اختبار فعالية بعض البكتريا من نوع endophytes المعزولة من نباتات طماطة في تثبيط الفطر Alternaria solani في ظروف المختبر

Tomato is a significant vegetable grown for its essential vitamins and antioxidant-producing potential. The rhizosphere microbes of plants are involved in promoting plant growth through increased availability of nutrients and improving the health status of the plants. This study was designed to explore the bacteria and fungi dwelling in the rhizospheric soil samples of healthy and diseased tomato plants employing a culture-dependent approach. Bacterial and fungal communities were isolated from the rhizosphere soil obtained from tomato plants by culture-dependent techniques. The biochemical and molecular characterizations were conducted on the isolates using 16S rRNA gene and ITS sequencing for the isolated bacterial and fungal isolates, respectively. The results revealed that various species of Bacillus and Streptomyces were obtained for ten bacterial isolates while species of Trichoderma, Purpureocillium, Mortierella, Chaetomidium, and Mortierella were obtained for five fungal isolates. The results further revealed that the microorganisms were greater in healthy tomato plants' soil samples than in the diseased tomato rhizosphere. The prevalence of bacterial and fungal species revealed the importance of these rhizospheric microbes and how they contribute to enhancing the growth and productivity of tomato plants.

Ralstonia solanacearum is a soil-borne bacterium causing bacterial wilt, particularly in Solanaceae crops, including tomatoes. Due to pathogen’s wide host plant range, pesticide resistance, and ability to overcome cultivars utilized for innate resistance, not even a single measure is effective against the pathogen. Screening the rhizosphere of bacterial wilt tolerant tomato plants from Bomet, Kiambu, Kajiado and Kirinyaga regions of Kenya for beneficial bacterial and fungal isolates was done using nutrient agar and potato dextrose agar, respectively. Morphological, biochemical, and microscopic characterization to identify the genus of fungal and microbial isolates revealed a total of 41 bacterial and 42 fungal isolates distributed as Bomet>Kiambu>Kajiado>kirinyaga while fungal isolates were as Bomet>Kiambu>Kirinyaga>Kajiado. Methyl Red (MR) and Voges-Proskauer (VP) tests, catalase reaction, citrate reaction, starch hydrolysis, and triple iron sugar (TSI) tests showed that the predominant bacteria were Burkholderia, Bacillus and Micrococcus species. Pseudomonas, Streptomyces, Serratia, and Enterobacter species were the least. Aspergillus, Trichoderma, and Fusarium species were the most dominant fungal isolates from the four counties. Hierarchical cluster analysis was done using DARwin software V6 to reveal different dissimilarity levels among the isolates based on biochemical and morphological characteristics. Key words: Ralstonia solanacearum, rhizosphere screening, fungal isolates, bacterial isolates, biological control.

A reproducible workflow is presented that integrates fruit‑health stratification, stringent surface sterilization, culture‑based isolation, molecular identification, enzyme phenotyping, and a low‑injury needle‑transfer pathogenicity assay to isolate, classify and functionally characterize bacterial endophytes, saprophytic colonizers and pathogens associated with postharvest tomato (Solanum lycopersicum) fruits. The method is designed to distinguish ecological guilds (endophytes vs soft‑rot pathogens vs saprophytes) rather than simply list "bacteria present", and can be implemented in standard microbiology laboratories without specialized equipment. Tomato fruits were stratified by fruit-health status and surface‑sterilized to distinguish internal endophytes from epiphytic and saprophytic surface‑associated communities. All bacterial isolates were cultured on tryptone soya agar, purified, assigned to an ecological niche (healthy or spoiled/diseased fruits), and tested for in planta pathogenicity on tomato fruits. All the isolates were identified using biochemical and 16S rRNA gene sequencing, while preliminary phenotypic screening was used to quantify cell wall‑degrading activities relevant to soft‑rot. The workflow yielded 14 characterized bacterial isolates spanning three ecological groups (non‑pathogenic endophytic Bacillus species, soft‑rot‑inducing Enterobacterales, and saprophytic colonizers), with ecological niche separation statistically supported by Fisher's exact test (p < 0.001). The method can be adapted to other fruit or vegetable systems to link bacterial community composition with plant health outcomes.•Provides a low-injury and contamination-reduced approach for fruit pathogenicity assays based on a needle‑transfer inoculation technique adapted for routine microbiology laboratories.•Enables the functional differentiation of endophytic, saprophytic, and pathogenic bacterial isolates relevant to fruits and vegetables through combined ecological sources, in planta pathogenicity, and enzyme phenotyping.•The approach is adaptable to multiple fruit and vegetable host crops in a resource-limited and efficient laboratory setting.

