N2-Acetylornithine deacetylase functions as a Cys-Gly dipeptidase in the cytosolic glutathione degradation pathway in Arabidopsis thaliana.

Glutathione (GSH) is required for various physiological processes in plants, including redox regulation and detoxification of harmful compounds. GSH also functions as a repository for assimilated sulfur and is actively catabolized in plants. In Arabidopsis, GSH is mainly degraded initially by cytosolic enzymes, γ-glutamyl cyclotransferase, and γ-glutamyl peptidase, which release cysteinylglycine (Cys-Gly). However, the subsequent enzyme responsible for catabolizing this dipeptide has not been identified to date. In the present study, we identified At4g17830 as a Cys-Gly dipeptidase, namely cysteinylglycine peptidase 1 (CGP1). CGP1 complemented the phenotype of the yeast mutant that cannot degrade Cys-Gly. The Arabidopsis cgp1 mutant had lower Cys-Gly degradation activity than the wild type and showed perturbed concentrations of thiol compounds. Recombinant CGP1 showed reasonable Cys-Gly degradation activity in vitro. Metabolomic analysis revealed that cgp1 exhibited signs of severe sulfur deficiency, such as elevated accumulation of O-acetylserine (OAS) and the decrease in sulfur-containing metabolites. Morphological changes observed in cgp1, including longer primary roots of germinating seeds, were also likely associated with sulfur starvation. Notably, At4g17830 has previously been reported to encode an N2-acetylornithine deacetylase (NAOD) that functions in the ornithine biosynthesis. The cgp1 mutant did not show a decrease in ornithine content, whereas the analysis of CGP1 structure did not rule out the possibility that CGP1 has Cys-Gly dipeptidase and NAOD activities. Therefore, we propose that CGP1 is a Cys-Gly dipeptidase that functions in the cytosolic GSH degradation pathway and may play dual roles in GSH and ornithine metabolism.

The Application of Sulfur Influences Microbiome of Soybean Rhizosphere and Nutrient-Mobilizing Bacteria in Andosol.

This study aimed to determine the effect of sulfur (S) application on a root-associated microbial community resulting in a rhizosphere microbiome with better nutrient mobilizing capacity. Soybean plants were cultivated with or without S application, the organic acids secreted from the roots were compared. High-throughput sequencing of 16S rRNA was used to analyze the effect of S on microbial community structure of the soybean rhizosphere. Several plant growth-promoting bacteria (PGPB) isolated from the rhizosphere were identified that can be harnessed for crop productivity. The amount of malic acid secreted from the soybean roots was significantly induced by S application. According to the microbiota analysis, the relative abundance of Polaromonas, identified to have positive association with malic acid, and arylsulfatase-producing Pseudomonas, were increased in S-applied soil. Burkholderia sp. JSA5, obtained from S-applied soil, showed multiple nutrient-mobilizing traits among the isolates. In this study, S application affected the soybean rhizosphere bacterial community structure, suggesting the contribution of changing plant conditions such as in the increase in organic acid secretion. Not only the shift of the microbiota but also isolated strains from S-fertilized soil showed PGPB activity, as well as isolated bacteria that have the potential to be harnessed for crop productivity.

Diversity of Fast-Growth Spore-Forming Microbes and Their Activity as Plant Partners.

Biofertilizers are agricultural materials capable of reducing the usage amounts of chemical fertilizers. Spore-forming microorganisms (SFM) could be used for plant growth promotion or to improve plant health. Until now, biofertilizers based on SFM have been applied for rice and other crops. In this study, we isolated and characterized SFM, which were colonized on the Oryza sativa L. roots. SFM were analyzed regarding the short-term effects of biofertilization on the nursery growths. Analysis was performed without nitrogen or any inorganic fertilizer and was divided into two groups, including bacteria and fungi. SF-bacteria were dominated by the Firmicutes group, including species from Viridibacillus, Lysinibacillus, Solibacillus, Paenibacillus, Priestia, and mainly Bacillus (50%). The fungi group was classified as Mucoromycota, Basidiomycota, and mainly Ascomycota (80%), with a predominance of Penicillium and Trichoderma species. In plant performance in comparison with B. pumilus TUAT1, some bacteria and fungus isolates significantly improved the early growth of rice, based on 48 h inoculum with 107 CFU mL-1. Furthermore, several SFM showed positive physiological responses under abiotic stress or with limited nutrients such as phosphorous (P). Moreover, the metabolic fingerprint was obtained. The biofertilizer based on SFM could significantly reduce the application of the inorganic fertilizer and improve the lodging resistances of rice, interactively enhancing better plant health and crop production.

