Inhibitory effects of phytic acid on the in vitro and in vivo growth of Trichothecium roseum in apple fruit and the underlying mechanisms involved in its action.

This study evaluated the inhibitory impacts of phytic acid on the growth of T. roseum both in vitro and in apple fruit, as well as elucidated the potential mechanisms underlying its action. Results showed that phytic acid suppressed the lesion diameter caused by T. roseum inoculation in apples, as well as spore germination and mycelial growth of T. roseum in vitro. Phytic acid reduced intracellular conductivity and soluble sugar content, while increasing malondialdehyde and soluble protein contents. Phytic acid treatment inhibited the activities of pectin lyase, pectin methyl polygalacturonase, ß-glucosidase, cellulase, xylanase, pectin methyl trans-eliminase, polygalacturonase, and polygalacturonase both in vitro and in apples. In contrast, inoculation of control and phytic acid-treated fruit with T. roseum resulted in increased enzyme activity. These findings suggest that phytic acid decrease the occurrence of heart rot in apples through inducing disruption of the cell membrane of T. roseum and mediating cell wall metabolism.

Effects of TrPLDs on the pathogenicity of Trichothecium roseum infected apple fruit.

Phospholipase D plays a critical regulatory role in the pathogenicity of filamentous fungi. However, the molecular mechanism of PLD regulating the pathogenicity of filamentous fungi has not been reported. In this research, the previously constructed TrPLD1 and TrPLD2 (TrPLDs) mutants were used as test strains. Firstly, the function of TrPLDs in Trichothecium roseum was studied. Then, the effects of TrPLDs on the pathogenicity of T. roseum and the quality of the inoculated apples were verified. The results suggested that the deletion of TrPLD1 delayed the spore germination of ΔTrPLD1 and inhibited germ tube elongation by down-regulating the expressions of TrbrlA, TrabaA and TrwetA. By down-regulating the extracellular enzyme-coding gene expressions, ΔTrPLD1 inhibited the degradation of apple fruit cell wall and the change of fatty acid content during infection, reduced the cell membrane permeability and malondialdehyde (MDA) content of apple fruit, thereby maintaining the integrity of fruit cell membrane, and reduced the pathogenicity of ΔTrPLD1 to apple and kept the quality of apple. However, ΔTrPLD2 did not have a significant effect on the infection process of apple fruit by the pathogen.

ROS mediated by TrPLD3 of Trichothecium roseum participated cell membrane integrity of apple fruit by influencing phosphatidic acid metabolism.

Trichothecium roseum is a typical necrotrophic fungal pathogen that not only bring about postharvest disease, but contribute to trichothecenes contamination in fruit and vegetables. Phospholipase D (PLD), as an important membrane lipid degrading enzyme, can produce phosphatidic acid (PA) by hydrolyzing phosphatidylcholine (PC) and phosphatidylinositol (PI). PA can promote the production of reactive oxygen species (ROS) by activating the activity of NADPH oxidase (NOX), thereby increasing the pathogenicity to fruit. However, the ROS mediated by TrPLD3 how to influence T. roseum infection to fruit by modulating phosphatidic acid metabolism, which has not been reported. In this study, the knockout mutant and complement strain of TrPLD3 were constructed through homologous recombination, TrPLD3 was tested for its effect on the colony growth and pathogenicity of T. roseum. The experimental results showed that the knockout of TrPLD3 inhibited the colony growth of T. roseum, altered the mycelial morphology, completely inhibited the sporulation, and reduced the accumulation of T-2 toxin. Moreover, the knockout of TrPLD3 significantly decreased pathogenicity of T. roseum on apple fruit. Compared to inoculated apple fruit with the wide type (WT), the production of ROS in apple infected with ΔTrPLD3 was slowed down, the relative expression and enzymatic activity of NOX, and PA content decreased, and the enzymatic activity and gene expression of superoxide dismutase (SOD) increased. In addition, PLD, lipoxygenase (LOX) and lipase activities were considerably decreased in apple fruit infected with ΔTrPLD3, the changes of membrane lipid components were slowed down, the decrease of unsaturated fatty acid content was alleviated, and the accumulation of saturated fatty acid content was reduced, thereby maintaining the cell membrane integrity of the inoculated apple fruit. We speculated that the decreased PA accumulation in ΔTrPLD3-inoculated apple fruit further weakened the interaction between PA and NOX on fruit, resulting in the reduction of ROS accumulation of fruits, which decreased the damage to the cell membrane and maintained the cell membrane integrity, thus reducing the pathogenicity to apple. Therefore, TrPLD3-mediated ROS plays a critical regulatory role in reducing the pathogenicity of T. roseum on apple fruit by influencing phosphatidic acid metabolism.

