\u3cem\u3eRhaphiolepis indica\u3c/em\u3e Fruit Extracts for Control \u3cem\u3eFusarium solani\u3c/em\u3e and \u3cem\u3eRhizoctonia solani,\u3c/em\u3e the Causal Agents of Bean Root Rot

Numerous strategies have been suggested to reduce dependence on synthetic products, such as physical, microbial, and natural methods. Among the natural remedies, plant extracts have emerged as a popular option owing to their eco-friendly character, ease of degradation, and harmless nature to humans. In our study, we used the acetone and hexane extracts of Rhaphiolepis indica fruit to combat two fungal pathogens that were isolated from infected bean plants and showed root rot symptoms. The two pathogens were confirmed to be pathogenic by pathogenicity assays conducted in vivo. The morphological and molecular identification by ITS-region sequencing revealed that the two isolates were Rhizoctonia solani and Fusarium solani, and they were assigned accession numbers OQ880457 and OQ820158, respectively. Our data showed that both hexane and acetone extracts caused a significant decrease in the linear growth of F. solani at all concentrations used (1%, 2%, and 3%), compared to the control. However, at a concentration of 3%, the hexane extract caused much greater inhibition than the acetone extract. For R. solani, the hexane extract, shows a significant inhibition percentage at all concentrations, which further increases to 85.24% at 3% concentration. The HPLC of both extracts indicated the presence and absence of phenolic and flavonoid compounds. The obtained results revealed that five acetonic phenolic extract compounds were ferulic, p-coumaric, gallic, p-OH benzoic, and cinnamic, with concentrations of 5.31, 10.36, 7.24, 6.08, and 0.89 mg/mL, respectively. On the other hand, the five hexanoic phenolic compounds were catechol, caffeic, chlorogenic, p-OH benzoic, and cinnamic acids, with concentrations of 3.66, 5.14, 0.69, 6.31, and 13.47 mg/mL, respectively. The identified acetonic flavonoid extract compounds, namely rutin, chrysin, quercetin, kaempferol, chrysoeriol, 7-OH flavone, and naringin, had respective concentrations of 5.36, 10.23, 4.32, 15.33, 1.06, 0.087, and 0.069 mg/mL, respectively. In contrast, it was observed that the seven hexanoic flavonoid extracts comprised of rutin, quercetin, kampferol, luteolin, chrysoeriol, 7-OH flavone, and catechin exhibited concentrations of 5.36, 7.15, 18.20, 6.04, 2.04, 10.24, and 13.43 mg/mL, respectively. The results of the study suggest that plant extracts may be a useful natural remedy for combating fungal pathogens and reducing dependence on synthetic products

Nematocidal and Bactericidal Activities of Green Synthesized Silver Nanoparticles Mediated by \u3ci\u3eFicus sycomorus\u3c/i\u3e Leaf Extract

Nanoparticles effectively control most plant pathogens, although research has focused more on their antimicrobial than their nematocidal properties. This study synthesized silver nanoparticles (Ag-NPs) through a green biosynthesis method using an aqueous extract of Ficus sycomorus leaves (FS-Ag-NPs). The nanoparticles were characterized using SEM, TEM, EDX, zeta sizer, and FTIR. The TEM results showed that the synthesized NPs were nanoscale and had an average particle size of 33 ± 1 nm. The elemental silver signal at 3 keV confirmed the formation of Ag-NPs from an aqueous leaf extract of F. sycomorus. The FTIR analysis revealed the existence of several functional groups in the prepared Ag-NPs. The strong-broad band detected at 3430 cm-1 indicated the stretching vibration of -OH (hydroxyl) and -NH2 (amine) groups. The nematocidal activity of biosynthesized FS-Ag-NPs has been evaluated in vitro against the root-knot nematode Meloidogyne incognita at 24, 48, and 72 h. The FS-Ag-NPs at a 200 μg/mL concentration applied for 48 h showed the highest effectiveness, with 57.62% nematode mortality. Moreover, the biosynthesized FS-Ag-NPs were also tested for their antibacterial activity against Pectobacterium carotovorum, P. atrosepticum, and Ralstonia solanacearum. With the application of nanoparticles, the reduction in bacterial growth gradually increased. The most potent activity at all concentrations was found in R. solanacearum, with values of 14.00 ± 2.16, 17.33 ± 2.05, 19.00 ± 1.41, 24.00 ± 1.41, and 26.00 ± 2.83 at concentrations of 5, 10, 15, 20, and 25 μg/mL, respectively, when compared with the positive control (Amoxicillin 25 μg) with a value of 16.33 ± 0.94. At the same time, the nanoparticles showed the lowest reduction values against P. atrosepticum when compared to the control. This study is the first report on the nematocidal activity of Ag-NPs using F. sycomorus aqueous extract, which could be a recommended treatment for managing plant-parasitic nematodes due to its simplicity, stability, cost-effectiveness, and environmentally safe nature

