Bean Roots Research Articles

Comparison of Selenium Accumulation in Edible Parts of Wheat and Broad Bean

The concentration of selenium (Se) in agricultural products primarily depends on the concentration of Se in soil and the ability of plants to accumulate Se. Selenium deficiency not only leads to decreased body resistance, but also increases the risk of cancer. The form and concentration of bioavailable Se is important for diet. The present study was carried out via field experiment with wheat and broad beans in soil of different Se concentrations (0, 1.12, and 11.2 kg·ha−1), which was determined based on the national standard and the team’s previous experience. Results indicated that the concentration of Se in the edible organs of wheat was higher than in broad bean, while the enriched Se concentration in the root of broad bean was more than twice and three times higher than that of wheat at medium and high levels of Se, respectively. Selenomethionine, which accounted for over half of the total Se speciations, was the dominant species in the edible parts of the two crops, followed by Selenocystine and methylselenocysteine. Through the analysis of the rhizosphere soil, it was found that Fe-Mn oxide-bound Se exceeded 80% of the total Se. Additionally, there was a significant linear correlation between the Se content in the edible parts of the two crops and the Se content in the soil. Findings suggested that wheat was more favorable than broad beans as Se supplement crops in a Se-supplied field.

Hormonal crosstalk controls cell death induced by kinetin in roots of Vicia faba ssp. minor seedlings

Studies of vitality/mortality of cortex cells, as well as of the concentrations of ethylene (ETH), gibberellins (GAs), indolic compounds/auxins (ICs/AUXs) and cytokinins (CKs), were undertaken to explain the hormonal background of kinetin (Kin)-regulated cell death (RCD), which is induced in the cortex of the apical parts of roots of faba bean (Vicia faba ssp. minor) seedlings. Quantification was carried out with fluorescence microscopy, ETH sensors, spectrophotometry and ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC‒MS/MS). The results indicated that Kin was metabolized to the transport form, i.e., kinetin-9-glucoside (Kin9G) and kinetin riboside (KinR). KinR was then converted to cis-zeatin (cZ) in apical parts of roots with meristems, to cis-zeatin riboside (cZR) in apical parts of roots without meristems and finally to cis-zeatin riboside 5’-monophosphate (cZR5’MP), which is indicated to be a ligand of cytokinin-dependent receptors inducing CD. The process may be enhanced by an increase in the amount of dihydrozeatin riboside (DHZR) as a byproduct of the pathway of zeatin metabolism. It seems that crosstalk of ETH, ICs/AUXs, GAs and CKs with the cZR5’MP, the cis-zeatin-dependent pathway, but not the trans-zeatin-dependent pathway, is responsible for Kin-RCD, indicating that the process is very specific and offers a useful model for studies of CD hallmarks in plants.

RNA-Seq analysis of mung bean (Vigna radiata L.) roots shows differential gene expression and predicts regulatory pathways responding to taxonomically different rhizobia

Symbiotic interaction among legume and rhizobia is a complex phenomenon which results in the formation of nitrogen-fixing nodules. Mung bean is promiscuous host however expression profile of this important legume plant in response to rhizobial infection was particularly lacking and urgently needed. We have demonstrated the pattern of gene expression of mung bean roots inoculated with two symbionts Bradyrhizobium yuanmingense Vr50 and Sinorhizobium (Ensifer) aridi Vr33 and non-inoculated control (CK). The RNA-Seq data analyzed at two growth stages i.e., 1–3 h and 10–16 days post inoculation revealed significantly higher number of differentially expressed genes (DEGs) at nodulation stage. The DEGs encoding receptor kinases identified at early stage might be involved in perception of Nod factors produced by different rhizobia. At nodulation stage important genes involved in plant hormone signal transduction, nitrogen and sulfur metabolism were identified. KEGG pathway enrichment analysis showed that metabolic pathways were most prominent in both groups (Group 1: Vr33 vs CK; Group 2: Vr50 vs CK), followed by biosynthesis of secondary metabolites, plant hormone signal transduction and biosynthesis of amino acids. Furthermore, DEGs involved in cell communication and plant hormone signal transduction were found to be different among two symbiotic systems while DEGs involved in carbon, nitrogen and sulfur metabolism were similar but their expression varied in response to two rhizobial strains. This study provides the first insight into the mechanisms underlying interactions of mung bean host with two taxonomically different symbionts (Bradyrhizobium and Sinorhizobium) and the candidate genes for better understanding the mechanisms of symbiotic host-specificity.

