Department of Plant Protection, Faculty of Agriculture, Buali Sina University, Hamedan 65178-38695, Iran.
Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca 37001, Spain.
FEMS Microbiol Lett. 2022 Jul 1;369(1). doi: 10.1093/femsle/fnac045.
The diversity of fenugreek (Trigonella foenum-graecum L.) microsymbionts has been barely studied even though it is of great interest for being a spice and a medicinal plant. Here, we analyzed 59 bacterial strains isolated from fenugreek nodules originating from different geographic and climatic areas of Iran. Most of these strains exhibit phenotypic characteristics compatible with rhizobia and they nodulate fenugreek. Analysis of the recA and atpD genes shows that representative strains of ERIC-BOX-PCR groups cluster with the type strains of Ensifer meliloti and E. kummerowiae as well as with strains capable of nodulating different Trigonella species found in other countries. The closeness of E. meliloti and E. kummerowiae suggests there is a need to revise the taxonomic status of the latter species. The nodC gene analysis shows that most Trigonella-nodulating strains belong to the symbiovar meliloti except those nodulating Trigonella arcuata in China, which belong to the symbiovar rigiduloides. This analysis shows that the type strains of E. kummerowiae, E. meliloti, and E. medicae belonged to three well-defined groups within the symbiovar meliloti, with the Iranian strains belonging to the E. kummerowiae subgroup. The small group of strains unable to nodulate fenugreek isolated in this study belong to Enterobacter cloacae, reported for the first time as being a possible endophyte of fenugreek nodules.
尽管胡芦巴（Trigonella foenum-graecum L.）的微生物共生体具有多样性，但对其作为香料和药用植物的研究却很少。在这里，我们分析了从伊朗不同地理和气候地区的胡芦巴根瘤中分离出的 59 株细菌菌株。这些菌株中的大多数表现出与根瘤菌相容的表型特征，并且能够结瘤胡芦巴。recA 和 atpD 基因分析表明，ERIC-BOX-PCR 组的代表菌株与苜蓿根瘤菌和 Kummerowia 根瘤菌的模式菌株聚类，并且与能够在其他国家结瘤不同胡芦巴属植物的菌株聚类。苜蓿根瘤菌和 Kummerowia 根瘤菌的亲缘关系表明，有必要修订后者的分类地位。nodC 基因分析表明，大多数结瘤胡芦巴的菌株属于 symbiovar meliloti，除了在中国结瘤胡芦巴 arcuata 的菌株属于 symbiovar rigiduloides 外。该分析表明，Kummerowia 根瘤菌、苜蓿根瘤菌和 medicae 根瘤菌的模式菌株属于 symbiovar meliloti 中的三个明确的组，而伊朗菌株属于 Kummerowia 亚组。本研究中分离的不能结瘤胡芦巴的小菌株群属于阴沟肠杆菌，这是首次报道其可能是胡芦巴根瘤的内生菌。
