Seed-Coat Pigmentation Plays a Crucial Role in Partner Selection and N2 Fixation in Legume-Root-Microbe Associations in African Soils.

Legume-rhizobia symbiosis is the most important plant-microbe interaction in sustainable agriculture due to its ability to provide much needed N in cropping systems. This interaction is mediated by the mutual recognition of signaling molecules from the two partners, namely legumes and rhizobia. In legumes, these molecules are in the form of flavonoids and anthocyanins, which are responsible for the pigmentation of plant organs, such as seeds, flowers, fruits, and even leaves. Seed-coat pigmentation in legumes is a dominant factor influencing gene expression relating to N2 fixation and may be responsible for the different N2-fixing abilities observed among legume genotypes under field conditions in African soils. Common bean, cowpea, Kersting's groundnut, and Bambara groundnut landraces with black seed-coat color are reported to release higher concentrations of nod-gene-inducing flavonoids and anthocyanins compared with the Red and Cream landraces. Black seed-coat pigmentation is considered a biomarker for enhanced nodulation and N2 fixation in legumes. Cowpea, Bambara groundnut, and Kersting's bean with differing seed-coat colors are known to attract different soil rhizobia based on PCR-RFLP analysis of bacterial DNA. Even when seeds of the same legume with diverse seed-coat colors were planted together in one hole, the nodulating bradyrhizobia clustered differently in the PCR-RFLP dendrogram. Kersting's groundnut, Bambara groundnut, and cowpea with differing seed-coat colors were selectively nodulated by different bradyrhizobial species. The 16S rRNA amplicon sequencing also found significant selective influences of seed-coat pigmentation on microbial community structure in the rhizosphere of five Kersting's groundnut landraces. Seed-coat color therefore plays a dominant role in the selection of the bacterial partner in the legume-rhizobia symbiosis.

Efficacy of 10%,25% and 50% dextrose in the treatment of hypoglycemia in the emergency department - A randomized controlled study.

INTRODUCTION: Documented symptomatic hypoglycemia is defined as "event during which typical symptoms of hypoglycemia are accompanied by measured blood glucose of ≤70 mg/dL. Most of the studies and recommendations for the unconscious hypoglycemic adult advocate the use of 25 g of glucose as 50 mL of 50% dextrose solution intravenous or 1 mg of intramuscular glucagon. OBJECTIVE: To compare the efficacy and safety of 5 g boluses of 10%, 25% and 50% dextrose in the treatment of hypoglycemic patients presenting to our emergency department. METHODS: This was a randomized controlled single blinded study. Hypoglycemic patients in altered mental status were randomized into three treatment arms to be administered 10%, 25% or 50% dextrose. 5 g aliquots of intravenous 10%,25% or 50% dextrose were administered over 1 min. Time taken to achieve a Glasgow Coma Scale (GCS) of 15 and median total doses (g) were the primary outcomes. RESULTS: Data of 204 patients were analysed in the study. There was no difference in the median time to achieve a GCS of 15 in all three treatment arms (6 min). Total median dose administered in the 10% and 25% groups was lower than 50% (10 g vs 15 g). Proportion of patients who received the maximum dose of 25 g was higher in the 50% group as compared to 10% and 25% groups (12%, 3%, 4%). CONCLUSION: There was no difference in 10% dextrose and 25% dextrose as compared to 50% dextrose in achieving the baseline mental status (or GCS 15) in the treatment of hypoglycemia in the ED.

Managing Patients With Sympathetic Crashing Acute Pulmonary Edema (SCAPE) Using the SCAPE Treatment Protocol: A Case Series.

Pulmonary edema refers to the accumulation of excessive fluid in the alveolar walls and alveolar spaces of the lungs. It is a life-threatening condition with a high mortality rate and requires immediate assessment and management. Use of intravenous nitroglycerin has been advocated for such cases. The authors present a case series of 3 patients who presented to the emergency department with sympathetic crashing acute pulmonary edema (SCAPE) and were managed with high-dose intravenous nitroglycerin and bilevel positive airway pressure support using the SCAPE treatment protocol, leading to early correction of blood pressure, avoidance of endotracheal intubation, and no episodes of hypotension or rebound hypertension. The authors recommend emergency physicians utilize the SCAPE treatment protocol while managing patients with SCAPE.

