Figure 3
(a, b) Macrophomina phaseolina: mycelium masses of black microsclerotia produced on mycelia; and pycinidium. (c) Aspergillus niger conidiophore and conidia. (d, e) Nigrospora mature conidia attached to conidiogenous cells and (f ) Fusarium verticillioides micro and macro spores.
Source publication
the seeds of six cultivars of maize were screened by both blotter and agar methods for detection of fungal pathogens, and for testing the transmission of seed-borne fungi using test tube agar. Results showed that corn seeds infected by many pathogens included Fusarium, Aspergillus, Nigrospora, Macrophomina and Penicillium sp. to confirm the identif...
Context in source publication
Context 1
... of seed health testing on 6 corn samples which were achieved by agar, blotter and test tube standard methods are presented in Tables 1 and 2 Figure 3. In all cultivars tested, we were found that F. verticillioides was detected in all tested samples except loc69 cultivar sample, it was not appear with three standard methods. ...
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Background
Phytophthora plant pathogens secrete effector proteins that are translocated into host plant cells during infection and collectively contribute to pathogenicity. A subset of these host-translocated effectors can be identified by the amino acid motif RXLR (arginine, any amino acid, leucine, arginine). Bioinformatics analysis has identifie...
Citations
... The embryo may die from a severe infection before or after it emerges. Disease severity is influenced by planting depth, soil type, seed quality, and genetic resistance to infection (Gomaa 2021). The Fusarium genus is one of the most significant soil borne and seed pathogens for maize, causing seed rot, root rot, and seedling blight. ...
One of the most harmful diseases that infect maize plants is Fusarium wilt caused by Fusarium oxysporum. The novelty of this study was to investigate the antifungal and plant growth-promoting properties of some rhizobacteria (PGPR). PGPR enhances plant growth and manages plant diseases. In this study, some bacterial isolates were isolated from the rhizosphere of rice plants and selected based on their ability to produce β-1,3 glucanase. The two bacterial isolates that produced higher concentrations of β-1,3 glucanase were selected to complete the study and identified by 16S rDNA sequences as Pseudomonas pseudoalcaligenes with accession number EU921258 and Bacillus pumilus with accession number EU921259. Different biochemical properties of the two bacterial isolates were investigated. Additionally, the effectiveness of P. pseudoalcaligene and B. pumilus against Fusarium oxysporum, which causes maize wilt disease was assessed. The results showed that P. pseudoalcaligenes and B. pumilus, either alone or in combination caused a significant reduction in the percentage of disease severity and an increment in the percentage of protection. In addition, infection with Fusarium caused a significant decrease in the morphological parameters, photosynthetic pigments, and cell membrane stability as compared to healthy control plants. However, lipid peroxidation, osmoprotectant compounds (soluble sugars, glycine betaine, and proline), secondary metabolites (phenol, flavonoid, and lignin content), and the enzymatic antioxidants increased significantly in infected plants as compared to healthy control plants. Furthermore, inoculation with P. pseudoalcaligenes and B. pumilus alone or in a combination caused significantly increased in the morphological parameters, photosynthetic pigment, and cell membrane stability in infected plants. Induction of β-1,3 glucanase gene in maize was not recorded in non-inoculated plants, but detected in inoculated plants with P. pseudoalcaligenes and B. pumilus alone or in combination as 2.4 kb bands on agarose gel electrophoresis. In conclusion, PGPR is regarded as an environmentally friendly method of protecting plants from pathogen infection and increasing plant growth without the use of pesticides, which cause a variety of environmental pollutions.
... at 72°C. (Gomaa, 2021). PCR amplified products were purified and sequenced using forward primer of the DNA facility of Sigma Laboratories, Egypt. ...
