Phaseolus Vulgaris Research Articles

Prevalence, diversity and applications potential of nodules endophytic bacteria: a systematic review

Legumes are renowned for their distinctive biological characteristic of forming symbiotic associations with soil bacteria, mostly belonging to the Rhizobiaceae familiy, leading to the establishment of symbiotic root nodules. Within these nodules, rhizobia play a pivotal role in converting atmospheric nitrogen into a plant-assimilable form. However, it has been discerned that root nodules of legumes are not exclusively inhabited by rhizobia; non-rhizobial endophytic bacteria also reside within them, yet their functions remain incompletely elucidated. This comprehensive review synthesizes available data, revealing that Bacillus and Pseudomonas are the most prevalent genera of nodule endophytic bacteria, succeeded by Paenibacillus, Enterobacter, Pantoea, Agrobacterium, and Microbacterium. To date, the bibliographic data available show that Glycine max followed by Vigna radiata, Phaseolus vulgaris and Lens culinaris are the main hosts for nodule endophytic bacteria. Clustering analysis consistently supports the prevalence of Bacillus and Pseudomonas as the most abundant nodule endophytic bacteria, alongside Paenibacillus, Agrobacterium, and Enterobacter. Although non-rhizobial populations within nodules do not induce nodule formation, their presence is associated with various plant growth-promoting properties (PGPs). These properties are known to mediate important mechanisms such as phytostimulation, biofertilization, biocontrol, and stress tolerance, emphasizing the multifaceted roles of nodule endophytes. Importantly, interactions between non-rhizobia and rhizobia within nodules may exert influence on their leguminous host plants. This is particularly shown by co-inoculation of legumes with both types of bacteria, in which synergistic effects on plant growth, yield, and nodulation are often measured. Moreover these effects are pronounced under both stress and non-stress conditions, surpassing the impact of single inoculations with rhizobia alone.

Calibration, testing and application of the AquaCrop model for bean crop under irrigation regimes.

Crop growth simulation models relate the soil-water-plant-atmosphere components to estimate the development and yield of plants in different scenarios, enabling the identification of efficient irrigation strategies. The aim of this study was to calibrate crop coefficients for a common bean cultivar (IAPAR 57) and assess the AquaCrop model's efficacy in simulating crop growth under different irrigation regimes (T0 - non-irrigated, T1-fully irrigated, and T2-deficit irrigated) and sowing dates (S1-March 21, S2-April 24, and S3-August 23). Successful calibration was achieved for crop seasons with suitable temperatures to crop growth (S1 and S3). However, during periods with suboptimal temperatures (April 24 season), coupled with reduced irrigation supply (T0 and T2), the AquaCrop model did not appropriately account for the combined effects of thermal and water stresses. Despite adjustments to stress coefficients, this led to an overestimation of crop growth and yield. In long-term simulations, the model successfully replicated the variability of crop water availability over cropping seasons, reflecting the impact of precipitation variations. It recommended irrigation strategies for the study region (irrigate at depletion of 120 and 170% of readily available water for sowing on March 21 and August 24, respectively) to achieve high crop yield (> 2,769kgha-1) and water productivity (1,050 to 1,445kgm-3) with minimal application depths (< 150mm). While acknowledging the need for improvements in thermal stress calculations, the AquaCrop model demonstrates promising utility in studies and applications where water availability significantly influences crop production.

Assessment of Transgressive Segregants for Yield and its Component Traits in French Bean (Phaseolus vulgaris L.)

Background: Extreme phenotypes carried on by transgressive segregation are, moreover, heritably stable in contrast to heterosis. It has been hypothesized that the development of extreme or “transgressive” traits in segregating hybrid populations assists in the adaptive divergence of hybrid taxa. The investigation on French bean was experimented to evaluate transgressive segregants generated in the F2 generation for yield and related traits. Methods: The present study on French bean was conducted during rabi 2019 to 2022 to elicit data on transgressive segregants produced for yield and related traits in F2 generation. Fertile F1 hybrids were developed from three crosses: IC 632961 × Arka Sukomal, IC 632961 × Arka Arjun and Arka Arjun × IC 63296. Heterosis was estimated for yield and related traits in these hybrids. The F2 progeny were evaluated in open field condition. Mean, standard deviation and percentage of transgressive segregants were estimated for quantitative traits under investigation. Result: Transgressive segregants were observed in all three crosses, with the highest number of transgressive segregants for yield traits found in the progeny of the cross IC 632961 × Arka Sukomal. The identification and isolation of such transgressive segregants indicate that the parents possess favourable alleles and genes governing the traits of interest, which can be consolidated into a single or a few genotypes through stringent selection. Superior and desirable transgressive segregants were observed for all sixteen yield and its component traits, except for leaf length, in the two cross combinations Arka Arjun × IC 632961 and IC 632961 × Arka Arjun. The highest percentage of transgressive segregation was observed for the number of inflorescences per plant (79.49%), followed by the number of pods per plant (78.46%) and pod yield per plant (75.61%) in the F2 generation.