Therapeutic drug monitoring of Amikacin in hospitalized patients: A pilot study.

Background: Amikacin, an aminoglycoside, is a widely used parenteral antibiotic. Therapeutic drug monitoring (TDM) is recommended for aminoglycosides to avoid toxicity. However, the lack of infrastructure at most places precludes it. This pilot and novel study attempt to estimate the real-world serum levels of Amikacin in hospitalised patients. Methods: Thirty admitted patients, given Amikacin injections, were included in the study. In addition, 15 clinical specimens isolated with gram-negative bacteria were tested for minimum inhibitory concentration (MIC) value of Amikacin. Trough and peak serum levels of Amikacin were estimated by high-pressure liquid chromatography (HPLC). Results: The average MIC value of Amikacin estimated in our laboratory was 3.92 mcg/mL. Peak and trough serum levels of Amikacin ranged from 12.1 to 66.4 mcg/ml and 1.1 to 20.7 mcg/ml, respectively. More than 83% of our patients achieved peak Amikacin levels of 15 mcg/mL, and 37% had trough levels above 5 mcg/mL. These levels are desirable watersheds as per available literature. Conclusion: Trough levels of Amikacin in all cases and a review of dosing according to MIC values are recommended to achieve drug safety and therapeutic efficacy.

Phylogeny and symbiotic effectiveness of indigenous rhizobial microsymbionts of common bean (Phaseolus vulgaris L.) in Malkerns, Eswatini.

In most legumes, the rhizobial symbionts exhibit diversity across different environments. Although common bean (Phaseolus vulgaris L.) is one of the important legumes in southern Africa, there is no available information on the genetic diversity and N2-fixing effectiveness of its symbionts in Malkerns, Eswatini. In this study, we assessed the phylogenetic positions of rhizobial microsymbionts of common bean from Malkerns in Eswatini. The isolates obtained showed differences in morpho-physiology and N2-fixing efficiency. A dendrogram constructed from the ERIC-PCR banding patterns, grouped a total of 88 tested isolates into 80 ERIC-PCR types if considered at a 70% similarity cut-off point. Multilocus sequence analysis using 16S rRNA, rpoB, dnaK, gyrB, and glnII and symbiotic (nifH and nodC) gene sequences closely aligned the test isolates to the type strains of Rhizobium muluonense, R. paranaense, R. pusense, R. phaseoli and R. etli. Subjecting the isolates in this study to further description can potentially reveal novel species. Most of the isolates tested were efficient in fixing nitrogen and elicited greater stomatal conductance and photosynthetic rates in the common bean. Relative effectiveness (RE) varied from 18 to 433%, with 75 (85%) out of the 88 tested isolates being more effective than the nitrate fed control plants.

Contribution of 15 Years (2007-2022) of Indo-US Training Partnerships to the Emergency Physician Workforce Capacity in India.

BACKGROUND: Indo-US Masters in Emergency Medicine (MEM) certification courses are rigorous three-year emergency medicine (EM) training courses that operate as a partnership between affiliate hospitals or universities in the United States with established EM training programs and local partner sites in India. Throughout their 15 years of operation, these global training partnerships have contributed to the EM workforce in India. Our objective in this study was to describe Indo-US MEM program graduates, their work environments, and their contribution to the growth of academic EM and to the coronavirus disease 2019 (COVID-19) response. METHODS: An electronic survey was created by US and Indian MEM course stakeholders and distributed to 714 US-affiliated MEM program graduates. The survey questions investigated where graduates were working, their work environments and involvement in teaching and research, and their involvement in the COVID-19 response. We consolidated the results into three domains: work environment and clinical contribution; academic contribution; and contribution to the COVID-19 response. RESULTS: The survey response rate was 46.9% (335 responses). Most graduates reported working within India (210, 62.7%) and in an emergency department (ED) setting (304, 91.0%). The most common reason for practicing outside of India was difficulty with formal MEM certificate recognition within India (97, 79.5%). Over half of graduates reported dedicating over 25% of their work hours to teaching others about EM (223, 66.6%), about half reported presenting research projects at conferences on the regional, national, or international level (168, 50.5%), and almost all graduates were engaged in treating COVID-19 patients during the pandemic (333, 99.4%). Most graduates agreed or strongly agreed that they were satisfied with their overall MEM training (296, 88.4%) and confident in their ability to practice EM (306, 91.6%). CONCLUSION: Indo-US MEM graduates have made a notable contribution to EM in India through clinical service delivery, teaching, and research, even more essential in the context of the COVID-19 pandemic. The roles of these graduates should be acknowledged and can contribute further to expand EM specialty and systems development across India.