Synthesis of nano-Fe3O4/ZnO composites with enhanced antibacterial properties and plant growth promotion via one-pot reaction.

Bordeaux mixture is commonly used in agricultural production due to its certain antibacterial activity. However, it has been observed to promote plant growth at a slow pace. Therefore, it is crucial to explore an effective antibacterial agent that can enhance the antibacterial activity and promote plant growth in commercially available Bordeaux mixture, which can significantly contribute to the development of the agricultural economy. The investigation into inorganic agents with both bacteriostatic and plant-promoting properties has a broad application potential in agriculture. Fe3O4/ZnO (FZ) composites were synthesized from FeCl3, ZnCl2, and NaAc in a "one-pot approach" and analyzed using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and a vibrating sample magnetometer (VSM). To investigate the antibacterial activity and mechanism of FZ nanocomposites, Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were used as model bacteria, and human mammary epithelial cells and model plant mung bean were used as targets to study the effects of FZ on human and plant growth. The results revealed that at 300µg/mL for 80min, the antibacterial efficacy of FZ composites was 99.8% against E. coli, which was 20% greater than that of Bordeaux liquid (FC), and 99.9% against S. aureus, which was 28.6% higher than that of FC. The inhibitory mechanism demonstrated that the substance could efficiently damage the bacterial cell wall of a concentration of 300µg/mL. The IC50 of the material to human mammary epithelial cells was 49.518µg/mL, and it also increased mung bean germination, root growth, and chlorophyll content, indicating that the application performance was 1.5 times better than that of FC. Its exceptional performance can be used to treat agricultural diseases.

Assessment of Root Rot Pathogens of Common Bean (Phaseolus Vulgaris L.) and Reaction of Genotypes to the Pathogens in West Hararghe Zone, Ethiopia

Common bean root rot caused by fungal pathogens is an important disease affecting common bean crops in Ethiopia. Information on pathogen identification, characterization, and management options is lacking for the Ethiopian bean production system. This study aimed to assess the major causal fungal pathogens and their management through host resistance methods. Initially, a field survey was conducted in three districts in 2016. It was cored forty-five (45) common bean fields. In the mean time, disease samples were collected for laboratory analyses. Secondly, pathogen identification and characterization were done in Laboratory at Haramaya University, followed by a pathogenicity test. Thirdly, a genotypic reaction was done on twenty common bean varieties by using four fungal genera (F. oxysporum, S. rolfsii, M. phaseolina, and R. solani) as experimental materials that were arranged in (CRD) design with three replications. Out of forty-five (45) common bean fields assessed 33 farms exhibited the disease. In the pathogenicity test, all the isolates were found pathogenic and showed a significant (p < 0.05) difference. In addition, the analysis of variance also showed that out of the tested twenty varieties, some released varieties (Dandesu, Tinike, SER-125, Dursitu, and Chorie), Chorie and (Dursitu, Chorie, Cranscope, Argene and SAB 632) showed highly significant at (p≤ 0.001) to Fusarium oxysporum f.sp. phaseoli, Sclerotium rolfsii, and Rhizoctonia solani while they didn’t exhibit any significant (p < 0.05) difference to Macrophomina phaseolina. In conclusion, those varieties showing resistance characters were recommended for growers.

