Phosphate-solubilizing characteristic of a Penicillium pinophilum strain JP-NJ4

Abstract:

[Objective] The shortage of phosphorus in the soil is one of the causes for declining of Pinus massoniana stands. One fungal strain Penicillium pinophilum JP-NJ4 which had strong capability to soluble phosphate was isolated from Pi. massoniana rhizosphere early. The research studied on inorganic phosphorus and organophosphorus-solubilizing capability of the strain. [Methods] Phosphate-solubilizing efficiencies on different phosphorus compounds, secretion of organic acids and enzymes of P. pinophilum JP-NJ4 were measured. Then phosphate-solubilizing characteristics of JP-NJ4 were analyzed. [Results] Four insoluble inorganic phosphates were used as a sole phosphorus resource for P. pinophilum JP-NJ4. The results showed that the strain JP-NJ4 had the highest phosphate-solubilizing capability for Ca3(PO4)2. The capacity to solubilize four inorganic phosphates was Ca3(PO4)2>AlPO4>CaHPO4·2H2O>FePO4·4H2O. It revealed that P. pinophilum JP-NJ4 mainly secreted gluconic acid, oxalic acid and malonic acid. The results of determining the activity of phytase and phosphatase showed that the phosphatase activity of the strain is higher. The strain JP-NJ4 also had certain phytase activity. The strain had a promising biodegradation function and its degradation rate of glyphosate reached 49.6%. [Conclusion] It showed that different chemical bonds had different effects on phosphate-solubilizing capability of the strain JP-NJ4. Phosphate-solubilizing capability and pH of fermentation broth was negatively correlated. Gluconic acid and oxalic acid had predominance in solubilizing Ca3(PO4)2 and AlPO4. The tested strain JP-NJ4 had an excellent phosphate-solubilizing function and great application potential on forestry biological fertilizer.

Key words:Pinus massoniana, Phosphate-solubilizing fungi, Inorganic phosphorus, Organic phosphorus