Genetic and Physiological Characterization of Soybean-Nodule-Derived Isolates from Bangladeshi Soils Revealed Diverse Array of Bacteria with Potential Bradyrhizobia for Biofertilizers.

Genetic and physiological characterization of bacteria derived from nodules of leguminous plants in the exploration of biofertilizer is of paramount importance from agricultural and environmental perspectives. Phylogenetic analysis of the 16S rRNA gene of 84 isolates derived from Bangladeshi soils revealed an unpredictably diverse array of nodule-forming and endosymbiotic bacteria-mostly belonging to the genus Bradyrhizobium. A sequence analysis of the symbiotic genes (nifH and nodD1) revealed similarities with the 16S rRNA gene tree, with few discrepancies. A phylogenetic analysis of the partial rrn operon (16S-ITS-23S) and multi-locus sequence analysis of atpD, glnII, and gyrB identified that the Bradyrhizobium isolates belonged to Bradyrhizobium diazoefficiens, Bradyrhizobium elkanii, Bradyrhizobium liaoningense and Bradyrhizobium yuanmingense species. In the pot experiment, several isolates showed better activity than B. diazoefficiens USDA110, and the Bho-P2-B2-S1-51 isolate of B. liaoningense showed significantly higher acetylene reduction activity in both Glycine max cv. Enrei and Binasoybean-3 varieties and biomass production increased by 9% in the Binasoybean-3 variety. Tha-P2-B1-S1-68 isolate of B. diazoefficiens significantly enhanced shoot length and induced 10% biomass production in Binasoybean-3. These isolates grew at 1-4% NaCl concentration and pH 4.5-10 and survived at 45 °C, making the isolates potential candidates for eco-friendly soybean biofertilizers in salty and tropical regions.

Two synchronous pseudoaneurysms after bile duct resection for distal cholangiocarcinoma.

Pseudoaneurysm is a potentially life-threatening complication after hepatobiliary pancreatic surgery. Although various measures have been taken to prevent the formation of postoperative pseudoaneurysms, completely avoiding complications can be difficult. An 83-year-old man underwent bile duct resection and systematic regional lymphadenectomies for distal cholangiocarcinoma. Polyethylene glycolic acid mesh with fibrin glue was applied to the pancreas around the distal stump and detached artery to prevent leakage of pancreatic juice and reinforce the arterial wall. Screening contrast-enhanced computed tomography on the 7th postoperative day indicated no pseudoaneurysm. The patient was discharged on the 20th postoperative day after an uneventful course. However, 4 days later, the patient visited the emergency outpatient department with a complaint of fever. Contrast-enhanced computed tomography revealed an abscess formation and a pseudoaneurysm around it. Emergency celiac arteriography revealed two pseudoaneurysms at the left hepatic artery and posterior superior pancreaticoduodenal artery; they were successfully treated with transcatheter arterial embolization using microcoils and covered stent placement. The patient was discharged 9 days after interventional radiology treatment. At the 14 months postoperative follow-up, the patient had no recurrence or stent obstruction. Multiple synchronous pseudoaneurysms are rare; accurately identifying the site by angiography and selecting appropriate treatment for each site is important.

Glutathione degradation activity of γ-glutamyl peptidase 1 manifests its dual roles in primary and secondary sulfur metabolism in Arabidopsis.