\u3cem\u3e Swietenia mahagoni \u3c/em\u3e Leaves Extract: Antifungal, Insecticidal, and Phytochemical Analysis

In this study, we investigated the antifungal properties of an acetone extract derived from the leaves of Swietenia mahagoni (SMAL) against two isolated fungi, Fusarium equiseti (OQ820153) and Rhizoctonia solani (OQ820152), from rice sheath. The extract was effective in inhibiting the growth of both fungi at the highest concentration tested, 3000 μg·mL−1. Laboratory tests on the LC20 of SMAL extract (49.86 mg·L−1) versus pyriproxyfen 10% EC (1.96 mg·L−1) were accomplished on Aphis gossypii Glover. The extract potently reduced the survival of the nymphs (49.58%) more than the other treatments. The longevity of nymphs treated with the extract had the highest prolongation at 9.67 days. The olfactory choice test exhibited the lowest aphid attraction percentage (23.33%). The HPLC of SMAL extract contained various phenolic compounds, and the most abundant found were catechin (752.64 µg·g−1), gallic acid, and chlorogenic acid, as well as flavonoids such as rutin (585.24 µg·g−1) and naringenin. A GC–MS analysis revealed n-hexadecanoic acid (37.1%) as the major compound, followed by oleic acid. These results suggest that SMAL extract has the potential to help plants fight against fungal and insect infections, making it a promising natural and renewable solution for long-term plant pest regulation

Antimycotoxigenic Activity of Beetroot Extracts against Alternaria alternata Mycotoxins on Potato Crop

Alternaria species, mainly air-borne fungi, affect potato plants, causing black spots symptoms. Morphological identification, pathogenicity assessment, and internal transcribed spacer (ITS) molecular identification confirmed that all isolates were Alternaria alternata. The annotated sequences were deposited in GenBank under accession numbers MN592771–MN592777. HPLC analysis revealed that the fungal isolates KH3 (133,200 ng/g) and NO3 (212,000 ng/g) produced higher levels of tenuazonic acid (TeA) and alternariol monomethyl ether (AME), respectively. Beet ethanol extract (BEE) and beet methanol extract (BME) at different concentrations were used as antimycotoxins. BME decreased the production of mycotoxins by 66.99–99.79%. The highest TeA reduction rate (99.39%) was reported in the KH3 isolate with 150 µg/mL BME treatment. In comparison, the most effective AME reduction rate (99.79%) was shown in the NO3 isolate with 150 µg/mL BME treatment. In the same way, BEE application resulted in 95.60–99.91% mycotoxin reduction. The highest TeA reduction rate (99.91%) was reported in the KH3 isolate with 150 µg/mL BEE treatment, while the greatest AME reduction rate (99.68%) was shown in the Alam1 isolate with 75 µg/mL BEE treatment. GC-MS analysis showed that the main constituent in BME was the antioxidant compound 1-dodecanamine, n,n-dimethyl with a peak area of 43.75%. In contrast, oxirane, methyl- (23.22%); hexadecanoic acid, methyl ester (10.72%); and n-hexadecanoic acid (7.32%) were the main components in BEE found by GC-MS. They are probably antimicrobial molecules and have an effect on the mycotoxin in general. To our knowledge, this is the first study describing the antimycotoxigenic activity of beet extracts against A. alternata mycotoxins-contaminated potato crops in Egypt, aimed to manage and save the environment

