Effect of Roundup ۳۶۰ SL on Survival of Pseudomonas sp. SP۰۱۱۳ Strain and Effective Control of Phytopathogens

Studies on determination of the effect of herbicides on survivability of Plant Growth Promoting Bacteria have a strategic usefulness in determination of plant health and the fate of applied agrochemicals in agroecosystem. Antimicrobial potential was assessed using estimation of a minimum inhibitory concentration of the Roundup ۳۶۰ SL against Pseudomonas sp. A quantitative analysis of bacteria was performed, and the tendency of physicochemical changes in the mineral medium was evaluated during long-term exposure to the herbicide. Furthermore, the antagonism of the SP۰۱۱۳ strain against F. culmorum and F. oxysporum under stress conditions caused by Roundup® ۳۶۰ SL was verified. It was demonstrated that use of the undiluted and ۲.۶-fold diluted product resulted in the inhibition of growth of the investigated strain. Pseudomonas sp. SP۰۱۱۳ showed survivability and resistance to near recommended dose concentration of Roundup® ۳۶۰ SL. The possibility of bacterial development on the Tryptic Soy Agar (TSA) medium at contact concentrations of ۱۴.۴ and ۵.۴ mg mL-۱, as per the diluents quantity declared by the producer, indicates the role of cofactors such as: adiuvant or pH, redox potential (mV) or salinity. They comprise pH change, oxidation and salinity that may be due to the reaction of the active substance of the herbicide with mineral nutrient ingredients. The high salinity of environment, as a result of the reactions with the ingredients contained in the medium, is characteristic for concentrations higher than those recommended in practice. Furthermore, it was found that glyphosate limits the growth of fungi of the Fusarium genus, which support plant protection using strain SP۰۱۱۳.

Keywords:

Biocontrol , Glyphosate , Plant growth promotion bacteria , PGPB