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Microbiological Research Aug 2024Fusarium crown rot (FCR) caused by Fusarium pseudograminearum poses a significant threat to wheat production in the Huang-Huai-Hai region of China. However, the...
The critical roles of the ZnCys transcription factor Fp487 in the development and virulence of Fusarium pseudograminearum: A potential target for Fusarium crown rot control.
Fusarium crown rot (FCR) caused by Fusarium pseudograminearum poses a significant threat to wheat production in the Huang-Huai-Hai region of China. However, the pathogenic mechanism of F. pseudograminearum is still poorly understood. ZnCys transcription factors, which are exclusive to fungi, play pivotal roles in regulating fungal development, drug resistance, pathogenicity, and secondary metabolism. In this study, we present the functional characterization of a ZnCys transcription factor F. pseudograminearum, designated Fp487. In F. pseudograminearum, Fp487 is shown to be required for mycelial growth through gene knockout and phenotypic analyses. Compared with wild-type CF14047, the ∆Fp487 mutant displayed a slight reduction in growth rate but a significant decrease in conidiogenesis, pathogenicity and 3-acetyl-deoxynivalenol (3AcDON) production. Moreover, the mutant exhibited heightened sensitivity to oxidative and cytomembrane stress. Furthermore, we synthesized dsRNA from the Fp487 gene in vitro, resulting in a reduction in the growth rate of F. pseudograminearum and its virulence on barley leaves through spray-induced gene silencing (SIGS). Notably, this study makes the first instance of inducing the expression of abundant dsRNA from F. pseudograminearum by engineering the Escherichia coli strain HT115 (DE3) and utilizing the SIGS technique to evaluate the virulence effect of dsRNA on F. pseudograminearum. In conclusion, our findings revealed the crucial role of Fp487 in regulating pathogenicity, stress responses, DON production, and conidiogenesis in F. pseudograminearum. Furthermore, Fp487 is a potential RNAi-based target for FCR control.
Topics: Fusarium; Plant Diseases; Virulence; Fungal Proteins; Transcription Factors; Gene Expression Regulation, Fungal; Hordeum; Spores, Fungal; Triticum; Plant Leaves; Gene Knockout Techniques; China; Mycelium; Gene Silencing
PubMed: 38824820
DOI: 10.1016/j.micres.2024.127784 -
Ecotoxicology and Environmental Safety Jul 2024Microplastics (MP) can influence a plethora of fungal species within the rhizosphere. Nevertheless, there are few studies on the direct impacts of MPs on soil fungi and...
Microplastics (MP) can influence a plethora of fungal species within the rhizosphere. Nevertheless, there are few studies on the direct impacts of MPs on soil fungi and their intricate interplay with plants. Here, we investigated the impact of polyethylene microspheres (PEMS) on the ecological interactions between Fusarium solani, a plant pathogenic fungus, and Trichoderma viride, a fungal plant growth promotor, within the rhizosphere of Solanum lycopersicum (tomato). Spores of F. solani and T. viride were pre-incubated with PEMS at two concentrations, 100 and 1000 mg L. Mycelium growth, sporulation, spore germination, and elongation were evaluated. Tomato seeds were exposed to fungal spore suspensions treated with PEMS, and plant development was subsequently assessed after 4 days. The results showed that PEMS significantly enhanced the sporulation (106.0 % and 70.1 %) but compromised the spore germination (up to 27.3 % and 32.2 %) and radial growth (up to -5.2% and -21.7 %) of F. solani and T. viride, respectively. Furthermore, the 100 and 1000 mg L concentrations of PEMS significantly (p<0.05) enhanced the mycelium density of T. viride (9.74 % and 22.30 %, respectively), and impaired the germ-tube elongation of F. solani after 4 h (16.16 % and 11.85 %, respectively) and 8 h (4 % and 17.10 %, respectively). In addition, PEMS amplified the pathogenicity of F. solani and boosted the bio-enhancement effect of T. viride on tomato root growth. Further, PEMS enhanced the bio-fungicidal effect of T. viride toward F. solani (p<0.05). In summary, PEMS had varying effects on F. solani and T. viride, impacting their interactions and influencing their relationship with tomato plants. It intensified the beneficial effects of T. viride and increased the aggressiveness of F. solani. This study highlights concerns regarding the effects of MPs on fungal interactions in the rhizosphere, which are essential for crop soil colonization and resource utilization.
