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Frontiers in Fungal Biology 2022The filamentous ascomycete is a plant pathogen that causes corn leaf blight and has been used in cytological studies of sexual reproduction. In this fungus, when null...
The filamentous ascomycete is a plant pathogen that causes corn leaf blight and has been used in cytological studies of sexual reproduction. In this fungus, when null mutants of each septin are crossed with the wild-type strain, all ascospores derived from the same asci show abnormal morphology. The phenomenon was remarkably similar to the event known as "ascus dominance" in , which is known to be caused by MSUD (meiotic silencing by unpaired DNA). However, it is not clear whether possesses functional MSUD. The object of this study is to elucidate whether this fungus carries a functional MSUD system that causes ascus dominance in the crosses of septin mutants and the wild-type strain. The results of homozygous and heterozygous crossing tests with mutants, having the insertional -septin gene sequence into the genome, suggested that the ascus dominance in is triggered by the unpaired DNA as in . To investigate whether MSUD is caused by the same mechanism as in , an RNA-dependent RNA polymerase, one of the essential factors in MSUD, was identified and disrupted (Δ) in . When the Δ strain was crossed with each mutant of the septins, ascus dominance did not occur in all crosses. These results suggest that this ascus dominance is caused by RNA silencing triggered by an unpaired gene, as in , and septin genes were affected by this silencing. To date, although MSUD has been found only in and , which are classified as Sordariomycetes, this study showed that MSUD is also functional in , which is classified as a Dothideomycete. These results showed the possibility that this posttranscriptional regulation is extensively conserved among filamentous ascomycetes.
PubMed: 37746229
DOI: 10.3389/ffunb.2022.931888 -
Frontiers in Plant Science 2022In recent years, Brown spot disease of rice (BSR) has been observed on leaves and seeds of rice in all rice-growing areas of Burkina Faso. and are the main fungal...
In recent years, Brown spot disease of rice (BSR) has been observed on leaves and seeds of rice in all rice-growing areas of Burkina Faso. and are the main fungal species isolated from BSR infected tissues and they are frequently observed in the same field. However, we are lacking information on the genetic diversity and population structure of these fungi in Burkina Faso. The mode of reproduction is also unknown. The genetic diversity of isolates of (n=61) and (n=151), collected from major rice-growing areas of Burkina Faso, was estimated using genotyping-by-sequencing (GBS). The mean values for nucleotide diversity (π) were 1.9 x10 for and 4.8 x10 for . There is no genetic differentiation between the geographical populations of each species. The analysis of molecular variance revealed that 89% and 94% of the genetic variances were within the populations of and , respectively. For each species, four genetic clusters were identified by two clustering methods (DAPC and sNMF). The distribution of these genetic groups was independent of the geographical origin of the isolates. Evidence of recombination was detected in the populations of and For balanced mating type ratios were supporting sexual reproduction. For overrepresentation of MAT1-2 isolates (79%) suggested a predominant asexual reproduction. This study provides important information on the biology and genetics of the two major fungi causing brown spot disease of rice in Burkina Faso.
PubMed: 36507371
DOI: 10.3389/fpls.2022.1022348 -
Pathogens (Basel, Switzerland) Mar 2020Many species of the genus are important plant pathogens and often cause leaf spot, root rot, and seedling blight in an extremely wide range of hosts around the world....
Many species of the genus are important plant pathogens and often cause leaf spot, root rot, and seedling blight in an extremely wide range of hosts around the world. In recent years, maize leaf spot caused by species has frequently occurred with complex symptoms and is becoming increasingly serious in Sichuan Province of China. To investigate the population diversity of spp. and their corresponding symptoms in maize, 747 samples of maize leaf spot were collected from 132 sampling sites in 19 administrative districts of Sichuan Province from 2011 to 2018. Based on morphological characteristics, pathogenicity testing, and phylogenetic analysis of the rDNA internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes, a total of 1186 isolates were identified as , , , , and , among which and were the dominant pathogenic species, accounting for 57.34% and 42.07% of the isolates, respectively. We found that isolates were mainly distributed in high altitude and cool mountainous areas, while was more widely distributed in Sichuan Province. The typical symptoms caused by the species were clearly distinct in maize. The typical symptoms caused by were elongated strip lesions, or fusiform, elliptical lesions, and those caused by were narrow linear lesions. Herein, was first reported on maize and caused subrotund lesions. This study provides useful information for disease diagnosis and management for leaf spot in maize.
PubMed: 32244886
DOI: 10.3390/pathogens9030229 -
Mycoscience 2021The NY1 strain, isolated from a diseased green foxtail plant in Henan Province, China, showed strong pathogenicity towards green foxtail. In order to clarify the role...
