CRISPR/Cas9-mediated mutagenesis of phytoene desaturase in pigeonpea and groundnut.

The CRISPR/Cas9 technology, renowned for its ability to induce precise genetic alterations in various crop species, has encountered challenges in its application to grain legume crops such as pigeonpea and groundnut. Despite attempts at gene editing in groundnut, the low rates of transformation and editing have impeded its widespread adoption in producing genetically modified plants. This study seeks to establish an effective CRISPR/Cas9 system in pigeonpea and groundnut through Agrobacterium-mediated transformation, with a focus on targeting the phytoene desaturase (PDS) gene. The PDS gene is pivotal in carotenoid biosynthesis, and its disruption leads to albino phenotypes and dwarfism. Two constructs (one each for pigeonpea and groundnut) were developed for the PDS gene, and transformation was carried out using different explants (leaf petiolar tissue for pigeonpea and cotyledonary nodes for groundnut). By adjusting the composition of the growth media and refining Agrobacterium infection techniques, transformation efficiencies of 15.2% in pigeonpea and 20% in groundnut were achieved. Mutation in PDS resulted in albino phenotype, with editing efficiencies ranging from 4 to 6%. Sequence analysis uncovered a nucleotide deletion (A) in pigeonpea and an A insertion in groundnut, leading to a premature stop codon and, thereby, an albino phenotype. This research offers a significant foundation for the swift assessment and enhancement of CRISPR/Cas9-based genome editing technologies in legume crops.

Limestone and yellow gypsum can reduce cadmium accumulation in groundnut (Arachis hypogaea): A study from a three-decade old landfill site.

Cadmium (Cd) toxicity has cropped up as an important menace in the soil-plant system. The use of industrial by-products to immobilise Cd in situ in polluted soils is an interesting remediation strategy. In the current investigation, two immobilizing amendments of Cd viz., Limestone (traditionally used) and Yellow gypsum (industrial by-product) have been used through a green-house pot culture experiment. Soil samples were collected from four locations based on four graded levels of DTPA extractable Cd as Site 1 (0.43 mg kg-1), Site 2 (0.92 mg kg-1), Site 3 (1.77 mg kg-1) and Site 4 (4.48 mg kg-1). The experiment was laid out in a thrice replicated Factorial Complete Randomized Design, with one factor as limestone (0, 250, 500 mg kg-1) and the other being yellow gypsum (0, 250, 500 mg kg-1) on the collected soils and groundnut was grown as a test crop. Results revealed that the DTPA-extractable Cd content in soil and Cd concentration in plants decreased significantly with the increasing doses of amendments irrespective of initial soil available Cd and types of amendment used. The effect of amendment was soil specific and in case of Site 1 (low initial Cd) the effect was more prominent. The reduction in DTPA-extractable Cd in combined application of limestone and yellow gypsum @500 mg kg-1 over the absolute control in soil under groundnut for the sites was by far the highest with the values of 83.72%, 77.17%, 48.59% and 40.63% respectively. With the combined application, Target Cancer Risk (TCR) of Cd was also reduced. Hence, combined application of limestone and yellow gypsum can be beneficial in the long run for mitigating Cd pollution.

Efficacy of yellow gypsum application on mitigating arsenic bioavailability in groundnut and Boro-rice grown under arsenic contaminated soil.

Agricultural soils naturally enriched with Arsenic (As) represent a significant global human health risk. In the present investigation, a series of pot experiments were conducted to study the efficacy of three levels of Yellow Gypsum (YG) application on bioavailability of As to kharif groundnut followed by boro-rice grown under 17 different levels of soil As contamination for two consecutive years. The results revealed that application of YG @ 60 kg ha-1 effectuated the lowest soil As content and the highest percent decline in soil extractable As at pegging (9.42 mg kg-1 and 9.81%) and harvesting (8.81 mg kg-1 and 11.85%) in groundnut, maximum tillering (7.52 mg kg-1 and 16.95%) and harvesting (6.77 mg kg-1 and 19.85%) in boro-rice respectively. It was also observed that irrespective of its level, the extractable As content of soil decreased significantly (P < 0.05) with increasing dosage of YG. Increase in YG dose effectuated a significant (P < 0.05) increasing trend and increase in As content in soil indicated a decreasing trend of Ca:As, Fe:As and S:As ratios which pointed out the potentiality of YG for reducing As bio-availability in contaminated soils and thus could be a good option for mitigating the risk of As contamination in food chain.

Draft genome sequence data of Nothopassalora personata, peanut foliar pathogen from Argentina.

