两株溶磷真菌的筛选、鉴定及溶磷效果的评价

Isolation and evaluation of two phosphate-dissolving fungi

摘要:

[目的]从作物根围土壤中筛选高效溶磷菌株。[方法]结合溶磷圈筛选法和钼锑抗比色法评价菌株的溶磷能力；利用菌株的形态学特性、培养性状和微管蛋白β-tubulin基因序列分析方法进行菌株的鉴定；采用气相色谱-质谱法（GC-MS）对溶磷菌的产酸物质进行分析；并用平板亲和性实验测定菌株间的兼容性。[结果]筛选得到2株高效溶磷菌株P1-1、P2-2；经鉴定，菌株P1-1为黑曲霉（Aspergillus niger），P2-2为塔宾曲霉（A.tubingensis）。2株溶磷菌株的产酸物质相同，均为草酸、葡萄糖酸、乳酸和甘油酸。这2株溶磷菌与杀线虫功能菌株淡紫拟青霉（Purpureocillium lilacinum）、橄榄色链霉菌（Streptomyces olivaceus）和苍白杆菌（Ochrobactrum pseudogrignonense）兼容性好。2菌株分别在Ca₃（PO₄）₂、Zn₃（PO₄）₂、羟基磷灰石为磷源的无机磷固体培养基中25℃培养5 d，测定溶磷圈的直径（D）与菌落直径（d），通过计算其比值D/d的大小对比，以及在Ca₃（PO₄）₂、Zn₃（PO₄）₂、羟基磷灰石为磷源的液体培养基中培养5 d，测定发酵液中有效磷含量进行比较后判定，这2株溶磷菌溶解磷的能力强且效果相当。[结论]获得了2株高效的溶磷真菌。它们能活化多种难溶性磷源，同时伴随挥发性酸性物质的产生；2个菌株与1组杀根结线虫微生物菌群兼容性均良好。

关键词:溶磷真菌;曲霉属;筛选;复合微生物菌剂

Abstract:

[Objective] To isolate phosphate-solubilizing strains from crop rhizosphere soil for functional composite microbial community and bio-fertilizer production.[Methods] The phosphate-solubilizing capacity was evaluated by the halo zone of dissolving phosphate and molybdenum antimony colorimetric. Phosphate-solubilizing fungi were identified based on their morphological and cultural characteristics and β-tubulin sequence analysis. Acid producing substances of phosphate solubilizing fungus were analyzed by GC-MS and the biological compatibility of microbial strains was tested by medium method.[Results] Two phosphate-solubilizing fungi were screened from soybean rhizosphere soil, P1-1, P2-2, which were identified as Aspergillus niger and A. tubingensis. The volatile acids (oxalic acid, gluconic acid, lactic acid and glycerol acid) were detected in both fungi. They were compatible with a group of nematicidal microorganisms (Purpureocillium lilacinum + Streptomyces olivaceus + Ochrobactrum pseudogrignonense). The D/d (diameter of the halo zone/diameter of the colony) value of P1-1 and P2-2 was detected after culturing on three media with Ca₃(PO₄)₂, Zn₃(PO₄)₂ and phosphorite at 25℃ for 5 days, and the available phosphorus contents were detected after 5 days culturing in liquid medium containing Ca₃(PO₄)₂, Zn₃(PO₄)₂ and phosphorite. The results indicated that the two phosphate-dissolving fungi had similar capability in dissolving phosphorus.[Conclusion] Two high-efficient phosphate solubilize fungi were obtained, and they could activate a variety of insoluble phosphorus sources accompanied by the production of volatile acidic substances. The two strains showed good biological compatibility with a group of nematicidal microorganisms.

Key words:phosphate-solubilizing fungi;Aspergillus;screening;multi-microbial agent