Effect of pesticides on Exopolysaccharide (EPS) production, antibiotic sensitivity and phosphate solubilization by Rhizobial isolates from Sesbania bispinosa in Bangladesh

Abstract

Rhizobium spp. retains a symbiotic relationship with leguminous plants including Sesbania bispinosa by fixing N 2 through nodule formation. Several researches suggest that Exopolysaccharides (EPSs) are required for nodule formation. Rhizobial growth parameters as well as the EPS production are affected by the presence of pesticides. The present investigation was performed using three different pesticides which were Imitaf 20SL (Insecticide), Tafgor 40EC (Insecticide) and Tilt 250EC (Fungicide). Production of EPS was exceptionally increasing with the escalating concentrations of pesticides. The effects of pesticides were also observed on the antibiotic resistance of these organisms. Some gained resistance against Kanamycin while some got more sensitive than before. Detection of nodC gene and nifH gene ensured the fact that they are the residents of rhizobia bacteria. This study uncovers the fact that extensive use of pesticides may cause an unfavourable environment for survival of rhizobia and a decrease in EPS production resulting in poor N 2 fixation and thus affecting the whole agricultural economy of a country.

Biodegradation of chlorpyrifos by soil bacteria and their effects on growth of rice seedlings under pesticide-contaminated soil

“…Similarly, the plant growth-promoting traits of beneficial soil bacteria decreased in pesticide concentrations exceeding the recommended doses (Madhaiyan et al 2006). Therefore, pesticides may cause a decrease in IAA and EPS production by microorganisms (Sultana et al 2019). This study indicates that the amounts of EPS produced by all strains tested were inhibited by CP toxicity.…”

Diversity of Plant Growth Promoters (PGP) Isolated from Agricultural Fields of Bangladesh

“…Placing organisms on Pikovskaya's agar and incubating them for 48 hours at 30°C 10,[13][14] . phosphate digestion was confirmed by a clear zone surrounding the growth line; failure was shown by a blue, purple, or black zone.…”