Unilateral Traumatic Adrenal Hemorrhage with Shock.

Trauma to the adrenal glands is very rare. The variation in clinical manifestations is marked and markers for its diagnosis being limited, makes it tough to be diagnosed. Computed tomography remains the gold standard for detecting this injury. Prompt recognition and the potential for mortality with adrenal insufficiency can provide the best guidance for the treatment and care of the severely injured. We present a case of a 33-year-old trauma patient who was not responding to the management of his shock. He was finally found to have a right adrenal haemorrhage leading to adrenal crisis. The patient was resuscitated in the Emergency Department but succumbed 10 days post admission.

National Early Warning Score 2 is superior to quick Sequential Organ Failure Assessment in predicting mortality in sepsis patients presenting to the emergency department in India: A prospective observational study.

Background: High in-hospital mortality in sepsis patients remains challenging for clinicians worldwide. Early recognition, prognostication, and aggressive management are essential for treating septic patients. Many scores have been formulated to guide clinicians to predict the early deterioration of such patients. Our objective was to compare predictive values of quick Sequential Organ Failure Assessment (qSOFA) and National Early Warning Score 2 (NEWS2) with respect to in-hospital mortality. Methods: This prospective observational study was conducted in a tertiary care center in India. Adults with suspected infection with at least two Systemic Inflammatory Response Syndrome criteria presenting to the emergency department (ED) were enrolled. NEWS2 and qSOFA scores were calculated, and patients were followed until their primary outcome of mortality or hospital discharge. The diagnostic accuracy of qSOFA and NEWS2 for predicting mortality was analyzed. Results: Three hundred and seventy-three patients were enrolled. Overall mortality was 35.12%. A majority of patients had LOS between 2 and 6 days (43.70%). NEWS2 had higher area under curve at 0.781 (95% confidence interval [CI] (0.59, 0.97)) than qSOFA at 0.729 (95% CI [0.51, 0.94]), with P < 0.001. Sensitivity, specificity, and diagnostic efficiency to predict mortality by NEWS2 were 83.21% (95% CI [83.17%, 83.24%]); 57.44% (95% CI [57.39%, 57.49%]); and 66.48% (95% CI [66.43%, 66.53%]), respectively. qSOFA score had sensitivity, specificity, and diagnostic efficiency to predict mortality of 77.10% (95% CI [77.06%, 77.14%]); 42.98% (95% CI [42.92%, 43.03%]); and 54.95% (95% CI [54.90%, 55.00%]), respectively. Conclusion: NEWS2 is superior to qSOFA in predicting in-hospital mortality for sepsis patients presenting to the ED in India.

Seasonal Effect on Bacterial Communities Associated with the Rhizospheres of Polhillia, Wiborgia and Wiborgiella Species in the Cape Fynbos, South Africa.

The Cape fynbos biome in South Africa is home to highly diverse and endemic shrub legumes, which include species of Aspalathus, Polhillia, Wiborgia and Wiborgiella. These species play a significant role in improving soil fertility due to their ability to fix N2. However, information regarding their microbiome is still unknown. Using the 16S rRNA Miseq illumina sequencing, this study assessed the bacterial community structure associated with the rhizospheres of Polhillia pallens, Polhillia brevicalyx, Wiborgia obcordata, Wiborgia sericea and Wiborgiella sessilifolia growing at different locations during the wet and dry seasons in the Cape fynbos. The results showed that the most dominant bacterial phylum was Actinobacteria during both the dry (56.2-37.2%) and wet (46.3-33.3%) seasons. Unclassified bacterial genera (19.9-27.7%) were the largest inhabitants in the rhizospheres of all five species during the two seasons. The other dominant phyla included Bacteroidetes, Acidobacteria, Proteobacteria and Firmicutes. Mycobacterium and Conexibacter genera were the biggest populations found in the rhizosphere soil of all five test species during both seasons, except for W. obcordata soil sampled during the dry season, which had Dehalogenimonas as the major inhabitant (6.08%). In this study plant species and growth season were the major drivers of microbial community structure, with W. obcordata having the greatest influence on its microbiome than the other test species. The wet season promoted greater microbial diversity than the dry season.