PvSPS4 is involved in regulation of root sugar balance in common bean under salt stress

Salinity is a stress factor that decreases global agricultural yield. Crops such as rice, tomato, potato, and legumes are susceptible to salt, thus this problem requires urgent attention. Disruption of carbohydrate metabolism can have negative effects on stress tolerance. Sucrose phosphate synthase (SPS) enzymes operate in a key regulatory step in sucrose synthesis. Therefore, they have a significant role in the regulation of sugar metabolism. This study focused on the function of the SPS homolog -pvSPS4- in the roots of legume crop common bean under salinity stress. We previously showed that pvSPS4 expression is root-specific and is upregulated under salt stress in a salt-tolerant common bean genotype. This upregulation was accompanied by an accumulation of sugars in the roots. In the current study, using the same genotype, we generated composite common bean plants with wild-type shoot and pvSPS4 knock-down roots. Composite plants exhibited a more sensitive phenotype under salt stress compared to control and mock plants. pvSPS4 knock-down disturbed the root glucose/sucrose ratio and balance of Ca+2, Mg+2, and K+ in both root and leaves which resulted in a reduction in photosynthetic pigments together with osmoregulation and antioxidant capability. Our results imply that pvSPS4 is an important gene for carbohydrate balance regulation under salt-stress in the common bean root tissues and sets an example for the significance of mainly disregarded roles of SPS genes in sink tissues.

Phytopathological and biochemical impacts of Trichoderma harzianum and certain plant resistance inducers on faba bean root rot disease

BackgroundFaba bean attacked by soil-borne pathogens causing root rot disease. This disease has serious damage to both plant stand and produced yield. The present study aimed to evaluate effectiveness of the bioagents; Trichoderma harzianum and some plant resistance inducers as fungicide alternatives against root rot disease incidence at both pre- and post-emergence growth stages.ResultsUnder open greenhouse conditions, the incidence of faba bean root rot in pre- and post-emergence growth phases was considerably reduced by using six inorganic salts and five antioxidants individually or combining with each other or with the bio-stimulator T. harzianum that exceeded the used fungicide, Rhizolex-T. Application of enervit agitated the highest significant defensive impact during pre-emergence stage versus root rot incidence (5.0%), followed by calcium sulfate and [cysteine + T. harzianum] (6.7%). At post-emergence stage, majority of the treatments completely suppressed (100.0%) root rot incidence, except vitamax plus and the fungicide (Rizolex-T) which expressed by 91.7 and 18.8%, respectively. Duplicate irrigations of 23 treatments after faba bean dressing improved the synthesis of different protein contents with the 2nd of which enhanced higher protein contents than the 1st one, except [T. harzianum + vitamin E + vitamin C + enervit + selenium + vitamax plus], [T. harzianum + vitamax plus] and cysteine. Disodium phosphate induced the highest catalase (CAT) activity (1820.8 and 1677.2 U/g FWt) after both irrigations. [T. harzianum + vitamax plus] and vitamin E induced the highest peroxidase (POD) activity 217.4 and 356.9 U/g FWt after 1st and 2nd irrigations, respectively. Disodium phosphate and [T. harzianum + vitamin E + vitamin C + enervit + selenium + vitamax plus] induced the highest chitinase (CHIA) activity 52.8 and 54.4 U/g FWt after 1st and 2nd irrigations, respectively. Application of disodium phosphate, calcium sulfate, potassium metabisulfite, sodium sulfate, cysteine, [cysteine + potash alum], enervit, vitamin E, [vitamin E + vitamin C + enervit + selenium + vitamax plus], [T. harzianum + enervit], [T. harzianum + selenium], [T. harzianum + vitamin E], [T. harzianum + vitamin E + vitamin C + enervit + selenium + vitamax plus] and vitamin C stimulated the formation of new protein bands on SDS-PAGE after the 2nd irrigation treatment.ConclusionsSuch treatments are considered good and environmentally safe alternatives against root diseases for getting rid of the negative effects of fungicides.

Production status and research advancement on root rot disease of faba bean (Vicia faba L.) in China.

