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.

Comparative Genomics across Three Ensifer Species Using a New Complete Genome Sequence of the Medicago Symbiont Sinorhizobium (Ensifer) meliloti WSM1022

Here, we report an improved and complete genome sequence of Sinorhizobium (Ensifer) meliloti strain WSM1022, a microsymbiont of Medicago species, revealing its tripartite structure. This improved genome sequence was generated combining Illumina and Oxford nanopore sequencing technologies to better understand the symbiotic properties of the bacterium. The 6.75 Mb WSM1022 genome consists of three scaffolds, corresponding to a chromosome (3.70 Mb) and the pSymA (1.38 Mb) and pSymB (1.66 Mb) megaplasmids. The assembly has an average GC content of 62.2% and a mean coverage of 77X. Genome annotation of WSM1022 predicted 6058 protein coding sequences (CDSs), 202 pseudogenes, 9 rRNAs (3 each of 5S, 16S, and 23S), 55 tRNAs, and 4 ncRNAs. We compared the genome of WSM1022 to two other rhizobial strains, closely related Sinorhizobium (Ensifer) meliloti Sm1021 and Sinorhizobium (Ensifer) medicae WSM419. Both WSM1022 and WSM419 species are high-efficiency rhizobial strains when in symbiosis with Medicago truncatula, whereas Sm1021 is ineffective. Our findings report significant genomic differences across the three strains with some similarities between the meliloti strains and some others between the high efficiency strains WSM1022 and WSM419. The addition of this high-quality rhizobial genome sequence in conjunction with comparative analyses will help to unravel the features that make a rhizobial symbiont highly efficient for nitrogen fixation.

Formulation of a Gluten-free Cookie with Prebiotics and an Edible Cover Enriched with Probiotics

Gluten-free foods are products that have become relevant today due to the prevalence of diseases related to the consumption of gluten proteins. This study developed a gluten-free cookie based on buckwheat flour and corn, reduced in fat with symbiotic properties. Several formulations were tested, the best cookies were selected based on texture, color, and sensory. The five most significant samples were evaluated using a hedonic test. Subsequently, the two samples that showed a higher score in the hedonic scale on color and texture parameters were selected. The two formulations were covered with a film-forming solution enriched with probiotics. No significant differences were shown for both cookies related to preference or texture by the panelists. The caloric intake and fat content were lower in formulation two. While formulation one has a greater contribution of fiber and protein. According to the Oficial Mexican regulations, the formulations presented an adequate microbiological quality in the period (4 weeks) and evaluated conditions (35 ºC with 70% relative humidity). Despite this time, the attributes of color and texture were affected after the storage period, finding significant differences between the cookies and time.

Publisher Correction: Identification of type III effectors modulating the symbiotic properties of Bradyrhizobium vignae strain ORS3257 with various Vigna species

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Bradyrhizobium agreste sp. nov., Bradyrhizobium glycinis sp. nov. and Bradyrhizobium diversitatis sp. nov., isolated from a biodiversity hotspot of the genus Glycine in Western Australia

Strains of the genus Bradyrhizobium associated with agronomically important crops such as soybean (Glycine max) are increasingly studied; however, information about symbionts of wild Glycine species is scarce. Australia is a genetic centre of wild Glycine species and we performed a polyphasic analysis of three Bradyrhizobium strains—CNPSo 4010T, CNPSo 4016T, and CNPSo 4019T—trapped from Western Australian soils with Glycine clandestina, Glycine tabacina and Glycine max, respectively. The phylogenetic tree of the 16S rRNA gene clustered all strains into the Bradyrhizobium japonicum superclade; strains CNPSo 4010T and CNPSo 4016T had Bradyrhizobium yuanmingense CCBAU 10071T as the closest species, whereas strain CNPSo 4019T was closer to Bradyrhizobium liaoningense LMG 18230T. The multilocus sequence analysis (MLSA) with five housekeeping genes—dnaK, glnII, gyrB, recA and rpoB—confirmed the same clusters as the 16S rRNA phylogeny, but indicated low similarity to described species, with nucleotide identities ranging from 93.6 to 97.6% of similarity. Considering the genomes of the three strains, the average nucleotide identity and digital DNA–DNA hybridization values were lower than 94.97 and 59.80 %, respectively, with the closest species. In the nodC phylogeny, strains CNPSo 4010T and CNPSo 4019T grouped with Bradyrhizobium zhanjiangense and Bradyrhizobium ganzhouense , respectively, while strain CNPSo 4016T was positioned separately from the all symbiotic Bradyrhizobium species. Other genomic (BOX-PCR), phenotypic and symbiotic properties were evaluated and corroborated with the description of three new lineages of Bradyrhizobium . We propose the names of Bradyrhizobium agreste sp. nov. for CNPSo 4010T (=WSM 4802T=LMG 31645T) isolated from Glycine clandestina, Bradyrhizobium glycinis sp. nov. for CNPSo 4016T (=WSM 4801T=LMG 31649T) isolated from Glycine tabacina and Bradyrhizobium diversitatis sp. nov. for CNPSo 4019T (=WSM 4799T=LMG 31650T) isolated from G. max.