Cell structure damage contributes to antifungal activity of sodium propylparaben against Trichothecium roseum.

Trichothecium roseum is a type of fungus that causes pink rot in muskmelon after the melons are harvested. Pink rot leads to severe decay during storage and causes the production of toxins that can be harmful to human health. Sodium propylparaben (SPP, IUPAC name: sodium; 4-propoxycarbonylphenolate) is an antimicrobial preservative that can be used to treat the inedible parts of fruits in addition to food, medications, and packaging. In this study, the effectiveness of SPP in inhibiting T. roseum was tested, and the inhibition mechanism was investigated. The results show that SPP inhibited the growth and spore germination of T. roseum. The malondialdehyde (MDA) content, propidium iodide staining, alkaline phosphatase (AKP) activity, and calcofluor white (CFW) staining results show that SPP produced a disruption of the cell membrane and cell wall integrity of T. roseum. Scanning and transmission electron microscopy (SEM and TEM, respectively) results also indicate that SPP disrupted the cellular structure of T. roseum. Meanwhile, the large amounts of superoxide anion and hydrogen peroxide in T. roseum accumulated due to the effects of SPP on the activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, superoxide dismutase, and decreased catalase. In addition, SPP caused a significant reduction in the incidence rate and disease degree of muskmelon pink rot in vivo. In conclusion, SPP appears to be effective against T. roseum via disruption of the cell membrane and wall. SPP could be used to manage melon pink rot after fruit harvesting because of its disease inhibition effect in vivo.

High-Quality Genome and Annotation Resource of Orange Pink Rot Pathogen Trichothecium roseum Strain YXFP-22015 Isolated from Hubei, China.

Trichothecium roseum is widely distributed throughout the world and forms pink powdery molds on various fruits and vegetables, lowering their quality and leading to great economic losses. Due to the limited availability of high-quality genomic and annotation resources, little is known about the pathogenesis of T. roseum at the molecular level. In this study, we reported a high-quality genome assembly of strain YXFP-22015 using Oxford Nanopore Technologies (ONT) for long read sequencing and MGISEQ-2000 for short read sequencing. The genome was also well-annotated based on the combination of RNA-seq by MGISEQ-2000 and in silico prediction. Further analysis on this will contribute to a better understanding of T. roseum infection mechanisms.

First report of alfalfa root rot caused by Trichothecium roseum in China.