China is the largest producer of faba bean with a total harvested area of 8.11×105 ha and a total production of 1.69 ×106 tons (dry beans) in 2020, accounting for 30% of the world production. Faba bean is grown in China for both fresh pods and dry seed. East China cultivates large seed cultivars for food processing and fresh vegetables, while northwestern and southwestern China grow cultivars for dry seeds, with an increased production of fresh green pods. Most of the faba bean is consumed domestically, with limited exports. The absence of unified quality control measures and simple traditional cultivation practices contributes to the lower competitiveness of the faba bean industry in international markets. Recently, new cultivation methods have emerged with improved weed control, as well as better water and drainage management, resulting in higher quality and income for producers. Root rot disease in faba bean is caused by multiple pathogens, including Fusarium spp., Rhizoctonia spp., and Pythium spp. Fusarium spp. is the most prevalent species causing root rot in faba bean crops and is responsible for severe yield loss, with different species causing the disease in different regions in China. The yield loss ranges from 5% to 30%, up to 100% in severely infected fields. The management of faba bean root rot disease in China involves a combination of physical, chemical, and bio-control methods, including intercropping with non-host crops, applying rational nitrogen, and treating seeds with chemical or bio-seed treatments. However, the effectiveness of these methods is limited due to the high cost, the broad host range of the pathogens, and potential negative impacts on the environment and non-targeted soil organisms. Intercropping is the most widely utilized and economically friendly control method to date. This review provides an overview of the current status of faba bean production in China, the challenges faced by the industry due to root rot disease, and the progress in identifying and managing this disease. This information is critical for developing integrated management strategies to effectively control root rot in faba bean cultivation and facilitating the high-quality development of the faba bean industry.

Impact of Tillage Intensity on the Development of Faba Bean Cultivation

At the time of tillage, the properties of the soil change, thereby changing the conditions of crop development and, ultimately, their productivity and quality. The effect of non-inversion tillage or no-till on faba bean development is still not widely understood. For this reason, on the basis of a long-term experiment (since 1988), investigations of tillage systems using deep and shallow ploughing, chiselling, disking and no-till were undertaken at Vytautas Magnus University, Agriculture Academy, Lithuania, in 2016–2019. The aim of this study was to highlight the interaction between tillage methods and crop vegetative conditions, and its effect on faba bean development parameters. Soil chiselling generally led to better faba bean canopy development rates than other treatments. Faba bean roots developed somewhat better in non-tilled plots. Different tillage methods had less impact on faba bean development than vegetative conditions during the growing seasons. This shows that, due to rapid climate change, the conditions of each vegetative season are unique, which may lead to significant changes in crop development parameters. In addition, in this case, agrotechnologies must be precisely used, such as the use of varieties resistant to abiotic stresses, as well as technical and technological approaches. The complex effects of these agrotechnological elements should be investigated in more detail.

Litter mixing promoted decomposition and altered microbial community in common bean root litter

BackgroundDecomposition of plant litter is a key driver of carbon and nutrient cycling in terrestrial ecosystems. Mixing litters of different plant species may alter the decomposition rate, but its effect on the microbial decomposer community in plant litter is not fully understood. Here, we tested the effects of mixing with maize (Zea mays L.) and soybean [Glycine max (Linn.) Merr.] stalk litters on the decomposition and microbial decomposer communities of common bean (Phaseolus vulgaris L.) root litter at the early decomposition stage in a litterbag experiment.ResultsMixing with maize stalk litter, soybean stalk litter, and both of these litters increased the decomposition rate of common bean root litter at 56 day but not 14 day after incubation. Litter mixing also increased the decomposition rate of the whole liter mixture at 56 day after incubation. Amplicon sequencing found that litter mixing altered the composition of bacterial (at 56 day after incubation) and fungal communities (at both 14 and 56 day after incubation) in common bean root litter. Litter mixing increased the abundance and alpha diversity of fungal communities in common bean root litter at 56 day after incubation. Particularly, litter mixing stimulated certain microbial taxa, such as Fusarium, Aspergillus and Stachybotrys spp. In addition, a pot experiment with adding litters in the soil showed that litter mixing promoted growth of common bean seedlings and increased soil nitrogen and phosphorus contents.ConclusionsThis study showed that litter mixing can promote the decomposition rate and cause shifts in microbial decomposer communities, which may positively affect crop growth.

Complete Genome Sequence Data of Pseudomonas bijieensis SP1 Associated with Root Soft Rot of Yam Bean.