This study investigated the effect of high dilution preparations on the development of Alternaria solani mycelium, which causes early blight on tomato plants. Twelve bioassays were conducted under controlled conditions. Colony discs, 0.7 cm diameter, of A. solani were transferred into Petri dishes containing potato dextrose agar (PDA) or PDA+V8® vegetable juice media. High dilution preparations of Arsenicum album, Nitricum acidum and Staphysagria at 6, 12, 25, 30, 50, 60, 80 and 100 CH (centesimal Hahnemannian dilution scale) were applied either over the media or mixed in with it. Results showed that high dilution preparations have different effects on A. solani mycelium growth, according to the dynamization level. A. solani colonies were reduced by A. album 80 CH, by N. acidum 80 and 100 CH, and by Staphysagria 6, 30 and 60 CH compared with the control when applied over PDA medium. Higher mycelium reduction was observed in the PDA assays when the treatments were applied over the medium than when incorporated into it. The differences among high dilution treatments were distinctly greater on the PDA medium than on the PDA+V8®. Bioassay is a suitable method for screening high dilution preparations before studying them under field conditions.

Transmission characteristics of Tomato chlorosis virus (ToCV) by Bemisia tabaci MED and its effects on host preference of vector whitefly

Exploitation of phosphate solubilizing bacteria (PSB) and fungi as bioinoculants instead of chemical fertilizers is known to promote plant growth through the supply of plant nutrients. In view of this, the present investigation was planned to assess the phytobeneficial traits of phosphate solublizing bacterial and fungal isolates recovered from coffee arabica rhizosphere/ vermicompost and to determine their potential in growth promotion of coffee seedlings. They were isolated and purified following standard methods. A total number of 154 bacteria and 72 fungi were isolated from vermicompost and coffee rhizosphere. Out of these, twelve potent bacterial and nine fungal isolates were selected and investigated. Among twelve bacterial isolates, three of them showed significant potential to solubilize Ca₃ (PO₄)₂ and had phytobeneficial traits, viz, indole acetic acid, NH₃, HCN production and N-fixing ability. The three bacterial isolates (RCHVCB₁, RScB1.19 and RMaB2.11) exhibited also remarkable tolerance to ecophysiological factors such as heavy metal, acidity and salinity. These potent isolates were selected for further identification based on morphological and biochemical characteristics and presumptively identified as genera of Pseudomonas (RCHVCB₁) and <i>Bacillus</i> (RScB1.19 and RMaB2.11). Similarly, three fungal isolates with superior phosphate solubilizeation ability were characterized and identified as genera <i>Penicillium</i> (RSCF1.19) and <i>Aspergillus</i> (RCHVCF2 and RLVCF2). Consequently, these three efficient bacterial and fungal isolates were evaluated on the coffee seed germination on Petri dish based trial under laboratory condition. The results of inoculated seeds showed significant (p≤0.05) differences in germination rate and vigor index compared to the control. Among all inoculums RScB1.19, RMaB2.11+RSCF1.19 and RMaB2.11 + RLVCF2 showed significantly (p≤0.05) high germination rate (20.59%) over the control (13.33%). Moreover, a single inoculation of RLVCF2, RSCF1.19 and co-inoculation of RMaB2.11 with RLVCF2 also showed significant (p≤0.05) mean root length (1.31cm) and mean shoot length (1.48cm) over the control. These effective bacterial and fungal solublizers can be recommended under field condition as biofertilizer agent and reducing the cost required for chemical fertilizers and providing a step forward towards sustainable agriculture.