Alfalfa (Medicago sativa L.) is perennial leguminous forage, which is cultivated throughout the world due to its high yield, high quality, satisfactory palatability, and wide adaptability. With the increase of planting area in China, root diseases caused by Fusarium spp., Sclerotium rolfsii, Phytophthora spp. (Yang et al. 2022), and new pathogens have been found that reduce the yield and quality of alfalfa and cause economic losses (Li at al. 2019). In 2021, an alfalfa disease occurred under conditions of high temperature and high humidity at the Jiaozhou Experimental Base of Qingdao Agricultural University (Jiaozhou Modern Agricultural Science and Technology Demonstration Park, 36.33°N 120.40°E, Qingdao, Shandong, China), and about 2 ha of alfalfa were infected. The disease affected up to 35% of the plants and caused grass spots. Infected plants developed black-brown lesions with irregular shapes on roots with yellowing of the foliage; the leaves of the whole plant turned yellow. In the late stage of the disease, defoliation occurred and the plants stopped growing, wilted and died. Ten infected plants with typical symptom were collected for isolation and identification of pathogen. The infected roots were cut into 3-5 mm2 sections and then soaked in 75% ethanol for 30 s, followed by a 3-minute immersion in 2% sodium hypochlorite for surface sterilization. Next, the tissues were rinsed in sterile water five times and then placed on potato dextrose agar (PDA) medium. After three subcultures and subsequent single spore isolation, one representative strain named as DC1 was isolated from the infected roots. Based on morphological observation, the colony of DC1 was flat, granular, and powdery in appearance. Four days after inoculation on PDA medium, the size of the colony were 2.1-2.6 cm. After 8 to 20 days, the colonies were initially white and gradually change a light pink to peach color. The conidia are two-celled (Hamid et al. 2014), elliptic to pear-shaped, colorless or translucent, smooth to slightly rough with thick walls. The size of conidia ranged from 11.3 to 23.5 µm long × 6.1 to 12.7 µm wide (n =30). For the identification, the rDNA--ITS gene of the fungus was amplified using the primers ITS1/ITS4 (White et al.1990), and the EF1α gene was amplified using primers EF1-983F/EF1-2218R (Rehner and Buckley 2005). Then the PCR amplicons were cloned into the pCE2 TA/Blunt-Zero vector. The results of the rDNA-ITS (OM049197.1, 515 bp) and EF1α (OM069381.1, 926 bp) sequences were deposited in GenBank. DNA analysis showed that the two sequences were 100% similar to the rDNA-ITS sequence (MN882763.1) and EF1α sequence (DQ676610.1) of Trichothecium roseum, respectively. A pathogenicity test was done by placing one piece (0.5 cm in diameter) of fungal culture (PDA plug) 1cm below the crown of 40-day-old healthy alfalfa (cv. Zhongmu No.3) plants, 3 replicates and 20 plants in each replicate. PDA plug without the pathogen were used for control. All plants were cultivated in a growth chamber at 25±1°C with a light cycle of 15 h (90% relative humidity). After 18 days, the roots of inoculated plants had dark brown lesions and the leaves of their plants turn yellow, while those control plants had no symptoms. To fulfilling Koch's postulates, the same pathogen was re-isolated from necrotic root tissue of inoculated plants and confirmed by morphology and the rDNA-ITS and EF1-α sequences. Based on disease symptoms, morphological characteristics DNA sequences and pathogenicity, the pathogen of alfalfa disease in Jiaozhou Experimental Base of Qingdao Agricultural University was identified as T. roseum. To our knowledge, this is first report of T. roseum causing alfalfa root rot. The newly emerging disease may pose threat to alfalfa production of central and southern China in future.

First Report of Trichothecium roseum Causing Postharvest Fruit Rot on Purple Passion Fruit in China.

