Search Results (45)

Cowpeas are a legume widely consumed in Brazil. Given this, the objective of this study was to investigate the presence of metals (loids) in pods and leaves of Vigna unguiculata located near a highway with high vehicle traffic and a landfill, and to assess possible risks to human health. Pod and leaf samples were collected at nine points between the highway and the landfill. The elements were analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and quantified. The risk to human health was assessed using risk quotient and risk index values. A quantitative analysis of the chemical elements was also performed using the maximum tolerable intake level. Element concentrations were higher in the leaves than in the pods. The human health risk analysis showed that the average daily consumption of both pods (44 g/day) and leaves (67 g/day) may pose a chronic health risk to adult men and women, due to simultaneous exposure to multiple metals. It was concluded that the plant is contaminated and that its ingestion can cause toxicity, warranting warnings against cultivating areas near anthropogenic activities that may be contaminated with heavy metals, thereby affecting nutritional safety. Full article

Soybean (Glycine max) is relatively recalcitrant to genetic manipulations; hence, it is often interrogated with transient means such as virus-induced gene silencing (VIGS). We earlier modified cowpea severe mosaic virus (CPSMV) to develop a soybean-friendly VIGS system referred to as QUIN-FZ. Here we report additional calibrations of this system. We enhanced the intra-bacterial stability of plasmid QUIN, which contained a CPSMV RNA1 cDNA embedded with four introns, by adding a fifth intron, resulting in PENTIN. We separately upgraded the plasmid FZ, which contained a modified CPSMV RNA2 cDNA with a cloning site in the middle of the viral polyprotein, by creating another cloning site within the 3′ untranslated region, leading to ZY. We next used the new PENTIN-ZY system to investigate a putative soybean protein kinase designated QL18. Virus-mediated overexpression of two allelic, 147-amino-acid (aa) protein fragments, derived from two different QL18 orthologs, elicited drastically different responses in soybeans. While the fragment derived from soybean accession OX20-8 prevented the cognate virus from infecting top young leaves in at least 50% of inoculated seedlings, its allelic counterpart derived from soybean accession PI427105B elicited apical necrosis in 100% of soybean seedlings. By examining progeny viruses as well as viruses encoding chimeras of the two fragments, we identified more than a dozen mutations that abrogated these unique phenotypes. Our findings establish the PENTIN-ZY system as a versatile tool for overexpressing small proteins and protein fragments, accelerating their functional characterization. Full article

Crop failures are common in rain-fed farming in sub-Saharan Africa, especially in water-scarce South Africa. Inadequate rainfall necessitates innovative solutions to enhance food production. Water-saving irrigation technologies can significantly reduce crop failures, particularly for smallholder farms with limited access to irrigation water. This study evaluated the effects of Self-Regulating, Low-Energy, Clay-Based Irrigation System (SLECI), subsurface (SDI) and surface drip (DI) on the performance of moringa (Moringa oleifera) and cowpea (Vigna unguiculata), cultivated either as mono (sole) crops or in intercropping systems, in an open experimental field in South Africa. The experimental design was a factorial Randomized Complete Block Design (RCBD) replicated three times. The main aim was to assess water productivity and yield performance in different irrigation systems over two growing seasons. The results showed that the SLECI irrigation system was more suitable for M. oleifera, while V. unguiculata performed best with standard drip irrigation. Moringa oleifera fresh leaf biomass was higher under SLECI with sand around the clay element and surface drip irrigation with 1.42 t/ha, followed by the SLECI treatment without sand with 1.25 t/ha, while the least yield was noted in subsurface drip irrigation treatment with 1.18 t/ha. Vigna unguiculata (a dual-purpose crop for grain and leaves) produced higher total fresh biomass yield under subsurface drip irrigation treatment with 66.26 t/ha, followed by the SLECI treatment without sand (61.51 t/ha), while drip and SLECI with sand showed similar yield with 52.34 and 52.31 t/ha, respectively. In M. oleifera, the irrigation water productivity (IWP) varied from 0.26 kg/m³ below the surface to 0.65 kg/m³ after the SLECI treatment with sand. IWP in V. unguiculata treatments ranged from 27.52 kg/m³ in SLECI without sand to 9.52 kg/m³ under surface drip irrigation. In addition, chlorophyll content and stem diameter were elevated under SLECI, reflecting enhanced nutrient and water availability. The findings have important implications for sustainable agriculture under water-limited conditions. Full article