Assessment of genotypic variability and genome‐wide association analysis of cooking time and canning quality traits in common bean (Phaseolus vulgaris L.)

AbstractDeveloping improved common bean varieties with short cooking time (CT) and good canning quality traits (CQTs) is very key for accelerating bean consumption among the urban and middle‐class population. The objective of this study was to assess the genotypic variability and identify single nucleotide polymorphism (SNP) markers associated with CT and CQTs in common bean. A total of 250 common bean accessions were evaluated under field conditions for two seasons using alpha lattice design with two replications. Three months post‐harvest, the dry bean grains were evaluated for CT and CQTs. Significant variation was observed among the 250 common bean accessions tested for both traits. CT ranged from 51 to 215 min, with 11 genotypes cooking in less than 60 min. The percentage total CQTs' score ranged from 41% to 84% with 31 genotypes scoring 76% and above. Forty‐seven significant GWAS signals were detected for CT on chromosomes Pv01, Pv04, Pv05 and Pv11 and CQTs on Pv01, Pv02, Pv03, Pv04, Pv05, Pv06, Pv07, Pv08, Pv10 and Pv11, respectively. Positional candidate genes including Phvul.005G161200 on chromosome Pv05, Phvul.007G2803001 and Phvul.007G280700 on chromosome Pv07 were associated with seed coat colour retention of the canned beans. Besides their usefulness in breeding research, the identified bean genotypes with shorter CT and good CQTs could enhance bean consumption and processing industries.

Possibilities of Using Phaseolus Vulgaris and Phaseolus Lunatus Beans in Pasta Production

In last decade, in scientific literature, various pulses dominate as raw material of new pasta development. The production of pulse pasta is complex technological process, generally based on extrusion technology. The aim of the study was to produce spaghetti-type pasta from Phaseolus vulgaris (variety unknown) and Phaseolus lunatus (variety Kontra). The recipes made with xanthan gum and corn starch as a binder, the optimal cooking time and water absorption capacity was determined. In the experiment, wheat semolina spaghetti was used as a control sample. Four types of spaghetti were prepared using a single-screw extruder, then dried in a rotary oven and stored until analysis. Pasta cooking properties have been determined. The obtained data were compared using t-test. There were significant differences between obtained spaghetti and control sample. The results confirm that beans can be used in pasta production.

Effect of Cricket Frass Fertilizer on growth and pod production of green beans (Phaseolus vulgaris L.)

Cricket Frass Fertilizer (CFF) was tested for its efficiency and potential as a fertilizer on the growth of green beans (Phaseolus vulgaris L.) in central Madagascar from April 2020 to October 2020. We grew green beans experimentally for 93 days with seven different fertilizer treatments: NPK 200 kg/ha (0.47 g of N/plant), GUANOMAD (guano from bat) 300 kg/ha (0.26 g of N/ plant), CFF 100 kg/ha (0.12 g of N/plant), CFF 200 kg/ha (0.24 g of N/plant), CFF 300 kg/ha (0.38 g of N/plant), CFF 400 kg/ha (0.52 g of N/plant), and no fertilizer (0 g of N/plant). Three plant traits were measured: survival proportion, vegetative biomass, and pod biomass. The survival proportion of plants treated with the highest dose of CFF (400 kg/ha, 88.1%), NPK (79.8%), and GUANOMAD (81.2%) were similar, but plants treated with the former yielded significantly higher vegetative (35.5 g/plant) and pod biomass (11 g/plant). These results suggest that fertilizing green beans with CFF at a 400 kg/ha dose is sufficient for plant survival and growth, and improves pod production. In Madagascar where soil quality is poor, dependence on imported chemical fertilizers (NPK) and other organic fertilizer (GUANOMAD) can be reduced. Cricket Frass Fertilizer can be used as an alternative sustainable fertilizer for beans.