Late leaf spot (LLS) caused by the Ascomycete Nothopassalora personata (N.p.) (Syn. Cercosporidium personatum) is the main foliar disease of peanuts in Argentina and in peanut producing areas of the world, causing up to 70% yield losses. The extremely slow growth of this fungus in culture, that takes around one month to form a 1 cm colony (0.45 mm/day), and the lack of adequate young tissues from where to extract nucleic acids, have hindered genetic studies of this pathogen. Here, we report the first genome sequence of a N. personata isolate from South America, as well as genetic variants on its conserved genes, and the complete sequence of its mating-type locus MAT1-2 idiomorph. The N. personata isolate IPAVE 0302 was obtained from peanut leaves in Córdoba, Argentina. The whole genome sequencing of IPAVE 0302 was performed as paired end 150 bp NovaSeq 6000 and de novo assembled. Clean reads were mapped to the reference genome for this species NRRL 64463 and the genetic variants on highly conserved genes and throughout the genome were analyzed. Sequencing data were submitted to NCBI GenBank Bioproject PRJNA948451, accession number SRR23957761. Additional Fasta files are available from Harvard Dataverse (https://doi.org/10.7910/DVN/9AGPMG and https://doi.org/10.7910/DVN/YDO3V6). The data reported here will be the basis for the analysis of genetic diversity of the LLS pathogen of peanut in Argentina, information that is critical to make decisions on management strategies.

Machine learning optimization of bio-sandcrete brick modelling using response surface methodology.

In this study, raw grinded groundnut shell (RGGNS) was used as a fine aggregate in the brick industry to reuse agricultural waste in building materials. In this study, an experimental approach was used to examine a new cement brick with raw groundnut shells integrated with compressive strength, water absorption and dry density optimization utilizing response surface methodology (RSM). The raw ground-nut shell content improved the fine aggregate performance of the 40%, 50%, and 60% samples. The 28-day high compressive strength with the raw ground-nut shell was 6.1 N/mm2 maximum, as needed by the technical standard. Samples made from 40%, 50%, and 60% raw groundnut shells yielded densities of 1.7, 2.2, and 1.9 kg/cm3 for groundnut shell (GNS) brick, respectively. A product's mechanical properties meet the IS code standard's minimum requirements. RSM was then utilized to develop a model for the addition of raw groundnut shell to concrete. R-square and Adeq precision values indicated that the results are highly significant, and equations for predicting compressive strength, water absorption, and dry density have been developed. In addition, optimization was performed on the RSM findings to determine the efficiency optimization of the model. Following the optimization results, experiments were conducted to determine the applicability of the optimized model.

Acidified groundnut cake for enhanced bio adsorption of anionic textile dye Reactive Red 195.

This study focuses on the improvement of bioremediation of textile dye Reactive Red 195 using agro-industrial waste, groundnut oil cake (GNOC) obtained after oil-pressing. The treatment of GNOC with 1 N H2SO4 had resulted in physiochemical changes on the insoluble porous adsorbent, which improved their adsorption efficiency. The dye removal efficiency increased from 55% to 94% on acidification of GNOC. The raw groundnut oil cake (RGNOC) and acid-treated groundnut oil cake (AGNOC) were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction, and zeta potential. The rate and efficiency of dye adsorption were examined using adsorption kinetics and isotherm models. The results confirm that acid-treated GNOC eliminates impurities, alter the surface functional groups, and significantly increase porous surface areas of RGNOC. The investigation of key factors such as contact time, initial concentration of dye, static/agitation impact, particle size, and adsorbent dose had significantly influenced adsorption capacity of GNOC. Adsorption of dye fits best into the Langmuir model and equilibrium data of dye on AGNOC was explained by psuedo-second-order reaction with maximum adsorption capacity of 12.65 mg/g. This emphasis AGNOC has a very excellent potential to remove the textile dye Reactive Red dye from industrial effluent.

This study reports the primary investigation exploring the application of groundnut oil cake (RGNOC) and its acid-modified (AGNOC) version for the bioremediation of industrially used textile dye Reactive Red 195 (RR195). The core objective of this study is to use a low-cost biosorbent to remove RR195 dye from effluent that pose risk to the health and environment. This study analyses the adsorption capacity of RGNOC and its acid-modified version AGNOC to treat contaminated water and the influencing parameters. AGNOC adsorption potential for RR195 dye sequestration was shown to be higher compared to RGNOC. Acidification of the adsorbent is simple, cost expensive, and more efficient alternate approaches to scale up for industrial application. As a result, an attempt has been made to add a new adsorbent to the database.