Curly Parsley (Petroselinum crispum) seeds were planted for the purpose of essential oil extraction from dried plants by hydro-distillation. GC-MS analysis of parsley essential oil (PEO) showed that Parsley-apiol (40.42%) and myristicin (34.77%) were the major components. PEO and its nanoemulsion (PEO-NE) were tested for their antifungal activities against Alternaria solani, the causal agent of tomato early blight, and Rhizoctonia solani, the causal agent of faba bean root rot. Isolated fungi were verified by ITS1and ITS4 primers. Their partial region was deposited in the GenBank (NCBI) under OL305707 and OL305708 accession numbers for A. solani and R. solani, respectively. In vitro treatments with PEO and PEO-NE showed a significant difference in the growth of both fungi under study when compared with their negative and positive controls. PEO highest effect was recorded at 3000 mg/L while PEO-NE was recorded at 1500mg/L without significant difference from the commercial fungicide (positive control). Pathogenicity test was confirmed by evaluating the antifungal activity by detached leaf assay on tomato and radical assay on faba bean for A. solani and R. solani, respectively. This study reflects the possibility of replacing harmful fungicides with natural products, such as PEO and its nanoemulsion, against A. solani and R. solani. Eco-friendly products, e.g., natural extracts, are a must now, to be used to decrease the negative impact towards general health and pollution from using commercial chemicals.
Noran Adel Moustafa AL-Ansary: Seed-borne Fungi of Stored Corn Grains and their Effect on the Contamination with Mycotoxins
Published Ph.D. Thesis, Department of Plant Pathology, Faculty of Agriculture, Ain Shams University, 2023.
Mycotoxin-producing moulds which considered as common maize grains contaminants are of the genera Fusarium, Aspergillus and Penicillium. There are natural and safe ways to protect grains from mould contamination as the use of biological control, antioxidents, salts, essential oils, plant extracts and nano technology. A total number of 25 samples were used to study the natural frequency in five governorates in Egypt, Morphological and molecular identification indicated that the most frequent fungi were Fusarium moniliforme, Aspergillus niger,
Penicillium sp., Aspergillus flavus and Aspergillus terreus. The in vitro studies have been done to determine mycelial growth and spore germination inhibition of the five pathogenic tested fungi. All treatments were tested in direct contact assay. All treatments showed significant
impact on mycelial growth and spore germination inhibition. Trichoderma harzianum, Chaetomium globosum, Bacillus megaterium, Brevibacillus brevis, Saccharomyces cerevisiae and Nostoc sp. were effective as biocontrol agents. Potassium bicarbonate was the most effective as chemical treatment. Thyme showed the best inhibitory effect
while, methyl anthranilate and rosemary were the most effective EOs for spore germination inhibition. Halfabar (water extract) was the most effective as plant extract treatment. The efficacies of liquid formulation of safe techniques against natural infection of maize crop were conducted during season 2021. The percentage (%) of the grain germination, total frequency of fungal isolates and frequency of fungal isolates associated with grains was calculated. After the foliar application (in vivo) and at the zero time of storage, the most effective treatments were: Trichoderma
harzianum, Pseudomonas putida and Chaetomium sp. as biocontrol agents, Potassium bicarbonate, Chitosan and Salicylic acid as chemical treatments, Thyme and Citral as essential oils treatments, Halfabar (petroleum ether and water extract) as plant material treatments. After three months of storage, the most effective treatments were: Chaetomium sp. and Brevibacillus brevis as biocontrol agents, Potassium bicarbonate, Nano silica, Chitosan and Salicylic acid as chemical treatments, Thyme, Citral and Rosemary as essential oils treatments, Halfabar (petroleum
ether and water extract) as plant material treatments. After six months of
storage, the most effective treatments was: Chaetomium sp., Brevibacillus brevis and Pseudomonas putida as biocontrol agents, Potassium bicarbonate, Chitosan and Salicylic acid as chemical treatments, Citral and Clove as essential oils treatments, Halfabar and lemongrass (water extract) as plant material treatments. In the postharvest treatments: as vapour contact assay, Acetic acid was effective as a chemical treatment, while Clove, Methyl anthranilate and Thyme were the most effective treatments as essential oils treatments, while as carrier assay, Acetic acid was effective as a chemical treatment, while Clove, Methyl anthranilate and Thyme were the most effective treatments as essential oils treatments. About inhibition of aflatoxin production, both treatments thyme and acetic acid in both vapour and carrier assays succeeded in reducing AFB1 while they inhibited completely the production of AFB2