Genome-wide analysis of C2H2 zinc finger gene family and its response to drought stress in common bean (Phaseolus vulgaris L.)

Genome-wide analysis of C2H2 zinc finger gene family and its response to drought stress in common bean (Phaseolus vulgaris L.)

Study of molecular dynamic interactions during the optimized extrusion processing of corn (Zea mays) and substandard bean (Phaseolus vulgaris)

Within the agri-food industry, substantial quantities of by-products are generated during the collection of raw materials and the preparation of derived food products. A common by-product is the low-value substandard bean that might have structural damages but retains its nutritional characteristics. This research aimed to evaluate the compatibility of bean protein with corn flour starch within an extruded snack model through molecular dynamics simulation by the calculation of the solubility parameter (δ). For the extrusion processing, a central composite design was used with four factors: temperature [150–190 °C], screw speed [150–210 rpm], moisture content [14–18%] and substandard bean content [20–80%]. Simulation calculations were performed using Materials Studio 8.0 software (Accelrys, San Diego, CA). The bean protein was identified as ARC5A, and its structure was obtained from the UniProt database. Starch and protein models evaluated within a temperature profile [25–150 °C] emulating the extrusion processing showed Δδ < 7.0 MPa0.5, indicating that are likely miscible. Optimal processing conditions of the extruded snack were obtained. This research developed an extruded snack using an agro-industrial by-product while predicting the solubility and miscibility parameters of more compounds using molecular dynamics simulations.

Pulse Consumption and Health Outcomes: A Scoping Review

Pulses—comprising the dry, edible seeds of leguminous plants—have long been lauded for their culinary flexibility and substantial nutritional advantages. This scoping review aimed to map the evidence on how pulses contribute to overall human health. Four electronic databases were searched for clinical and observational studies in English. We identified 30 articles (3 cross-sectional studies, 1 federated meta-analysis, 8 prospective cohort studies, 1 before-and-after study, and 17 randomized controlled trials) that met our inclusion criteria. Predominant among the pulses studied were lentils, chickpeas, common bean varieties (e.g., pinto, black, navy, red, kidney), black-eyed peas, cowpeas, and split peas. Consumption modalities varied; most studies examined mixed pulses, while five isolated individual types. In intervention studies, pulses were incorporated into diets by allotting a fixed pulse serving on top of a regular diet or by substituting red meat with pulses, offering a comparative analysis of dietary effects. The health outcomes evaluated were multifaceted, ranging from lipid profiles to blood pressure, cardiovascular disease risk and mortality, type 2 diabetes and glycemic control, metabolic syndrome indicators, inflammatory markers, oxidative stress biomarkers, and hormonal profiles. The most frequently assessed study outcomes included changes in low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, diastolic blood pressure, fasting blood sugar, hemoglobin A1c, waist circumference, and C-reactive protein or high-sensitivity C-reactive protein. This review should serve as a call to action for the scientific community to build upon the existing evidence, enriching our understanding of the nutritional and health-promoting attributes of pulses.

Genetic Diversity, Linkage Disequilibrium, and Population Structure in a Common Bean Reference Collection

An in-depth understanding of the extent and pattern of genetic diversity and population structure in crop populations is of paramount importance for any crop improvement program to efficiently promote the translation of genetic diversity into genetic gain. A reference collection of 150 common bean genotypes selected from the International Center for Tropical Agriculture’s global core collection was evaluated using single-nucleotide polymorphism (SNP) markers to quantify the amount of genetic diversity, linkage disequilibrium, and population structure. The cultivars and landraces of the collection were diverse and originated from 14 countries, and wild accessions were used as controls for each gene pool. The collection was genotyped using an SNP array, generating a total of 5398 locus calls distributed across the entire bean genome. The SNP data quality was checked, and two datasets were generated. The first dataset (Dataset_1) comprised a set of 5108 SNPs and 150 genotypes after filtering for 10% missing alleles and an MAF &lt; 0.05. The second dataset (Dataset_2) comprised a set of 2300 SNPs that remained after removing any null-allele SNPs and LD pruning for a criterion of r2 &lt; 0.2. Dataset_1 was used for a principal coordinate analysis (PCoA), phylogenetic relationship determination, an analysis of molecular variance (AMOVA), and a discriminant analysis of principal components. Dataset_2 was used for a population structure analysis using STRUCTURE software and is proposed for a genome-wide association study (GWAS). The population structure analysis split the reference collection into two subpopulations according to an Andean or Mesoamerican gene pool. The Mesoamerican populations displayed higher genetic differentiation and tended to split into more groups that were somewhat aligned with common bean races. Andean beans were characterized by a larger average LD but lower LD percentage, a small average genetic distance between members of the population, and a higher major allele frequency, which suggested narrower genetic diversity compared to the Mesoamerican gene pool. In conclusion, the results indicated the presence of high genetic diversity, which is useful for a GWAS. However, the presence of significant linkage disequilibrium requires that genetic distance be considered as a co-factor for any further genetic studies. Overall, the molecular variation observed in the genotypes shows that this reference collection is valuable as a genebank-derived diversity panel which is useful for marker trait association studies.