A Single-Nucleus Resolution Atlas of Transcriptome and Chromatin Accessibility for Peanut (Arachis Hypogaea L.) Leaves.

The peanut is an important worldwide cash-crop for edible oil and protein. However, the kinetic mechanisms that determine gene expression and chromatin accessibility during leaf development in peanut represented allotetraploid leguminous crops are poorly understood at single-cell resolution. Here, a single-nucleus atlas of peanut leaves is developed by simultaneously profiling the transcriptome and chromatin accessibility in the same individual-cell using fluorescence-activated sorted single-nuclei. In total, 5930 cells with 50 890 expressed genes are classified into 18 cell-clusters, and 5315 chromatin fragments are enriched with 26 083 target genes in the chromatin accessible landscape. The developmental trajectory analysis reveals the involvement of the ethylene-AP2 module in leaf cell differentiation, and cell-cycle analysis demonstrated that genome replication featured in distinct cell-types with circadian rhythms transcription factors (TFs). Furthermore, dual-omics illustrates that the fatty acid pathway modulates epidermal-guard cells differentiation and providescritical TFs interaction networks for understanding mesophyll development, and the cytokinin module (LHY/LOG) that regulates vascular growth. Additionally, an AT-hook protein AhAHL11 is identified that promotes leaf area expansion by modulating the auxin content increase. In summary, the simultaneous profiling of transcription and chromatin accessibility landscapes using snRNA/ATAC-seq provides novel biological insights into the dynamic processes of peanut leaf cell development at the cellular level.

Dietary habits of lesser bandicoot rat (Bandicota Bengalensis) in an agro-ecosystem, Pothwar Plateau, Pakistan

Abstract Dietary habits of bandicoot rats (bandicota bengalensis) were investigated in the agricultural crops of the Pothwar Plateau, Pakistan by analysing stomach contents. The research activities were conducted in major field crops including wheat-groundnut and in the fallow lands during non-crop season at the field boundaries. The specimens were captured from the fields using kill/snap traps, and dissected to collect their stomach samples for laboratory analysis. Light microscopic slides of the plant material were recovered from stomach samples and the reference materials were collected from the field. Results revealed that the bandicoot rat predominantly fed upon cultivated crops during cropping season but consumed wild vegetation during non-cropping season. There was no significance difference between summer and winter diets. Most frequently consumed crop food items were wheat (Triticum aestivum; 28.57%), groundnut (Arachis hypogea; 11.26%), sorghum (Sorghum bicolor; 10.17%), chickpea (Cicer arietinum; 9.52%), maize (Zea mays; 6.49%), millet (Pennisetum glaucum; 5.84%), barley (Hordeum vulgare; 4.98%) and mustard (Brassica campestris; 4.98%). Among wild vegetation were consumed khbal gha (Cynodon dactylon; 7.79%), baron dhab (Demostachya bipinnata; 7.36%) and Prickly flower (Achyranthes aspera; 3.03%). The study concludes that, in addition to consuming wheat and groundnut crops, the Lesser bandicoot rat also subsists on grasses, weeds, and some fodder crops, as important component of its diet in agro-ecosystem of the Pothwar Plateau.

Resumo Os hábitos alimentares de ratos bandicoot (Bandicota bengalensis) foram investigados nas plantações agrícolas do planalto de Pothwar, Paquistão, por meio da análise do conteúdo estomacal. As atividades da pesquisa foram conduzidas nas principais culturas de campo, incluindo trigo e amendoim, e em terras de pousio durante a estação não agrícola nos limites do campo. Os espécimes foram capturados dos campos usando armadilhas kill/snap e dissecados para coletar suas amostras de estômago para análise laboratorial. Lâminas de microscopia de luz do material vegetal foram recuperadas de amostras de estômago; os materiais de referência foram coletados no campo. Os resultados revelaram que o rato bandicoot alimentava-se predominantemente de culturas cultivadas durante a época de cultivo, mas consumia vegetação selvagem durante a época de não colheita. Não houve diferença significativa entre as dietas de verão e inverno. Os alimentos agrícolas mais frequentemente consumidos foram trigo (Triticum aestivum; 28,57%), amendoim (Arachis hypogea; 11,26%), sorgo (Sorghum bicolor; 10,17%), grão de bico (Cicer arietinum; 9,52%), milho (Zea mays; 6,49%), milheto (Pennisetum glaucum; 5,84%), cevada (Hordeum vulgare; 4,98%) e mostarda (Brassica campestris; 4,98%). Entre a vegetação silvestre foram consumidos khbal gha (Cynodon dactylon; 7,79%), barão dhab (Demostachya bipinnata; 7,36%) e flor espinhosa (Achyranthes aspera; 3,03%). O estudo conclui que, além de consumir culturas de trigo e amendoim, o rato bandicoot pequeno também subsiste de gramíneas, ervas daninhas e algumas culturas forrageiras, componentes importantes de sua dieta no agroecossistema do planalto de Pothwar.

