Phosphate solubilization by fungi with nematicidal potential

Abstract

We evaluated the nematicidal potential and phosphate solubilization ability of the fungal species Geomyces pannorum and Paecilomyces carneus, which are associated with the potato cyst nematode Globodera rostochiensis. In a broth medium containing calcium phosphate, the two fungi solubilized between 67%-96% of the insoluble phosphorus that was present in the medium, and in a broth medium containing iron phosphate, the phosphorus that was solubilized by the two fungi ranged between 2%-13%. In a greenhouse experiment, G. pannorum and P. carneus were applied to soil that was naturally infested with G. rostochiensis and planted with Avena sativa. The fungi increased the available phosphorus in the soil by more than 30%, and Paecilomyces carneus also reduced the nematode population by 71%. This study is the first to report on the ability of G. pannorum and P. carneus to increase the available phosphorus in the soil, suggesting that these fungal species may have potential uses in agricultural soils with insoluble phosphorus. Moreover, this study provides a new alternative that contributes to the sustainable management of crops with bio-agents that have dual activity; they increase the available phosphorus in the soil and mitigate plant parasitic nematodes.

Paecilomyces and Its Importance in the Biological Control of Agricultural Pests and Diseases

“…There are many examples where Paecilomyces spp. act as nematicidal agents, especially against Meloidogyne spp., but also against other genera such as Globodera [ 52 ], Rotylenchulus, Heterodera , Xiphinema or Pratylenchus [ 51 ] ( Table 2 ). One example is the use of P. lilacinus and P. fumosoroseus against M. incognita or M. javanica , which drastically reduces their populations [ 44 , 51 , 148 , 149 ], in both in vitro [ 43 , 87 ] and field tests [ 50 , 150 ].…”

“…Numerous species of the genus Paecilomyces produce a wide variety of secondary metabolites with different chemical structures and diverse biological activities, such as herbicidal [ 45 ], insecticidal [ 46 , 47 ], bactericidal [ 48 ], fungicidal [ 49 ], nematicidal [ 50 , 51 , 52 ] or cytotoxic [ 53 ]. There are also descriptions of metabolites with antitumour activity [ 54 , 55 ] or enzyme inhibitors, such as Paecilomide, which acts as an acetylcholinesterase inhibitor and can be used to control human diseases such as Alzheimer’s [ 56 ].…”

Paecilomyces variotii as A Plant-Growth Promoter in Horticulture

“…Phosphate solubilization was detected by the formation of transparent zones surrounding fungal colonies in both media [41]. For the quantitative estimation of phosphate solubilization, a modified version of the procedure by Lima-Rivera [42] was followed. Flasks (250 mL capacity) containing 50 mL of NBRIP broth were inoculated with two disks of agar (5 mm diameter) that had been taken from pure cultures of P. variotii.…”

Filamentous fungi in biological control: current status and future perspectives

“…Phosphorus can be found in great amounts in soil; however it is not in an assimilable form. Insoluble forms are not available for plant uptake, so fungal action on these substrates modify them, allowing to provide this essential element to plants (Rinu and Pandey, 2011;Lima-Rivera et al, 2016).…”