Peptide Inhibitors of Angiotensin-I Converting Enzyme (ACE) Bioavailability in Legumes Subjected to Hydrothermal Treatment

The objective of this study was to evaluate the effect of Angiotensin-I Converting Enzyme (ACE) inhibitory peptides derived from five legumes (Vigna unguiculata, Cicer arietinum, Lens culinaris, Vicia faba, and Phaseolus vulgaris) after undergoing a hydrothermal treatment. The seeds were divided into two groups: one was subjected to drying and grinding, and the other one to cooking for 2 hours (100 °C), followed by drying and grinding. The flours obtained from the different processes were subjected to digestion with pepsin-pancreatin, and the resulting peptides were evaluated for their ACE inhibitory activity. The obtained results were subjected to analysis of variance and Tukey's test. The group consisting of the treatments V. unguiculata (82.63%), V. unguiculata cooked (96.41%), and C. arietinum (80.84%) showed the highest percentages of ACE inhibition, while the group comprising V. faba (6.0%), cooked L. culinaris (3.03%), and P. vulgaris (4.0%) exhibited the lowest inhibition percentages. These results demonstrate that V. unguiculata, V. faba, and C. arietinum can undergo hydrothermal treatment while still retaining their bioactive potential, ensuring a cooked flour, ready for formulating a multifunctional food.

Nutritional Composition, Bioactive Compounds, Food Applications, and Health Benefits of Pigeon Pea (Cajanus cajan L. Millsp.): A Review

ABSTRACTPigeon pea is one of the most multipurpose grain legumes in the tropical and subtropical world. It is highly resilient to climate change due to drought tolerance. It ranks sixth following common beans, chickpeas, field peas, cowpeas, and lentils globally. Pigeon pea is an excellent source of high‐quality protein, essential amino acids, and minerals. Furthermore, pigeon pea is endowed with valuable water‐soluble vitamins such as thiamin, ascorbic acid, riboflavin, and niacin. With low levels of saturated fat and sodium and being cholesterol free, pigeon peas emerge as a nutritious dietary choice. Pigeon peas are rich sources of bioactive compounds with various potential health properties, including anti‐inflammatory, antibacterial, antioxidant, anticarcinogenic, and antidiabetic effects. Pigeon peas can be consumed in diverse forms, including whole seeds, split seeds (known as dhal), vegetables using green seeds, and fresh pods. Moreover, pigeon peas find application in a variety of food products, including bread, pasta, noodles, snacks, and biscuits. Despite their nutritional and medicinal properties, pigeon peas remain among the least utilized legumes globally. This review paper aims to provide up‐to‐date information on the nutritional compositions, bioactive compounds, food applications, and health benefits of pigeon peas.

Legumes and common beans in sustainable diets: nutritional quality, environmental benefits, spread and use in food preparations

Legumes and common beans in sustainable diets: nutritional quality, environmental benefits, spread and use in food preparations