Coinoculation impact on plant growth promotion: a review and meta-analysis on coinoculation of rhizobia and plant growth-promoting bacilli in grain legumes.

Coinoculation of symbiotic N2-fixing rhizobia and plant growth-promoting Bacillus on legume seeds can increase crop productivity. We collected highly resolved data on coinoculation of rhizobia and bacilli on 11 grain legume crops: chickpea, common bean, cowpea, faba bean, groundnut, lentil, mung bean, pea, pigeon pea, soybean, and urad bean to verify the magnitude of additive effects of coinoculation in relation to single inoculation of rhizobia on plant growth and yield of grain legumes. Coinoculation of rhizobia and bacilli on legume seeds and/or soil during sowing significantly increased nodulation, nitrogenase activity, plant N and P contents, and shoot and root biomass, as well as the grain yield of most grain legumes studied. There were however a few instances where coinoculation decreased plant growth parameters. Therefore, coinoculation of rhizobia and Bacillus has the potential to increase the growth and productivity of grain legumes, and can be recommended as an environmental-friendly agricultural practice for increased crop yields.

Phylogenetic relationships among Bradyrhizobium species nodulating groundnut (Arachis hypogea L.), jack bean (Canavalia ensiformis L.) and soybean (Glycine max Merr.) in Eswatini.

This study assessed the genetic diversity and phylogenetic relationships of rhizobial isolates obtained from root nodules of groundnut, jack bean and soybean planted in different locations within Eswatini. Seventy-six rhizobial isolates were studied using ERIC-PCR (enterobacterial repetitive intergenic consensus) fingerprinting and PCR amplification of 16S rRNA, housekeeping genes (atpD, dnaK, glnll and rpoB) and symbiotic genes (nifH and nodC). The dendrogram generated from the ERIC-PCR banding patterns grouped the test rhizobial isolates into 16 major clusters (Cluster I-XVI), with three isolates, namely TUTAHeS60, TUTGMeS3 and TUTAHeS127, forming outgroups of Clusters IV, VI and IX, respectively. Furthermore, the 76 test isolates were grouped into 56 ERIC-PCR types at 70% similarity level. The phylogenetic analysis of the 16S rRNA gene and multilocus sequence analysis of four housekeeping (atpD, dnaK, glnII and rpoB) and two symbiotic (nifH and nodC) genes showed that all three legumes (groundnut, jack bean and soybean) were nodulated by bacterial symbionts belonging to the genus Bradyrhizobium, with some isolates exhibiting high divergence from the known reference type strains. The results also showed that B. arachidis, B. iriomotense and B. canariense were the closest type strains to the groundnut isolates, while B. pachyrhizi and B. elkanii were the closest relatives to the bacterial symbionts associated with the nodulation of both jack bean and soybean. This study is the first report to describe of the bacterial symbionts nodulating jack bean in African soils.

Rapid Thrombolysis Protocol: Results from a Before-and-after Study.

Objective: Intravenous thrombolysis within 4.5 hours from time of onset has proven benefit in stroke. Universal standard for the door-to-needle (DTN) time is within 60 minutes from the time of arrival of patients to the emergency department. Our rapid thrombolysis protocol (RTPr) was developed with an aim to reduce the DTN time to a minimum by modifying our stroke post-intervention processes. Materials and methods: This before-and-after study was conducted at a single center on patients who received intravenous thrombolysis in the emergency department. Consecutive patients who were thrombolysed using our RTPr (post-intervention group) were compared to the pre-intervention group who were thrombolysed before the implementation of the protocol. The primary outcomes were DTN time, time to recovery, and modified ranking score (mRS) on discharge. Secondary outcomes were mortality, symptomatic intracerebral hemorrhage, and hospital and intensive care unit length of stay. Results: Seventy-four patients were enrolled in each group. Mean DTN time in pre- and post-intervention group was 56.15 minutes (95% CI 49.98-62.31) and 34.91 minutes (95% CI 29.64-40.17) (p <0.001), respectively. In pre-intervention and post-intervention groups, 43.24% (95% CI 32.57-54.59) and 41.89% (95% CI 31.32-53.26) patients, respectively, showed neurological recovery in 24 hours. About 36.49% (95% CI 26.44-47.87) in pre-intervention group and 54.05% (95% CI 42.78-64.93) in post-intervention group had discharge mRS 0-2. Conclusion: The RTPr can be adapted by clinicians and hospitals to bring down the DTN times and improve outcomes for stroke patients. How to cite this article: Verma A, Sarda S, Jaiswal S, Batra A, Haldar M, Sheikh WR, et al. Rapid Thrombolysis Protocol: Results from a Before-and-after Study. Indian J Crit Care Med 2022;26(5):549-554.

