and protein degradation, along with membrane dysfunction and nuclear damage. Plants form a linking bridge between the underground and above-ground communities to escape from the unfavourable conditions. Association with beneficial rhizobacteria promotes the growth and development of the plants. Plant hormones are crucial regulators of basically every aspect of plant development. The growing significance of plant hormones in mediating plant–microbe interactions in stress recovery in plants has been extensively highlighted. Hence, the goal of the current study was to investigate the effect of 24-epibrassinolide (EBL) and PGPRs (Pseudomonas aeruginosa (Ma), Burkholderia gladioli (Mb)) on growth and the antioxidative defence system of CP-stressed Brassica juncea L. seedlings. CP toxicity reduced the germination potential, hypocotyl and radicle development and vigour index, which was maximally recuperated after priming with EBL and Mb. CP-exposed seedlings showed higher levels of superoxide anion (O2.−), hydrogen peroxide (H2O2), lipid peroxidation and electrolyte leakage (EL) and a lower level of nitric oxide (NO). In-vivo visualisation of CP-stressed seedlings using a light and fluorescent microscope also revealed the increase in O2.−, H2O2 and lipid peroxidation, and decreased NO levels. The combination of EBL and PGPRs reduced the reactive oxygen species (ROS) and malondialdehyde (MDA) contents and improved the NO level. In CP-stressed seedlings, increased gene expression of defence enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APOX), glutathione peroxidase (GPOX), dehydroascorbate reductase (DHAR) and glutathione reductase (GPOX) was seen, with the exception of catalase (CAT) on supplementation with EBL and PGPRs. The activity of nitrate reductase (NR) was likewise shown to increase after treatment with EBL and PGPRs. The results obtained from the present study substantiate sufficient evidence regarding the positive association of EBL and PGPRs in amelioration of CP-induced oxidative stress in Brassica juncea seedlings by strengthening the antioxidative defence machinery.

The Impact of Pesticide Use on Tree Health in Riparian Buffer Zone

“…CPS toxicity was manifested by abnormal production of O 2− and H 2 O 2 in CPS-treated Brassica juncea seedlings, which drastically increased O 2− by 70.5% and H 2 O 2 by 45.7% compared to the control [ 16 ]. SOD starts the detoxification process by catalyzing the conversion of free radicals to molecular oxygen and hydrogen peroxide.…”

“…The uptake of CPS by plants was also investigated, and a reduction of growth was demonstrated [ 14 , 15 , 16 ]. Most often, the primary route by which pesticides are taken up by the plant and eventually translocated to the aboveground parts is their uptake by the roots from the aqueous solution in the soil pores [ 17 ].…”

Amelioration of Chromium-Induced Oxidative Stress by Combined Treatment of Selected Plant-Growth-Promoting Rhizobacteria and Earthworms via Modulating the Expression of Genes Related to Reactive Oxygen Species Metabolism in Brassica juncea

“…Cr exposure enhanced the activities of SOD, POD, APX, GPOX, GR, DHAR, and GST but inhibited the activity of CAT ( Table 2 ). The reduction in CAT activity might be due to excessive ROS accumulation, intrusion with the subunits, or altered synthesis ( Bakshi et al, 2021 ). A similar decrease in CAT activity was observed in Oryza sativa ( Ma et al, 2016 ), B. juncea ( Mahmud et al, 2017 ), and Zea mays ( Islam et al, 2016 ).…”

Use of plant growth regulators to reduce 2-methyl-4-chlorophenoxy acetic acid-Na (MPCA-Na) damage in cotton (Gossypium hirsutum)

“…It is necessary to use them reasonably according to the characteristics of their effects to reduce herbicide damage. 24-epibrassinolide can effectively improve the chlorophyll content and photosynthetic efficiency of plants [56,57], protect flowers and fruits [58], and reduce the occurrence of drug damage [59]. GA 3 can promote plant flowering [60], increase fruit setting rate and yield [61].…”