Search Results (6)

Charcoal rot of common bean, caused by Macrophomina, is one of the most economically important diseases worldwide. In Mexico, charcoal rot of bean has been associated exclusively with M. phaseolina; however, in recent years, new Macrophomina species affecting various crops have been described globally. Information on this pathogen in common bean in Mexico remains limited. Therefore, the objectives of this study were to characterize Macrophomina isolates obtained from bean fields in northern Sinaloa morphologically and molecularly using species-specific primers, and to determine their aggressiveness and vegetative compatibility groups (VCGs). During the 2020–2021 growing season, 50 Macrophomina isolates were obtained from common bean tissues exhibiting charcoal rot symptoms collected from 12 fields in the municipalities of Ahome and Guasave, Sinaloa, Mexico. Molecular analysis using species-specific primers for three Macrophomina species (M. phaseolina, M. pseudophaseolina, and M. euphorbiicola) identified all 50 isolates as M. phaseolina. Pathogenicity tests indicated that the M. phaseolina isolates differed in aggressiveness toward common bean plants. Mycelial compatibility assays revealed at least seven vegetative compatibility groups among M. phaseolina isolates distributed across northern Sinaloa. To our knowledge, this is the first study to provide phenotypic characterization, aggressiveness assessment, vegetative compatibility grouping, and species-specific primer-based identification of M. phaseolina isolates from common bean fields in Sinaloa, Mexico. Full article

Floccularia luteovirens is an edible and medicinal fungus with great development value on the Qinghai–Tibet Plateau, but its artificial domestication and cultivation are limited by the lack of systematic research on cultivation substrate formulas and key parameters. This study adopted the technical route of “preliminary screening—single-factor optimization—response surface collaborative optimization” to conduct research on the screening and optimization of its domestication cultivation substrate. Firstly, through the preliminary screening of 26 groups of formulas, a basic cultivation substrate formula with compatible complex nutrition and physical structure was determined. Secondly, single-factor experiments clarified that mixed sawdust was the optimal main substrate, corn flour was the optimal auxiliary substrate, the suitable substrate-to-water ratio was 1:1.6, and the suitable compactness was a substrate surface height of 12–12.5 cm (corresponding to a bulk density of 1.10–1.15 g/cm³ and a porosity of 60.6–63.3%). Finally, based on the response surface Box–Behnken model, with the main substrate, substrate-to-water ratio, and compactness as independent variables, and the total mycelial growth in 30 days as the response value, response surface optimization was performed to obtain the optimal formula: main substrate 76.002%, substrate-to-water ratio 1:1.721, and compactness 12.845 cm. Under these conditions, the mycelial growth reached 28.75 mm, which was highly consistent with the model’s predicted value (28.012 mm), and the constructed quadratic regression model showed excellent fitness (R² = 0.9920, p = 0.0008). This study clarified the core influencing factors and adaptation mechanism of the cultivation substrate for Floccularia luteovirens, filled the research gap in the domestication cultivation substrate of this fungus, and provided basic technical parameters for its large-scale artificial cultivation. Full article

Rhizoctonia solani is a basidiomycete phytopathogenic fungus that causes rapid necrosis in a wide range of crop species, leading to substantial agricultural losses worldwide. The species complex is divided into 13 anastomosis groups (AGs) based on hyphal fusion compatibility and further subdivided by culture morphology. While R. solani classifications were shown to be independent of host specificity, it remains unclear whether different R. solani isolates share similar virulence mechanisms. Here, we investigated the infectivity of Japanese R. solani isolates on Brachypodium distachyon and barley. Two isolates, AG-1 IA (from rice) and AG-4 HG-I+II (from cauliflower), infected leaves of both plants, but only AG-4 HG-I+II infected roots. B. distachyon accessions Bd3-1 and Gaz-4 and barley cultivar ‘Morex’ exhibited enhanced resistance to both isolates compared to B. distachyon Bd21 and barley cultivars ‘Haruna Nijo’ and ‘Golden Promise’. During AG-1 IA infection, but not AG-4 HG-I+II infection, resistant Bd3-1 and Morex induced genes for salicylic acid (SA) and N-hydroxypipecolic acid (NHP) biosynthesis. Pretreatment with SA or NHP conferred resistance to AG-1 IA, but not AG-4 HG-I+II, in susceptible B. distachyon Bd21 and barley Haruna Nijo. On the leaves of susceptible Bd21 and Haruna Nijo, AG-1 IA developed extensive mycelial networks with numerous infection cushions, which are specialized infection structures well-characterized in rice sheath blight. In contrast, AG-4 HG-I+II formed dispersed mycelial masses associated with underlying necrosis. We propose that the R. solani species complex encompasses at least two distinct infection strategies: AG-1 IA exhibits a hemibiotrophic lifestyle, while AG-4 HG-I+II follows a predominantly necrotrophic strategy. Full article