Dietary habits of lesser bandicoot rat (Bandicota Bengalensis) in an agro-ecosystem, Pothwar Plateau, Pakistan / Hábitos alimentares de rato bandicoot (Bandicota Bengalensis) em um agroecossistema do Planalto de Pothwar, Paquistão

Abstract Dietary habits of bandicoot rats (bandicota bengalensis) were investigated in the agricultural crops of the Pothwar Plateau, Pakistan by analysing stomach contents. The research activities were conducted in major field crops including wheat-groundnut and in the fallow lands during non-crop season at the field boundaries. The specimens were captured from the fields using kill/snap traps, and dissected to collect their stomach samples for laboratory analysis. Light microscopic slides of the plant material were recovered from stomach samples and the reference materials were collected from the field. Results revealed that the bandicoot rat predominantly fed upon cultivated crops during cropping season but consumed wild vegetation during non-cropping season. There was no significance difference between summer and winter diets. Most frequently consumed crop food items were wheat (Triticum aestivum; 28.57%), groundnut (Arachis hypogea; 11.26%), sorghum (Sorghum bicolor; 10.17%), chickpea (Cicer arietinum; 9.52%), maize (Zea mays; 6.49%), millet (Pennisetum glaucum; 5.84%), barley (Hordeum vulgare; 4.98%) and mustard (Brassica campestris; 4.98%). Among wild vegetation were consumed khbal gha (Cynodon dactylon; 7.79%), baron dhab (Demostachya bipinnata; 7.36%) and Prickly flower (Achyranthes aspera; 3.03%). The study concludes that, in addition to consuming wheat and groundnut crops, the Lesser bandicoot rat also subsists on grasses, weeds, and some fodder crops, as important component of its diet in agro-ecosystem of the Pothwar Plateau.

Resumo Os hábitos alimentares de ratos bandicoot (Bandicota bengalensis) foram investigados nas plantações agrícolas do planalto de Pothwar, Paquistão, por meio da análise do conteúdo estomacal. As atividades da pesquisa foram conduzidas nas principais culturas de campo, incluindo trigo e amendoim, e em terras de pousio durante a estação não agrícola nos limites do campo. Os espécimes foram capturados dos campos usando armadilhas kill/snap e dissecados para coletar suas amostras de estômago para análise laboratorial. Lâminas de microscopia de luz do material vegetal foram recuperadas de amostras de estômago; os materiais de referência foram coletados no campo. Os resultados revelaram que o rato bandicoot alimentava-se predominantemente de culturas cultivadas durante a época de cultivo, mas consumia vegetação selvagem durante a época de não colheita. Não houve diferença significativa entre as dietas de verão e inverno. Os alimentos agrícolas mais frequentemente consumidos foram trigo (Triticum aestivum; 28,57%), amendoim (Arachis hypogea; 11,26%), sorgo (Sorghum bicolor; 10,17%), grão de bico (Cicer arietinum; 9,52%), milho (Zea mays; 6,49%), milheto (Pennisetum glaucum; 5,84%), cevada (Hordeum vulgare; 4,98%) e mostarda (Brassica campestris; 4,98%). Entre a vegetação silvestre foram consumidos khbal gha (Cynodon dactylon; 7,79%), barão dhab (Demostachya bipinnata; 7,36%) e flor espinhosa (Achyranthes aspera; 3,03%). O estudo conclui que, além de consumir culturas de trigo e amendoim, o rato bandicoot pequeno também subsiste de gramíneas, ervas daninhas e algumas culturas forrageiras, componentes importantes de sua dieta no agroecossistema do planalto de Pothwar.

Comparative evaluation of milk proteins and oil-seed-cake-derived proteins extracted by chemical and biological methods for obesity management.