Features of the protection of phaseolus vulgaris crops from weeds

Goal. To determine the effect of herbicides on the weediness of crops and the yield of Phaseolus vulgaris seeds in the conditions of the Right Bank Forest Steppe of Ukraine. Methods. Informational and analytical (collection of materials and analysis of literary sources), field research (setting up experiments, observing the development of plants, determining biometric indicators, accounting for the number of weeds, collecting and determining the structure of the harvest), mathematical and statistical (processing of research results). The field experiment design included weeded and weed-protected plots to compare the development of common bean plants under different growing conditions. The results. It was established that the dominant weeds among cereals were chicken millet and gray mouse millet, and among dicotyledonous weeds - ragweed, white quinoa, common sedge, black solanum, field mustard, etc. The use of herbicide protection significantly improves the yield of Phaseolus vulgaris. The obtained yield increased on average by 1.93 - 2.01 t/ha compared to the weeded control. Conclusions. Weeding can significantly reduce the yield of common bean crops by competing for resources such as light, water and nutrients. Weed control helps conserve these resources for the Phaseolus vulgaris and increase its yield. The use of herbicides is an effective method of weed control, which promotes optimal growth of Phaseolus vulgaris. The increase in yield due to the application of herbicide protection can offset the costs of purchasing and applying the herbicide. It is important to consider the effectiveness of specific herbicides when choosing crop protection methods. Different herbicides can have different spectrums of action, that is, be effective against different types of weeds. The right choice will help optimize results and save costs. Therefore, weed control in common Phaseolus vulgaris crops through the application of herbicide protection is an important and effective strategy that can increase the yield and economic efficiency of common bean cultivation technology.

Implementation of Eco-Friendly Control Tactics against Infestations of Aphis craccivora and Tetranychus urticae on Common Bean Plants

Implementation of Eco-Friendly Control Tactics against Infestations of Aphis craccivora and Tetranychus urticae on Common Bean Plants

Trichoderma harzianum enhances root biomass production and promotes lateral root growth of soybean and common bean under drought stress

AbstractDrought stress (DS) is one of the main environmental stresses that determines crop productivity. It has been estimated that DS depresses over 40%–60% of soybean (Glycine max (L.) Merr.) and common bean (Phaseolus vulgaris L.) production worldwide, respectively. Although different agronomic strategies are sometimes implemented, the current goal in sustainable agriculture could involve the inoculation with native microorganisms to mitigate DS effects. A potential fungal candidate is Trichoderma, which is recognized as a ubiquitous soil inhabitant with growth‐promoting and biocontrol potentiality. However, its potential for mitigating the stress for water deficit is less well‐documented. Our objective was to evaluate the effect of inoculation with native Trichoderma harzianum strains on soybean and common bean growth under contrasting conditions of water availability. Seeds were independently inoculated (or not) with IB‐J15 and IB‐363 strains, and plants were submitted to DS or were kept under optimal irrigation (well‐watered, WW). In both legumes, the most evident effect after being inoculated was the modification of plant root architecture, the increase in root area and the development of lateral roots in plants under WW and DS conditions. In soybean, both Trichoderma strains had a positive inoculation response, both fresh and dry root biomass increased under WW, and remarkably under DS conditions. The main effect was an increase of about 110% in root dry weight under WW and, about 330% in DS in plants inoculated with IB‐J15 strain, meanwhile, plants inoculated with IB‐363 increased root dry weight 60% in WW and 177% in DS conditions. Notably in soybean, the inoculation with both Trichoderma strains increased the root area more than 70% in both WW and DS conditions. Common beans inoculated with IB‐363 under WW conditions, reached a positive inoculation responsiveness of around 247% in shoot dry weight biomass, and under WW both strains increased the root area more than 50%. Further, IB‐363 increased leaf area by 25% in WW and 72% in DS. Additionally, the in vitro co‐culture between both Trichoderma strains and nodulating Rhizobium etli and Bradyrhizobium japonicum E109 showed compatibility between microorganisms, since no inhibition of their growth was observed. We emphasize that plants inoculated with Trichoderma showed better resistance to water deficit, as seen by redistribution of photosynthates, prioritizing mainly, the development of the root system. © 2024 Association of Applied Biologists.

Role of processing and encapsulation in the protection and bioaccessibility of phenolic compounds from Chilean Tórtola Common Bean (Phaseolus vulgaris L.)

The aim of this study was to extract, protect and increase the bioaccessibility of phenolic compounds extracted from the Chilean Tórtola common bean. For obtaining phenolic compounds, two methods were analyzed, focusing on their extraction and their drying. In the method where ultrasound-assisted extraction and spray drying were used, we obtained a yield five times greater than the conventional method. Thereafter, we evaluated an encapsulation system with two material shells, alginate and Eudragit L-100. The protective capacity of the capsules was verified by determining antioxidant capacity, total phenolic compounds content, as well as biomedical capacities of powder-encapsulated extract. Antithrombotic activity was evaluated as biomedical capacity, observing a 30% reduction in platelet aggregation. Additionally, quality characteristics were assessed using FITR, microscopic confocal, TGA, and hygrometry techniques. TGA analyses demonstrated the thermal protection of the capsule, reducing the degradation of encapsulated phenolic compounds by threefold compared to the non-encapsulated extract. Finally, two in vitro digestion models were used to simulate the physiological digestion. In both models, we observed an increase in TPC bioaccessibility even over 100%. These results would benefit biomedical applications and industrial processing of phenolic compounds extracted from common beans.

