Whole-genome sequence of Kosakonia cowanii strain W006, isolated from seeds of Triticum aestivum L

In this study, we sequence, assemble, and annotate Kosakonia cowanii strain W006, isolated from seeds of Triticum aestivum L. W006 has a single circular chromosome of 4,788,099 bp and 4,466 genes, with a mean G +C content of 56.1%.

Phytohormone Production by the Endophyte Bacillus safensis TS3 Increases Plant Yield and Alleviates Salt Stress

Endophytic bacteria can be used to overcome the effect of salinity stress and promote plant growth and nutrient uptake. Bacillus safensis colonizes a wide range of habitats due to survival in extreme environments and unique physiological characteristics, such as a high tolerance for salt, heavy metals, and ultraviolet and gamma radiations. The aim of our study was to examine the salt resistance of the endophytic strain TS3 B. safensis and its ability to produce phytohormones and verify its effect on plant yield in field trials and the alleviation of salt stress in pot experiments. We demonstrate that the strain TS3 is capable of producing enzymes and phytohormones such as IAA, ABA and tZ. In pot experiments with radish and oat plants in salinization, the strain TS3 contributed to the partial removal of the negative effect of salinization. The compensatory effect of the strain TS3 on radish plants during salinization was 46.7%, and for oats, it was 108%. We suppose that such a pronounced effect on the plants grown and the salt stress is connected with its ability to produce phytohormones. Genome analysis of the strain TS3 showed the presence of the necessary genes for the synthesis of compounds responsible for the alleviation of the salt stress. Strain B. safensis TS3 can be considered a promising candidate for developing biofertilizer to alleviate salt stress and increase plant yield.

Whole-genome sequence of Paenibacillus amylolyticus strain W018, isolated from Triticum aestivum L. seeds, obtained using nanopore sequencing

In this study, we performed nanopore sequencing of the genome of Paenibacillus amylolyticus strain W018, isolated from the seeds of winter wheat, cv. Bezostaya 100. The genome size is 7.07 Mb, with a GC content of 45.8%, and contains 8,190 genes.

Endophytes from Halotolerant Plants Aimed to Overcome Salinity and Draught

The aim of our research was to study the endosphere of four halophytic plants: Salicornia europaea L., Salsola australis (R.Br.), Bassia sedoides (Pall.) and Kochia prostrata (L.) Schrad. from arid and saline areas of the Stavropol Territory, Russia. In total, 28 endophyte strains were isolated from the roots and stems of these halophytic plants. Most of the isolates (23 out of 28) were identified as Bacillus sp. while others belonged to the genera Oceanobacillus, Paenibacillus, Pantoea, Alcaligenes and Myroides. Three strains of Bacillus sp. (Se5R, Se1-1R, and Se1-3S), isolated from the S. europaea were capable of growth at 55 °C and in 10% of NaCl. Strains Se1-4S, Kp20-2S, and Bs11-2S Bacillus sp. (isolated from the S. australis, K. prostrata and B. sedoides, respectively) demonstrated strong plant growth promoting activity: 85-265% over control lettuce plants and a high degree of growth suppression (59.1-81.2%) of pathogenic fungi Fusarium oxysporum, Bipolaris sorokiniana and Rhizoctonia solani. Selected strains can be promising candidates for the development of bioinoculants to facilitate salt soil phytoremediation and be beneficial for mitigating the salt stress to the plants growing in salt-affected habitats.

Efficacy of a Plant-Microbe System: Pisum sativum (L.) Cadmium-Tolerant Mutant and Rhizobium leguminosarum Strains, Expressing Pea Metallothionein Genes PsMT1 and PsMT2, for Cadmium Phytoremediation

Two transgenic strains of Rhizobium leguminosarum bv. viciae, 3841-PsMT1 and 3841-PsMT2, were obtained. These strains contain the genetic constructions nifH-PsMT1 and nifH-PsMT2 coding for two pea (Pisum sativum L.) metallothionein genes, PsMT1 and PsMT2, fused with the promoter region of the nifH gene. The ability of both transgenic strains to form nodules on roots of the pea wild-type SGE and the mutant SGECdt, which is characterized by increased tolerance to and accumulation of cadmium (Cd) in plants, was analyzed. Without Cd treatment, the wild type and mutant SGECdt inoculated with R. leguminosarum strains 3841, 3841-PsMT1, or 3841-PsMT2 were similar histologically and in their ultrastructural organization of nodules. Nodules of wild-type SGE inoculated with strain 3841 and exposed to 0.5 μM CdCl2 were characterized by an enlarged senescence zone. It was in stark contrast to Cd-treated nodules of the mutant SGECdt that maintained their proper organization. Cadmium treatment of either wild-type SGE or mutant SGECdt did not cause significant alterations in histological organization of nodules formed by strains 3841-PsMT1 and 3841-PsMT2. Although some abnormalities were observed at the ultrastructural level, they were less pronounced in the nodules of strain 3841-PsMT1 than in those formed by 3841-PsMT2. Both transgenic strains also differed in their effects on pea plant growth and the Cd and nutrient contents in shoots. In our opinion, combination of Cd-tolerant mutant SGECdt and the strains 3841-PsMT1 or 3841-PsMT2 may be used as an original model for study of Cd tolerance mechanisms in legume-rhizobial symbiosis and possibilities for its application in phytoremediation or phytostabilization technologies.

Complete Genome Sequences of Endophytic Bacilli Isolated from Grapevine Plants

The endophytic strains Bacillus amyloliquefaciens V417 and V167 were isolated from cultured grape plants. We sequenced the complete genomes of these strains to reveal their potential beneficial properties for plant growth promotion and control of fungal pathogens. Genes responsible for the synthesis of antimicrobial compounds and siderophores were identified.

Matching population diversity of rhizobial nodA and legume NFR5 genes in plant-microbe symbiosis

We hypothesized that population diversities of partners in nitrogen-fixing rhizobium-legume symbiosis can be matched for "interplaying" genes. We tested this hypothesis using data on nucleotide polymorphism of symbiotic genes encoding two components of the plant-bacteria signaling system: (a) the rhizobial nodA acyltransferase involved in the fatty acid tail decoration of the Nod factor (signaling molecule); (b) the plant NFR5 receptor required for Nod factor binding. We collected three wild-growing legume species together with soil samples adjacent to the roots from one large 25-year fallow: Vicia sativa, Lathyrus pratensis, and Trifolium hybridum nodulated by one of the two Rhizobium leguminosarum biovars (viciae and trifolii). For each plant species, we prepared three pools for DNA extraction and further sequencing: the plant pool (30 plant indiv.), the nodule pool (90 nodules), and the soil pool (30 samples). We observed the following statistically significant conclusions: (a) a monotonic relationship between the diversity in the plant NFR5 gene pools and the nodule rhizobial nodA gene pools; (b) higher topological similarity of the NFR5 gene tree with the nodA gene tree of the nodule pool, than with the nodA gene tree of the soil pool. Both nonsynonymous diversity and Tajima's D were increased in the nodule pools compared with the soil pools, consistent with relaxation of negative selection and/or admixture of balancing selection. We propose that the observed genetic concordance between NFR5 gene pools and nodule nodA gene pools arises from the selection of particular genotypes of the nodA gene by the host plant.