SYMBIOTIC PROPERTIES OF BLACK MEDIC OF THE MIRA VARIETY

The first Russian variety of black medic of the Mira was created and included in the State Register of Breeding Achievements. The study of the symbiotic properties of this variety showed that the most promising strains for pre-sowing inoculation were LX1 and 412b, the first increased the collection of dry matter and seeds by 96 and 115%, and the second – by 81 and 73%, respectively. Both strains can be used when cultivating this variety for feed and seeds. Inoculation with the LX6 strain increased seed productivity by 84%. Strains LX2, LX5 and LX6 increase the adaptive ability of varieties of the Mira, shifting the metabolism of the alfalfa-rhizobial system towards increasing seed productivity. The proportion of seeds in plants inoculated with the above-mentioned strains increases to 24–31% of the total plant weight, and in other symbiotic systems this indicator was 19–22%. Strain LX1 was isolated from nodules of plants belonging to the same population on the basis of which the Mira variety was created and it is the most genetically complementary to this variety. The yield of black medic of the Mira variety without inoculation for two years of use was 3.3 t/ha of dry matter, 0.67 t/ha of seeds. Pre-sowing inoculation of seeds with the LX1 strain increased the yield of this variety to 6.48 t/ha (+96%) of dry matter and seeds – to 1.44 t/ha (+115%). In the vegetation experiment, inoculation with the rhizobium strain LX1 significantly increased the height of plants by 4.2 cm, the leaf area by 0.69 cm2 (+49%), productivity by 176%. The total nitrogen content in the aboveground part of the plants reached 3.63%, the roots 3.31%, the control indicators were 3.02 and 2.77%, respectively.

Temperature Tolerant Rhizobium leguminosarum bv. viciae Strains with Plant Growth Promotion Traits

Rhizobacteria (PGPR) that promote the plant growth are essential component of sustainable agriculture. Pea (Pisum sativum L.) root nodule Rhizobium leguminosarum bv. viciae ten strains were cultured at two different temperatures (28°C and 45°C). Out of eight strains screened the three N25, N30 and N40 were temperature tolerant while only one strain (N40) showed tolerance to pH11. The growth of Rhizobium strain N40 at 45 °C was 96.8 percent as compared to the growth of the at 28°C. The temperature tolerant strain N40 produced maximum IAA and solubilized insoluble tri calcium phosphate compared to other strains and thus can be used microbial inoculant in biofertilizer technology.

Draft Genome Sequence of Bradyrhizobium elkanii BR 2003, an Efficient Rhizobium Strain for Cajanus, Canavalia, Crotalaria, and Indigofera

We report here the annotated draft genome sequence of the rhizobium strain BR 2003. This strain is able to establish symbiosis and to fix nitrogen with a broad range of leguminous species. The estimation of the average nucleotide identity confirmed the strain as a member of Bradyrhizobium elkanii.

Isolation and Identification of Endophytic Bacteria from the Roots of the Endangered Plant Ostrya rehderiana

Ostrya rehderiana Chun, one of the most endangered species in China mainly because of difficult transplantation, is distributed in Western Tianmu Mountain of the Zhejiang Province in China. There are presently only five plants still remaining in the wild. Since plant endophytes affect the growth and development of the host plant either directly or indirectly, in this study, we adopted the tissue block separation method to isolate 22 endophytic bacteria strains from the roots of O. rehderiana, with 10 strains from wild O. rehderiana and 12 from O. rehderiana plantations. From morphological analysis and 16S rDNA sequence analysis, 6 known genera were identified from the 22 strains. Among the isolated strains, eight were Bacillus (the dominant endophytic bacteria in the root of O. rehderiana), six were Paenibacillus, three were Agrobacterium, three were Paraburkholderia, one was Rhizobium, and one was Pseudomonas. Both wild and plantation O. rehderiana contained Bacillus, Paenibacillus and Paraburkholderia, which presumably could promote the growth of O. rehderiana. Besides, the Rhizobium strain isolated from wild O. rehderiana might be beneficial to the growth of O. rehderiana, but the Agrobacterium strains from the plantations might impair the growth of O. rehderiana. © 2020 Friends Science Publishers