The NY1 strain, isolated from a diseased green foxtail plant in Henan Province, China, showed strong pathogenicity towards green foxtail. In order to clarify the role of phytotoxic substances in the fungal pathogenicity, bioassay-directed isolation and bioactivity assays of secondary metabolites produced by the fungal strain were carried out. Five ophiobolins were obtained: 3-anhydro-ophiobolin A, 6-epi-ophiobolin A, 6-epi-ophiobolin B, 3-anhydro-6-epi-ophiobolin B and ophiobolin I. Bioassays on punctured and intact detached leaves of green foxtail indicated that 3-anhydro-ophiobolin A was the most phytotoxic, followed by 6-epi-ophiobolin A. The other three ophiobolins appeared to be inactive against green foxtail. The effects of 3-anhydro-ophiobolin A and 6-epi-ophiobolin A were synergistic. The symptoms on green foxtail caused by 3-anhydro-ophiobolin A or its mixture with 6-epi-ophiobolin A resembled those caused by the fungus. 3-Anhydro-ophiobolin A and 6-epi-ophiobolin A are likely the main pathogenic determinants of . 6-epi-Ophiobolin A caused cytotoxicity against five kinds of human cancer cells: human colon adenocarcinoma cells (HCT-8), human liver cancer cells (Bel-7402), human gastric cancer cells (BGC-823), human lung adenocarcinoma cells (A549), and human ovarian adenocarcinoma cells (A2780). The results provide information for the development of herbicides and antitumor potential of the ophiobolin sesterterpenes.
PubMed: 37090018
DOI: 10.47371/mycosci.2020.11.002 -
American Journal of Ophthalmology Case... Mar 2022To describe 2 cases of recalcitrant fungal keratitis successfully treated with intracameral Amphotericin B.
PURPOSE
To describe 2 cases of recalcitrant fungal keratitis successfully treated with intracameral Amphotericin B.
METHODS
Interventional case series.
RESULTS
A 59-year-old female and a 41-year-old male each presented with fungal keratitis, caused by spp. and spp. respectively. Both cases were unresponsive to topical antifungals, causing persistent discomfort and decreased vision. The two patients subsequently received a single dose of intracameral amphotericin B (ICAMB) 10mcg/0.1 mL, in addition to continued topical natamycin. Both patients had remarkable results following ICAMB, with best corrected visual acuity of 20/20 and full corneal reepithelization following treatment.
CONCLUSIONS
We report 2 cases of intractable fungal keratitis that benefited from intracameral injections of amphotericin B. This route of delivery appears to be very effective because the medication is delivered directly to the deeper layers of the cornea, where fungal infections tend to reside, and where topical and systemic routes have difficulty accessing.
PubMed: 35146213
DOI: 10.1016/j.ajoc.2022.101369 -
Brazilian Journal of Biology = Revista... 2022Southern corn leaf blight (SCLB) is one of the most important corn leaf diseases. Appropriate management strategies and the use of resistant cultivars allow disease...
Southern corn leaf blight (SCLB) is one of the most important corn leaf diseases. Appropriate management strategies and the use of resistant cultivars allow disease control. Therefore, knowing the aspects related to the pathogen and the response of hosts makes it possible to design efficient strategies for selecting genotypes resistant to this disease. In this sense, the objective was to carry out the Bipolaris maydis isolate characterization, evaluating the pathogenicity in different popcorn lines and the symptoms generated in the host after inoculation. The isolate characterization consisted of the macromorphological evaluation of the colonies and the micromorphological evaluation of the conidia in the PDA medium. An experiment was carried out in a greenhouse to evaluate the pathogenicity of the isolate, using 20 inbred lines of popcorn in a randomized block design with four replicates. Inoculation was carried out by spraying leaves, with a suspension containing 1.0 x 104 conidia.ml-1 of the CF/UENF 501 isolate of B. maydis. An incidence assessment and three assessments of disease symptom severity were performed, with seven days intervals between evaluations. The morphological characterization data of the isolate were analyzed using descriptive statistics, and for disease severity, the linear regression model was applied the first-degree model. The variance analysis was performed for the linear and angular coefficients obtained for each treatment. When a difference was found, the Scott-Knott clustering algorithm at 5% significance was applied. The isolate had gray-green colonies, a cottony appearance, and an irregular shape. The lines L353, L354, and L624 show more resistance at the beginning and throughout the evaluations. The high virulence of the CF/UENF 501 isolate made it possible to differentiate the lines in terms of disease intensity and the pattern of symptoms presented.
Topics: Bipolaris; Genotype; Plant Diseases; Virulence; Zea mays
PubMed: 35137841
DOI: 10.1590/1519-6984.256799 -
Studies in Mycology Mar 2017Genera of Phytopathogenic Fungi (GOPHY) is introduced as a new series of publications in order to provide a stable platform for the taxonomy of phytopathogenic fungi....
Genera of Phytopathogenic Fungi (GOPHY) is introduced as a new series of publications in order to provide a stable platform for the taxonomy of phytopathogenic fungi. This first paper focuses on 21 genera of phytopathogenic fungi: , , , , , , , , , , , , , , , , , , , and . For each genus, a morphological description and information about its pathology, distribution, hosts and disease symptoms are provided. In addition, this information is linked to primary and secondary DNA barcodes of the presently accepted species, and relevant literature. Moreover, several novelties are introduced, i.e. new genera, species and combinations, and neo-, lecto- and epitypes designated to provide a stable taxonomy. This first paper includes one new genus, 26 new species, ten new combinations, and four typifications of older names.