Topics: Solanum lycopersicum; Fusarium; Spores, Fungal; Microplastics; Rhizosphere; Soil Microbiology; Soil Pollutants; Polyethylene; Hypocreales; Microspheres; Plant Roots
PubMed: 38820874
DOI: 10.1016/j.ecoenv.2024.116518 -
Mycorrhiza May 2024The introduction of Reduced height (Rht) dwarfing genes into elite wheat varieties has contributed to enhanced yield gain in high input agrosystems by preventing...
The introduction of Reduced height (Rht) dwarfing genes into elite wheat varieties has contributed to enhanced yield gain in high input agrosystems by preventing lodging. Yet, how modern selection for dwarfing has affected symbiosis remains poorly documented. In this study, we evaluated the response of both the plant and the arbuscular mycorrhizal fungus to plant genetic variation at a major Quantitative Trait Locus called QTL 4B2, known to harbor a Rht dwarfing gene, when forming the symbiosis. We used twelve inbred genotypes derived from a diversity base broadened durum wheat Evolutionary Pre-breeding Population and genotyped with a high-throughput Single Nucleotide Polymorphism (SNP) genotyping array. In a microcosm setup segregating roots and the extra-radical mycelium, each wheat genotype was grown with or without the presence of Rhizophagus irregularis. To characterize arbuscular mycorrhizal symbiosis, we assessed hyphal density, root colonization, spore production, and plant biomass. Additionally, we split the variation of these variables due either to genotypes or to the Rht dwarfing genes alone. The fungus exhibited greater development in the roots of Dwarf plants compared to non-Dwarf plants, showing increases of 27%, 37% and 51% in root colonization, arbuscules, and vesicles, respectively. In addition, the biomass of the extra-radical fungal structures increased by around 31% in Dwarf plants. The biomass of plant roots decreased by about 43% in mycorrhizal Dwarf plants. Interestingly, extraradical hyphal production was found to be partly genetically determined with no significant effect of Rht, as for plant biomasses. In contrast, variations in root colonization, arbuscules and extraradical spore production were explained by Rht dwarfing genes. Finally, when mycorrhizal, Dwarf plants had significantly lower total P content, pointing towards a less beneficial symbiosis for the plant and increased profit for the fungus. These results highlight the effect of Rht dwarfing genes on both root and fungal development. This calls for further research into the molecular mechanisms governing these effects, as well as changes in plant physiology, and their implications for fostering arbuscular mycorrhizal symbiosis in sustainable agrosystems.
PubMed: 38816524
DOI: 10.1007/s00572-024-01150-y -
Spectrochimica Acta. Part A, Molecular... Oct 2024Antibiotic mycelia residues (AMRs) contain antibiotic residues. If AMRs are ingested in excess by livestock, it may cause health problems. To address the current problem...
Antibiotic mycelia residues (AMRs) contain antibiotic residues. If AMRs are ingested in excess by livestock, it may cause health problems. To address the current problem of unknown pixel-scale adulteration concentration in NIR-HSI, this paper innovatively proposes a new spectral simulation method for the evaluation of AMRs in protein feeds. Four common protein feeds (soybean meal (SM), distillers dried grains with solubles (DDGS), cottonseed meal (CM), and nucleotide residue (NR)) and oxytetracycline residue (OR) were selected as study materials. The first step of the method is to simulate the spectra of pixels with different adulteration concentrations using a linear mixing model (LMM). Then, a pixel-scale OR quantitative model was developed based on the simulated pixel spectra combined with local PLS based on global PLS scores (LPLS-S) (which solves the problem of nonlinear distribution of the prediction results due to the 0%-100% content of the correction set). Finally, the model was used to quantitatively predict the OR content of each pixel in hyperspectral image. The average value of each pixel was calculated as the OR content of that sample. The implementation of this method can effectively overcome the inability of PLS-DA to achieve qualitative identification of OR in 2%-20% adulterated samples. In compared to the PLS model built by averaging the spectra over the region of interest, this method utilizes the precise information of each pixel, thereby enhancing the accuracy of the detection of adulterated samples. The results demonstrate that the combination of the method of simulated spectroscopy and LPLS-S provides a novel method for the detection and analysis of illegal feed additives by NIR-HSI.