Effectiveness of Clinical Presentation (CP) Curriculum in teaching clinical medicine to undergraduate medical students: A cross-sectional study.

Introduction: The Clinical Presentation (CP) curriculum was first formulated in 1990 at the University of Calgary, Canada. Since then, it has been adopted at various medical schools, including Patan Academy of Health Sciences (PAHS), a state-funded medical school in a low-income country (LIC), Nepal. This study aims to evaluate the perceived effectiveness of the CP curriculum by students and faculty at PAHS, and test knowledge retention through a surprise non-routine exam administered to students.  Method: This is a cross-sectional study to evaluate the efficacy of the CP curriculum in teaching clinical medicine to the first batch of MBBS students of PAHS School of Medicine. Ethical approval was obtained from the Institutional Review Committee (IRC)-PAHS (Ref no std1505911069). Perceived effectiveness was evaluated using a set of questionnaires for faculty and students. A total of 33 students and 34 faculty filled the perception questionnaires. Subsequently, a questionnaire consisting of 50 Multiple Choice Questions (MCQs) from different clinical medicine disciplines was administered to test students' knowledge retention. Out of 49 students, 38 participated in the surprise non-routine exam.   Result: A significantly higher number of faculty preferred the CP curriculum compared to the traditional system of teaching clinical medicine (16 vs 11, Kruskal Wallis: 0.023, ie. P-value < 0.05). A significantly higher number of the students liked and recommended CP curriculum in the clinical year of medical education (20 vs. 13 with p-value < 0.05). In the non-routine surprise exam, two thirds of the students scored 60% or above.  Conclusion: Both faculty and students perceive that the CP curriculum system is an effective teaching and learning method in medical education, irrespective of their different demographic and positional characteristics. The students' overall performance was good in surprise, non-routine exams taken without scheduling or reminders.

Characteristics and outcomes of hospitalized adults with COVID-19 in Nepal: a multicenter, prospective cohort study.

INTRODUCTION: There is limited data on clinical course and outcomes of hospitalized adults with COVID-19 in Nepal. Thus, it is imperative to characterize the features of this disease in the domestic context. METHODOLOGY: We identified all adult patients with laboratory-confirmed COVID-19 admitted to five different hospitals in Nepal from June 15 to July 15, 2020. We collected epidemiological, socio-cultural and clinicopathologic data, and stratified the patients based on their symptom status. RESULTS: The study included 220 patients with an overall median age of 31.5 (25-37) years, and 181 (82.3%) were males. 159 (72.3%) were asymptomatic, and 163 (74.1%) were imported cases. Of 217 patients with the available data, 110 (50.7%) reported their annual household income less than 2000 US dollars, and 122 (56.2%) practiced Pranayama (yogic rhythmic breathing techniques) regularly. Eight patients (3.6%) required supplemental oxygen and two patients (0.9%) died. None of the patients who practiced Pranayama regularly required supplemental oxygen. Compared to asymptomatic patients, symptomatic patients had greater proportion of females (31.1% vs. 12.6%, p = 0.001), imported cases (85.2% vs. 69.8%, p = 0.02), illiterates (26.8% vs. 12.1%, p = 0.01), alcohol users (43.3% vs. 24.5%, p = 0.01), and had higher platelet count (253×109/L vs. 185×109/L, p = 0.02). CONCLUSIONS: Most cases were imported, asymptomatic young males, with very few deaths. Pranayama practice was associated with protection against severe COVID-19, but more data is needed to substantiate this. The association of platelets count with symptom status in the Nepalese population needs further exploration.

Ecological adaptation and phylogenetic analysis of microsymbionts nodulating Polhillia, Wiborgia and Wiborgiella species in the Cape fynbos, South Africa.