Purple Passion fruit (Passiflora edulis) is widely cultivated in many regions of southern China as an edible tropical fruit with excellent nutritional value and high economic value. In July 2021, postharvest fruit rot was observed on 20-25% of purple passion fruit in several fruit markets of Dehong City in Yunnan Province. Symptoms on infected fruits were irregular, pink-brown, soft, and water-soaked lesions, which enlarged and formed sunken patches with time as well as producing a small amount of white mycelium. To isolate the causal organism, five diseased fruits were collected from different fruit markets. A conidial mass from an individual sorus observed on an infected fruit was isolated and cultured on potato dextrose agar (PDA) supplemented with 50 µg ml-1 of streptomycin, and five fungal isolates were obtained. These isolates were morphologically similar and produced pale pink colonies on PDA for 7 days containing several conidiophores with abundant conidia. Mycelia were hyaline, 2 µm in diameter, and conidiophores were simple or branched (100 to 286 × 1.5 to 2.5 µm, n=50). Conidia were pyriform, ovate, with papillary protuberances at one end. Almost all conidia were two-celled and single-septate (5.8 to 9.1 × 1.7 to 4.9 µm, n=50). The morphology of the fungi resembled Trichothecium roseum as reported previously (Inácio et al. 2011). To further confirm the fungal species, isolate PASF4 was selected for molecular identification by amplifying and sequencing the ribosomal internal transcribed spacer (ITS) and large subunit (LSU) genes. Primers and PCR amplification were described by Fell et al. (2000). Results showed that both the ITS (GenBank accession OL336243) and LSU (OL336242) gene sequences had 100% similarity to T. roseum in NCBI database (MH856757 and MH868278). Maximum likelihood tree was constructed using MEGA 7 (Felsenstein, 1981) based on concatenated sequences (ITS and LSU) of isolate PASF4 and reference strains. Phylogenetic analysis showed that isolate PASF4 belonged to T. roseum clade. Based on morphological characteristics and phylogenetic analysis, isolate PASF4 was identified as T. roseum (Inácio et al. 2011). To confirm their pathogenicity, healthy purple passion fruits (cv. Tainong-1) were disinfected in 0.5% NaClO solution for 2 min, and then washed with sterile water. After wounding with a sterile needle, the fruits were inoculated by placing mycelium agar plugs on the wounds, and mock inoculation with mycelium-free PDA plugs served as control. Five fruits were used in each treatment. All fruits were maintained in plastic boxes at 25 °C. Disease symptoms appeared after inoculation for 4-7 days on all inoculated fruits, which were similar to those observed in fruit markets. No symptoms were observed on fruits used as control. The Trichothecium isolates were re-isolated from symptomatic fruits thus fulfilling Koch's postulates. Trichothecium roseum has been reported to cause fruit rot of tomato, apple and orange in Pakistan (Hamid et al., 2014) and fruit rot of pepper in China (Lin et al., 2016). To our knowledge, this is the first report of T. roseum causing fruit rot on purple passion fruit worldwide, and these data will provide useful information for developing effective control strategies.

The Effect of Environmental pH during Trichothecium roseum (Pers.:Fr.) Link Inoculation of Apple Fruits on the Host Differential Reactive Oxygen Species Metabolism.

Trichothecium roseum is an important postharvest pathogen, belonging to an alkalizing group of pathogens secreting ammonia during fungal growth and colonization of apple fruits. Fungal pH modulation is usually considered a factor for improving fungal gene expression, contributing to its pathogenicity. However, the effects of inoculation with T. roseum spore suspensions at increasing pH levels from pH 3 up to pH 7, on the reactive oxygen species (ROS) production and scavenging capability of the apple fruits, affecting host susceptibility, indicate that the pH regulation by the pathogens also affects host response and may contribute to colonization. The present results indicate that the inoculation of T. roseum spores at pH 3 caused the lowest cell membrane permeability, and reduced malondialdehyde content, NADPH oxidases activity, O2●- and H2O2 production in the colonized fruit. Observations of the colonized area on the 9th day after inoculation at pH 3, showed that the rate of O2●- production and H2O2 content was reduced by 57% and 25%, compared to their activities at pH 7. In contrast, antioxidative activities of superoxide dismutase, catalase and peroxidases of fruit tissue inoculated with spores' suspension in the presence of a solution at pH 3.0 showed their highest activity. The catalase and peroxidases activities in the colonized tissue at pH 3 were higher by almost 58% and 55.9%, respectively, on the 6th day after inoculation compared to inoculation at pH 7. The activities of key enzymes of the ascorbate-glutathione (AsA-GSH) cycle and their substrates and products by the 9th day after fruit inoculation at pH 3 showed 150%, 31%, 16%, and 110% higher activities of ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase, respectively, compared to pH 7. A similar pattern of response was also observed in the accumulation of ascorbic acid and dehydroascorbate which showed a higher accumulation at pH 3 compared to the colonization at pH 7. The present results indicate that the metabolic regulation of the pH environment by the T. roseum not only modulates the fungal pathogenicity factors reported before, but it induces metabolic host changes contributing both together to fungal colonization.

Entomopathogenic effect of Trichothecium roseum (Pers.) Link (Hypocreales: Ascomycota) against Pauropsylla buxtoni (Psylloidea: Hemiptera) infesting Ficus carica leaves and its potential use as biocontrol agent of the insect.

