Stable low molecular weight RNA profiling showed variations within Sinorhizobium meliloti and Sinorhizobium medicae nodulating different legumes from the alfalfa cross-inoculation group

Diversity and phylogeny of the bacterial strains isolated from nodules of fenugreek (Trigonella foenum-graecum L.) in Iran

The diversity of fenugreek (Trigonella foenum-graecum L.) microsymbionts has been barely studied even though it is of great interest for being a spice and a medicinal plant. Here we analyzed fifty-nine bacterial strains isolated from fenugreek nodules originating from different geographic and climatic areas of Iran. Most of these strains exhibit phenotypic characteristics compatible with rhizobia and they nodulate fenugreek. Analysis of the recA and atpD genes shows that representative strains of ERIC-BOX-PCR groups cluster with the type strains of Ensifer meliloti and Ensifer kummerowiae as well as with strains capable of nodulating different Trigonella species found in other countries. The closeness of E. meliloti and E. kummerowiae suggests there is a need to revise the taxonomic status of the latter species. The nodC gene analysis shows that most Trigonella-nodulating strains belong to the symbiovar meliloti except those nodulating Trigonella arcuata in China, which belong to the symbiovar rigiduloides. This analysis shows that the type strains of E. kummerowiae, E. meliloti and E. medicae belonged to three well-defined groups within the symbiovar meliloti, with the Iranian strains belonging to the E. kummerowiae subgroup. The small group of strains unable to nodulate fenugreek isolated in this study belong to Enterobacter cloacae, reported for the first time as being a possible endophyte of fenugreek nodules.

The use of biological fabaceae resources of the cretaceous south of Russia in breeding on the example of the species Melilotus albus medik

The morpho-biological traits of the breeding sample POD 17/13, created on the basis of genetic material of wild populations of M. albus of the Cretaceous south of the Central Russian Upland, were evaluated in comparison with the well-known zoned variety “Obskoy gigant”. The purpose of breeding work is to obtain a combination in one genotype of high yield traits of feed mass and leaf coverage; high protein content and low fiber content while maintaining seed productivity at the standard level. Three sets of field experiment were carried out: in 2016, 2017 and 2018. The setting years were the first years of life for the biennial M. albus crop. Individuals of the POD 17/13 breeding sample tend to increase the length of the growing season: by an average of 3.7 days in the first year of life, and by 7.3 days in the second year. According to the seed yield, the breeding sample M. albus POD 17/13 is at the standard level. In terms of protein content, the POD 17/13 variety significantly exceeds the standard in the first year of life by 6.8…9.2%, in the second - by 15.1…19.2%. At the same time, its herbage is more tender, since the fiber content in the aboveground mass is lower than that of the standard – in the first year of life – by 2.1…7.1%, in the second year of life - 6.9…9.9%. Thus, the POD 17/13 variety sample, created on the basis of the source material of wild populations of M. albus, is promising for obtaining a new variety based on it.

MALDI-TOF mass spectrometry is a fast and reliable platform for identification and ecological studies of species from family Rhizobiaceae

Family Rhizobiaceae includes fast growing bacteria currently arranged into three genera, Rhizobium, Ensifer and Shinella, that contain pathogenic, symbiotic and saprophytic species. The identification of these species is not possible on the basis of physiological or biochemical traits and should be based on sequencing of several genes. Therefore alternative methods are necessary for rapid and reliable identification of members from family Rhizobiaceae. In this work we evaluated the suitability of Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) for this purpose. Firstly, we evaluated the capability of this methodology to differentiate among species of family Rhizobiaceae including those closely related and then we extended the database of MALDI Biotyper 2.0 including the type strains of 56 species from genera Rhizobium, Ensifer and Shinella. Secondly, we evaluated the identification potential of this methodology by using several strains isolated from different sources previously identified on the basis of their rrs, recA and atpD gene sequences. The 100% of these strains were correctly identified showing that MALDI-TOF MS is an excellent tool for identification of fast growing rhizobia applicable to large populations of isolates in ecological and taxonomic studies.

Rhizobia from Lanzarote, the Canary Islands, that nodulate Phaseolus vulgaris have characteristics in common with Sinorhizobium meliloti isolates from mainland Spain

The stable, low-molecular-weight (LMW) RNA fractions of several rhizobial isolates of Phaseolus vulgaris grown in the soil of Lanzarote, an island of the Canary Islands, were identical to a less-common pattern found within Sinorhizobium meliloti (assigned to group II) obtained from nodules of alfalfa and alfalfa-related legumes grown in northern Spain. The P. vulgaris isolates and the group II LMW RNA S. meliloti isolates also were distinguishable in that both had two conserved inserts of 20 and 46 bp in the 16S-23S internal transcribed spacer region that were not present in other strains of S. meliloti. The isolates from P. vulgaris nodulated bean but not Medicago sativa, while those recovered from Medicago, Melilotus, and Trigonella spp. nodulated both host legumes. The bean isolates also were distinguished from those of Medicago, Melilotus, and Trigonella spp. by nodC sequence analysis. The nodC sequences of the bean isolates were most similar to those reported for S. meliloti bv. mediterranense and Sinorhizobium fredii bv. mediterranense (GenBank accession numbers DQ333891 and AF217267, respectively). None of the evidence placed the bean isolates from Lanzarote in the genus Rhizobium, which perhaps is inconsistent with seed-borne transmission of Rhizobium etli from the Americas to the Canaries as an explanation for the presence of bean-nodulating rhizobia in soils of Lanzarote.