1株溶磷真菌的分离鉴定及溶磷特性分析

Screening,identification and phosphate solubilizing properties of a fungi strain isolated from saline-alkali land

【目的】对从长春市农安县西盐碱地土壤样品中筛选出的溶磷能力强的菌株进行溶磷特性研究,为盐碱地改良提供菌种资源。【方法】以160份采自长春市农安县西的盐碱土为样品,利用NBRIP培养基对菌株进行筛选,对筛选出的菌种P1通过形态学特征、培养特征和ITSrDNA序列分析进行鉴定,分析该菌株溶解磷酸钙、磷酸铝和磷酸铁的能力,通过L25(54)正交试验,以溶磷量为考察指标,碳源、氮源、pH和磷酸钙为考察因素,分析该菌株培养的最优条件,最后分析了该菌株利用硝酸盐的能力。【结果】从160份供试土壤中分离出307株溶磷菌,其中菌株P1生长表现最好。经鉴定菌株P1为绳状青霉(Penicillium funiculosum),其96h能将9cm培养皿内的白色无机磷固体培养基溶解至完全透明;在NBRIP液体培养基中培养168h,溶磷量可达1 064.21μg/mL。菌株P1对磷酸铝和磷酸铁有较好的溶解能力,最高溶磷量为96.02和15.34μg/mL;在磷酸钙、磷酸铝和磷酸铁的培养液中,菌株P1的溶磷量与pH值呈显著负相关。以可溶性淀粉为碳源、蛋白胨为氮源、初始pH值为7、底物磷酸钙用量为10g/L时,培养菌株P1的溶磷效果最好,溶磷量达1 276.75μg/mL。此外,菌株P1对硝态氮也有一定的利用能力,在以硝酸钠、硝酸钾为唯一氮源的液体培养基中培养168h后,使硝态氮含量分别下降了92.90和196.79μg/mL。【结论】从盐碱土中筛选到1株对难溶性磷酸盐有较强溶解能力、对硝态氮有一定利用能力的绳状青霉P1菌株,其具有良好的应用前景。

【Objective】This paper investigated the phosphate solubilizing properties of a fungi strain screened from west saline-alkali land soil samples from Nong＇an,Changchun to provide strains resources for improving saline-alkali land.【Method】A total of 160 samples were collected from Xianshan soil in Nong＇an,Changchun,and strains were screened by NBRIP medium.The strains were then identified by morphological characteristics,culture characteristics and ITS rDNA sequence analysis,and their capacity of solubilizing calcium phosphate,aluminum phosphate and iron phosphate was analyzed.The effects of carbon source,nitrogen source,pH and calcium phosphate on phosphate solubilizing amount were analyzed and the optimal conditions were obtained by orthogonal design L25（54）.The ability of the strain to utilize nitratewas also analyzed.【Result】A total of 307 phosphate-solubilizing strains were isolated from 160 soil samples,and the growth of strain P1 was the best,which was identified as Penicillium funiculosum.All inorganic phosphorus solid medium in 9 centimeter petri dish was dissolved within 96 hours and the phosphate solubilizing capacity was up to 1 064.21μg/mL in NBRIP liquid within 168 hours.P1 strain had a good ability to dissolve aluminum phosphate and iron phosphate with the highest soluble phosphorus amounts of96.02μg/mL and 15.34μg/mL.The phosphate solubilizing capacity and pH value had significantly negative correlation in liquid medium of calcium phosphate,aluminum phosphate and iron phosphate.The highest capacity of solubilizing phosphate（1 276.75μg/mL）was obtained when strain P1 was supplied with soluble starch and peptone as carbon source and nitrogen source at the initial pH of 7 and the substrate calcium phosphate dosage of 10 g/L.Strain P1 had certain ability to use nitrate nitrogen,it decreased nitrate nitrogen by 92.90 and 196.79μg/mL when sodium nitrate and potassium nitrate were the sole nitrogen source after 168 hours.【Conclusion】P.funiculosum P1 with strong ability of dissolving insoluble phosphate and using nitrate nitrogen was isolated from saline-alkali soil.It has a good application prospect.