Management of tomato early blight pathogen (Alternaria solani) has relied principally on application of&#13;\nsynthetic fungicides. The use of biological control agents has been recognized as a viable option to&#13;\nsynthetic chemicals in plant disease control. The present study evaluated the effects of Pseudomonas&#13;\nfluorescens, P. aeruginosa, P. putida, and P. cepacia on tomato early blight pathogen and investigated&#13;\ntheir efficacy on the yield components and yield of tomato plants infected with A. solani. Tomato seeds&#13;\nraised in the nursery beds were transplanted to the main field after three weeks. The experiment was&#13;\nlaid in a randomized complete block. Treatment application was done by immersion of roots of threeweek-&#13;\nold seedlings of tomato in Pseudomonas solution prior to transplanting. The treatments&#13;\nconsisted of plots treated with P. fluorescens, P. aeruginosa, P. putida, P. cepacia and the control. Data&#13;\nwere collected on disease severity, plant height, stem girth, number of fruits per plant, fruit length and&#13;\nfruit weight. Tomato plants in the control plot had significantly (p&lt;0.05) higher disease severity (52.0)&#13;\nThere was no significant difference in the severities of early blight on tomato plants treated with P.&#13;\nfluorescens, P. putida and P. cepacia. Tomato plants treated with P. aeruginosa had significantly&#13;\n(p&lt;0.05) higher height (39.0 cm) than all other treatments. There was no significance difference in the&#13;\nfruit weights of tomato plants treated with P. fluorescens, P. aeruginosa, P. putida, and P. cepacia.&#13;\nTomato plants in the control plots had a significantly lower fruit weight (69.5 g). Findings of the present&#13;\nstudy demonstrated a promising approach of biological control of early blight pathogen with&#13;\nPseudomonas species. Results of this work could be used as bedrock for formulation of an effective&#13;\nand eco-friendly strategy for the management of early blight disease.

&lt;b&gt;Background and Objective:&lt;/b&gt; Exploration of drought-tolerant endophytic bacteria is significant to identify bacteria that can provide plant resistance to drought stress. This study aims to obtain the potential of endophytic bacteria to promote plant growth from tomato plants in dry land. &lt;b&gt;Materials and Methods:&lt;/b&gt; Exploration of endophytic bacteria from healthy tomato plants in a dry and rocky land, Muna Regency, Indonesia. Selection of drought-tolerant endophytic bacteria using polyethylene glycol 6000. Selected isolates were tested to increase the viability of tomato seeds using a Completely Randomized Design (CRD). &lt;b&gt;Results:&lt;/b&gt; There were 123 isolates of endophytic bacteria isolated from the roots and stems of local tomato plants in a dry and rocky land, Muna Regency, Indonesia. There were 39 (31.70%) isolates sensitive to drought, 55 (44.71%) isolates very sensitive to drought, 8 (6.50%) isolates tolerant to drought and 21 (17.02%) isolates very tolerant to drought. Dryness for the maximum polyethylene glycol concentration at osmotic pressure of -2.00 MPa. Inoculation of endophytic bacteria in local tomato seeds increased the viability and vigour of local tomato seeds compared to the absence of endophytic bacteria. Of the 21 isolates of drought-tolerant endophytic bacteria, there were 12 potential isolates in increasing the viability of local tomato seeds belonging to the &lt;i&gt;Pseudomonas&lt;/i&gt; sp. and &lt;i&gt;Bacillus&lt;/i&gt; sp. bacterial groups. &lt;b&gt;Conclusion:&lt;/b&gt; &lt;i&gt;Pseudomonas &lt;/i&gt;sp. and Bacillus sp. isolates identified the endophytic bacteria, which can be drought-tolerant and increase tomato seeds' viability.