Drought significantly reduces global crop yields and agricultural productivity. This study aims to isolate drought-tolerant PGPR strains and evaluate their effects, both individually and in combination with salicylic acid (SA), on cowpea plants growth, physiological traits, antioxidant enzymes, and mineral content under both drought stress and non-stress conditions. Among fifteen bacterial isolates, AO7, identified as Streptomyces diastaticus subsp. ardesiacus PX459854 through 16S rRNA sequencing, demonstrated significant plant growth promotion in cowpea under gnotobiotic conditions. On the other hand, varying salicylic acid concentrations (0.5, 1.0, and 2.0 mM) was exposed to assess the plant growth of cowpea plants in a gnotobiotic system. A pot experiment in 2023 used a split-plot design with treatments for irrigation (unstressed and stressed) and different soaking treatments (control, S. diastaticus, salicylic acid (2 mM), and a combination). After 60 days, the combination treatment enhanced growth metrics, outpacing the control under stress. The microbial community in the T4 treatment exhibited the highest counts, while T8 (combination, stressed) showed lower counts but the highest chlorophyll content at 6.32 mg g⁻¹ FW. Notable increases in proline and significant changes in enzyme activities (PO, PPO, CAT, and APX) were observed, particularly in treatment T8 under stress, indicating a positive response to both treatments. Mineral content of cowpea leaves varied with soaking treatments of S. diastaticus and SA (2.0%) especially under drought stress which the highest values were 1.72% N, 0.16% P, and 2.66% K with treatment T8. Therefore, T8 (combination, stressed) > T6 (S. diastaticus, stressed) > T7 (salicylic acid, stressed) > T5 (control, stressed) for different applications under stressed conditions and T4 (combination, unstressed) > T2 (S. diastaticus, unstressed) > T3 (salicylic acid, unstressed) > T1 (control, unstressed) for the other applications under normal conditions. Thus, using S. diastaticus and SA (2.0%) in combination greatly enhanced the growth dynamics of cowpea plants under drought stress conditions. Full article

Cowpea (Vigna unguiculata L. Walp.) is a species with superior tolerance to drought stress compared to other legumes. It is a promising crop with increasing importance in the face of global climate changes. Local forms, well adapted to particular agro-climatic conditions, are useful germplasm resources. Five Bulgarian cowpea landraces, which had displayed differences in osmotic stress tolerance at the germination stage, were subjected to severe stress (15% PEG 6000 in Hoagland nutrient media) during 16 days at the vegetative growth stage (plants with expanded trifoliate leaves). All local forms responded to the imposed stress by biomass and leaf area diminution, a slight increase in leaf water deficit and electrolyte leakage, proline accumulation in roots and leaves, and an increase in root starch and leaf phenol content. Roots presented more pronounced metabolic changes than leaves, including increased total antioxidant activity, phenolic and carbohydrate content, and proline accumulation. Under osmotic stress, tight control of oxidative stress and concerted upregulation of superoxide dismutase, catalase, glutathione transferase, and peroxidase activities in leaves were registered along with changes in certain specific isoforms, while glutathione reductase activity diminished. Antioxidant enzyme activities had different changes in stressed roots, compared to leaves, and among genotypes. The accession most sensitive to osmotic stress at germination presented more symptoms of oxidative stress at the vegetative growth stage. Full article