Antigenic and pathogenicity activities of Ralstonia solanacearum race 3 biovar 2 molecularly identified and detected by indirect ELISA using polyclonal antibodies generated in rabbits

The efficiency of the antiserum was compared among 42 isolates that cause potato brown rot disease; our polyclonal antiserum (14 days) reacted positively with all tested isolates at a dilution of 1:6.4×103. Data indicated the different reactions of eight R. solanacearum isolates at various dilutions (1:1.6×103 to 1:5.12×106) at 14 days against polyclonal antiserumat a concentration of approximately 1×108 CFU/mL and we found the lowest detection level by the indirect ELISA technique was 106 CFU/mL. Finally we recommended the reasonable sensitivity results of the ELISA technique to detect the bacterial pathogen given than the cost of this technique if much lower than that of other expensive molecular techniques.Eight molecular-characterized isolates of Ralstonia solanacearum from potato belonging to race 3 biovar 2, their virulence were evaluated on potato cv. Lady Rosette, tomato cv. Strain B, eggplant cv. Balady and pepper cv. Balady and showed high virulence on potato and tomato, and lower virulence on eggplant and pepper. A laboratory study conducted to produce polyclonal antibodies against the potato brown rot bacterium; R. solanacearum cells were generated in female New Zealand white rabbits. A modification were made on the technique of indirect enzyme-linked immunosorbent assay (ELISA) to improve the sensitivity of detection, including antigenic and sensitivity to R. solanacearum race 3 biovar 2 isolates. Determination of the optimum period to collect the antiserum (including, polyclonal antibodies) showed that the best collection dates were at 14, 3 and 7 days, in that order

First Report of Protective Activity of <i>Paronychia argentea</i> Extract against Tobacco Mosaic Virus Infection

The widespread use of chemical control agents and pesticides for plant-pathogen control has caused many human health and environmental issues. Plant extracts and biocontrol agents have robust antimicrobial activity against different plant pathogens. However, their antiviral activities are still being investigated. In the present study, the methanol extract of Paronychia argentea was characterized and evaluated for its protective activity against the tobacco mosaic virus (TMV) infection in tomato plants under greenhouse conditions at 21 days post-inoculation. The results showed that the foliar application of P. argentea extract (10 µg/mL) enhanced tomato plant growth, resulting in significant increases in shoot and root parameters and total chlorophyll contents. Moreover, a significant reduction in TMV accumulation level in P. argentea-treated plants of 77.88% compared to non-treated plants was reported. Furthermore, induction of systemic resistance with significant elevation in production of antioxidant enzymes (PPO, CAT, and SOD) and transcriptional levels of the pathogenesis-related proteins (PR-1 and PR-7) and polyphenolic genes (CHS and HQT) were also observed. Out of 16 detected compounds, HPLC analysis revealed that the most abundant polyphenolic compounds found in P. argentea extract were gallic acid (5.36 µg/mL), kaempferol (7.39 µg/mL), quercetin (7.44 µg/mL), ellagic acid (7.89 µg/mL), myricetin (8.36 µg/mL), and ferulic acid (8.69 µg/mL). The findings suggest that the use of P. argentea extract as an effective and safe source for the production of bioactive compounds may offer a solution for a promising approach for the management of plant viral infections. To the best of our knowledge, this is the first report of the protective activity of P. argentea extract against plant viral diseases

Protective and Curative Effects of Trichoderma asperelloides Ta41 on Tomato Root Rot Caused by Rhizoctonia solani Rs33