AIMS: To isolate and characterize a native strain of Trichothecium roseum infecting the immatures of Pauropsylla buxtoni on fig leaves, to study the morphological features of the isolated strain, then to test the entomopathogenic effect of the isolated strain against the immatures of P. buxtoni on fig leaves. METHODS AND RESULTS: The isolated strain of T. roseum produced pink mycelial growth on culture medium with septate mycelium and conidiophores. It also produced two-celled conidia with elliptical to pyriform shape born at the tip of conidiophores. Molecular characterization of the isolated strain confirmed the identity of the strain as T. roseum. In bioassays, application of conidial suspension of the isolated strain against the 4th instar of P. buxtoni immatures infesting fig leaves showed an obvious entomopathogenic effect of the applied fungus strain against the targeted insect. This effect was exhibited by the death of treated P. buxtoni immatures with the fungus. The dead insects were characterized by the presence of pinkish mycelial growth on the outer surface which is characteristic to the fungus, in addition to the positive isolation of the fungus from internal tissues of treated insects after a proper external disinfection. Moreover, significant differences (at P < 0·018) were obtained between the means of mortality % of P. buxtoni immatures treated with different concentrations of conidial suspension of the fungus. CONCLUSIONS: The overall results confirm the entomopathogenic effect of T. roseum against P. buxtoni immatures infesting fig leaves. Significant mortalities of P. buxtoni immatures were obtained when the different concentrations of the fungus conidial suspension were bio-assessed against the insect. SIGNIFICANCE AND IMPACT OF THE STUDY: The tested strain of T. roseum can be applied as biocontrol agent of P. buxtoni on fig leaves within an integrated control programme to reduce the impact of pest on fig trees.

Trichothecium roseum Enters 'Fuji' Apple Cores Through Stylar Fissures.

Apple core rot, an economically important disease worldwide, appears both before and during harvest. Current gaps in understanding of the infection cycle impede progress toward more effective management of this disease. The fungus Trichothecium roseum is the main pathogen of core rot on apple in China. In this study, we used fluorescent labeling to trace colonization of T. roseum in floral tissues, characterizing routes of penetration to the core of 'Fuji' apples. T. roseum infected petals, anthers, filaments, stigmas and separated styles of flowers, and floral debris served as inoculum for core infection. In field inoculations, T. roseum entered styles initially through stylar fissures and colonized pluricellular hairs of these fissures during early stages of fruit development. Subsequently, hyphae grew along the extending fissures, which are continuations of stylar fissures located between stylar bases and carpel cavities. The hyphae remained in the extending fissures from mid-June to late July. When fruit developed an open sinus in late July, the sinus eventually fused with extending fissures and carpel cavities in late August, hyphae invaded carpel cavities, and ultimately fruit flesh via cracks on carpel cavity walls. Our results revealed for the first time the routes by which T. roseum penetrates apple fruit, and provided significant insights for strategic management of core rot.

Cuminal Inhibits Trichothecium roseum Growth by Triggering Cell Starvation: Transcriptome and Proteome Analysis.

Trichothecium roseum is a harmful postharvest fungus causing serious damage, together with the secretion of insidious mycotoxins, on apples, melons, and other important fruits. Cuminal, a predominant component of Cuminum cyminum essential oil has proven to successfully inhibit the growth of T. roseum in vitro and in vivo. Electron microscopic observations revealed cuminal exposure impaired the fungal morphology and ultrastructure, particularly the plasmalemma. Transcriptome and proteome analysis was used to investigate the responses of T. roseum to exposure of cuminal. In total, 2825 differentially expressed transcripts (1516 up and 1309 down) and 225 differentially expressed proteins (90 up and 135 down) were determined. Overall, notable parts of these differentially expressed genes functionally belong to subcellular localities of the membrane system and cytosol, along with ribosomes, mitochondria and peroxisomes. According to the localization analysis and the biological annotation of these genes, carbohydrate and lipids metabolism, redox homeostasis, and asexual reproduction were among the most enriched gene ontology (GO) terms. Biological pathway enrichment analysis showed that lipids and amino acid degradation, ATP-binding cassette transporters, membrane reconstitution, mRNA surveillance pathway and peroxisome were elevated, whereas secondary metabolite biosynthesis, cell cycle, and glycolysis/gluconeogenesis were down regulated. Further integrated omics analysis showed that cuminal exposure first impaired the polarity of the cytoplasmic membrane and then triggered the reconstitution and dysfunction of fungal plasmalemma, resulting in handicapped nutrient procurement of the cells. Consequently, fungal cells showed starvation stress with limited carbohydrate metabolism, resulting a metabolic shift to catabolism of the cell's own components in response to the stress. Additionally, these predicaments brought about oxidative stress, which, in collaboration with the starvation, damaged certain critical organelles such as mitochondria. Such degeneration, accompanied by energy deficiency, suppressed the biosynthesis of essential proteins and inhibited fungal growth.

