Hernández-Oaxaca Diana, Claro Karen, Rogel Marco A, Rosenblueth Mónica, Martinez-Romero Julio, Martinez-Romero Esperanza
Genomic Science Center, UNAM Cuernavaca México, México.
Genomic Science Center, UNAM Cuernavaca México, México.
Syst Appl Microbiol. 2023 Jul;46(4):126433. doi: 10.1016/j.syapm.2023.126433. Epub 2023 May 11.
Inga vera and Lysiloma tree legumes form nodules with Bradyrhizobium spp. from the japonicum group that represent novel genomospecies, for which we describe here using genome data, symbiovars lysilomae, lysilomaefficiens and ingae. Genes encoding Type three secretion system (TTSS) that could affect host specificity were found in ingae but not in lysilomae nor in lysilomaefficiens symbiovars and uptake hydrogenase hup genes (that affect nitrogen fixation) were observed in bradyrhizobia from the symbiovars ingae and lysilomaefficiens. nolA gene was found in the symbiovar lysilomaefficiens but not in strains from lysilomae. We discuss that multiple genes may dictate symbiosis specificity. Besides, toxin-antitoxin genes were found in the symbiosis islands in bradyrhizobia from symbiovars ingae and lysilomaefficiens. A limit (95%) to define symbiovars with nifH gene sequences was proposed here.
银合欢属植物和猴耳环属豆科植物与来自日本根瘤菌组的慢生根瘤菌形成根瘤，这些慢生根瘤菌代表了新的基因组种，我们在此利用基因组数据对其共生变种进行描述，包括猴耳环共生变种、高效猴耳环共生变种和银合欢共生变种。在银合欢共生变种中发现了可能影响宿主特异性的编码三型分泌系统（TTSS）的基因，但在猴耳环共生变种和高效猴耳环共生变种中未发现，并且在银合欢共生变种和高效猴耳环共生变种的慢生根瘤菌中观察到了摄取氢化酶hup基因（影响固氮作用）。在高效猴耳环共生变种中发现了nolA基因，但在猴耳环属菌株中未发现。我们讨论了多个基因可能决定共生特异性。此外，在银合欢共生变种和高效猴耳环共生变种的慢生根瘤菌的共生岛中发现了毒素-抗毒素基因。本文提出了用nifH基因序列定义共生变种的一个界限（95%）。