Topics: Anti-Bacterial Agents; Animal Feed; Spectroscopy, Near-Infrared; Mycelium; Hyperspectral Imaging; Drug Residues; Least-Squares Analysis
PubMed: 38815312
DOI: 10.1016/j.saa.2024.124536 -
Plant Disease May 2024Hylocereus megalanthus (syn. Selenecereus megalanthus), commonly known as Yanwo fruit (bird's nest fruit), is an important tropical fruit, which is popular and widely...
Hylocereus megalanthus (syn. Selenecereus megalanthus), commonly known as Yanwo fruit (bird's nest fruit), is an important tropical fruit, which is popular and widely planted due to its high nutritional and economic value in southern China. In September 2022, a serious stem and fruit canker was observed on Ecuadorian variety of Yanwo fruit plant in a 0.2 ha orchard in Guangdong (N21°19'1.24" E110°7'28.49"). Almost all plants were infected and disease incidence of fruits and stems was about 80% and 90% respectively. Symptoms on the stem and fruits were small, circular or irregular, sunken, orangish brown spots that developed into cankers (Fig 1 A, B and C). Black pycnidia were embedded under the surface of the cankers at the initial stage, subsequently they became erumpent from the surface, and the infected parts rotted. Five symptomatic stems from five plants were collected, 0.2 cm2 tissues adjacent to cankers were surface sterilized and placed on potato dextrose agar (PDA) to incubate at 25 to 28 ℃. Fungal isolates each with similar morphology grew from 100% of the tissues. Colonies covered with aerial mycelium were grayish white, and then gradually turned to grayish black. Septate hyphae were hyaline to brown and constricted into arthroconidial chains. The arthroconidia were variously shaped and colored, orbicular to rectangular, hyaline to dark brown, thick-walled, and zero- to one- septate, averaging 7.7 × 3.6 μm (n>50) (Fig 1 D, E, F and G). To identify the fungus, the internal transcribed spacer region (ITS), translation elongation factor 1-alpha (tef1), beta-tubulin (tub2), histone H3 (his3) and chitin synthase (chs) gene of isolate ACCC 35488 and ACCC 35489 (Agricultural Culture Collection of China) were amplified and sequenced with primer pairs: ITS1/ITS4 (White et al. 1990), EF1-728F/EF2-rd (Carbone & Kohn 1999; O'Donnell et al.1998), TUB2Fd/ TUB4Rd(Aveskamp et al 2009), CYLH3F/H3-1b (Crous et al. 2004) and CHS-79F/CHS-345R (Carbone & Kohn 1999) (ITS: OQ381102 and PP488350; tef1: OQ408545 and PP510454; tub2: OQ408546 and PP510455; his3: OQ408544 and PP510453; chs: OQ408543 and PP510452). Sequence Blastn results showed above 99% identical with those of Neoscytalidium dimidiatum ex-type strain CPC38666. Phylogenetic tree inferred from Maximum Likelihood analysis of the combined ITS, tub2 and tef1 sequences revealed two isolates clustered with N. dimidiatum (Fig 2). Pathogenicity was tested on healthy one-year-old cuttings and fruits of Ecuadorian variety at room temperature. Six sites were pin-pricked on each stem and fruit. Both wounded stems and fruits were inoculated with spore suspensions (106 spore/ml) and 6-mm fungal plugs respectively. Sterile water and agar were used as control. The test was repeated twice. Stems and fruits were enclosed in plastic boxes with 80% relative humidity. Symptoms described above were observed on inoculated stems and fruits at five days post inoculation (Fig 1 H and I). No symptoms developed on the controls. Neoscytaliudium dimidiatum was reisolated from the cankers with a frequency of 100% via morphological and molecular analysis. This is first report of stem and fruit canker caused by N. dimidiatum on H. megalanthus in China and this disease represents a serious risk of Yanwo fruit yield losses. This fungus is widespread occurring throughout the world causing diseases on a wide variety of plants. The finding will be helpful for its prevention and control.