Polhillia, Wiborgia and Wiborgiella species are shrub legumes endemic to the Cape fynbos of South Africa. They have the ability to fix atmospheric N2 when in symbiosis with soil bacteria called 'rhizobia'. The aim of this study was to assess the morpho-physiological and phylogenetic characteristics of rhizobia associated with the nodulation of Polhillia, Wiborgia and Wiborgiella species growing in the Cape fynbos. The bacterial isolates from root nodules consisted of a mixture of fast and intermediate growers that differed in colony shape and size. The isolates exhibited tolerance to salinity (0.5-3% NaCl) and pH (pH 5-10) and different antibiotic concentrations, and could produce 0.51 to 51.23 µg mL-1 of indole-3-acetic acid (IAA), as well as solubilize tri-calcium phosphate. The ERIC-PCR results showed high genomic diversity in the rhizobial population and grouped them into two major clusters. Phylogenetic analysis based on 16S rRNA, atpD, glnII, gyrB, nifH and nodC gene sequences revealed distinct and novel evolutionary lineages related to the genus Rhizobium and Mesorhizobium, with some of them being very close to Mesorhizobium australicum. However, the phylogenetic analysis of glnII and nifH genes of some isolates showed incongruency.

Increased Length of Stay of Critically Ill Patients in the Emergency Department Associated with Higher In-hospital Mortality.

OBJECTIVES: Emergency department (ED) length of stay (LOS) is defined as the time a patient is registered to the time the patient is shifted to a hospital bed or discharged. Increasing demand for quality emergency care has resulted in increased wait times due to demand and supply mismatch. It is perceived that longer LOS in the ED of critical patients leads to poor outcomes. Our goal was to study the impact of LOS in the ED on the patients who required critical care admissions. METHODS: This was a retrospective study conducted in the ED of a tertiary center. Data were collected using electronic health records (EHR) for patients admitted to the intensive care units (ICUs). Patient's LOS in ED was divided into 0-4, 4-8, 8-12, 12-24, and >24 hours. ED LOS was calculated from the registration time to the time patient was handed over in the ICU. Patients were divided into four categories (1-4) based on their criticality. LOS in ED, mortality, and total hospital LOS were analyzed in the study. RESULTS: Three thousand four hundred and twenty-nine patients were enrolled in the study. Mean age was 62.69 years (95% CI 62.11-63.26). A total of 42.09% (95% CI 40.5-43.8) were Category 1 patients. Overall mortality rate was 52.46% (95% CI 50.79-54.13). LOS of 48.15% (95% CI 46.54-49.88) patients in the ED was between 0 and 4 hours, 19.90% (95% CI 18.62-21.29) between 4 and 8 hours, 8.21% (95% CI 7.35-9.19) between 8 and 12 hours, 15.50% (95% CI 14.34-16.77) between 12 and 24 hours, and 8.13% (95% CI 7.27-9.10) >24 hours. Mortality for LOS of 0-4 hours was 51.30% (95% CI 48.89-53.70), 54.03% (95% CI 50.28-57.73) for 4-8 hours, 48.94% (95% CI 43.16-54.75) for 8-12 hours, 51.50% (95% CI 47.26-55.72) for 12-24 hours, and 60.57% (95% CI 54.73-66.13) for >24 hours. CONCLUSION: We concluded that the longer the critically ill patients are boarded in the ED, the higher is the chance for mortality. Processes should be implemented to ease the throughput from the ED. HOW TO CITE THIS ARTICLE: Verma A, Shishodia S, Jaiswal S, Sheikh WR, Haldar M, Vishen A, et al. Increased Length of Stay of Critically Ill Patients in the Emergency Department Associated with Higher In-hospital Mortality. Indian J Crit Care Med 2021;25(11):1221-1225.

Adaptability to local conditions and phylogenetic differentiation of microsymbionts of TGx soybean genotypes in the semi-arid environments of Ghana and South Africa.