Antifungal activity of Lactobacillus plantarum C10 against Trichothecium roseum and its application in promotion of defense responses in muskmelon (Cucumis melo L.) fruit.

The antifungal effect of Lactobacillus plantarum C10 on pink rot caused by Trichothecium roseum and its application in muskmelon fruit were investigated. Cell-free supernatant (CFS) produced by Lactobacillus plantarum C10 strongly inhibited the growth of T. roseum and seriously damaged the structures of spores and mycelia of T. roseum. Acid compounds produced by Lb. plantarum C10 were the major antifungal substances and exhibited a narrow pH range from 3.5 to 6.5. Application of the CFS on muskmelon fruit reduced the contamination zone of T. roseum by enhancing the activities of defensive enzymes (phenylalanine ammonialyase, peroxidase and polyphenoloxidase) and promoting the accumulation of phenolics and flavonoids. These results suggested that Lb. plantarum C10 could be used as a biocontrol agent to control pink rot caused by T. roseum in muskmelon fruit.

Two novel cationic antifungal peptides isolated from Bacillus pumilus HN-10 and their inhibitory activity against Trichothecium roseum.

Public concern for food safety and environmental issues and the increase in fungicide-resistant pathogen have enhanced the interest in developing alternative methods to fungicides to control postharvest fruit decay. In this study, a bacterial strain isolated from stale potato vermicelli was identified as Bacillus pumilus HN-10 based on morphological characteristics and 16S rRNA gene sequence analysis. Furthermore, two novel cationic antifungal peptides named P-1 and P-2 were purified from B. pumilus HN-10 using macroporous adsorbent resin AB-8, Sephadex G-100 chromatography, and reversed-phase high-performance liquid chromatography. The primary structure of P-1 and P-2, which were proved to be novel antifungal peptides by BLAST search in NCBI database, was PLSSPATLNSR and GGSGGGSSGGSIGGR with a molecular weight of 1142.28 and 1149.14 Da, respectively, as indicated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Both P-1 and P-2 exhibited strong antifungal activity against Trichothecium roseum with minimum inhibitory concentrations starting from 1 µg/mL. The two novel antifungal peptides were stable below 80 °C for 2 h, but lost their activity in 15 min at 121 °C. In addition, they were resistant to the proteolytic action of pepsin, trypsin, and papain, and stable within a wide range of pH (2.0-12.0). These results showed that P-1 and P-2 are novel cationic antifungal peptides with specific activity against T. roseum.

Activation of phenylpropanoid pathway and PR of potato tuber against Fusarium sulphureum by fungal elicitor from Trichothecium roseum.

The induced resistance of potato tuber (Solanum tuberosum cv. Xindaping) tissue against Fusarium sulphureum by a fungal elicitor from the incompatible pathogen Trichothecium roseum and its possible mechanism were studied. The results showed that the lesion development of the wound-inoculated potato tuber was significantly reduced by treatment with the fungal elicitor from T. roseum (P < 0.05). Inoculation with F. sulphureum on the 16th day after treatment with the fungal elicitor80 at 15.0 µg/ml had the best resistant effect in the potato tuber, with the diameter being only reduced by 47 % that of the control. In addition, the results also showed that the potato tuber treated with the fungal elicitor80 could systemically induce lignin deposition, total phenolic content, flavonoid content and defense enzymes, including three keys phenylpropanoid pathway (PAL, 4CL and C4H) and pathogenesis-related (GLU and CHT) enzymes. The fungal elicitor80 also enhanced the up-regulation of the transcription and expression of PAL, C4H, 4CL, GLU and CHT genes. The treatment with the fungal elicitor80 + F. sulphureum caused the marked and/or prompt enhancement of all indexes when compared to treatment with the fungal elicitor80 or inoculation with the pathogen alone. The results suggested that the fungal elicitor of T. roseum could significantly enhance defense responses in potato tuber against dry rot mainly due to the up-regulation of the transcription and expression of resistance-related genes as well as increasing the activity of resistance-related enzymes and antifungal compounds.