PubMed: 38812367
DOI: 10.1094/PDIS-05-23-0915-PDN -
Plant Disease May 2024Pepper ( L.) is a popular vegetable and condiment consumed around the world. In the Guizhou Province of China, peppers are the most commonly grown crop on 300,000...
Pepper ( L.) is a popular vegetable and condiment consumed around the world. In the Guizhou Province of China, peppers are the most commonly grown crop on 300,000 planted hectares. A variety of diseases routinely occur on peppers in this province, resulting in yield losses (Liu et al., 2022). Root rot is one of the most common symptoms and produces poor root growth and wilting of pepper. In April 2023, symptomatic pepper plants displaying stunting, dwarfism, wilting, and root browning were collected from five fields in Guizhou, with disease incidence ranging from 10% to 20%. The collected rotten roots were cleaned with sterilize distilled water and placed in selective V8 juice agar (V8A) medium (15% clarified V8 juice with 2.5 g/L CaCO and 2% agar) containing nystatin, ampicillin, rifampicin, and miconazole, and incubated at 25℃ for 1 to 2 days (Morita and Tojo, 2007). Eight isolates with similar colony morphology were transferred to V8A medium via hyphal tipping, and incubated at 25℃ in the dark. Colony and sexual structures were observed using a microscope. Mycelium was aseptate and formed white cottony colonies. Globose, intercalary, or terminal hyphal swellings were observed with a diameter of 20.5 to 25 µm (average: 22 µm), and aplerotic oospores had a diameter of 15 to 20 µm (average: 17.5 µm) with a wall thickness of approximately 2 µm. Three representative isolates HSLJ-3, LJG-1, and LJY-2 were chosen for further molecular identification. Sequences of the internal transcribed spacer (ITS) and mitochondrial cytochrome c oxidase subunit 1 () genes were identified using primer sets ITS4/ITS5 (White et al., 1990) and OomCoxI-Levup/OomCoxI-Levlo (Robideau et al., 2011), respectively. All sequences were deposited in GenBank (accession nos. OR554005, PP083310, and PP083420 for ITS, and OR529247, PP093821 and PP093822 for ). BLAST analysis revealed all ITS and sequences exhibited 100% identity with () isolate BR850 (GenBank accession nos. HQ643892.1 and HQ708933.1 for ITS and , respectively). Phylogenetic analysis was performed by the maximum-likelihood method on the CIPRES web portal (https://www.phylo.org/portal2/login!input.action, accessed on 9 January 2024). For pathogenicity tests, each isolate was cultured in V8A medium containing 50 autoclaved wheat seeds at 25℃ for 7 days. Budding pepper seedling (cv. Huaxi) was transplanted into a 0.4 L pot containing sterilized commercial potting mix (Seedling Cultivation Substrate, Hunan Xianghui Agricultural E-commerce Co., Ltd.) which was saturated with deionized water. Eight infected and non-infected wheat seeds were placed near the roots of five pepper seedlings, respectively. Plants were placed in an artificial climate chamber, with a 14 h photoperiod and approximately 75% relative humidity at 25℃. After 14 days, inoculated seedlings showed symptoms of stunting, wilting, and rotting roots similar to those observed in the field. No disease was observed on the non-inoculated control plants. The pathogen was isolated from infected pepper roots and confirmed as by morphological and molecular analyses as previously described. This is the first report of causing root rot on pepper in Guizhou, China. This finding is critical to the discover of treatment options for this pathogen, thereby improving management practices to reduce yield losses in pepper.
PubMed: 38812366
DOI: 10.1094/PDIS-01-24-0127-PDN -
The Journal of Antibiotics May 2024Strain HUAS CB01 was a novel actinobacterium which was isolated from the rhizosphere soil of Cathaya argyrophylla, Chengbu Miao Autonomous County of Hunan Province,...
