Central southern Mexico contains highly diverse legumes. In this study, nodule-associated bacteria (NAB) were isolated from wild legume nodules and from nodules on Phaseolus vulgaris plants used as a plant-trap in soils from the same areas as the wild legumes. The bacteria were identified through the 16S rRNA gene sequence analysis, tested for plant growth-promoting (PGP) activities and the production of antimicrobial compounds, and analyzed for potential nodulation by amplifying the nodC gene. Several genera with PGP activity were isolated from legume nodules, including Achromobacter, Acinetobacter, Bacillus, Brevibacillus, Brevibacterium, Burkholderia, Cupriavidus, Dyella, Ensifer, Enterobacter, Herbaspirillum, Kosakonia, Labrys, Microbacterium, Moraxella, Paraburkholderia, Pseudomonas, Rhizobium, Stenotrophomonas; and Aeromonas, Marinococcus Pseudarthrobacter and Pseudoxanthomonas were found in plant legume nodules for the first time. Pseudomonas was the most common bacteria, and Mimosa pudica was colonized by the largest number of genera (6 different genera). A Burkholderia strain from the Burkholderia cepacia complex and a firmicutes strain harbor the nodC gene, identifying them as potential novel nodulating bacteria and showing that most of the strains isolated in this study were NAB. The most frequent PGP activity identified among the strains isolated from wild legumes was IAA synthesis. Two bacteria, Stenotrophomonas sp. and Rhizobium sp., synthesized more than 250 μg/ml, which is more than the level of synthesis reported in this study for Azospirillum brasilense Sp7 (59.77 μg/ml). Nitrogen fixation and antimicrobial compound production were not common, but the production of siderophores was frequently found among all the strains. This study shows that diverse NAB with PGP activity are very common in the legume nodules from central southern Mexico.

墨西哥中南部含有高度多样化的豆类。在这项研究中，结节相关细菌（NAB）是从野生豆类结节和菜豆中的结节中分离出来的，该植物用作与野生豆类相同地区土壤中的植物诱集物。通过16S rRNA基因序列分析鉴定细菌，测试植物的促生长（PGP）活性和生产抗菌化合物，并通过扩增nodC基因分析潜在的结瘤现象。从豆类结节中分离出具有PGP活性的几个属，包括无色杆菌，不动杆菌，芽孢杆菌，短杆菌，短杆菌属，伯克霍尔德氏菌，铜杯菌，狄拉菌，恩氏菌，肠杆菌，草螺菌，科萨科尼亚，拉布斯，微细菌，莫拉氏菌，副伯克霍尔德氏菌，假单胞菌，根瘤菌，嗜单胞菌; 与气单胞菌，Marinococcus Pseudarthrobacter和Pseudoxanthomonas在首次植物豆科植物根瘤中发现。假单胞菌是最常见的细菌，而含羞草（Mimosa pudica）则以数量最多的属（6个不同属）定殖。甲伯克霍尔德从菌株洋葱伯克霍尔德菌复合物和厚壁菌门应变怀有NODC基因，将其鉴定为潜在的新型结瘤细菌，并表明本研究中分离出的大多数菌株均为NAB。从野生豆类中分离出的菌株中最常见的PGP活性是IAA合成。两种细菌，Stenotrophomonas sp。和根瘤菌（Rhizobium sp。）的合成量超过250μg/ ml，高于本研究报道的巴西拟南螺旋藻（Azospirillum brasilense Sp7）的合成水平（59.77μg/ ml）。固氮和抗菌化合物的产生并不普遍，但在所有菌株中都经常发现铁载体的产生。这项研究表明，具有PGP活性的各种NAB在来自墨西哥中南部的豆类结核中非常普遍。