Glutathione (GSH) functions as a major sulfur repository and hence occupies an important position in primary sulfur metabolism. GSH degradation results in sulfur reallocation and is believed to be carried out mainly by γ-glutamyl cyclotransferases (GGCT2;1, GGCT2;2, and GGCT2;3), which, however, do not fully explain the rapid GSH turnover. Here, we discovered that γ-glutamyl peptidase 1 (GGP1) contributes to GSH degradation through a yeast complementation assay. Recombinant proteins of GGP1, as well as GGP3, showed high degradation activity of GSH, but not of oxidized glutathione (GSSG), in vitro. Notably, the GGP1 transcripts were highly abundant in rosette leaves, in agreement with the ggp1 mutants constantly accumulating more GSH regardless of nutritional conditions. Given the lower energy requirements of the GGP- than the GGCT-mediated pathway, the GGP-mediated pathway could be a more efficient route for GSH degradation than the GGCT-mediated pathway. Therefore, we propose a model wherein cytosolic GSH is degraded chiefly by GGP1 and likely also by GGP3. Another noteworthy fact is that GGPs are known to process GSH conjugates in glucosinolate and camalexin synthesis; indeed, we confirmed that the ggp1 mutant contained higher levels of O-acetyl-l-Ser, a signaling molecule for sulfur starvation, and lower levels of glucosinolates and their degradation products. The predicted structure of GGP1 further provided a rationale for this hypothesis. In conclusion, we suggest that GGP1 and possibly GGP3 play vital roles in both primary and secondary sulfur metabolism.

Isolation and Characterization of Phosphate Solubilizing Bacteria from Paddy Field Soils in Japan.

Phosphorus (P) is abundant in soil and is essential for plant growth and development; however, it is easily rendered insoluble in complexes of different types of phosphates, which may lead to P deficiency. Therefore, increases in the amount of P released from phosphate minerals using microbial inoculants is an important aspect of agriculture. The present study used inorganic phosphate solubilizing bacteria (iPSB) in paddy field soils to develop microbial inoculants. Soils planted with rice were collected from different regions of Japan. Soil P was sequentially fractionated using the Hedley method. iPSB were isolated using selective media supplemented with tricalcium phosphate (Ca-P), aluminum phosphate (Al-P), or iron phosphate (Fe-P). Representative isolates were selected based on the P solubilization index and soil sampling site. Identification was performed using 16S rRNA and rpoB gene sequencing. Effectiveness was screened based on rice cultivar Koshihikari growth supplemented with Ca-P, Al-P, or Fe-P as the sole P source. Despite the relatively homogenous soil pH of paddy field sources, three sets of iPSB were isolated, suggesting the influence of fertilizer management and soil types. Most isolates were categorized as ß-Proteobacteria (43%). To the best of our knowledge, this is the first study to describe the genera Pleomorphomonas, Rhodanobacter, and Trinickia as iPSB. Acidovorax sp. JC5, Pseudomonas sp. JC11, Burkholderia sp. JA6 and JA10, Sphingomonas sp. JA11, Mycolicibacterium sp. JF5, and Variovorax sp. JF6 promoted plant growth in rice supplemented with an insoluble P source. The iPSBs obtained may be developed as microbial inoculants for various soil types with different P fixation capacities.

[A Case of Advanced Gastric Cancer Successfully Treated with FOLFOX].

The Japanese gastric cancer clinical practice guideline recommends FOLFOX as one of the first-line chemotherapy for advanced gastric cancer. Since FOLFOX is administered intravenously, it is helpful for patients who have difficulty in oral intake. Herein, we report a patient in which FOLFOX was significantly effective after failure to treatment with S-1 plus CDDP. A 75-year-old gastric cancer patient with paraaortic lymph node metastasis and multiple liver metastases(Stage ⅣB)was treated. Severe stomatitis and impaired consciousness due to dehydration appeared after administration of S-1 plus CDDP. After his general condition recovered, we changed his regimen to FOLFOX. No serious adverse events were observed, and partial response was achieved after 4 courses of treatment. Partial response was maintained until the onset of oxaliplatin drug allergy in the 10th course. FOLFOX is a promising option for patients with difficulties in oral intake.