PubMed: 28663602
DOI: 10.1016/j.simyco.2017.04.002 -
Frontiers in Microbiology 2023is the popular pathogenic fungi fungus which lead to common root rot and leaf spot on wheat. Generally, chemical fungicides are used to control diseases. However, the...
INTRODUCTION
is the popular pathogenic fungi fungus which lead to common root rot and leaf spot on wheat. Generally, chemical fungicides are used to control diseases. However, the environmental pollution resulting from fungicides should not be ignored. It is important to study the mode of antagonistic action between biocontrol microbes and plant pathogens to design efficient biocontrol strategies.
RESULTS
An antagonistic bacterium DB2 was isolated and identified as . The inhibition rate of cell-free culture filtrate (, 20%, v/v) of DB2 against reached 92.67%. Light microscopy and scanning electron microscopy (SEM) showed that the significantly altered the mycelial morphology of and disrupted cellular integrity. Fluorescence microscopy showed that culture filtrate destroyed mycelial cell membrane integrity, decreased the mitochondrial transmembrane potential, induced reactive oxygen species (ROS) accumulation, and nuclear damage which caused cell death in . Moreover, the strain exhibited considerable production of protease and amylase, and showed a significant siderophore and indole-3-acetic acid (IAA) production. In the detached leaves and potted plants control assay, DB2 had remarkable inhibition activity against and the pot control efficacy was 75.22%. Furthermore, DB2 suspension had a significant promotion for wheat seedlings growth.
CONCLUSION
DB2 can be taken as a potential biocontrol agent to inhibit on wheat and promote wheat growth.
PubMed: 37125175
DOI: 10.3389/fmicb.2023.1149363 -
Frontiers in Plant Science 2023In wheat, major yield losses are caused by a variety of diseases including rusts, spike diseases, leaf spot and root diseases. The genetics of resistance against all... (Review)
Review
In wheat, major yield losses are caused by a variety of diseases including rusts, spike diseases, leaf spot and root diseases. The genetics of resistance against all these diseases have been studied in great detail and utilized for breeding resistant cultivars. The resistance against leaf spot diseases caused by each individual necrotroph/hemi-biotroph involves a complex system involving resistance (R) genes, sensitivity (S) genes, small secreted protein (SSP) genes and quantitative resistance loci (QRLs). This review deals with resistance for the following four-leaf spot diseases: (i) Septoria nodorum blotch (SNB) caused by ; (ii) Tan spot (TS) caused by -; (iii) Spot blotch (SB) caused by and (iv) Septoria tritici blotch (STB) caused by .
PubMed: 37063191
DOI: 10.3389/fpls.2023.1023824 -
Ecotoxicology and Environmental Safety Feb 2024Chemical fertilizers are the primary source of crop nutrition; however, their increasing rate of application has created environmental hazards, such as heavy metal...
Enhanced use of chemical fertilizers and mitigation of heavy metal toxicity using biochar and the soil fungus Bipolaris maydis AF7 in rice: Genomic and metabolomic perspectives.
Chemical fertilizers are the primary source of crop nutrition; however, their increasing rate of application has created environmental hazards, such as heavy metal toxicity and eutrophication. The synchronized use of chemical fertilizers and eco-friendly biological tools, such as microorganisms and biochar, may provide an efficient foundation to promote sustainable agriculture. Therefore, the current study aimed to optimize the nutrient uptake using an inorganic fertilizer, sulfate of potash (SOP) from the plant growth-promoting fungus Bipolaris maydis AF7, and biochar under heavy metal toxicity conditions in rice. Bioassay analysis showed that AF7 has high resistance to heavy metals and a tendency to produce gibberellin, colonize the fertilizer, and increase the intake of free amino acids. In the plant experiment, the co-application of AF7 +Biochar+MNF+SOP significantly lowered the heavy metal toxicity, enhanced the nutrient uptake in the rice shoots, and improved the morphological attributes (total biomass). Moreover, the co-application augmented the glucose and sucrose levels, whereas it significantly lowered the endogenous phytohormone levels (salicylic acid and jasmonic acid) in the rice shoots. The increase in nutrient content aligns with the higher expression of the OsLSi6, PHT1, and OsHKT1 genes. The plant growth traits and heavy metal tolerance of AF7 were validated by whole-genome sequencing that showed the presence of the heavy metal tolerance and detoxification protein, siderophore iron transporter, Gibberellin cluster GA4 desaturase, and DES_1 genes, as well as others that regulate glucose, antioxidants, and amino acids. Because the AF7 +biochar+inorganic fertilizer works synergistically, nutrient availability to the crops could be improved, and heavy metal toxicity and environmental hazards could be minimized.
Topics: Soil; Fertilizers; Oryza; Gibberellins; Charcoal; Metals, Heavy; Genomics; Fungi; Amino Acids; Glucose; Bipolaris
PubMed: 38218102
DOI: 10.1016/j.ecoenv.2024.115938