Effect of an Organophosphate Pesticide, Monocrotophos, on Phosphate-Solubilizing Efficiency of Soil Fungal Isolates

Abstract

Soil is a sink of pesticide residues as well as microorganisms. Fungi are well known for solubilization of inorganic phosphates, and this activity of fungal isolates may be affected by the presence of pesticide residues in the soil. In the present study, five generically different fungal isolates, viz. Aspergillus niger JQ660373, Aspergillus flavus, Penicillium aculeatum JQ660374, Fusarium pallidoroseum and Macrophomina sp., were tested and compared for their phosphate-solubilizing ability in the absence and presence of monocrotophos (500 mg L(-1)). After 168 h of incubation, four times high amount of tricalcium phosphate was solubilized by isolates in the growth medium containing monocrotophos in comparison to control (without monocrotophos). Concurrently, 78 % of the applied monocrotophos was degraded by these fungal isolates. Kinetics of phosphate solubilization shifted from logarithmic to power model in the presence of monocrotophos. Similarly, the phosphatase activity was also found significantly high in the presence of monocrotophos. The combined order of phosphate solubilization as well as monocrotophos degradation was found to be A. niger JQ660373 > P. aculeatum JQ660374 > A. flavus > F. pallidoroseum > Macrophomina sp. On the contrary, phosphate solubilization negatively correlated with the pH of the growth medium. Hence, it could be concluded that these fungal species efficiently solubilize inorganic phosphates and monocrotophos poses a positive effect on their ability and in turn degraded by them. To the best of our knowledge, this is the first report on P solubilization by Macrophomina sp. and F. pallidoroseum.

Multifarious Characterization and Efficacy of Three Phosphate-Solubilizing Aspergillus Species as Biostimulants in Improving Root Induction of Cassava and Sugarcane Stem Cuttings

“…Moreover, several previous studies have reported that the capacity to solubilize phosphatases was contingent on the specific fungal genus, species, and strain [14,40,44,70,71]. Our results are corroborated by previous studies that demonstrated that PSF belonging to the genera Aspergillus, Fusarium, Macrophomina, Penicillium, Talaromyces, and Trichoderma produced phosphatases for solubilizing phosphate minerals [41,[72][73][74][75]. Additionally, the ability to produce organic acids for solubilizing various forms of insoluble phosphorus sources relies on the specific fungal genus, species, and strain [41,[76][77][78].…”

Impact of Pesticides on Selected Soil Mycoflora

“…Soil is a sink of pesticide residues as well as microorganisms. Fungi are well known for solubilization of inorganic phosphates and this activity of fungal isolates may be affected by the presence of pesticide residues in the soil (Jain et al, 2015). Pesticides are extensively used in agriculture as a part of pest control strategies.…”