Comparison of cell viability between mouse-derived ES-D3 cells and Balb/c 3T3 cells using denture-base lining materials.

The study was done to compare cell viability between ES-D3 and Balb/c 3T3 cells, and evaluate the difference in cell viability between these cell lines using denture-base lining materials for prosthetic dentistry. To compare the cytotoxicity, three acrylic and three silicone dental materials were used. The cell viability was examined by MTT and lactate dehydrogenase (LDH) methods. The cell viability immediately after malaxation or light irradiation was lower only for the acrylic materials in 3T3 cells, and for both silicone and acrylic materials in ES-D3 cells. However, the cell viability determined 24 h after malaxation or light irradiation by the MTT and LDH methods did not significantly differ between samples. It was observed that ES-D3 cells are more sensitive depending on the type of material. The results suggest that ES-D3 cells can be used as in vitro systems for conducting biosafety assessment to predict embryotoxicity.

Plant Growth-promoting Effects of Viable and Dead Spores of Bacillus pumilus TUAT1 on Setaria viridis.

Spores are a stress-resistant form of Bacillus spp., which include species that are plant growth-promoting rhizobacteria (PGPR). Previous studies showed that the inoculation of plants with vegetative cells or spores exerted different plant growth-promoting effects. To elucidate the spore-specific mechanism, we compared the effects of viable vegetative cells, autoclaved dead spores, and viable spores of Bacillus pumilus TUAT1 inoculated at 107 CFU plant-1 on the growth of the C4 model plant, Setaria viridis A10.1. B. pumilus TUAT1 spores exerted stronger growth-promoting effects on Setaria than on control plants 14 days after the inoculation. Viable spores increased shoot weight, root weight, shoot length, root length, and nitrogen uptake efficiency 21 days after the inoculation. These increases involved primary and crown root formation. Additionally, autoclaved dead spores inoculated at 108 or 109 CFU plant-1 had a positive impact on crown root differentiation, which increased total lateral root length, resulting in a greater biomass and more efficient nitrogen uptake. The present results indicate that an inoculation with viable spores of B. pumilus TUAT1 is more effective at enhancing the growth of Setaria than that with vegetative cells. The plant response to dead spores suggests that the spore-specific plant growth-promoting mechanism is at least partly independent of symbiotic colonization.

Influence of potassium-solubilizing bacteria on the growth and radiocesium phyto-transfer of Brassica rapa L. var. perviridis grown in contaminated Fukushima soils.

The supply of K, being the chemical analog of Cs, affects the phytotransfer of radiocesium such as 137Cs from contaminated soils and its accumulation in plant tissues. Since K and Cs have high affinity to the same clay particle surfaces, the presence of potassium-solubilizing bacteria (KSB) could increase the availability of not only K+ in the rhizosphere but also of radiocesium. In this study, we obtained five KSB isolates with the highest solubilization capacities from soybean rhizosphere on modified Aleksandrov medium containing sericite as K source. Based on biochemical and 16S rRNA gene sequence analysis, we identified the bacteria as Bacillus aryabhattai MG774424, Pseudomonas umsongensis MG774425, P. frederiksbergensis MG774426, Burkholderia sabiae MG774427, and P. mandelii MG774428. We evaluated the KSB isolates based on plant growth promotion and 137Cs accumulation in komatsuna (Brassica rapa L. var. Perviridis) grown in three soils collected from Miyanoiri, Takanishi, and Ota contaminated by 137Cs from the Fukushima accident. Inoculation with KSB showed beneficial effects on plant growth and increased the overall plant biomass production (~40%). On the average, KSB inoculation resulted in the removal of 0.07 ± 0.04% of 137Cs from the soil, more than twice the control. But similar to the effect of KSB inoculation on komatsuna biomass production, different KSBs performed variably and exhibited site-specific responses independent of their K-solubilizing capacities, with higher 137Cs phyto-transfer in roots than in shoots. In terms of root transfer factor (TF), values were highest in komatsuna plants grown in Miyanoiri and Ota soils inoculated with P. frederiksbergensis and Burkholderia sabiae, while they were highest in Takanishi soils inoculated with Bacillus aryabhattai and P. umsongensis. These TF values were also much higher than previously reported values for komatsuna grown in 137Cs-contaminated Fukushima soils inoculated with other rhizobacteria. Thus, KSB inoculation significantly enhance not only the growth of komatsuna but 137Cs uptake.

