Rejili Mokhtar, Bouznif Besma, Benabderrahim Mohamed Ali, Mars Mohamed
Department of Life Sciences, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, 11623, Saudi Arabia.
Laboratory of Biodiversity and Valorization of Arid Areas Bioresources (BVBAA), Faculty of Sciences of Gabes, University of Gabes Erriadh, 6072, Zrig, Tunisia.
World J Microbiol Biotechnol. 2024 Dec 30;41(1):22. doi: 10.1007/s11274-024-04236-z.
In this study, we investigated various chromosomal and symbiotic markers in 40 bacterial strains that nodulate an invasive alien plant, Acacia salicina Lindl. in Tunisia. Our findings showed that the native rhizobia associated to A. salicina are grouped into eight distinct RAPD electrophoretic types (RETs) (genotypes). Sequence analyses of rrs gene and three housekeeping genes (recA, rpoB and glnII) assigned sixteen isolates to three putative new lineages within the genus Bradyrhizobium. Seven strains clustered with B. rifense CTAW71 with a 91% bootstrap support, five strains grouped with B. niftali CNPSo3448 with a very low bootstrap support (60%), and four strains formed a group phylogenetically related with B. shewense ERR11 and B. centrosematis A9. Based on nodC phylogeny and cross inoculation tests, the 16 strains are clustered within symbiovar retamae (six strains) and cyanophyllae (ten strains). Moreover, we showed by the first time in this work that the type strains B. diversitatis CNPSo4019 and B. xenonodulans 14AB, which nodulated soybean and A. dealbata respectively, belong to the symbiovar cyanophyllae according to the results of the nodC gene analysis.
在本研究中，我们调查了40株能使突尼斯一种入侵外来植物——柳叶相思树（Acacia salicina Lindl.）结瘤的细菌菌株中的各种染色体和共生标记。我们的研究结果表明，与柳叶相思树相关的本地根瘤菌可分为8种不同的随机扩增多态性DNA电泳类型（RETs）（基因型）。对rrs基因和三个管家基因（recA、rpoB和glnII）的序列分析将16个分离株归入慢生根瘤菌属内的三个假定新谱系。7个菌株与里氏慢生根瘤菌CTAW71聚类，自展支持率为91%，5个菌株与尼氏慢生根瘤菌CNPSo3448聚类，自展支持率非常低（60%），4个菌株形成一个与谢氏慢生根瘤菌ERR11和中央慢生根瘤菌A9系统发育相关的组。基于nodC系统发育和交叉接种试验，16个菌株聚类在retamae共生变种（6个菌株）和cyanophyllae共生变种（10个菌株）内。此外，根据nodC基因分析结果，我们在本研究中首次表明，分别使大豆和银荆结瘤的模式菌株多样性慢生根瘤菌CNPSo4019和外来根瘤菌14AB属于cyanophyllae共生变种。
