Genetic relationship of<i>Sinorhizobium meliloti</i>and<i>Sinorhizobium medicae</i>strains isolated from Caucasian region

Biondi, Emanuele G.; Pilli, Elena; Giuntini, Elisa; Roumiantseva, M. L.; Andronov, E. E.; Onichtchouk, O. P.; Курчак, О. Н.; Симаров, Б. В.; Dzyubenko, N. I.; Mengoni, Alessio; Bazzicalupo, Marco

doi:10.1016/s0378-1097(03)00098-3

Cited by 59 publications

(51 citation statements)

References 38 publications

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“…Interestingly, the lower diversity of Sinorhizobium medicae than of Sinorhizobium meliloti (both species nodulate Medicago spp.) was recurrently observed in the same sampling sites (65,66). Even though they can cooccur in sympatry, significant differentiation of chromosomal loci between S. medicae and S. meliloti was observed (67).…”

Section: Discussionmentioning

confidence: 77%

Replicon-Dependent Differentiation of Symbiosis-Related Genes in Sinorhizobium Strains Nodulating Glycine max

Guo

Wang

Zhang

et al. 2014

Appl Environ Microbiol

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In order to investigate the genetic differentiation of Sinorhizobium strains nodulating Glycine max and related microevolutionary mechanisms, three housekeeping genes (SMc00019, truA, and thrA) and 16 symbiosis-related genes on the chromosome (7 genes), pSymA (6 genes), and pSymB (3 genes) were analyzed. Five distinct species were identified among the test strains by calculating the average nucleotide identity (ANI) of SMc00019-truA-thrA: Sinorhizobium fredii, Sinorhizobium sojae, Sinorhizobium sp. I, Sinorhizobium sp. II, and Sinorhizobium sp. III. These species assignments were also supported by population genetics and phylogenetic analyses of housekeeping genes and symbiosis-related genes on the chromosome and pSymB. Different levels of genetic differentiation were observed among these species or different replicons. S. sojae was the most divergent from the other test species and was characterized by its low intraspecies diversity and limited geographic distribution. Intergenic recombination dominated the evolution of 19 genes from different replicons. Intraspecies recombination happened frequently in housekeeping genes and symbiosis-related genes on the chromosome and pSymB, whereas pSymA genes showed a clear pattern of lateral-transfer events between different species. Moreover, pSymA genes were characterized by a lower level of polymorphism and recombination than those on the chromosome and pSymB. Taken together, genes from different replicons of rhizobia might be involved in the establishment of symbiosis with legumes, but these symbiosis-related genes might have evolved differently according to their corresponding replicons.

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Section: Discussionmentioning

confidence: 77%

Replicon-Dependent Differentiation of Symbiosis-Related Genes in Sinorhizobium Strains Nodulating Glycine max

Guo

Wang

Zhang

et al. 2014

Appl Environ Microbiol

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“…An alternative explanation which has previously been proposed is that S. medicae emerged from an ancestral population of S. meliloti bv. meliloti (6,42). According to this scenario, the monophyly of the nod sequences of S. medicae and S. meliloti bv.…”

Section: Discussionmentioning

confidence: 97%

Horizontal Gene Transfer and Homologous Recombination Drive the Evolution of the Nitrogen-Fixing Symbionts of Medicago Species

et al. 2007

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Using nitrogen-fixing Sinorhizobium species that interact with Medicago plants as a model system, we aimed at clarifying how sex has shaped the diversity of bacteria associated with the genus Medicago on the interspecific and intraspecific scales. To gain insights into the diversification of these symbionts, we inferred a topology that includes the different specificity groups which interact with Medicago species, based on sequences of the nodulation gene cluster. Furthermore, 126 bacterial isolates were obtained from two soil samples, using Medicago truncatula and Medicago laciniata as host plants, to study the differentiation between populations of Sinorhizobium medicae, Sinorhizobium meliloti bv. meliloti, and S. meliloti bv. medicaginis. The former two can be associated with M. truncatula (among other species of Medicago), whereas the last organism is the specific symbiont of M. laciniata. These bacteria were characterized using a multilocus sequence analysis of four loci, located on the chromosome and on the two megaplasmids of S. meliloti. The phylogenetic results reveal that several interspecific horizontal gene transfers occurred during the diversification of Medicago symbionts. Within S. meliloti, the analyses show that nod genes specific to different host plants have spread to different genetic backgrounds through homologous recombination, preventing further divergence of the different ecotypes. Thus, specialization to different host plant species does not prevent the occurrence of gene flow among host-specific biovars of S. meliloti, whereas reproductive isolation between S. meliloti bv. meliloti and S. medicae is maintained even though these bacteria can cooccur in sympatry on the same individual host plants.

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“…The gram-negative bacterium Sinorhizobium meliloti is able to interact with roots of alfalfa to form nitrogen (N)-fixing nodules (Biondi et al 2003;Elboutahiri et al 2010). Soil salinity adversely affects the nodulation and N fixation capacities of rhizobia, resulting in lower productivity of legumes (Valdenegro et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Co-inoculations of arbuscular mycorrhizal fungi and rhizobia under salinity in alfalfa

Ashrafi

Zahedi

Razmjoo

2014

Soil Science and Plant Nutrition

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Alfalfa (Medicago sativa L.) is cultivated in arid and semi-arid regions where salinity is one of the main limiting factors for its production. Thus, this experiment was conducted to evaluate the efficacy of arbuscular mycorrhizal fungus (AMF), Glomus mosseae, alfalfa rhizobia Sinorhizobium meliloti (R) seed inoculation in the development of salinity tolerance of different alfalfa cultivars (Rehnani, Pioneer and Bami) under a variety of salinity levels. The results revealed that under non-stress condition, root mycorrhizal infection, nodulation (the number and weight of nodules per plant), potassium (K), calcium (Ca), phosphorus (P), zinc (Zn), copper (Cu) and magnesium (Mg) contents of the root and shoot, the value of the K/ Na ratio, protein [calculated from the nitrogen (N) content] and proline contents of the shoot and the alfalfa yield were found to be the highest while Na contents of the root and shoot were seen to be the lowest when seeds were double inoculated followed by mycorrhizae, rhizobium and control treatments, respectively. Similarly, under salinity condition, the greatest amounts of mycorrhizal infection, nodulation, root and shoot P contents, the value of K/Na ratio, the shoot proline content and the root Ca content were enhanced with the least amount of leaf Na content related to the cases of seeds which were double inoculated, followed by mycorrhizae, rhizobium and control treatments respectively. The results suggested that inoculation of alfalfa seed with AMF or R, especially double inoculation, causes a considerable increase in alfalfa yield under both saline and non-saline conditions by increasing colonization, nodulation and nutrient uptake.

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Genetic relationship ofSinorhizobium melilotiandSinorhizobium medicaestrains isolated from Caucasian region

Cited by 59 publications

References 38 publications

Replicon-Dependent Differentiation of Symbiosis-Related Genes in Sinorhizobium Strains Nodulating Glycine max

Replicon-Dependent Differentiation of Symbiosis-Related Genes in Sinorhizobium Strains Nodulating Glycine max

Horizontal Gene Transfer and Homologous Recombination Drive the Evolution of the Nitrogen-Fixing Symbionts of Medicago Species

Co-inoculations of arbuscular mycorrhizal fungi and rhizobia under salinity in alfalfa

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