Screening, identification and salt-tolerant characteristics of phosphate-solubilizing fungi

Abstract:

[Background] Salinity is one of the most brutal environmental factors limiting the productivity of crop plants and soil quality. There is a need to develop simple and low cost biological methods for salinity stress management. [Objective] The fungi with phosphate solubilizing properties and salt-tolerance were selected from different soil samples and biological fertilizer in order to provide good application candidate as soil remediation. [Methods] The method of plate culture was used to screen the fungi with phosphate solubilizing ability. The classification status of the strains were determined preliminarily based on internal transcribed spacer (ITS) sequence analysis. The effects of NaCl on phosphate solubilizing ability of four isolates were measured. The correlation between phosphate solubilizing capability and pH value was analyzed. [Results] A total of 16 phosphate solubilizing fungi were obtained, and 4 strains of them increased the growth of rice germination significantly, including 1 strain (MF-1) identified as Trichoderma longibarchiatum and 3 strains (SD-2, XJ-7 and HLJ-3) identified as Talaromyces. The tolerance of salt depend on different strains. The salt-tolerance of SD-2 and XJ-7 were better than MF-1 and HLJ-3. XJ-7 was able to grow in media with 5% NaCl, the P solubilizing rate was 9.50%. HLJ-3 was able to grow in media with 1% NaCl, the P solubilizing rate was 6.93%. The P solubilizing rate of SD-2 and MF-1 were 9.07% and 3.73% without NaCl, respectively. The phosphate solubilizing capability and pH value had significant negative correlation in liquid medium for Talaromyces. [Conclusion] The present study found that the phosphate solubilizing ability of 4 strains were significantly different in different saline environments. These phosphate solubilizing fungi have great application prospect as biological fertilizer in saline soil.