内蒙古荒漠灌木根际解磷菌多样性及其解磷和产铁载体能力

为深入挖掘解磷菌资源，采用无机磷和有机磷培养基对内蒙古荒漠灌木根际解磷菌（phosphorus-solubilizing bacteria，PSB）进行分离筛选，以16S rRNA基因序列初步分析PSB的分类地位；采用钼锑钪比色法和钒钼比色法分别测定菌株的解无机磷和有机磷能力；采用铬天青S（CAS）蓝色平板法筛选可产铁载体的菌株，根据分光光度法定量测定产铁载体能力.结果表明:从荒漠灌木根部共分离到62株解磷细菌，分属6纲和21属，其中放线菌纲（Actinobacteria，32.26%）为最优势菌纲，芽孢杆菌属（Bacillus，17.74%）为最优势菌属；其中23株菌可以使PVK培养基变色，解无机磷能力较强，为4.2~33.99 g/mL；32株菌可在有机磷培养基上生长，其解有机磷能力为0.30~191.03 IU；有22株菌具有产铁载体能力，其铁载体的相对含量（A_s/A_r）范围为0.47~0.99.研究显示:内蒙古荒漠灌木根际PSB类群多样，且不同灌木间PSB组成差异较为明显；含有多种较高解有机磷能力和产铁载体能力的PSB菌株是多种植物根际促生菌的重要来源. 

Diversity of Phosphorus-Solubilizing Bacteria in Rhizosphere of Desert Shrubs in Inner Mongolia and Their Phosphorus-Solubilizing and Siderophore-Producing Capabilities

Phosphorus-solubilizing bacteria (PSB) in soil play a fundamental role in the transformation of phosphorus. In order to excavate PSB resources, PSB was isolated from the rhizosphere of desert shrubs in Inner Mongolia, and its phosphorus-solubilizing and siderophore-producing capabilities were analyzed. The PSB was isolated in inorganic and organic phosphorus media, and identified through PCR based on 16S rRNA gene. Spectrophotometry of molybdate-antimony-scandium and vanadium-ammonium-molybdate was used to measure the inorganic and organic phosphorus-solubilizing capabilities, respectively. chrome azurol S (CAS) blue plate and spectrophotometer were used for qualitative screening the strains and quantitative determination of their products. The results showed that a total of 62 strains were isolated, including 6 phyla and 21 genera. Phylum Actinobacteria (32.26%) and the genus Bacillus (17.74%) were predominated taxa. Among them, 23 strains changed the color of PVK medium with inorganic phosphorus-solubilizing capability of 4.2-33.99 g/mL; 32 strains grew on organic phosphorus medium with organic phosphorus-solubilizing capability of 0.30-191.03 IU; 22 strains could produce siderophore and the production capability (A_s/A_r) was 0.47-0.99. Overall, there are a variety of PSB in the rhizosphere of desert shrubs in Inner Mongolia, and there are significant differences between the shrubs. Most PSBs have high phosphorus-solubilizing and siderophore-producing capability. Thus, they can be used as an important source of plant growth-promoting rhizobacteria (PGPR).