Pseudomonas bijieensis is a newly established species with antifungal activity. Here, we report the high-quality and complete genome sequence for P. bijieensis strain SP1, created by hybrid assembly using both short reads and long reads. The length of the circular chromosome is about 6.67 Mb, with a GC content of 60.89%. Bioinformatic analyses revealed gene clusters for the biosynthesis of antimicrobial metabolites 2,4-diacetylphloroglucinol as well as bacterial secretion systems (type I to III and type V to VI). Interestingly, this strain can cause soft rot symptoms in the roots of yam bean, showing the potential to be a plant pathogen. The genomic data will be a valuable resource for exploring the virulence mechanism and antifungal activity of this strain.

The Phytochemical and Antifungal Efficiency of Bean Leaf and Root against Some Pathogenic Fungi Isolated from Spoilt Vegetables Sold within Anambra Metropolies

Investigated in vitro were the phytochemical and antifungal properties of bean leaf and root against certain pathogenic fungi isolated from spoiled vegetables marketed in Anambra metropolises. By combining 100g, 100ml of sterile distilled water, and ethanol with each plant part, two (2) distinct extract concentrations were produced from each plant component. The plants were subjected to phytochemical screening using several conventional techniques, which identified the presence of alkaloids, saponins, tannins, flavonoids, phytate, oxalate, and phenol in all of the plants but at various amounts. The effects of common antibiotics (Fluconazole 30 g/ml) were compared to those of plant extracts. According to a pathogenicity test, good vegetables rot was caused by Aspergillus niger, Fusarium solani, Penicillium sp, Rhizopus sp, and Mucor spp. The ethanol extract from beans root turned out to be more effective. The extraction solvent, extract concentration, and test pathogens all had an impact on the extract's effectiveness. When extract concentration rose, the amount of fungal growth inhibition also rose. All of the test fungi's mycelia development was effectively/highly inhibited by beans root, although water extracts exhibited a lower degree of inhibition. Farmers should utilise bean root ethanolic extracts instead of synthetic or commercial fungicides due to their fungitoxic potential against vegetable storage fungi.

Rhizobium tropici and Riboflavin Amendment Condition Arbuscular Mycorrhiza Colonization in Phaseolus vulgaris L.

Phaseolus vulgaris L. (Fabaceae) forms symbioses with arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing rhizobia (NFB). The tripartite relationship uses molecular singals to establish intracellular symbioses in roots. The goal of this study was to determine if Rhizobium tropici CIAT 899 and exogenous riboflavin (vitamin B2) have an effect on AMF species selection and root colonization of P. vulgaris. Using SSU rRNA fragment amplification of DNA extracted from P. vulgaris roots, we found that the presence of R. tropici altered the relative distribution of AMF species. Dominikia bernensis (Ohel) was the most abundant AMF species in P. vulgaris roots but when R. tropici was co-inoculated, Glomus species dominated. Rhizobacteria such as R. tropici, secrete riboflavin and could affect AMF symbiosis. Addition of 50 μM riboflavin to P. vulgaris, increased plant growth (28%), dry nodule weight (18%), AMF colonization (248%) and mycorrhizal vesicle frequency (56%) in bean roots. 3.12 and 12.5 µM riboflavin favored the presence of Glomus macrocarpum in P. vulgaris roots. This work provides the basis to further study of rhizobial and mycorrhizal co-inoculation of Phaseolus vulgaris bean.

Nitrogen Fertilization in a Faba Bean-Wheat Intercropping System Can Alleviate the Autotoxic Effects in Faba Bean.