BACKGROUND: In light of the exponential rise in global population, there is a critical requirement to reduce food waste on a global scale. According to studies, agricultural wastes such as oil-seed cakes offer great nutritional value. Acid precipitation (A) and alkaline extraction methods (traditional methods) were used to extract protein from oil-seed cakes; however, both procedures are linked to decreased protein quality and quantity, which prompted the development of a novel strategy known as the biological/microbial/probiotic (B) method. Therefore, the present study aimed to highlight the optimal way of protein extraction from oil-seed cakes and the effect of extraction methods on protein efficacy against obesity. The outcomes were also compared with milk proteins. RESULTS: In vitro study provided evidence that proteins from both sources (plant and milk) suppressed adipogenesis and stimulated adipolysis in 3T3L-1 cells. For the in vivo study, mice were fed with different protein extracts: soya protein preparation (SPP), ground protein preparation (GPP), whey protein (WP) and casein protein (CP) containing 40% of their calories as fat. Body weight decreased significantly in all the rats except CP-fed rats. Body mass index, atherogenic index, plasma triglyceride and very-low-density lipoprotein cholesterol level decreased significantly in all the groups in comparison to the model group (high-fat-diet group), but the decrease was more pronounced in plant proteins than milk proteins. In hepatocytes, the expression of fasting-induced adipose factor, carnitine palmitoyltransferase I and peroxisome proliferator-activated receptor α genes was increased significantly in SPP-fed groups. Adiponectin gene expression was upregulated significantly in visceral fat tissue in groups fed SPP-B, GPP-A and CP, whereas leptin gene was downregulated significantly in all groups except SPP-A. CONCLUSION: This study demonstrates that SPP-B showed the most effective anti-obesity property, followed by WP. Additionally, we found that the biological precipitation approach produced better outcomes for plant proteins isolated from oil-seed cakes than the acid precipitation method. © 2023 Society of Chemical Industry.

Groundnut harbours non-nodulating non-rhizobial plant growth-promoting bacterial endophytes.

The present study was carried out to assess the growth-promoting ability of non-rhizobial endophytes in groundnut (Arachis hypogaea). Thirteen endophytic bacteria with different morphologies were isolated from the root and nodules of groundnut. These isolates significantly enhanced the growth of groundnut in sterilised vermiculite, though the isolates were unable to nodulate the host plant. The endophytic nature of these isolates was confirmed by their re-isolation from the sterilised and macerated roots of the plants. The isolates exhibited in vitro tricalcium phosphate and zinc solubilization, production of siderophores, auxins and ammonia as well as growth on different nitrogen-free media. The phosphate solubilization and auxin production varied from 50 to 196 and 17 to 71 µg/ml, respectively by the isolates. Based on phenotypic tests and 16S rRNA gene sequencing, four potential strains were identified as Klebsiella sp. R3, Pseudomonas putida R6, Klebsiella oxytoca GRE5 and Pseudomonas proteolytica GRE6. A significant increase in plant growth, chlorophyll content, nodule count and shoot nutrient content of groundnut was observed with these bacterial inoculations over the uninoculated control in greenhouse. The bacterial treatments resulted in increased N, P and K content in the shoot up to 87, 96 and 44%, respectively, over the control. Physico-chemical properties and available nutrient content of soil were also improved on bacterial inoculations. The results indicated that groundnut harbours beneficial non-rhizobial bacterial endophytes with the potential to be used as microbial inoculants in groundnut. Klebsiella oxytoca as a non-nodulating nodule endophyte of groundnut is reported for the first time.

Prevalence of groundnut dry root rot (Macrophomina phaseolina (Tassi) Goid.) and its pathogenic variability in Southern India.

Macrophomina phaseolina is the most devastating and emerging threat to groundnut production in India. An increase in average temperature and inconsistent rainfalls resulting from changing climatic conditions are strongly believed to aggravate the disease and cause severe yield losses. The present study aims to conduct a holistic survey to assess the prevalence and incidence of dry root rot of groundnut in major groundnut growing regions of Southern India, viz., Andhra Pradesh, Telangana, Karnataka, and Tamil Nadu. Furthermore, the pathogenic variability was determined using different assays such as morphological, cultural, pathogenic, and molecular assays. Results indicate that disease incidence in surveyed locations ranged from 8.06 to 20.61%. Both temperature and rainfall played a major role in increasing the disease incidence. The pathogenic variability of M. phaseolina isolates differed significantly, based on the percent disease incidence induced on cultivars of JL-24 groundnut and K-6 groundnut. Morphological variations in terms of growth pattern, culture color, sclerotia number, and sclerotia size were observed. The molecular characterization of M. phaseolina isolates done by ITS rDNA region using ITS1 and ITS4 primers yielded approximately 600 bp PCR amplicons, sequenced and deposited in GenBank (NCBI). Molecular variability analysis using SSR primers indicated the genetic variation among the isolates collected from different states. The present investigation revealed significant variations in pathogenic variability among isolates of M. phaseolina and these may be considered important in disease management and the development of resistant cultivars against groundnut dry root rot disease.