Under the principles of the circular economy and sustainability, consumers, the food industry and health authorities have interest in new natural food preservatives to prevent foodborne diseases and increase produce shelf life. This work aimed to evaluate the antimicrobial properties of cowpea plant extracts. Grain, pod and leaf extracts from five Portuguese cowpea accessions were characterized in terms of their phenolic content. The values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined against pathogenic and non-pathogenic bacteria, as well as on post-harvest pathogenic filamentous fungi. In general, the phenolic content of pod extracts was higher than that of grains and leaves, although leaf extracts had the highest content of a broad-spectrum antibacterial flavonoid, quercetin. Grain extracts exhibited no detectable antimicrobial activity. In contrast, leaf and pod extracts from all five accessions generally displayed bactericidal effects. For bacteria, pod extracts showed MICs ranging from 5.1 to 87.7 mg/mL and MBCs from 20.3 to 87.7 mg/mL. Leaf extracts showed the most promising results, with MICs and MBCs ranging from 1.1 to 9.1 mg/mL. The results against fungi were not so expressive; nevertheless, P. expansum was inhibited by 9 L leaf extract even if at a higher concentration (MIC = 18 mg/mL) than those obtained for bacteria. The Portuguese variety Fradel (1E) showed very promising antibacterial activity, with leaf extracts showing low MBC values (from 2.3 to 9.1 mg/mL). The obtained results indicate that cowpea pods and leaves have antimicrobial properties and could potentially be used as a source of compounds for food preservation. Full article

Micronutrient deficiencies and the increased incidences of non-communicable diseases are public health challenges for the sub-Saharan population. Leafy vegetables reportedly contain several minerals, vitamins and antioxidant compounds which could help reduce the above challenges. However, overall vegetable consumption is still low in Uganda, partly due to limited information about the nutritional quality and health-promoting properties of the available vegetable species. To provide scientific justification for increased growth/production and utilisation of specific leafy vegetable species as food, the nutrient and phytochemical compositions were determined in nine African leafy vegetables. The ‘true’ protein and dietary fibre contents were 13–33 and 29–43 g/100 g DW, respectively, whereas the starch content was below 6 g/100 g DW. As for the minerals, the Ca, Mg, and Fe contents were 630–3395, 324–1428, and 14–78 mg/100 g DW, respectively, whereas the Zn content was below 6 mg/100 g DW. High carotenoid contents were observed with lutein and β-carotene as the predominant carotenoids (25–60 and 12–29 mg/100 g DW, respectively). The vitamin C and total polyphenol contents were 24–253 mg/100 g DW and 17–43 mg GAE/g DW, respectively. The leafy vegetables studied are low-calorie and can be considered alternative protein sources. They are generally health-beneficial foods as they contain natural antioxidant compounds, vitamin C, carotenoids and polyphenols. African nightshade, Amaranthus sp., cowpea leaves, and spider plant are potential sources of provitamin A (β-carotene) and minerals (Ca and Fe); hence, they can help reduce incidences of related deficiencies. Full article

Biochar is a multifunctional tool that enhances soil quality, with particularly positive effects on acidic soils with low nutrient content, common in tropical regions worldwide, such as in the Amazon region in Brazil. This study investigates the effects of açaí fruit waste biochar (Euterpe oleracea Mart.) amendment and phosphate fertilisation on the chemical characteristics of a Ferralsol and on the biological components of cowpea (Vigna unguiculata (L.) Walp). In a greenhouse setting, a randomised block design was employed, testing five doses of biochar (0, 7.5, 15, 30, and 60 t ha⁻¹) combined with four doses of phosphorus (P) (0, 40, 80, and 120 kg ha⁻¹), resulting in 20 treatments with three replicates and 60 experimental units. Cowpea responded to inorganic fertilisation, with lower doses of P limiting the biological components (height, leaves, leaf area, dry biomass, and dry root mass). Higher doses of biochar and P increased the soil’s available P content by up to 2.3 times, reflected in the P content of cowpea dry biomass. However, this increase in biochar and P levels led to a maximum increase of 7.7% in agronomic phosphorus efficiency (APE) in cowpea in the short term. The higher doses of biochar promoted increases in pH value, cation exchange capacity (CEC), and the contents of potassium (K), calcium (Ca), and total nitrogen (N). In contrast, a decrease in magnesium (Mg) and aluminium (Al) levels was observed, while the concentration of easily extractable glomalin (EE-GRSP) was not significantly affected during the evaluated period. We conclude that biochar altered the soil environment, promoting the increased solubility and availability of phosphorus. Full article