Continuous cultivation of the faba bean will lead to its autotoxicity. Faba bean-wheat intercropping can effectively alleviate the autotoxicity of the faba bean. In order to investigate the autotoxicity of water extracts of various parts of the faba bean, we prepared water extracts of various parts of the faba bean, such as the roots, stems, leaves, and rhizosphere soil. The results showed various parts of the faba bean significantly inhibited the germination of faba bean seeds. The main autotoxins in these parts were analyzed using HPLC. Six autotoxins, namely, p-hydroxybenzoic acid, vanillic acid, salicylic acid, ferulic acid, benzoic acid, and cinnamic acid, were identified. The exogenous addition of these six autotoxins significantly inhibited the germination of faba bean seeds in a concentration-dependent manner. Furthermore, field experiments were conducted to investigate the effects of various levels of nitrogen fertilizer on the autotoxin content and the aboveground dry weight of the faba bean in a faba bean-wheat intercropping system. The application of various levels of nitrogen fertilizer in the faba bean-wheat intercropping system could significantly reduce the content of autotoxins and increase the aboveground dry weight in faba bean, particularly at the N2 level (90 kg/hm2). The above results showed that the water extracts of faba bean roots, stems, leaves, and rhizosphere soil inhibited faba bean seed germination. The autotoxicity in faba bean under continuous cropping could be caused by p-hydroxybenzoic acid, vanillic acid, salicylic acid, ferulic acid, benzoic acid, and cinnamic acid. The autotoxic effects in the faba bean were effectively mitigated by the application of nitrogen fertilizer in a faba bean-wheat intercropping system.

A novel pathogen Fusarium cuneirostrum causing common bean (Phaseolus vulgaris) root rot in China

Several fungal pathogens cause root rot of common bean, among which Fusarium spp. are the most common pathogens causing Fusarium root rot (FRR) worldwide. FRR has been becoming an increasingly severe disease of common bean in China, but the species of Fusarium spp. have remained unclear. Thus, this study was performed to identify the pathogen causing common bean root rot in Liangcheng County, Inner Mongolia, China. Nineteen Fusarium-like isolates were obtained after pathogen isolation and purification. The pathogenicity test indicated that eight isolates caused severe disease symptoms on common bean, while 11 other isolates were not pathogenic. The eight pathogenic isolates, FCL1–FCL8, were identified as Fusarium cuneirostrum by morphological characterization and phylogenetic analysis using partial sequences of EF-1α, ITS, 28S, and IGS regions. Host range test showed that the representative F. cuneirostrum isolate FCL3 was also pathogenic to mung bean, while not pathogenic to adzuki bean, chickpea, cowpea, faba bean, pea, and soybean. Moreover, 50 common bean and 50 mung bean cultivars were screened for resistance to FRR, and seven highly resistant or resistant cultivars of common bean were identified, while no resistant cultivars of mung bean were screened. This study revealed that F. cuneirostrum was one of common bean FRR pathogens in Inner Mongolia and it could induce mung bean root rot as well. To our knowledge, this is the first report of F. cuneirostrum causing FRR of common bean in China.

Assessment of wastewater toxicity from the pharmaceutical industry of salicylic acid and paracetamol on the roots of a plant species: Phaseolus vulgaris

Pharmaceutical compounds are currently a group of emerging environmental contaminantswhere their presence is reported in all ecosystems (water, soil, etc.). Their effects often resultin strong metabolic disturbances which affect all vital functions of organisms, including plantswhich are non-target species. During their development, plants can absorb and accumulatemany xenobiotics, including pharmaceutical compounds that are able to cross the root walls.In order to evaluate the toxic effects of salicylic Acid (SA) and Paracetamol (PAR) on bean(Phaseolus vulgaris) were investigated. The root length showed significant reduction with anincrease in the concentration of PAR in parallel, with an increase in the length of the rootsobtained at the highest concentration of SA. On increasing the concentration from PAR andSA, the gradual increase in fresh weight of roots was observed compared to the control. Afterexposure to the different concentrations, PAR and SA treatments caused damage to theprotein synthesis. In addition, a significant stimulation of proline synthesis is recorded aftertreatment with PAR compared with the value obtained in the presence of SA at the highestconcentration. Lipid peroxidation supported by a significant increase in MDA and H 2 O 2levels, particularly for PAR treatments, are also observed. The evaluation of the respiratoryactivity of the isolated bean roots shows an oxygen consumption related to the PARconcentrations. This consumption is much higher in the presence of SA. Finally, our resultsshow that pharmaceutical products and their residues (such as PAR and SA), released into theenvironment in large quantities and without treatment, can produce morphological,biochemical and metabolic changes in the roots of non-target plant species such as bean thatcan seriously disrupt root functioning.

Faba Bean-Wheat Intercropping Can Control the Occurrence of Faba Bean Fusarium Wilt by Alleviating the Inhibitory Effect of Benzoic Acid on Disease Resistance Metabolism and the Expression of Resistance Genes.