Purpose: We aim to report the microbiological spectrum of organisms cultured from extubated silicone stents after a dacryocystorhinostomy and their antibiotic sensitivity patterns.Study Design: Prospective interventional study.Methods: 50 silicone stents of 50 consecutive patients who underwent either external or endonasal dacryocystorhinostomy were enrolled for the study. All the stents were retrieved under endoscopic guidance from the nasal cavity at 3 months following surgery. All the tubes were immediately inoculated onto blood agar, chocolate agar, brain-heart infusion broth, Saboraud’s dextrose agar and potato dextrose agar. Data collected and analyzed include demographics, diagnosis, type of dacryocystorhinostomy and the microbiological profile. The culture results, organisms isolated and their antibiotic sensitivity were studied.Results: The mean age of patients at the time of dacyrocystorhinostomy was 34.4 years. Bacterial growth was noted in 88% (44/50) of all the stents cultured, whereas 60% (30/50) grew fungi and 6% (3/50) showed sterile cultures. 48% (24/50) of the stents showed mixed bacterial and fungal isolates. Among the fungal isolates, Aspergillus species accounted for 66.6% (20/30) followed by Fusarium species, which were seen in 26.6% (8/30). Among the bacterial isolates, gram negative organisms were the most common seen in 54.5% (24/44) and the commonest species isolated was Pseudomonas aeruginosa from 27% (12/44) of the stents. Staphylococcus aureus was the commonest gram positive isolate accounting for 18% of all the bacterial isolates. Gram positive organisms were commonly sensitive to cephalosporins and vancomycin whereas gram negative organisms were sensitive to quinolones and aminoglycosides. The surgical success rate was 96% (48/50).Conclusions: Fungal isolates were cultured from significant number of stents retrieved following dacryocystorhinostomy. Gram negative organisms are more common as compared to the gram positive. The organisms isolated were not found to influence the success of dacryocystorhinostomy.

Tomato (Lycopersicum esculentum) is a vital agricultural crop globally, yet it is significantly affected by various microbial pathogens leading to post-harvest rot, which threatens food security and economic stability. This study aimed to identify the microorganisms associated with tomato rot in Makurdi Metropolis and evaluate the efficacy of neem (Azadirachta indica) extract as a biocontrol agent. A total of 60 tomato fruits were sampled from the five major markets within the Makurdi metropolis. They were cultured on Nutrient agar, MacConkey agar, Potato Dextrose agar, Mannitol salt agar, and Eosin Methylene blue agar. The organisms identified were Klebsiella sp, Salmonella sp, Proteus vulgaris, Enterobacter sp, Shigella sp, Staphylococcus sp, Bacillus sp, Escherichia coli, Rhizopus sp, Mucor sp, Aspergillus sp, and Fusarium sp. Neem extract was used for susceptibility tests on the bacterial isolates at 10%, 50%, and 100% concentration, and it was found most effective on some bacterial isolates at higher concentrations of 100% with wider zones of inhibitions. Vegetative growth of the fungi on neem extract decreased with increase in concentrations. This finding proved the potentiality of plant extracts for controlling the fungal rot of tomato fruit. A pathogenicity test was conducted with readings taken at intervals of days and it was noticed that the microbial isolates were actually the cause of tomato rot. This study underscores the importance of identifying microbial threats to tomato crops and highlights neem extract as a promising natural alternative for managing tomato rot, promoting sustainable agricultural practices in Makurdi Metropolis and Nigeria at large.

