Berseem clover (T. alexandrinum) is the main forage legume crop used as animal feed in Egypt. Here, eighty rhizobial isolates were isolated from root nodules of berseem clover grown in different regions in Egypt and were grouped by RFLP-16S rRNA ribotyping. Representative isolates were characterized using phylogenetic analyses of the 16S rRNA, rpoB, glnA, pgi, and nodC genes. We also investigated the performance of these isolates using phenotypic tests and nitrogen fixation efficiency assays. The majority of strains (<90%) were closely related to Rhizobium aegyptiacum and Rhizobium aethiopicum and of the remaining strains, six belonged to the Rhizobium leguminosarum genospecies complex and only one strain was assigned to Agrobacterium fabacearum. Despite their heterogeneous chromosomal background, most of the strains shared nodC gene alleles corresponding to symbiovar trifolii. Some of the strains closely affiliated to R. aegyptiacum and R. aethiopicum had superior nodulation and nitrogen fixation capabilities in berseem clover, compared to the commercial inoculant (Okadein®) and N-added treatments. R. leguminosarum strain NGB-CR 17 that harbored a nodC allele typical of symbiovar viciae, was also able to form an effective symbiosis with clover. Two strains with nodC alleles of symbiovar trifolii, R. aegyptiacum strains NGB-CR 129 and 136, were capable of forming effective nodules in Phaseolus vulgaris in axenic greenhouse conditions. This adds the symbiovar trifolii which is well-established in the Egyptian soils to the list of symbiovars that form nodules in P. vulgaris.

Berseem三叶草（T. alexandrinum）是埃及主要的饲料用豆类作物，用作动物饲料。在这里，从埃及不同地区生长的贝叶三叶草的根瘤中分离出80个根瘤菌分离株，并通过RFLP-16S rRNA核型分型。使用16S rRNA，rpoB，glnA，pgi和nodC基因的系统发育分析来表征代表性分离株。我们还使用表型测试和固氮效率分析研究了这些分离株的性能。大多数菌株（<90％）的密切相关根瘤菌aegyptiacum和根瘤菌aethiopicum，其余菌株，六属于豆科根瘤菌属基因属复合体，仅一种菌株被分配到农杆菌中。尽管它们的染色体背景不同，但大多数菌株共享对应于三叶草共生体的nodC基因等位基因。与商业接种剂（Okadein®）和添加N的处理方法相比，与埃及古埃及拟杆菌（R. aegyptiacum）和aethiopicum（R. aethiopicum）密切相关的某些菌株在伯西弗三叶草中具有更好的结瘤和固氮能力。豆科根瘤菌菌株NGB-CR 17窝藏一个NODC等位基因典型的symbiovar蚜，也能够形成具有三叶草有效共生。两株nodC共生植物三叶草（R. aegyptiacum菌株NGB-CR 129和136）的等位基因能够在菜豆温室条件下在菜豆中形成有效的结节。这将在埃及土壤中建立良好的三生共生植物添加到寻常小菜蛾中形成结核的共生生物列表中。