Two molecularly identified tomato isolates, Trichoderma asperelloides Ta41 and Rhizoctonia solani Rs33, were characterized and antagonistically evaluated. The dual culture technique showed that Ta41 had a high antagonistic activity of 83.33%, while a light microscope bioassay demonstrated that the Ta41 isolate over-parasitized the pathogen completely. Under greenhouse conditions, the application of Ta41 was able to promote tomato plant growth and had a significant increase in plant height, root length, and shoot fresh, shoot dry, root fresh, and root dry weight. It also improved chlorophyll content and total phenol content significantly, both in protective and in curative treatments. The protective treatment assay exhibited the lowest disease index (16.00%), while the curative treatment showed a disease index of 33.33%. At 20 days post-inoculation, significant increases in the relative expression levels of four defense-related genes (PR-1, PR-2, PR-3, and CHS) were observed in all Ta41-treated plants when compared with the non-treated plants. Interestingly, the plants treated with Ta41 alone showed the highest expression, with relative transcriptional levels of CHS, PR-3, PR-1, and PR-2 that were, compared with the control, 3.91-, 3.13-, 2.94-, and 2.69-fold higher, respectively, and the protective treatment showed relative transcriptional levels that were 3.50-, 3.63-, 2.39-, and 2.27-fold higher, respectively. Consequently, the ability of Ta41 to promote tomato growth, suppress Rs33 growth, and induce systemic resistance supports the incorporation of Ta41 as a potential bioagent for controlling root rot disease and increasing the productivity of crops, including tomatoes

Comparative Analysis of the Expression Profiles of Pathogenesis-Related Genes in Tomato Systemically Infected with Tobacco Mosaic and Cucumber Mosaic Viruses

In this study, we used RT-qPCR to examine how PR genes were expressed in model tomato (Solanum lycopersicum L.) plants that had been infected with TMV or CMV. Under greenhouse conditions, the indirect ELISA data showed that both viruses were detected for the first time at 6 dpi. Then, the levels of accumulation increased very quickly, reaching a peak of 15 dpi. During the course of the study (1–15 dpi), the Delta CT, NormFinder, BestKeeper, and GeNorm software tools revealed that the β-actin gene was the most informative reference gene in the virally infected tomato tissues. For both the TMV- and CMV-infected tomato plants, the transcriptional expression levels of most tested genes changed between activation and repression, especially in the first 12 dpi. Compared to mock-inoculated plants, the expression levels of PR-1 were induced at all time intervals except at 8 dpi for CMV and at 6, 7, and 8 dpi for TMV infection. Conversely, the greater activation and accumulation of both viruses were associated with the greater up-regulation of PR-2 at 8 dpi, with relative expression levels of 7.28- and 5.84-fold for TMV and CMV, respectively. The up-regulated expression of PR-3, PR-4, and PR-7 was shown at 4 dpi. In contrast, the PR-5 gene was inhibited in TMV at 1 dpi until 9 dpi, and the induction of this gene at 10 dpi increased by 1.72-fold, but PR-5 was observed to up-regulate the expression of CMV at 1 dpi. This study provides the first valuable information on the comparative transcriptional levels of these tomato genes between TMV and CMV infections

The Phytochemical, Antifungal, and First Report of the Antiviral Properties of Egyptian Haplophyllum tuberculatum Extract

In this study, ethanol whole plant extract (WPE) of Haplophyllum tuberculatum was characterized and tested for its antifungal and antiviral activities against Fusarium culmorum, Rhizoctonia solani and tobacco mosaic virus (TMV). High Performance Liquid Chromatography (HPLC) analysis showed that the main phytochemical constituents of H. tuberculatum WPE were resveratrol (5178.58 mg/kg), kaempferol (1735.23 mg/kg), myricetin (561.18 mg/kg), rutin (487.04 mg/kg), quercetin (401.04 mg/kg), and rosmarinic acid (387.33 mg/kg). By increasing H. tuberculatum WPE at concentrations of 1%, 2%, and 3%, all of the fungal isolates were suppressed compared to the two positive and negative controls. Under greenhouse conditions, WPE-treated Chenopodium amaranticolor plants strongly inhibited TMV infection and significantly reduced TMV accumulation levels when compared to non-treated plants. Moreover, the induction of systemic resistance with significant increases in the transcriptional levels of the pathogenesis-related protein-1 (PR-1), chalcone synthase (CHS), and hydroxycinnamoyl-CoA quinate transferase (HQT) genes for treated plants were noticed at 3 and 5 days post-inoculation (dpi) for both assays. To the best of our knowledge, this is the first reported observation of the antiviral activity of H. tuberculatum extract against plant viral infections. Finally, the results obtained suggest that H. tuberculatum WPE can be considered a promising source of both antifungal and antiviral substances for practical use and for developing plant-derived compounds for the effective management of plant diseases