Mehta Preeti, Walia Abhishek, Kulshrestha Saurabh, Chauhan Anjali, Shirkot Chand Karan
Department of Advance Bioenergy Research, Research and Development Centre, Indian Oil Corporation Limited, Government of India, Faridabad, New Delhi, India.
J Basic Microbiol. 2015 Jan;55(1):33-44. doi: 10.1002/jobm.201300562. Epub 2014 Jan 25.
P-solubilizing bacterial isolate CB7 isolated from apple rhizosphere soil of Himachal Pradesh, India was identified as Bacillus circulans on the basis of phenotypic characteristics, biochemical tests, fatty acid methyl esters analysis, and 16S rRNA gene sequence. The isolate exhibited plant growth-promoting traits of P-solubilization, auxin, 1-aminocyclopropane-1-carboxylate deaminase activity, siderophore, nitrogenase activity, and antagonistic activity against Dematophora necatrix. In vitro studies revealed that P-solubilization and other plant growth-promoting traits were dependent on the presence of glucose in PVK medium and removal of yeast extract had no significant effect on plant growth-promoting traits. Plant growth-promoting traits of isolate CB7 were repressed in the presence of KH2 PO4 . P-solubilization activity was associated with the release of organic acids and a drop in the pH of the Pikovskaya's medium. HPLC analysis detected gluconic and citric acid as major organic acids in the course of P-solubilization. Remarkable increase was observed in seed germination (22.32%), shoot length (15.91%), root length (25.10%), shoot dry weight (52.92%) and root dry weight (31.4%), nitrogen (18.75%), potassium (57.69%), and phosphorus (22.22%) content of shoot biomass over control. These results demonstrate that isolate CB7 has the promising PGPR attributes to be developed as a biofertilizer to enhance soil fertility and promote plant growth.
从印度喜马偕尔邦苹果根际土壤中分离出的解磷细菌菌株CB7，根据其表型特征、生化试验、脂肪酸甲酯分析和16S rRNA基因序列，被鉴定为环状芽孢杆菌。该菌株表现出多种促进植物生长的特性，包括解磷、产生生长素、1-氨基环丙烷-1-羧酸脱氨酶活性、产生铁载体、固氮酶活性以及对恶疫霉的拮抗活性。体外研究表明，解磷和其他促进植物生长的特性取决于PVK培养基中葡萄糖的存在，去除酵母提取物对促进植物生长的特性没有显著影响。菌株CB7的促进植物生长特性在KH2PO4存在时受到抑制。解磷活性与有机酸的释放以及Pikovskaya培养基pH值的下降有关。高效液相色谱分析检测到解磷过程中主要的有机酸为葡萄糖酸和柠檬酸。与对照相比，种子发芽率（22.32%）、地上部长度（15.91%）、根长度（25.10%）、地上部干重（52.92%）和根干重（31.4%）、地上部生物量中的氮（18.75%）、钾（57.69%）和磷（22.22%）含量均有显著增加。这些结果表明，菌株CB7具有作为生物肥料开发以提高土壤肥力和促进植物生长的良好促生植物根际细菌属性。