Adoption and impact of improved groundnut varieties on household food security in Nigeria.

Improved agricultural technologies are promoted as cost-effective and sustainable ways of improving rural households' food security and reducing poverty in developing countries. This study evaluates the relationship between improved groundnut varieties (IGVs) and household food security using detailed household and plot level data from a sample of over 1300 farm households in Northern Nigeria. Endogenous switching regression models are employed to control for potential endogeneity biases. Results show that about 30 % of groundnut plots are planted with improved varieties, and the adoption of IGVs significantly increases the likelihood of household per capita groundnut consumption by about 13 % and reduces the probability of households' vulnerability to food (access) insecurity by 22 %. Counterfactual analyses show that non-adopting households could have enjoyed comparable benefits had they adopted IGVs. These results suggest that development interventions aimed at improving the diffusion and impacts of IGVs in Nigeria need to target farmers' access to information about the technologies while developing groundnut seed systems to make quality seeds readily available to smallholder farmers at affordable prices.

Can different types of tree nuts and peanuts induce varied effects on specific blood lipid parameters? A systematic review and network meta-analysis.

Tree nuts and peanuts have shown cardioprotective effects through the modulation of blood lipid levels. Despite the abundance of scientific evidence available, it remains uncertain whether the type of nut consumed influences these changes. The objective of this study was to evaluate and rank the effects of six types of nuts on total cholesterol (total-c), low-density lipoprotein (LDL-c), triglyceride (TG) and high-density lipoprotein (HDL-c) levels through a systematic search of randomized controlled trials (RCTs), a frequentist network meta-analysis (NMA), and the estimation of SUCRA values. A total of 76 RCTs were ultimately analyzed. The total c for pistachios, almond, and walnuts; LDL-c for cashews, walnuts, and almond; and TG for hazelnuts and walnuts significantly decreased, while only peanuts exhibited a significant increase in HDL-c levels. According to the rankings, the most effective type of nut for reducing total cholesterol was pistachio, cashew for LDL-c, hazelnut for TG, and peanut for increasing HDL-c levels. It should be noted that every type of nut analyzed exhibited a significant positive impact on some parameters, and specific types demonstrated enhanced advantages for particular blood lipids. These results endorse the use of personalized nutritional strategies to address and prevent dyslipidemia.Registration: PROSPERO database CRD42021270779.

Towards inoculant development for Bambara groundnut (Vigna subterranean (L.) Verdc) pulse crop production in Namibia.

Introduction: The globally expanding population, together with climate change, poses a risk to the availability of food for humankind. Bambara groundnut (BGN) (Vigna subterranea (L.) Verdc) is a neglected, relatively drought-tolerant native legume of Sub-Saharan Africa that has the potential to become a successful food crop because of its nutritional quality and climate-smart features. Nitrogen fixation from root nodule symbiosis with climate-adapted rhizobial symbionts can contribute nitrogen and organic material in nutrient-poor soil and improve yields. However, high soil temperature and drought often reduce the abundance of native rhizobia in such soil. Therefore, the formulation of climate-smart biofertilizers has the potential to improve the farming of BGN at a low cost in a sustainable manner. Method: The effect of seven Bradyrhizobium spp. strains native to Namibia, including B. vignae and B. subterraneum, were tested on three Namibian BGN varieties (red, brown, cream) in greenhouse pot experiments in Namibia, using soil from the target region of Kavango. Each variety was treated with a mixed inoculant consisting of seven preselected strains ("MK") as well as with one promising single inoculant strain. Results: The results revealed that in all three varieties, the two inoculants (mixed or single) outperformed the non-inoculated cultivars in terms of shoot dry weight by up to 70%; the mixed inoculant treatment performed significantly better (p < 0.05) in all cases compared to the single inoculant used. To test whether the inoculant strains were established in root nodules, they were identified by sequence analysis. In many cases, the indigenous strains of Kavango soil outcompeted the inoculant strains of the mix for nodule occupancy, depending on the BGN variety. As a further preselection, each of the individual strains of the mix was used to inoculate the three varieties under sterile conditions in a phytotron. The agronomic trait and root nodulation response of the host plant inoculations strongly differed with the BGN variety. Even competitiveness in nodule occupancy without involving any indigenous strains from soil differed and depended strictly on the variety. Discussion: Severe differences in symbiont-plant interactions appear to occur in BGN depending on the plant variety, demanding for coupling of breeding efforts with selecting efficient inoculant strains.