Background: Continuous cropping leads to the accumulation of autotoxic substances in faba beans, which limits their global production. Intercropping is widely used to alleviate these problems. Aim: This study aims to explore the important role of Fusarium oxysporum f. sp. fabae (FOF) and benzoic acid stress in enhancing the occurrence of faba bean Fusarium wilt and the potential mechanism of faba bean-wheat intercropping to control the occurrence of this disease. Methods: We analyzed the pathogenic mechanism of FOF and benzoic acid and the defense response of faba bean-wheat intercropping against the autotoxicity of benzoic acid under hydroponic conditions that included the pathogen alone and in combination with different concentrations of benzoic acid. Results: The dual stress of FOF and benzoic acid inhibited the activity of defensive enzymes, the synthesis of defensive substances, and the expression of defensive genes in faba bean roots and reduced the disease resistance of faba bean. This shows that benzoic acid plays an important role in helping FOF cause disease. Faba bean-wheat intercropping improves plant resistance by alleviating benzoic acid stress and reducing the incidence and disease index of Fusarium wilt. Conclusion: The dual stress of FOF and benzoic acid promotes the occurrence of faba bean Fusarium wilt by destroying the root defense system of faba bean. Faba bean-wheat intercropping can effectively alleviate the autotoxicity of benzoic acid and control the occurrence of Fusarium wilt by improving the physiological and biochemical resistance of faba beans and the expression of defense genes.

Studies on the Growth and Development of Root-Knot Nematode Meloidogyne incognita of Phaseolus vulgaris in Tissue Culture Media

The study was conducted to study the growth and development of root-knot nematode, Meloidogyne incognita of Phaseolus vulgaris in tissue culture media. The data revealed the developmental common bean cv. Paulista of M.S media as the following: the seed swelling stage after three days, the radical appearance stage after five days. The cotyledons leaves appear after six days, the cotyledon leaves appear after eight days, and the seedling stage after twelve days. The life cycle of M. incognita completed about thirty-seven days in root tissues of Paulista cultivar. Microscopic examinations of the infected bean roots revealed the following: Second-stage juveniles of M. incognita penetrated the roots within 24 hrs after nematode inoculation. Third-stage juveniles were observed in roots (six-eight) days after nematode inoculation. While, fourth stage juveniles were observed in roots 12-14 days after nematode inoculation. The pre-adult females were seen inside roots within twenty days after nematode inoculation. The adult females were seen inside roots within twenty-seven days after nematode inoculation. Egg laying females with deposit egg masses of M. incognita was observed thirty-seven days after nematode inoculation.

Research Article Improvement of common bean root system phenotyping for identification of superior genotypes

Research Article Improvement of common bean root system phenotyping for identification of superior genotypes

Isolation and identification of Rhizobium bacteria from Faba bean (Vicia faba L.) roots grown in gypsiferous soil and testing their efficiency in production growth regulate(IAA) and siderophorses

In this study 30 samples were collected from the root nodules of Faba bean plants (Vicia faba L.) grown in gypsiferous soil in the College of Agriculture / Tikrit University / Salah al-Din Governorate in 5/12/2020, and the isolation process was carried out on selective mediumYeast Extract Mannitol Agar , and the phenotypically pure isolates were identified based on the culture, microscopic and biochemical characteristics, and the phenotypic identification results showed that 23 isolate gave the characteristics of Rhizobium sp. ,it was color of the colonies between white, cream and yellow, shiny, convex and smooth, gram-negative and most of able to move and has color between light pink and white on Congo red stain medium (0.025%) and it most of fast growing giving them yellow color on bromothymol blue medium and unable to grow on Hofer alkaline medium, and the efficient isolate was selected in the production of indole acetic acid, chelating compounds, and identificated molecularly by PCR, the 16SrRNA gene was amplified, then the sequence of nitrogenous bases, the results showed that there is a 99.69% similarity with the Rhizobium leguminosarum bv. Viciae strain SMV12a, and therefore the isolate is genetically close to Rhizobium bacteria.