Effects of heat-moisture treatment duration and bean condition on the physicochemical properties of red bean (Phaseolus vulgaris L) starch

Phaseolus vulgaris L (red beans) contain starch that is primarily composed of 44.8% amylose and 55.2% amylopectin but exhibit temperature instability despite their dietary prevalence. This study used Heat Moisture Treatment (HMT) to improve starch attributes in red beans, testing the effects of 4, 5, and 6-hour treatments at 110°C on both fresh and dried samples. The results indicated that both the HMT duration and the beans’ initial state significantly affected the starch’s properties. For fresh beans, the moisture content was reduced from 11.56%±0.54 to 3.04%±0.18, while in dried beans, it decreased from 9.32%±0.94 to 3.81%±0.04. Ash content changed minimally ranging from 1.14%±0.25 to 1.96%±0.02. Bulk density in native fresh and dried starches initially recorded at 0.71 g/mL±0.01 and 0.81 g/mL±0.01, respectively, was observed to decrease after HMT, particularly to 0.51 g/mL±0.01 for dried beans treated for 4 hours. Tapped density varied slightly, reaching up to 0.86 g/mL±0.04. Water activity in both bean types also reduced to 0.42±0.01. In conclusion, HMT significantly enhances Phaseolus vulgaris L starch by lowering moisture, bulk density, and water activity, while maintaining ash content. Further studies should explore the best HMT duration and examine the modified starch’s functional attributes.

Physicochemical, nutraceutical, and sensory evaluation of plant-based beverage type milk by common bean (Phaseolus vulgaris L.) extruded added with extruded protein isolate and iron

Milk-type beverages are popular vegan products requiring iron and calcium fortification to improve their nutritional value, as iron deficiency is the world’s most prevalent nutritional problem. This research aimed to develop and characterize an extruded common bean (Phaseolus vulgaris L.)-based milk-type beverage added with bean protein isolate and iron. The formulations included flavors (non-flavored, vanilla, and nut) and two iron concentrations (2 and 3 mg FeSO4/100 mL). Extrusion increased the beverages’ protein (+17.38 %) and starch digestibility, and reduced their antinutritional compounds (trypsin inhibitors, condensed tannins, and carbonates). Developed beverages’ formulations differed from a commercial soybean beverage in their physicochemical properties but were more nutritious (protein: 3.33–3.44 %; fiber: 3.43–4.08 %). Iron-added beverages displayed a medium sensory acceptance (best overall likeness: 5.3–6.2). The developed beverage is a suitable, sensory-accepted, and nutritious bean-based beverage, suggesting novel research lines improving vegan beverage formulations to increase average daily iron intake.

The symbiovar mediterranense of Sinorhizobium meliloti nodulates Phaseolus vulgaris across Lanzarote (Canary Islands): A revision of this symbiovar supports a proposal to delimit symbiovars boundaries in Sinorhizobium and to define four new symbiovars

The symbiovar mediterranense of Sinorhizobium meliloti was initially found in Phaseolus vulgaris nodules in Tunisia and in an eastern location of Lanzarote (Canary Islands). Here we show that the symbiovar mediterranense of S. meliloti also nodulates P. vulgaris in two western locations of this Island. The analyses of the symbiotic nodA and nodC genes reveal the complexity of the symbiovar mediterranense which encompasses strains belonging to several phylogenetic lineages and clusters. The comparison of the nodA and nodC phylogenies showed that the nodC was the most resolutive phylogenetic marker for the delineation of Sinorhizobium symbiovars. Considering that the similarity of this gene within several symbiovars, particularly mediterranense, is around 95 %, the cut-off value for their differentiation should be lower. Considering that a nodC gene cut-off similarity value of around 92 % is accepted for the genus Bradyrhizobium and that the symbiovar concept is identical in all rhizobial genera, we propose to apply this value for symbiovars delineation within all these genera. Therefore, using this cut-off value for the nodC gene analysis of Sinorhizobium symbiovars, we propose to merge the symbiovars aegeanense and fredii into the single symbiovar fredii and to define four novel symbiovars with the names asiaense, culleni, sudanense and tunisiaense.