A method of analysis for T-2 toxin and neosolaniol by UPLC-MS/MS in apple fruit inoculated with Trichothecium roseum.

Trichothecenes are one of the most important groups of mycotoxins produced by Trichothecium roseum, which causes core rot of apple. A reliable and sensitive method was developed and successfully applied for the rapid detection of trichothecenes including T-2 toxin and neosolaniol in harvested apple using UPLC-MS/MS. After the extraction of the two mycotoxins from the apple matrix with methanol/water (80/20, v/v), the concentrated extracts were cleaned-up by PriboFast M270 columns and then analysed by UPLC-MS/MS. T-2 toxin and neosolaniol were effectively separated as unique peaks. The validity of this method was established by its linearity (R(2) ≥ 0.9995), precision (relative standard deviation ≤ 3.6%), accuracy, selectivity, limit of detection of 2-5 µg kg(-1), limit of quantification of 5-10 µg kg(-1) and average recovery of 73-96%. Levels of T-2 toxin were found in the range 7.1-128.4 µg kg(-1) in the core rot lesion of three cultivars apple (cvs. Red Delicious, Fuji and Ralls). T-2 was detected not only in the lesion, but also in the tissue without any disease symptoms. However, neosolaniol was only detected in the lesion on 'Red Delicious' apples. In addition, the concentration of T-2 toxin in the susceptible cultivar (cv. Fuji) was significantly higher than that in the resistant one (cv. Ralls). This method proved to be suitable at detecting T-2 and neosolaniol simultaneously in apples infected with T. roseum.

Identification of Acremonium acutatum and Trichothecium roseum isolated from Grape with White Stain Symptom in Korea.

During 2010 and 2012 grape harvest seasons in Gyeonggi-do, Korea, a white stain symptom was observed on the harvested grape fruits in 'Campbell-Early' and 'Kyoho' varieties. In samples collected from the infected vine, two different strains of pathogenic fungi have been found and identified as Acremonium acutatum and Trichothecium roseum based on fungal morphology and nucleotide sequence of internal transcribed spacer (ITS) and supported by the phylogenetic analysis of the rDNA-ITS region. The DNA homologies of the isolated strains were 99.8% and 99.6% identical with T. roseum (IFB-22133) and A. acutatum (CBS682.71), respectively. In the pathogenicity test, the spores of A. acutatum and T. roseum sprayed on the grapes caused white stain symptoms on the fruits in two weeks after the artificial inoculation, which is similar to observations in the field. To our knowledge, this is the first report of white stain symptoms caused by A. acutatum and T. roseum on the grapes in Korea.

Identification of Acremonium acutatum and Trichothecium roseum isolated from Grape with White Stain Symptom in Korea

During 2010 and 2012 grape harvest seasons in Gyeonggi-do, Korea, a white stain symptom was observed on the harvested grape fruits in 'Campbell-Early' and 'Kyoho' varieties. In samples collected from the infected vine, two different strains of pathogenic fungi have been found and identified as Acremonium acutatum and Trichothecium roseum based on fungal morphology and nucleotide sequence of internal transcribed spacer (ITS) and supported by the phylogenetic analysis of the rDNA-ITS region. The DNA homologies of the isolated strains were 99.8% and 99.6% identical with T. roseum (IFB-22133) and A. acutatum (CBS682.71), respectively. In the pathogenicity test, the spores of A. acutatum and T. roseum sprayed on the grapes caused white stain symptoms on the fruits in two weeks after the artificial inoculation, which is similar to observations in the field. To our knowledge, this is the first report of white stain symptoms caused by A. acutatum and T. roseum on the grapes in Korea.