Effect of silencing Thrips palmi Btk29A and COL3A1 on fitness and virus acquisition.

Thrips palmi (Thysanoptera: Thripidae) is a major agricultural pest infesting over 200 plant species. Along with direct injury caused by feeding, T. palmi spreads several orthotospoviruses. Groundnut bud necrosis orthotospovirus (GBNV, family Tospoviridae, genus Orthotospovirus) is the predominant orthotospovirus in Asia, vectored by T. palmi. It is responsible for almost 89 million USD losses in Asia annually. Several transcripts of T. palmi related to innate immune response, receptor binding, cell signaling, cellular trafficking, viral replication, and apoptosis are responsive to the infection of orthotospoviruses in thrips. Expression of T. palmi tyrosine kinase Btk29A isoform X1 (Btk29A) and collagen alpha-1(III) chain-like (COL3A1) are significantly regulated post-GBNV and capsicum chlorosis orthotospovirus infection. In the present study, T. palmi Btk29A and COL3A1 were silenced and the effect on virus titer and fitness was assessed. The expression of Btk29A and COL3A1 was significantly reduced by 3.62 and 3.15-fold, respectively, 24 h post-dsRNA exposure. Oral administration of Btk29A and COL3A1 dsRNAs induced 60 and 50.9% mortality in T. palmi. The GBNV concentration in T. palmi significantly dropped post-silencing Btk29A. In contrast, the silencing of COL3A1 led to an increase in GBNV concentration in T. palmi compared to the untreated control. To the best of our knowledge, this is the first report on the effect of silencing Btk29A and COL3A1 on the fitness and GBNV titer in T. palmi.

The groundnut improvement network for Africa (GINA) germplasm collection: a unique genetic resource for breeding and gene discovery.

Cultivated peanut or groundnut (Arachis hypogaea L.) is a grain legume grown in many developing countries by smallholder farmers for food, feed, and/or income. The speciation of the cultivated species, that involved polyploidization followed by domestication, greatly reduced its variability at the DNA level. Mobilizing peanut diversity is a prerequisite for any breeding program for overcoming the main constraints that plague production and for increasing yield in farmer fields. In this study, the Groundnut Improvement Network for Africa assembled a collection of 1,049 peanut breeding lines, varieties, and landraces from 9 countries in Africa. The collection was genotyped with the Axiom_Arachis2 48K SNP array and 8,229 polymorphic single nucleotide polymorphism (SNP) markers were used to analyze the genetic structure of this collection and quantify the level of genetic diversity in each breeding program. A supervised model was developed using dapc to unambiguously assign 542, 35, and 172 genotypes to the Spanish, Valencia, and Virginia market types, respectively. Distance-based clustering of the collection showed a clear grouping structure according to subspecies and market types, with 73% of the genotypes classified as fastigiata and 27% as hypogaea subspecies. Using STRUCTURE, the global structuration was confirmed and showed that, at a minimum membership of 0.8, 76% of the varieties that were not assigned by dapc were actually admixed. This was particularly the case of most of the genotype of the Valencia subgroup that exhibited admixed genetic heritage. The results also showed that the geographic origin (i.e. East, Southern, and West Africa) did not strongly explain the genetic structure. The gene diversity managed by each breeding program, measured by the expected heterozygosity, ranged from 0.25 to 0.39, with the Niger breeding program having the lowest diversity mainly because only lines that belong to the fastigiata subspecies are used in this program. Finally, we developed a core collection composed of 300 accessions based on breeding traits and genetic diversity. This collection, which is composed of 205 genotypes of fastigiata subspecies (158 Spanish and 47 Valencia) and 95 genotypes of hypogaea subspecies (all Virginia), improves the genetic diversity of each individual breeding program and is, therefore, a unique resource for allele mining and breeding.

Association mapping in bambara groundnut [Vigna subterranea (L.) Verdc.] reveals loci associated with agro-morphological traits.