Genetic Diversity and Characterization of Symbiotic Bacteria Isolated from Endemic Phaseolus Cultivars Located in Contrasting Agroecosystems in Venezuela.

Phaseolus vulgaris is a grain cultivated in vast areas of different countries. It is an excellent alternative to the other legumes in the Venezuelan diet and is of great agronomic interest due to its resistance to soil acidity, drought, and high temperatures. Phaseolus establishes symbiosis primarily with Rhizobium and Ensifer species in most countries, and this rhizobia-legume interaction has been studied in Asia, Africa, and the Americas. However, there is currently no evidence to show that rhizobia nodulate the endemic cultivars of P. vulgaris in Venezuela. Therefore, we herein investigated the phylogenetic diversity of plant growth-promoting and N2-fixing nodulating bacteria isolated from the root nodules of P. vulgaris cultivars in a different agroecosystem in Venezuela. In comparisons with other countries, higher diversity was found in isolates from P. vulgaris nodules, ranging from α- and ß-proteobacteria. Some isolates belonging to several new phylogenetic lineages within Bradyrhizobium, Ensifer, and Mesorhizobium species were also specifically isolated at some topographical regions. Additionally, some isolates exhibited tolerance to high temperature, acidity, alkaline pH, salinity stress, and high Al levels; some of these characteristics may be related to the origin of the isolates. Some isolates showed high tolerance to Al toxicity as well as strong plant growth-promoting and antifungal activities, thereby providing a promising agricultural resource for inoculating crops.

[A Case of Liver Metastasis of Colorectal Cancer in a Hemodialysis Patient, Underwent Liver Resection and Chemotherapy after Colorectal Resection].

A 60 years old man has undergone hemodialysis due to chronic renal failure by diabetic nephropathy. A sigmoid colon cancer and multiple liver metastases(S2, S6)were found, and he had laparoscopic sigmoid colon resection first, it was local resection. The stage was pT3N2aH1, stage Ⅳ, and histopathological examination revealed that the tumor was well‒differentiated adenocarcinoma and RAS, BRAF mutation was negative. From the 4th week after surgery, mFOLFOX4 plus panitumumab( oxaliplatin 60 mg/m2[30% reduction]), continuous intravenous injection fluorouracil 600 mg/m2(regulated amount), rapid intravenous injection fluorouracil 400 mg/m2(regulated amount), Leucovorin 100 mg/m2(regulated amount), panitumumab 6 mg/kg(regulated amount)were given for 4 courses. Since partial response was obtained in both hepatic lesions, we underwent radiofrequency ablation for S6 lesion and laparoscopic partial hepatectomy for S2 lesion. Eight months have passed since the first visit, but no recurrence have been observed. The kidney is an organ that metabolizes many drugs, and it is necessary to adjust the drug volume and consider the timing of administration even in anticancer chemotherapy. We report that we experienced chemotherapy for colorectal cancer during hemodialysis with a review of the literature.

Prediction of portal vein thrombosis after hepatectomy for hepatocellular carcinoma.