Megalurothrips usitatus (Bagnall) feeds on the young tissues of plants, causing wilting and deformity of leaves as well as damage to flowers and fruits, thereby seriously affecting plant yield. Due to its small size and difficulty of control, the species is one of the most important pests in the legume family. To clarify the occurrence and damage pattern of M. usitatus on field crops, a study was conducted using eight different crops as experimental materials, and an age-stage, two-sex life table was constructed. The population density of M. usitatus was the highest on cowpeas (Vigna unguiculata L. Walp.), followed by green beans (Phaseolus vulgaris L.) and Vigna cylindrica (Vigna unguiculata subsp. cylindrica (L.) Verdc.) in terms of net reproductive rate and the intrinsic rate of increase. In terms of reproductive capacity, cowpeas and V. cylindrica were more suitable for M. usitatus growth and reproduction, followed by green beans. M. usitatus could develop into adults on courgettes (Cucurbita pepo L.), wax gourds (Benincasa hispida Thunb. Cogn.), Momordica charantia (Momordica charantia L.), and soybeans (Glycine max L. Merr.) but had difficulty reproducing on those plants. Cucumber (Cucumis sativus L.) was the least suitable for the survival of M. usitatus. Population parameter analysis showed that the cowpea was the most suitable host plant for M. usitatus, followed by green beans and V. cylindrica. M. usitatus had difficulty reproducing on courgette, wax gourd, M. charantia, and soybeans, and feeding on cucumbers inhibited M. usitatus development and reproduction. Full article

This study evaluates the efficacy of buried straw bioreactor (SBR) technology in enhancing soil properties, CO₂ efflux, and crop yield, specifically focusing on Indian cowpea cultivation within a greenhouse environment. Conducted at the Yuxi Demonstration Park in Fujian, China, the experiment utilized a randomized block design incorporating seven treatments with varying straw application rates (4.5, 6, and 7.5 kg m⁻²) and burial depths (20 and 30 cm) alongside a control group. The investigation revealed that SBR technology significantly increased soil temperature, CO₂ efflux, soil total nitrogen (TN), and total organic carbon (TOC), contributing to a marked improvement in the biomass of Indian cowpea roots, stems, and leaves. Notably, the optimal results were observed with 7.5 kg m⁻² straw applied at a 20 cm depth, enhancing soil temperature by 1.5–2.0 °C and multiplying cowpea biomass by 2.1–6.4 times relative to the control. This treatment also led to the highest increases in soil TOC and CO₂ efflux, demonstrating the potential of SBR technology for carbon sequestration and suggesting its application as a sustainable agricultural practice in cold regions to ameliorate the soil’s physical and nutritional characteristics, thus supporting enhanced crop production. The study underscores SBR technology’s role in addressing the challenge of agricultural waste through the effective reuse of crop straw, promoting the circular development of agriculture while safeguarding the ecological environment. Full article

Zinc oxide nanoparticles (ZnO NPs) exhibit diverse applications, including antimicrobial, UV-blocking, and catalytic properties, due to their unique structure and properties. This study focused on the characterization of zinc oxide nanoparticles (ZnO NPs) synthesized from Juglans regia leaves and their application in mitigating the impact of simultaneous infection by Meloidogyne arenaria (root-knot nematode) and Macrophomina phaseolina (root-rot fungus) in cowpea plants. The characterization of ZnO NPs was carried out through various analytical techniques, including UV–visible spectrophotometry, Powder-XRD analysis, FT-IR spectroscopy, and SEM-EDX analysis. The study confirmed the successful synthesis of ZnO NPs with a hexagonal wurtzite structure and exceptional purity. Under in vitro conditions, ZnO NPs exhibited significant nematicidal and antifungal activities. The mortality of M. arenaria juveniles increased with rising ZnO NP concentrations, and a similar trend was observed in the inhibition of M. phaseolina mycelial growth. SEM studies revealed physical damage to nematodes and structural distortions in fungal hyphae due to ZnO NP treatment. In infected cowpea plants, ZnO NPs significantly improved plant growth parameters, including plant length, fresh mass, and dry mass, especially at higher concentrations. Leghemoglobin content and the number of root nodules also increased after ZnO NP treatment. Additionally, ZnO NPs reduced gall formation and egg mass production by M. arenaria nematodes and effectively inhibited the growth of M. phaseolina in the roots. Furthermore, histochemical analyses demonstrated a reduction in oxidative stress, as indicated by decreased levels of reactive oxygen species (ROS) and lipid peroxidation in ZnO NP-treated plants. These findings highlight the potential of green-synthesized ZnO NPs as an eco-friendly and effective solution to manage disease complex in cowpea caused by simultaneous nematode and fungal infections. Full article