BACKGROUND: Genome-wide association studies (GWAS) are important for the acceleration of crop improvement through knowledge of marker-trait association (MTA). This report used DArT SNP markers to successfully perform GWAS on agro-morphological traits using 270 bambara groundnut [Vigna subterranea (L.) Verdc.] landraces sourced from diverse origins. The study aimed to identify marker traits association for nine agronomic traits using GWAS and their candidate genes. The experiment was conducted at two different locations laid out in alpha lattice design. The cowpea [Vigna unguiculata (L.) Walp.] reference genome (i.e. legume genome most closely related to bambara groundnut) assisted in the identification of candidate genes. RESULTS: The analyses showed that linkage disequilibrium was found to decay rapidly with an average genetic distance of 148 kb. The broadsense heritability was relatively high and ranged from 48.39% (terminal leaf length) to 79.39% (number of pods per plant). The GWAS identified a total of 27 significant marker-trait associations (MTAs) for the nine studied traits explaining 5.27% to 24.86% of phenotypic variations. Among studied traits, the highest number of MTAs was obtained from seed coat colour (6) followed by days to flowering (5), while the least is days to maturity (1), explaining 5.76% to 11.03%, 14.5% to 19.49%, and 11.66% phenotypic variations, respectively. Also, a total of 17 candidate genes were identified, varying in number for different traits; seed coat colour (6), days to flowering (3), terminal leaf length (2), terminal leaf width (2), number of seed per pod (2), pod width (1) and days to maturity (1). CONCLUSION: These results revealed the prospect of GWAS in identification of SNP variations associated with agronomic traits in bambara groundnut. Also, its present new opportunity to explore GWAS and marker assisted strategies in breeding of bambara groundnut for acceleration of the crop improvement.

Development and application of reverse transcription-loop mediated isothermal amplification assay for sensitive detection of groundnut bud necrosis virus infecting potato.

Reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for detection of groundnut bud necrosis virus (GBNV) causing potato stem necrosis disease. The isothermal temperatures, reaction periods and concentrations of reaction mixture were optimized where, the assay worked well at 65 °C for 50 min, 6 U of WarmStart Bst 2.0 DNA polymerase, 1.4 mM dNTPs and 2.0 mM MgSO4. The optimized assay proved to be specific to GBNV with no cross reactivity to other viruses infecting potato in India. The specificity of RT-LAMP assay was found to be 100 fold more sensitive than that of RT-PCR. The developed assay was applied for the detection of GBNV from 80 potato leaf samples where 24 samples were found infected which was confirmed by RT-PCR. It was concluded that the RT-LAMP assay developed for detection of GBNV was specific, sensitive and suitable for its use in virus indexing under potato seed production programme.

Assessment of early harvest in the prevention of aflatoxins in peanuts during drought stress conditions.

The present study aimed to evaluate the effectiveness of early harvest in preventing aflatoxins in peanuts under drought-stress conditions. A field experiment was conducted on the 2018-2019 and 2019-2020 growing seasons in a greenhouse with an irrigation system to induce three drought stress conditions: no stress, mild, and severe stress. In addition, three harvest dates were proposed: two weeks earlier, one week earlier, and ideal harvest time. The mean peanut yield was 2634 kg/ha, considering the two growing seasons, and the drought stress conditions and harvest dates did not influence significantly. The shelling percentage was significantly higher in samples harvested at ideal harvest (77.7 %) than two weeks earlier (76.2 %) and was not influenced by drought stress conditions. Although a low mean percentage of grains with insect damage was identified, this percentage was statistically higher under severe stress (0.4 %) compared to no-stress conditions (0.2 %). The soil contamination ranged from 2.52 × 103 to 1.64 × 104 CFU/g of Aspergillus section Flavi, and the drought stress resulted in significantly higher concentrations in mild and severe stressed samples. A. section Flavi was found to infect all the peanut kernel samples. The drought stress resulted in higher percentages of A. section Flavi infections in samples from mild and severe stress conditions. The harvest date did not influence the soil and peanut kernel occurrence of A. section Flavi. A total of 435 and 796 strains of A. section Flavi were isolated from soil and peanut kernels, respectively. The potential of aflatoxin production by soil isolates was 31, 44, and 25 % for aflatoxin non-producers, aflatoxin B producers, and aflatoxin B and G producers, respectively, while in peanut kernel isolates were 44, 44, and 12 %. Three different A. section Flavi species were identified from peanut kernels: A. flavus, A. parasiticus, and A. pseudocaelatus. The mean aflatoxin concentration in peanut kernels was 42, 316, and 695.5 µg/kg in samples under no stress, mild stress, and severe stress conditions, respectively. Considering the harvest time, the mean aflatoxin concentration was 9.9, 334.3, and 614.2 µg/kg in samples harvested two weeks earlier, one week earlier, and in ideal harvest, respectively. In conclusion, the early harvest proved to be a viable, cost-free alternative for controlling aflatoxin in the peanut pre-harvest, resulting in a safer product and a better quality for sale and economic gain.