Ondieki Damaris K, Nyaboga Evans N, Wagacha John M, Mwaura Francis B
School of Biological Sciences, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya.
Department of Biochemistry, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya.
Int J Microbiol. 2017;2017:8684921. doi: 10.1155/2017/8684921. Epub 2017 Dec 31.
Limited nitrogen (N) content in the soil is a major challenge to sustainable and high crop production in many developing countries. The nitrogen fixing symbiosis of legumes with rhizobia plays an important role in supplying sufficient N for legumes and subsequent nonleguminous crops. To identify rhizobia strains which are suitable for bioinoculant production, characterization of rhizobia is a prerequisite. The objective of this study was to assess the morphological and genetic diversity of rhizobia that nodulates cowpea in agricultural soils of lower eastern Kenya. Twenty-eight rhizobia isolates were recovered from soil samples collected from farmers' fields in Machakos, Makueni, and Kitui counties in lower eastern Kenya and characterized based on morphological characteristics. Thirteen representative isolates were selected and characterized using BOX repetitive element PCR fingerprinting. Based on the dendrogram generated from morphological characteristics, the test isolates were distributed into two major clusters at a similarity of 75%. Phylogenetic tree, based on BOX repetitive element PCR, grouped the isolates into two clusters at 90% similarity level. The clustering of the isolates did not show a relationship to the origin of soil samples, although the isolates were genetically diverse. This study is a prerequisite to the selection of suitable cowpea rhizobia to develop bioinoculants for sustainable crop production in Kenya.
土壤中有限的氮含量是许多发展中国家实现可持续高产作物生产面临的主要挑战。豆科植物与根瘤菌的固氮共生关系在为豆科植物及后续非豆科作物提供充足氮素方面发挥着重要作用。为了鉴定适合用于生产生物菌剂的根瘤菌菌株，对根瘤菌进行特性描述是先决条件。本研究的目的是评估肯尼亚东部低地农业土壤中能使豇豆结瘤的根瘤菌的形态和遗传多样性。从肯尼亚东部低地马查科斯、马库埃尼和基图伊县农民田地采集的土壤样本中分离出28株根瘤菌，并根据形态特征进行了特性描述。选取13株代表性菌株，采用BOX重复元件PCR指纹图谱技术进行特性描述。根据形态特征生成的树状图，测试菌株在相似度为75%时被分为两个主要类群。基于BOX重复元件PCR构建的系统发育树，在相似度为90%时将菌株分为两个类群。尽管菌株在遗传上具有多样性，但菌株的聚类情况与土壤样本的来源并无关联。本研究是选择合适的豇豆根瘤菌以开发生物菌剂用于肯尼亚可持续作物生产的先决条件。