The purpose of this research work is to determine the molecular identity of bacteria isolated from infected Zea maize using the 16s rRNA molecular sequencing protocol. The samples were obtained from Okeagbe, Akoko north-west local government in Ondo state with latitude and longitude of Okeagbe at 7.6450° N, and 5.7603° E respectively. Preparation of infected maize samples was cultured using the serial dilution method.. Confirmatory characterization of bacteria isolates using 16s rRNA (ribosomal RNA) sequencing procedures (purification, amplication, Sequencing, and DNA extraction) inclusive.The result shows the isolation of the bacteria isolates involved the culturing, inoculation, and plating of the isolate on a plated agar, the identification of the bacteria isolate includes the use of Gram staining, biochemical tests, and characterization using Bergey's manual and antibiotics Susceptibility Test. In Gram staining all bacteria isolates were positive except one, in the biochemical test most bacteria isolate was positive for sugar Fermentation and citrate test and all were negative for the Voges Proskauer test. In antibiotics Susceptibility test few were sensitive, most were susceptible to antibiotics used. With the use of the 16S rRNA and procedures (purification and application of product, Sequencing, and Extraction of DNA) the bacteria isolate were identified and characterized. The phylogenetic analysis and molecular identification of 16S rDNA sequencing revealed that Escherichia coli, Samonella enterica and Staphylococcus aureus were found to infect maize. Molecular characterization based on 16S rRNA Gene sequencing confirms the identity of bacteria. The conventional procedure shows the presence of different arrays of microorganisms in the infected maize, microbes identified are Bacillus subtilis, Bacillus anthracis, Micrococcus luteus, Clostridium sporogenes, Microbacterium lacticum, Clostridium sporogenes, Lactobacillus casei and Micrococcus luteus. The phylogenetic analysis and molecular identification of 16s rRNA sequencing revealed that Escherichia coli, Samonella enterica and Staphylococcus aureus were found to infect maize in Band fragment Base pair 1500bp. In conclusion, the hearsay that maize can only be infected by fungi, it was observed that the possibility of being infected with pathogenic bacteria is imminent. The bottom line is, there should be proper surveillance and food safety in our farm, market and food store, to prevent and totally eradicate emergence of pathogenic organism in our food item.

Quarenta isolados bacterianos endofíticos de plantas sadias de tomateiro foram avaliados quanto à sua potencialidade como agentes de biocontrole de doenças do tomateiro. Foi realizada, em casa de vegetação, uma seleção massal utilizando-se Pseudomonas syringae pv. tomato e Alternaria solani, como patógenos desafiantes. Com base na média do número de lesões por planta, quatro isolados foram selecionados como potenciais agentes de biocontrole dessas enfermidades fúngica e bacteriana do tomateiro. Esses isolados foram identificados, por meio do sequenciamento do gene 16S do DNA ribossômico, como Acinetobacter johnsonii (UFV-E05), Serratia marcescens (UFV-E13), Sinorhizobium sp. (UFV-E25) e Bacillus megaterium (UFV-E26). Os mesmos isolados selecionados para o biocontrole também foram avaliados quanto à sua capacidade de promover o crescimento em plantas e somente S. marcescens (UFV-E13) proporcionou aumento na altura das plantas.

Plant growth promoting rhizobacteria (PGPR) inhabit the rhizosphere region of plant and often found to be beneficial for the development and growth of plants. In this study, 17 pure isolates of bacteria from the rhizosphere of brinjal (Solanum melongena L.) and chilli (Capsicum annuum L.) were screened for their potential in growth promotion and antagonistic effect towards fungal pathogens of tomato plant (Solanum lycopersicum L.). Among the isolates, two bacterial strains (JB and JC) showed prominent activity and were further investigated. The selected bacterial isolates were identified as Pseudomonas aeruginosa and designated as P. aeruginosa JB and JC. Both the bacterial isolates enhanced the production of plant growth promoting compounds, such as phytohormones and salicylic acid. Seed inoculation with P. aeruginosa JB and JC also significantly improved the germination and growth of S. lycopersicum L. The bacterial strains were found to exhibit significant antagonistic effect towards the tested pathogens, Fusarium oxysporum and Alternaria solani. In the pot experiment, both the bacterial isolates P. aeruginosa JB and JC showed significant efficacy in decreasing the disease severity of test phytopathogens. These results suggested that both the rhizobacterial species could be further exploited as potential bio-inoculants for the improvement of plant growth, productivity and defence against phytopathogens.

The sustainable production of tomatoes (Solanum lycopersicum) is important, and this can be achieved by determining the rate of respiration of microbes in the tomato plants' rhizosphere soil. This study aimed at the potential of microbes to utilize carbon substrates embedded in the rhizosphere soil thereby contributing to the healthy nature of the tomato plants. The potential soil physiochemical features and utilization of carbon substrate by soil microorganisms as a result of their respiration to reveal their functions in the ecosystem were evaluated. The soil samples were amassed from the healthy tomato plant rhizosphere, diseased tomatoes, and bulk soil in this study. The physiochemical features and carbon substrate utilization in the bulk soil samples, and rhizosphere samples of powdery diseased, and healthy tomato plants were assessed. The MicroRespTM procedure was used to determine the community-level physiological profiles (CLPP) employing fifteen (15) carbon (C) substrates selected based on their importance to microbial communities embedded in the soil samples. Our results revealed that various physiochemical properties, moisture content, water retention, and C substrates including sugar, amino acid, and carboxylic acid were greater in HR and the substrates were not significantly different (p < 0.05). The study reveals higher soil respiration in HR as a result of the microbial communities inhabiting HR utilizing more of the C-substrates. This investigation contributes to the tomato plant's healthy state as the microbial communities utilized carbon substrate compared to DR after employing the CLPP assays.