Exclusive physicochemical and biological properties of carbon allotrope graphene have attracted the peer attention of researchers for the synthesis and development of newer topical remedies including films, scaffolds, microspheres, and hydrogels. Here, graphene nanoplatelets (GN) were embedded into a different ratio of polymeric ERL100/ERS100 solution and fabricated in the form of a scaffold through the electrospinning process. FTIR spectra displayed characteristic similar peaks present both in GN and GN-loaded scaffold owing to the compatibility of GN and polymeric mixture. XRD curve revealed a distinct GN peak at nearly 26° whereas from DSC/TGA thermal stability was observed between polymers and graphene nanoplatelets. FESEM images showed ultrathin architecture of GN-loaded scaffold in a range of 280 ± 90 nm. The fabricated scaffold exhibited hydrophilicity (contact angle 48.8 ± 2.8°) and desirable swelling index (646% in skin pH media) which were desired criteria for the scaffold for topical application. In vitro, antifungal activity was conducted through the broth microdilution method against different virulent dermatophytes i.e., Microsporum gypseum, M. canis, M. fulvum, and Trychophyton rubrum. For in vivo evaluation, T. rubrum inoculum was applied on the dorsal surface of each group of Swiss albino mice, and the degree and intensity of mycelial growth or erythema on skin surfaces was visually investigated. The study depicted complete signs of cure after 14 days of application of G3-loaded scaffold on the infected dorsal site. Hence graphene-loaded scaffold represented a possible alternative for the treatment of topical fungal infections caused by dermatophytes. Full article

The present systematic research on cultural, morphological, and pathogenic variability was carried out on eighty isolates of Sclerotinia sclerotiorum collected from major common bean production belts of North Kashmir. The isolates were found to vary in both cultural and morphological characteristics such as colony color and type, colony diameter, number of days for sclerotia initiation, sclerotia number per plate, sclerotial weight, and size. The colony color ranged between white and off-white with the majority. The colony was of three types, in majority smooth, some fluffy, and a few fluffy-at-center-only. Colony diameter ranged between 15.33 mm and 29 mm after 24 h of incubation. The isolates took 4 to 7 days for initiation of sclerotia and varied in size, weight, and number per plate ranging between 14 and 51.3. The sclerotial arrangement pattern on plates was peripheral, sub peripheral, peripheral, and subperipheral, arranged at the rim and scattered. A total of 22 Mycelial compatibility groups (MCGs) were formed with seven groups constituted by a single isolate. The isolates within MCGs were mostly at par with each other. The six isolates representing six MCGs showed variability in pathogenicity with isolate G04 as the most and B01 as the least virulent. The colony diameter and disease scores were positively correlated. Sclerotia were observed to germinate both myceliogenically and carpogenically under natural temperate conditions of Kashmir. Germplasm screening revealed a single resistant line and eleven partially resistant lines against most virulent isolates. Full article

Sclerotinia sclerotiorum is an important fungal pathogen on many economically important crops including cabbage worldwide. Even though population structure and genetic diversity of S. sclerotiorum is well studied in temperate climatic conditions, only a few studies have been conducted in tropical countries. It is also not clear whether the populations are clonal or recombining in the tropics. In filling this information gap, 47 isolates of S. sclerotiorum were collected from commercial cabbage (Brassica oleracea L.) fields in Nuwara Eliya district of Sri Lanka, where the disease has been previously reported. All the isolates were subjected to genetic diversity study using mycelial compatibility grouping and microsatellite markers. Fourteen mycelial compatibility groups (MCGs) and 23 multilocus haplotypes (MLHs) were recorded. Mean expected heterozygosity of the population was 0.56. MLHs were weakly correlated with MCGs. Population genetic structure analysis and principal coordinates identified three genetic clusters. Genetic recombination was inferred within each genetic cluster when isolates were subjected to clone correction. There was evidence of multiple infections on single plant as detected by the presence of more than one MCG on each cabbage plant. However, multiple infections did not increase the disease severity in detached leaf assay. We found high genetic diversity and recombination of S. sclerotiorum population in a tropical country, Sri Lanka. Importance of detecting genetic structure when inferring recombination was also highlighted. Full article