Isolation and characterization of two phosphate-solubilizing fungi from rhizosphere soil of moso bamboo and their functional capacities when exposed to different phosphorus sources and pH environments

Abstract

Phosphate-solubilizing fungi (PSF) generally enhance available phosphorus (P) released from soil, which contributes to plants’ P requirement, especially in P-limiting regions. In this study, two PSF, TalA-JX04 and AspN-JX16, were isolated from the rhizosphere soil of moso bamboo (Phyllostachys edulis) widely distributed in P-deficient areas in China and identified as Talaromyces aurantiacus and Aspergillus neoniger, respectively. The two PSF were cultured in potato dextrose liquid medium with six types of initial pH values ranging from 6.5 to 1.5 to assess acid resistance. Both PSF were incubated in Pikovskaya’s liquid media with different pH values containing five recalcitrant P sources, including Ca3(PO4)2, FePO4, CaHPO4, AlPO4, and C6H6Ca6O24P6, to estimate their P-solubilizing capacity. No significant differences were found in the biomass of both fungi grown in media with different initial pH, indicating that these fungi could grow well under acid stress. The P-solubilizing capacity of TalA-JX04 was highest in medium containing CaHPO4, followed by Ca3(PO4)2, FePO4, C6H6Ca6O24P6, and AlPO4 in six types of initial pH treatments, while the recalcitrant P-solubilizing capacity of AspN-JX16 varied with initial pH. Meanwhile, the P-solubilizing capacity of AspN-JX16 was much higher than TalA-JX04. The pH of fermentation broth was negatively correlated with P-solubilizing capacity (p<0.01), suggesting that the fungi promote the dissolution of P sources by secreting organic acids. Our results showed that TalA-JX04 and AspN-JX16 could survive in acidic environments and both fungi had a considerable ability to release soluble P by decomposing recalcitrant P-bearing compounds. The two fungi had potential for application as environment-friendly biofertilizers in subtropical bamboo ecosystem.

Biotransformation of struvite by Aspergillus niger: phosphate release and magnesium biomineralization as glushinskite

“…efficiencies in this regard through proton-and ligandmediated dissolution, and to the benefit of plant growth Sayer and Gadd, 2001;Jacobs et al, 2002aJacobs et al, , 2002bFomina et al, 2004Fomina et al, , 2006Xiao et al, 2008;Li et al, 2016;Zhang et al, 2018;Adhikari and Pandey, 2019). Efficient fungal P solubilizers occur in natural soils and have also been isolated from metal-polluted habitats, and the environs of phosphate mines (Sayer et al, 1995;Xiao et al, 2008;Li et al, 2016;Zhang et al, 2018). Organic acids are a key component of mineral dissolution mechanisms in fungi (Gadd, 1999(Gadd, , 2007Gadd et al, 2014).…”

“…Most strains of A . niger have been widely reported as geoactive, and phosphate‐solubilizing capability is superior to that of many other phosphate‐solubilizing organisms (Zhang et al ., ). Therefore, the ability of this fungus to transform P‐, Mg‐ and N‐containing struvite is a worthy topic of study with important environmental implications.…”

“…Concern over P recovery is increasing because of its agricultural and industrial importance and the accelerating depletion of natural resources . The use of struvite as a plant fertilizer could improve nutrient acquisition, mitigate the loss of a potential P resource, and support plant productivity in a sustainable manner (Zhang et al, 2018;Li et al, 2019). One economic feasibility analysis, which took environmental benefits into account, concluded that phosphorus recovery, e.g.…”

“…Oxalic acid is of high importance in metal mobilization and/or immobilization due to the formation of metal-oxalate complexes and/or precipitation of insoluble metal oxalates (M n+ (C 2 O 4 ) n/2 .xH 2 O) depending on the metal and environmental conditions . Most strains of A. niger have been widely reported as geoactive, and phosphate-solubilizing capability is superior to that of many other phosphate-solubilizing organisms (Zhang et al, 2018). Therefore, the ability of this fungus to transform P-, Mg-and N-containing struvite is a worthy topic of study with important environmental implications.…”

Monazite transformation into Ce‐ and La‐containing oxalates by Aspergillus niger

“…Such a mechanism may be of importance to the biogeochemical cycling of REE because P-solubilizing fungi and bacteria are ubiquitous in soil environments (Jacobs et al, 2002;Fomina et al, 2004;Fomina et al, 2005b;Fomina et al, 2006). The solubilization of REE-bearing phosphate compounds also releases inorganic phosphate (P i ) and thus can improve soil fertility (Zhang et al, 2018). In a metallurgical process, REE-oxalate can be readily converted into REE-oxides through hightemperature treatment and therefore may also serve as a precursor for other useful REE materials (Kang et al, 2019).…”