The study of the nitrogen fixation and phylogenetic diversity of nodule microsymbionts of grain legumes in many parts of the globe is often carried out in order to identify legume-rhizobia combinations for agricultural sustainability. Several reports have therefore found that rhizobial species diversity is shaped by edapho-climatic conditions that characterize different geographic locations, suggesting that rhizobial communities often possess traits that aid their adaptation to their habitat. In this study, the soybean-nodulating rhizobia from semi-arid savannahs of Ghana and South Africa were evaluated. The authenticated rhizobial isolates were highly diverse based on their colony characteristics, as well as their BOX-PCR profiles and gene sequences. In the 16S rRNA phylogeny, the isolates were placed in the different clades Bradyrhizobium iriomotense and Bradyrhizobium jicamae together with two superclades Bradyrhizobium japonicum and Bradyrhizobium elkanii. The multilocus (atpD, glnII, gyrB, recA) phylogenetic analyses indicated the dominance of Bradyrhizobium diazoefficiens and putative new Bradyrhizobium species in the semi-arid Ghanaian region. The phylogenetic analyses based on the symbiotic genes (nifH and nodC) clustered the test isolates into different symbiovars (sv. glycinearum, sv. retame and sv. sojae). Principal component analysis (PCA) showed that soil factors played a significant role in favoring the occurrence of soybean-nodulating microsymbionts in the tested local conditions. The results suggested that isolates had marked local adaptation to the prevailing conditions in semi-arid regions but further studies are needed to confirm new Bradyrhizobium species.

Diverse symbiovars nodulating cowpea (Vigna unguiculata L. Walp.) in highly adaptable agro-ecological zones in Mozambique.

The presence of effective microsymbionts in the soil and their compatibility with the host plant are the key determinants to the N2 fixation process. In Sub-Saharan Africa, nitrogen fixation in locally adapted cowpea and the distribution of their symbiovars are not well understood. The Aim of the study was to assess the distribution and symbiotic phylogenetic position of cowpea microsymbionts. Root nodules were sampled from various cowpea genotypes planted in Agro-Ecological Zone 7 and 8 (AEZ 7 and AEZ 8). Root-nodule bacteria were isolated and their molecular characterization was conducted. Physicochemical properties of soil were recorded. Enterobacterial Repetitive Intergenic Consensus (ERIC) distribution patterns in rhizobial genomes resulted in genetically diverse rhizobial population in Northern Mozambique. Principal component analysis showed that location-specific soil environment determined the presence of particular microsymbionts. Based on 16S rRNA and symbiotic gene analysis many diverse symbiovars were found in Mozambican soils. With few discrepancies, the results further confirmed the coevolution of the nifH, nodD, nodC and nodY/K genes, which was indicative of natural events such as vertical/horizontal gene transfer. The results suggested that ecological and phylogenetic studies of the microsymbionts are necessary to better reflect symbiovar identification and the ecological adaptation of the cowpea-nodulating rhizobial community.

Functional and genetic diversity of native rhizobial isolates nodulating cowpea (Vigna unguiculata L. Walp.) in Mozambican soils.

Identification and symbiotic characterization of indigenous rhizobial isolates are the basis for inoculant formulations needed for sustainable grain legume production. This study screened for morpho-genetic diversity of indigenous cowpea nodulating rhizobia in farmers' fields across two contrasting agroecological zones of Northern Mozambique. The photosynthetic function induced by the isolates in their homologous cowpea was assessed. The results showed high genetic variability among the isolates based on morphology and ERIC-PCR fingerprinting. The trap cowpea genotype did not influence the diversity of isolates collected from the two different agroecologies, suggesting that the cowpea-rhizobia compatibility may be conserved at species level. Phylogenetic analysis of the 16S rRNA gene assigned representative rhizobial isolates to species in the Bradyrhizobium and Rhizobium genera, with some isolates showing high divergence from the known reference type strains. The isolates from both agroecologies highly varied in the number and biomass of nodules induced in the homologous cowpea, resulting in variable plant growth and photosynthetic activities. A total of 72% and 83% of the isolates collected from the agroecological zones 7 and 8 were respectively classified as highly effective candidates with > 80% relative effectiveness compared to plants fertilized with nitrate, indicating that elite native strains populated the studied soils. Moreover, the top 25% of high N2-fixing isolates from the two agroecologies recorded relative effectiveness ranging from 115 to 154%, values higher than the effectiveness induced by the commercial Bradyrhizobium sp. strain CB756. These strains are considered as having potential for use in inoculant formulations. However, future studies should be done to assess the ecologically adaptive traits and symbiotic performance under field conditions.