PURPOSE: Portal vein thrombosis (PVT) following hepatectomy is potentially life-threatening. We aimed to evaluate the incidence of PVT after hepatectomy for hepatocellular carcinoma and identify coagulation and fibrinolytic factors that could predict early-stage postoperative PVT. METHODS: A retrospective analysis was conducted on 65 hepatocellular carcinoma patients who underwent radical hepatectomy. The risk factors for postoperative PVT were identified based on univariate and multivariate analyses, and the levels of coagulation and fibrinolytic factors were measured during the perioperative period. RESULTS: The incidence of PVT after hepatectomy was 20.0%. The patients were divided into two groups: those with PVT (n=13; PVT group) and those without PVT (n=52; no-PVT group). The frequency of the use of the Pringle maneuver during surgery was higher in the PVT group than in the no-PVT group, and the postoperative/preoperative ratios of thrombin-antithrombin III complex (TAT) and of D-dimer were significantly higher in the PVT group. CONCLUSION: A high incidence of PVT was found in hepatocellular carcinoma patients after hepatectomy. The frequency of the Pringle maneuver is a potential risk factor for postoperative PVT, and the postoperative/preoperative TAT and D-dimer ratios may be used as early predictors of PVT after hepatectomy for hepatocellular carcinoma.

Efficacy and safety of a new vedolizumab subcutaneous formulation in Japanese patients with moderately to severely active ulcerative colitis.

BACKGROUND/AIMS: A subgroup analysis was conducted in Japanese patients with moderate to severe ulcerative colitis (UC) enrolled in the phase 3 VISIBLE 1 study, which evaluated the safety and efficacy of a new vedolizumab subcutaneous (SC) formulation. METHODS: Eligible patients received open-label infusions of vedolizumab 300 mg intravenous (IV) at weeks 0 and 2 in the induction phase. Patients with clinical response by complete Mayo score at week 6 entered the double-blind maintenance phase and were randomized to vedolizumab 108 mg SC every 2 weeks, placebo, or vedolizumab 300 mg IV every 8 weeks. The primary endpoint was clinical remission (complete Mayo score ≤ 2 points; no individual subscore > 1 point) at week 52. RESULTS: Of 49 patients who entered the induction phase, 22 out of 49 patients (45%) had clinical response at week 6 and were randomized to vedolizumab 108 mg SC (n = 10), placebo (n = 10), or vedolizumab 300 mg IV (n = 2). At week 52, 4 out of 10 patients (40%) who received vedolizumab SC had clinical remission versus 2 out of 10 patients (20%) who received placebo (difference: 20% [95% confidence interval, -27.9 to 61.8]). Two patients (2/10, 20%) who received vedolizumab SC experienced an injection-site reaction versus none who received placebo. CONCLUSIONS: Our results indicate that the efficacy of vedolizumab SC in a subgroup of Japanese patients with UC are similar with those in the overall VISIBLE 1 study population, and with those established with vedolizumab IV. The safety and tolerability of vedolizumab SC were generally similar to that established for vedolizumab IV. (ClinicalTrials.gov ID NCT02611830; EudraCT 2015-000480-14).

Elemental diet therapy plays a significant role in preventing surgical recurrence of Crohn's disease in the era of biologics.

PURPOSE: Most patients with Crohn's disease (CD) experience surgical recurrence. In this era of novel therapies, we conducted this study to clarify which treatments effectively decrease the risk of surgical recurrence in patients with CD. METHODS: The subjects of this retrospective study were 37 patients with CD. We created cumulative surgery rate curves and performed univariate and multivariate analyses. RESULTS: Univariate analysis revealed that patients who consumed an elemental diet (ED; ≥ 900 kcal/day), anti-tumor necrosis factor-alpha, and thiopurines had a significantly better prognosis than those who did not (p = 0.011, p = 0.025, and p = 0.0080, respectively). Multivariate analysis revealed that ED therapy and thiopurines were independent significant factors for controlling surgical recurrence (p = 0.046 and p = 0.032, respectively). Additional analyses showed that the most promising ED therapeutic dose was ≥ 1200 kcal/day, while an ED therapeutic dose of ≥ 900 kcal/day was acceptable. CONCLUSIONS: Although univariate analyses revealed that all three treatment strategies had significant effects on surgical recurrence in patients with CD, multivariate analysis revealed that only ED therapy was significantly associated with surgical recurrence rates. Thus, ED therapy plays an important role in the management of CD, even in the era of biological therapies.

