Khalifa Ashraf Y Z, Alsyeeh Abdel-Moneium, Almalki Mohammed A, Saleh Farag A
Biological Sciences Department, College of Science, King Faisal University, Saudi Arabia; Botany and Microbiology Department, Faculty of Science, University of Beni-Suef, Beni-Suef, Egypt.
Biological Sciences Department, College of Science, King Faisal University, Saudi Arabia.
Saudi J Biol Sci. 2016 Jan;23(1):79-86. doi: 10.1016/j.sjbs.2015.06.008. Epub 2015 Jun 17.
The aim of the present study was to characterize the endophytic bacterial strain designated MSR1 that was isolated from inside the non-nodulating roots of Medicago sativa after surface-sterilization. MSR1 was identified as Enterobacter cloacae using both 16S rDNA gene sequence analysis and API20E biochemical identification system (Biomerieux, France). Furthermore, this bacterium was characterized using API50CH kit (Biomerieux, France) and tested for antibacterial activities against some food borne pathogens. The results showed that E. cloacae consumed certain carbohydrates such as glycerol, d-xylose, d-maltose and esculin melibiose as a sole carbon source and certain amino acids such as arginine, tryptophan ornithine as nitrogen source. Furthermore, MSR1 possessed multiple plant-growth promoting characteristics; phosphate solubility, production of phytohormones acetoin and bioactive compounds. Inoculation of Pisum sativum with MSR1 significantly improved the growth parameters (the length and dry weight) of this economically important grain legume compared to the non-treated plants. To our knowledge, this is the first report addressing E. cloacae which exist in roots of alfalfa growing in Al-Ahsaa region. The results confirmed that E. cloacae exhibited traits for plant growth promoting and could be developed as an eco-friendly biofertilizer for P. sativum and probably for other important plant species in future.
本研究的目的是对从表面消毒后的紫花苜蓿非结瘤根内部分离出的内生细菌菌株MSR1进行特性分析。通过16S rDNA基因序列分析和API20E生化鉴定系统（法国生物梅里埃公司），MSR1被鉴定为阴沟肠杆菌。此外，使用API50CH试剂盒（法国生物梅里埃公司）对该细菌进行了特性分析，并测试了其对一些食源性病原体的抗菌活性。结果表明，阴沟肠杆菌以甘油、d-木糖、d-麦芽糖和七叶苷蜜二糖等某些碳水化合物作为唯一碳源，以精氨酸、色氨酸、鸟氨酸等某些氨基酸作为氮源。此外，MSR1具有多种促进植物生长的特性；解磷能力、植物激素3-羟基丁酮和生物活性化合物的产生。与未处理的植物相比，用MSR1接种豌豆显著改善了这种经济上重要的豆类作物的生长参数（长度和干重）。据我们所知，这是第一份关于存在于阿哈萨地区生长的苜蓿根中的阴沟肠杆菌的报告。结果证实，阴沟肠杆菌表现出促进植物生长的特性，未来可能会被开发成为一种对豌豆以及其他重要植物物种生态友好的生物肥料。
