diCenzo George C, Gutmanis Samuel M, Esme Oona, Moulin Lionel
Department of Biology, Queen's University, Kingston, ON, Canada.
PHIM Plant Health Institute, IRD, CIRAD, INRAE, Institut Agro, Univ Montpellier, Montpellier, France.
Can J Microbiol. 2025 Jan 1;71:1-9. doi: 10.1139/cjm-2025-0100.
Rhizobia are soil-dwelling proteobacteria that can enter into symbiotic nitrogen-fixing relationships with compatible leguminous plants. Taxonomically, rhizobia are divided into alpha-rhizobia, which belong to the class , and beta-rhizobia, which belong to the class . To date, all bona fide alpha-rhizobia belong to the order . However, a recent study suggested that DSM 18106 is also a rhizobium and is capable of nodulating pea plants (), which would expand the known taxonomic distribution of alpha-rhizobia to include the order . Here, we attempted to replicate the results of that previous study. Resequencing and computational analysis of the genome of DSM 18106 failed to identify genes encoding proteins involved in legume nodulation or nitrogen fixation. In addition, experimental plant assays indicated that DSM 18106 is unable to nodulate the two cultivars of pea tested in our study, unlike the rhizobium 3841. Taken together, and in contrast to the previous study, these results suggest that DSM 18106 is not capable of inducing root nodule formation on pea, meaning that the taxonomic distribution of all known alpha-rhizobia remains limited to the class .
根瘤菌是一类生活在土壤中的变形菌，能够与相容的豆科植物建立共生固氮关系。在分类学上，根瘤菌分为α-根瘤菌（属于 纲）和β-根瘤菌（属于 纲）。迄今为止，所有真正的α-根瘤菌都属于 目。然而，最近的一项研究表明，DSM 18106 也是一种根瘤菌，能够使豌豆植株结瘤（），这将扩大已知的α-根瘤菌的分类分布范围，使其包括 目。在此，我们试图重复之前那项研究的结果。对 DSM 18106 的基因组进行重测序和计算分析，未能鉴定出编码参与豆科植物结瘤或固氮的蛋白质的基因。此外，植物实验分析表明，与根瘤菌 3841 不同，DSM 18106 无法使我们研究中测试的两个豌豆品种结瘤。综合来看，与之前的研究相反，这些结果表明 DSM 18106 不能诱导豌豆形成根瘤，这意味着所有已知α-根瘤菌的分类分布仍局限于 纲。