Laparoscopic Cholecystectomy During Pregnancy: A Case Report and Review of Literature in Japan.

Herein we report a case of laparoscopic cholecystectomy in a 26-year-old pregnant woman with no remarkable medical history. Laparoscopic cholecystectomy was performed at 21 weeks of gestation. To prevent uterus injury, the first trocar was inserted into the right hypochondrium using the open method after marking the site of the uterus via ultrasonography. After confirming the site of the uterus, the second trocar with a balloon was inserted 3 finger widths above the umbilicus. Additional 5-mm trocars were inserted into the epigastric and hypochondrial regions. A good surgical view was obtained with a pneumoperitoneal pressure of 8 mmHg. Laparoscopic cholecystectomy was successfully performed without any complications during or after the operation. She had a normal delivery at 39 weeks of gestation. Laparoscopic cholecystectomy is a viable treatment option during pregnancy, provided there is close consultation and cooperation between obstetricians and anesthesiologists.

Phylogenetic Analysis of Symbiotic Bacteria Associated with Two Vigna Species under Different Agro-Ecological Conditions in Venezuela.

Vigna is a genus of legumes cultivated in specific areas of tropical countries. Species in this genus are important crops worldwide. Vigna species are of great agronomic interest in Venezuela because Vigna beans are an excellent alternative to other legumes. However, this type of crop has some cultivation issues due to sensitivity to acidic soils, high temperatures, and salinity stress, which are common in Venezuela. Vigna species establish symbioses mainly with Bradyrhizobium and Ensifer, and Vigna-rhizobia interactions have been examined in Asia, Africa, and America. However, the identities of the rhizobia associated with V. radiata and V. unguiculata in Venezuela remain unknown. In the present study, we isolated Venezuelan symbiotic rhizobia associated with Vigna species from soils with contrasting agroecosystems or from fields in Venezuela. Several types of soils were used for bacterial isolation and nodules were sampled from environments characterized by abiotic stressors, such as high temperatures, high concentrations of NaCl, and acidic or alkaline pH. Venezuelan Vigna-rhizobia were mainly fast-growing. Sequencing of several housekeeping genes showed that in contrast to other continents, Venezuelan Vigna species were nodulated by rhizobia genus including Burkholderia, containing bacteria from several new phylogenetic lineages within the genus Bradyrhizobium. Some Rhizobium and Bradyrhizobium isolates were tolerant of high salinity and Al toxicity. The stress tolerance of strains was dependent on the type of rhizobia, soil origin, and cultivation history. An isolate classified as R. phaseoli showed the highest plant biomass, nitrogen fixation, and excellent abiotic stress response, suggesting a novel promising inoculant for Vigna cultivation in Venezuela.

Characterization of Rhizobia for the Improvement of Soybean Cultivation at Cold Conditions in Central Europe.

In central Europe, soybean cultivation is gaining increasing importance to reduce protein imports from overseas and make cropping systems more sustainable. In the field, despite the inoculation of soybean with commercial rhizobia, its nodulation is low. In many parts of Europe, limited information is currently available on the genetic diversity of rhizobia and, thus, biological resources for selecting high nitrogen-fixing rhizobia are inadequate. These resources are urgently needed to improve soybean production in central Europe. The objective of the present study was to identify strains that have the potential to increase nitrogen fixation by and the yield of soybean in German soils. We isolated and characterized 77 soybean rhizobia from 18 different sampling sites. Based on a multilocus sequence analysis (MLSA), 71% of isolates were identified as Bradyrhizobium and 29% as Rhizobium. A comparative analysis of the nodD and nifH genes showed no significant differences, which indicated that the soybean rhizobia symbiotic genes in the present study belong to only one type. One isolate, GMF14 which was tolerant of a low temperature (4°C), exhibited higher nitrogen fixation in root nodules and a greater plant biomass than USDA 110 under cold conditions. These results strongly suggest that some indigenous rhizobia enhance biological nitrogen fixation and soybean yield due to their adaption to local conditions.