The increasing demands for food, driven by shrinking arable land areas and a growing population, underscore the need for innovative agricultural practices to mitigate the effects of soil degradation due to salinity and promote food security, particularly in regions heavily impacted by salinity. In this study, we investigated the effects of inoculating the arbuscular mycorrhizal fungus (AMF) Rhizophagus clarus on the productivity of Vigna unguiculata cv. BRS Imponente plants in response to salinity (0, 25, 50, 75, and 100 mM). We found that NaCl concentrations ≥ 50 mM were phytotoxic, reducing plant growth and productivity. However, inoculation with AMF reduced plant oxidative stress (hydrogen peroxide concentration and lipid peroxidation) and ionic stress (Na⁺/K⁺ ratio). Inoculated plants exhibited increased antioxidant enzyme activity (ascorbate peroxidase and catalase), higher P and K concentrations, and lower Na concentrations in their leaves. As a result, salt did not interfere with grain production in the AMF-inoculated plants. For the first time, we demonstrate that inoculation with R. clarus can counteract the harmful effects of NaCl in V. unguiculata plants, ensuring their grain yields. Therefore, amid the escalating soil salinization globally, the AMF R. clarus emerges as a practical approach to ensure cowpea yields and enhance production in deteriorating agricultural lands, especially in saline areas. This can significantly contribute to promoting food security. Full article

Cowpeas (Vigna unguiculata L. Walp) have been credible constituents of nutritious food and forage in human and animal diets since the Neolithic era. The modern technique of Diversity Array Technology (DArTseq) is both cost-effective and rapid in producing thousands of high-throughputs, genotyped, single nucleotide polymorphisms (SNPs) in wide-genomic analyses of genetic diversity. The aim of this study was to assess the heterogeneity in cowpea genotypes using DArTseq-derived SNPs. A total of 92 cowpea genotypes were selected, and their fourteen-day-old leaves were freeze-dried for five days. DNA was extracted using the CTAB protocol, genotyped using DArTseq, and analysed using DArTsoft14. A total of 33,920 DArTseq-derived SNPs were recalled for filtering analysis, with a final total of 16,960 SNPs. The analyses were computed using vcfR, poppr, and ape in R Studio v1.2.5001-3 software. The heatmap revealed that the TVU 9596 (SB26), Orelu (SB72), 90K-284-2 (SB55), RV 403 (SB17), and RV 498 (SB16) genotypes were heterogenous. The mean values for polymorphic information content, observed heterozygosity, expected heterozygosity, major allele frequency, and the inbreeding coefficient were 0.345, 0.386, 0.345, 0.729, and 0.113, respectively. Moreover, they validated the diversity of the evaluated cowpea genotypes, which could be used for potential breeding programmes and management of cowpea germplasm. Full article

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. Full article

Plant endogenous mechanisms are not always sufficient enough to mitigate drought stress, therefore, the exogenous application of elicitors, such as salicylic acid, is necessary. In this study, we assessed the mitigating action of salicylic acid (SA) in cowpea genotypes under drought conditions. An experiment was conducted with two cowpea genotypes and six treatments of drought stress and salicylic acid (T1 = Control, T2 = drought stress (stress), T3 = stress + 0.1 mM of SA, T4 = stress + 0.5 mM of SA, T5 = stress + 1.0 mM of SA, and T6 = stress + 2.0 mM of SA). Plants were evaluated in areas of leaf area, stomatal conductance, photosynthesis, proline content, the activity of antioxidant enzymes, and dry grain production. Drought stress reduces the leaf area, stomatal conductance, photosynthesis, and, consequently, the production of both cowpea genotypes. The growth and production of the BRS Paraguaçu genotype outcompetes the Pingo de Ouro-1-2 genotype, regardless of the stress conditions. The exogenous application of 0.5 mM salicylic acid to cowpea leaves increases SOD activity, decreases CAT activity, and improves the production of both genotypes. The application of 0.5 mM of salicylic acid mitigates drought stress in the cowpea genotype, and the BRS Paraguaçu genotype is more tolerant to drought stress. Full article