Strain HUAS CB01 was a novel actinobacterium which was isolated from the rhizosphere soil of Cathaya argyrophylla, Chengbu Miao Autonomous County of Hunan Province, China. The strain formed well-growing substrate mycelium, diffusible pigments, and aerial mycelium, and differentiated into spiral-type spore chains composed of smooth-surface rod-shaped spores. Phylogenetic analysis on account of 16 S rRNA gene sequence demonstrated the strain HUAS CB01 was a member of the genus Streptomyces and had a close relationship with Streptomyces wuyuanensis CGMCC 4.7042 (100%) and Streptomyces marianii ICN19 (99.86%). Genome-based comparisons indicated that strain HUAS CB01 could be distinctly different from its closest species, Streptomyces wuyuanensis CGMCC 4.7042 , Streptomyces marianii ICN19, with ANIm and dDDH results of 92.78% and 45.90%, 92.22% and 43.30%, respectively, far less than 96.7 and 70% cut-off points recommended for delineating species. The main cellular fatty acids concluded anteiso-C, iso-C, iso-C, C and C 2OH. The menaquinones were MK-9(H), MK-9(H) and MK-9(H) and the whole-cell sugars consisted of ribose and mannose. The polar lipids included phosphatidyl ethanolamine, diphosphatidylglycerol, phosphatidylglycerol, mannosides and unidentified phospholipids. According to these genotypic and phenotypic characteristics, strain HUAS CB01 can be distinguished and representative to be a novel species of the genus Streptomyces, for which the name Streptomyces chengbuensis is proposed. The type strain is HUAS CB01 ( = MCCC 1K08666 = JCM 36277 ).
PubMed: 38811856
DOI: 10.1038/s41429-024-00745-z -
Microbiological Research Aug 2024Guanine nucleotide-binding proteins of the ADP ribosylation factor (Arf) family and their activating proteins (Arf-GAPs) are essential for diverse biological processes....
Guanine nucleotide-binding proteins of the ADP ribosylation factor (Arf) family and their activating proteins (Arf-GAPs) are essential for diverse biological processes. Here, two homologous Arf-GAPs, Age1 (AoAge1) and Age2 (AoAge2), were identified in the widespread nematode-trapping fungus Arthrobotrys oligospora. Our results demonstrated that AoAge1, especially AoAge2, played crucial roles in mycelial growth, sporulation, trap production, stress response, mitochondrial activity, DNA damage, endocytosis, reactive oxygen species production, and autophagy. Notably, transcriptome data revealed that approximately 62.7% of the genes were directly or indirectly regulated by AoAge2, and dysregulated genes in Aoage2 deletion were enriched in metabolism, ribosome biogenesis, secondary metabolite biosynthesis, and autophagy. Furthermore, Aoage2 inactivation caused a substantial reduction in several compounds compared to the wild-type strain. Based on these results, a regulatory network for AoAge1 and AoAge2 was proposed and verified using a yeast two-hybrid assay. Based on our findings, AoAge1 and AoAge2 are essential for vegetative growth and mycelial development. Specifically, AoAge2 is required for sporulation and trapping morphogenesis. Our results demonstrated the critical functions of AoAge1 and AoAge2 in mycelial growth, diverse cellular processes, and pathogenicity, offering deep insights into the functions and regulatory mechanisms of Arf-GAPs in nematode-trapping fungi.
Topics: Spores, Fungal; Fungal Proteins; Ascomycota; Secondary Metabolism; Gene Expression Regulation, Fungal; Reactive Oxygen Species; Autophagy; Mycelium; ADP-Ribosylation Factors; Animals; Transcriptome; Virulence; DNA Damage; Gene Expression Profiling
PubMed: 38810485
DOI: 10.1016/j.micres.2024.127779 -
Biotech (Basel (Switzerland)) May 2024The enzymatic hydrolysis of agricultural residues like wheat bran enables the valorization of otherwise unused carbon sources for biotechnological processes. The...