Identification of type III effectors modulating the symbiotic properties of Bradyrhizobium vignae strain ORS3257 with various Vigna species

The Bradyrhizobium vignae strain ORS3257 is an elite strain recommended for cowpea inoculation in Senegal. This strain was recently shown to establish symbioses on some Aeschynomene species using a cocktail of Type III effectors (T3Es) secreted by the T3SS machinery. In this study, using a collection of mutants in different T3Es genes, we sought to identify the effectors that modulate the symbiotic properties of ORS3257 in three Vigna species (V. unguiculata, V. radiata and V. mungo). While the T3SS had a positive impact on the symbiotic efficiency of the strain in V. unguiculata and V. mungo, it blocked symbiosis with V. radiata. The combination of effectors promoting nodulation in V. unguiculata and V. mungo differed, in both cases, NopT and NopAB were involved, suggesting they are key determinants for nodulation, and to a lesser extent, NopM1 and NopP1, which are additionally required for optimal symbiosis with V. mungo. In contrast, only one effector, NopP2, was identified as the cause of the incompatibility between ORS3257 and V. radiata. The identification of key effectors which promote symbiotic efficiency or render the interaction incompatible is important for the development of inoculation strategies to improve the growth of Vigna species cultivated in Africa and Asia.

Symbiotic Properties of Sinorhizobium meliloti and Ethylene Production by Alfalfa Plants at the Early Stages of the Symbiosis Formation under Different Water Supply and Seed Treatment by Lectin

The symbiotic properties of bacteria significantly influence on the effectiveness of symbiosis and the yield capacity of plants. Therefore, it is important and relevant to study the features of micro- and macrosymbionts interactions, in particular under stressful conditions, and to find ways to improve the productivity of symbiotic systems. Aim. The investigation of the nodulation and nitrogen-fixing activities of Sinorhizobium meliloti as well as the ethylene production by alfalfa plants at the early stages of the formation of symbiotic system under conditions of both optimal and insufficient water supply and the pre-sowing treatment of seeds by lectin. Methods. Microbiological (cultivation of bacteria culture, seed inoculation), physiological (pot experiment), biochemical (nitrogenase activity and ethylene production determination). Results. It was observed a decrease of the nodulation activity of Sinorhizobium meliloti under drought as well as under lectin application, which was accompanied by an increase in the amount of produced by macrosymbiont ethylene at the early stages of the symbiosis formation. At the same time, the nitrogen fixing activity was inhibited at the insufficient water supply only. The use of lectin promoted the symbiotic apparatus functioning under optimal and insufficient water supply. After renewal of irrigation an increase of the nodule weight and nitrogen fixing activity as well as the aboveground mass of alfalfa plants were noted under lectin treatment. Conclusions. It was identified the role of ethylene as a negative regulator of the nodulation processes at pre-sowing treatment of alfalfa seeds with lectin. The formation of the effective nitrogen-fixing system capable of full recovery after drought under lectin application confirms the prospects for further research in the use of lectins to create optimal conditions for the realization of the symbiotic potential of rhizobia and to increase the symbiotic systemˊ resistance to the action of stress factors.

CHARACTERISTICS OF THE PROPERTIES OF CHICKPEA NODULE BACTERIA EXTENDED IN THE FOREST-STEPPE AND STEPPE ZONES UKRAINE

Objective. To compare morphological, cultural, physiological, biochemical, and symbiotic properties of strains of nodule chickpea bacteria isolated from different soil and climatic zones of Ukraine. Methods. Microbiological, microscopic, gas-chromatographic, statistical. Results. From the nodules of chickpea plant of varieties Skarb, Admiral, Odissei, Budzhak, Triumf and Pamiat, grown in the steppe zone of Ukraine (Region of Odessa), where an active rhizobia population was formed due to the continuous cultivation of this crop, 58 isolates of bacteria were isolated; 11 iso-lates were isolated from the nodules of plants of Triumf and Pamiat varieties selected in the forest-steppe zone (Region of Lviv), in the fields where chickpea was grown for the first time. It has been established that the strains of Mesorhizobium sp. 1 and Mesorhizobium sp. 2, which were isolated from the nodules of chickpea plants grown in the fields with an active rhizobia population of this culture, form colonies of 2–4 mm in size at day 3–4 on the mannitol yeast agar and, according to cultural and morphological properties correspond to the characteristics of the species Mesorhizo-bium ciceri. Their use for pre-sowing chickpea inoculation increases the mass of nodules (2– 3 times) and nitrogenase activity (1.4–2 times) compared with the results obtained using the pro-duction strain of Mesorhizobium ciceri H-12. Inoculation with Mesorhizobium sp. 11, isolated from the forest-steppe zone, which on a mannitol yeast agar forms a colony of 1–2 mm in size at day 5–6, contributed to a significant increase in the number of nodules on the roots of plants (by 40.5 %), their mass (by 31 %), but the increase in nitrogenase activity was negligible. Conclusion. Strains of Mesorhizobium sp. isolated from chickpea nodules grown in different soil-climatic zones of Ukraine, have similar cell morphology, but differ in growth rate, cultural, physiological, biochemi-cal, and symbiotic properties.