Campanumoea javanica subsp. javanica, a member of the Campanulaceae family, is a distinctive ethnomedicine predominantly employed in Guizhou, China. In August 2023, a leaf spot disease was observed on C. javanica subsp. javanica in a cultivation field in Xiuwen County (106°46'48" E, 26°53'59" N), Guizhou Province. The symptoms initially appeared as yellow spots on the leaves, which progressively enlarge and develop into brown lesions, ultimately resulting in wilting and plant death. The disease incidence reached 30 to 55% at the flowering stage. Ten infected leaves were randomly selected, surface sterilized in 75% ethanol for 15 sec, 5% NaClO for 1 minute and washed three times with sterile water, then incubated on potato dextrose agar (PDA) at 28°C for 5 days. Seventeen morphologically similar strains were isolated through single hyphal tip culturing (Zhai et al. 2014). The colonies initially appeared as white flocculent growth, gradually turning gray-black, and finally becoming dark. In PDA liquid medium, the conidia were solitary, brown, ovate or ellipsoid in shape, with transverse septa and longitudinal septa, and measured 10.62 to 20.30 μm long and 3.20 to 7.55 μm wide (n=50). Based on these morphological features, the isolates were suspected to be Alternaria alternata (Wiltshire 1933). The isolate LH1 was selected as a representative for DNA extraction and molecular identification. Four genomic DNA regions including the internal transcribed spacer (ITS), translation elongation factor 1-alpha (TEF-1α), RNA polymerase II second largest subunit (RPB2), and Alternaria major allergen (Alt a1) genes were amplified and sequenced with the primers ITS1/ITS4 (White et al. 1990), TEF1-728F/TEF1-986R (Carbone and Kohn. 1999), RPB2-5F/RPB2-7cR (Liu et al.1999), and Alt-for/Alt-rev (Hong et al. 2005), respectively. The sequences of LH1 (accession number PV627907 [ITS]; PV628988 [TEF-1α]; PV628990 [RPB2]; PV628989 [Alt a1]) were deposited in GenBank, demonstrating a sequence homology of 99% to 100% (563/563, 281/281, 883/884, 489/489) with Alternaria alternata (accession numbers MN856385, PV054872, ON427970 and OM423572). Based on morphological characteristics of the asexual morph and maximum-likelihood analyses of combined rDNA-ITS, EF-1 α, Alt-1a and RPB2 gene sequences, it was identified as A. alternata. Pathogenicity assay was performed in a glasshouse at 27°C, 85% relative humidity, and a 12-h photoperiod. Leaves on three healthy one-year-old C. javanica subsp. javanica seedlings were inoculated with a conidial suspension (1 × 106 conidia/ml) of isolate LH1. Sterile water was used as the control. The experiment was repeated three times with consistent results. After 10 days, the leaves of the inoculated strains exhibited leaf spot symptoms analogous to those observed in the field, whereas the control group remained unaffected. A. alternata was subsequently re-isolated from the inoculated leaves but not from the controls, thus fulfilling Koch's postulates. Research has demonstrated that A. alternata is the pathogen responsible for leaf spot disease in Magnolia delavayi and Cyclocodon lancifolius in China (Suo et al. 2024; Dang et al. 2023). To the best of our knowledge, this is the first report of A. alternata causing leaf spot disease on C. javanica subsp. javanica. Consequently, the accurate identification of this pathogen will provide a basis for the prevention and control of C. javanica subsp. javanica leaf spot disease in the future.