The enzymatic hydrolysis of agricultural residues like wheat bran enables the valorization of otherwise unused carbon sources for biotechnological processes. The co-culture of and with wheat bran particles as substrate produces an enzyme set consisting of xylanases, amylases, and cellulases that is suitable to degrade lignocellulosic biomass to sugar monomers (D-glucose, D-xylose, and L-arabinose). An integrated one-pot process for enzyme production followed by hydrolysis in stirred tank bioreactors resulted in hydrolysates with overall sugar concentrations of 32.3 g L and 24.4 g L at a 25 L and a 1000 L scale, respectively, within 86 h. Furthermore, the residual solid biomass consisting of fermented wheat bran with protein-rich fungal mycelium displays improved nutritional properties for usage as animal feed due to its increased content of sugars, protein, and fat.
PubMed: 38804297
DOI: 10.3390/biotech13020015 -
Plant Disease May 2024In October 2023, a Connecticut grower contacted The Connecticut Agricultural Experiment Station about a field of strawberry plants ( × ) (cv. Ruby June) showing...
In October 2023, a Connecticut grower contacted The Connecticut Agricultural Experiment Station about a field of strawberry plants ( × ) (cv. Ruby June) showing symptoms of severe leaf spotting and visual wilting. Upon visiting the field, leaves had lesions with a diffuse black halo and a light brown center and wilting symptoms, which appeared driven by petiole lesions and presented as dark brown stripes with a reddish-purple halo. Symptoms were observed on 80 to 90% of plants within the block, nearly all of which (>90%) presented with both leaf spots and severe wilting. Diseased tissue was collected from 20 leaves and 25 petioles, sterilized in 0.6% NaOCL, and plated on potato dextrose agar. After hyphal tipping a morphologically identical fungus was isolated from 70% of leaves and 88% of petioles, which formed a dense white mycelial mat with moderate aerial mycelium and conidiomata that exuded dark brown conidial masses. The underside of the mycelial mat was yellowish. Conidia were fusoid, ellipsoid, straight to slightly curved, 4-septate with a single basal appendage and 2-5 apical, matching the description of species within the genus (Maharachchikumbura et al. 2014). The average conidia (n=74) length, not including appendages, was 29.9 ± 2.1 µm and the average width, at the widest point, was 7.5 ± 0.7 µm. Aerial hyphae were collected from two isolates, CT58-1 and CT62-2, and DNA was extracted for further molecular characterization. PCR was performed with primers targeting actin (), β-tubulin (), and ITS prior to amplicon sequencing (Carbone and Kohn 1999; Hassan et al. 2018). Sequences were queried against the NCBI whole genome shotgun database, and aligned sequences from 13 species (including , , and ) were collected for each locus. Sequences were aligned, trimmed, and concatenated using Mega11, and IQ-TREE was employed for model selection (Nguyen et al. 2015; Tamura et al. 2021). A maximum-likelihood tree placed the isolates in a high-confidence cluster with , confirming this placement of these isolates within the genus (CT58-1 Accession #: PP715979-89; PP707735). To confirm pathogenicity, CT58-1 was grown on autoclaved strawberry leaves to induce sporulation, and a suspension of 10 spores/ml was made. Five milliliters of this spore suspension was sprayed on six 6-week-old strawberries (cv. Jewel), and water was sprayed on the same number of control plants. Plants were at 100% humidity for two days and then kept in the greenhouse for 3 weeks to observe symptoms. Inoculated plants presented with identical leaf spot and petiole lesions to field samples and no visual symptoms were observed on control plants. New isolations were made from infected petioles, which produced morphologically identical spores to those described above, and ITS/ loci sequencing yielded sequences identical to those of CT58-1. Spore production and plant inoculations were repeated with this new isolate, and identical symptoms were observed. This is the first report of infecting strawberries in New England and given the high disease incidence in the initial infected field and relative lack of disease in a neighboring field, it is likely that this pathogen was introduced on bare root plants. As the plants were sourced from a nursery in Ontario, Canada, it is likely that the pathogen is capable of overwintering in the Northeastern United States.
PubMed: 38803068
DOI: 10.1094/PDIS-04-24-0893-PDN