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Bletilla striata is an endangered traditional medicinal herb in China. In May 2020, the emergence of white root rot severely impacted the quality and yield of B. striata, affecting about 5% of the plants at plant nurseries of the Chengdu Academy of Agricultural and Forestry Sciences. Through a series of experiments and evaluations, the pathogen was identified as Fusarium solani. This is the first report of B. striata white root rot caused by F. solani in Sichuan, China. To better understand this disease and provide data support for its control, a combination of morphological, molecular characterisation and pathogenicity determination was used in this study for assessment. Meanwhile, the effects of different carbon and nitrogen sources, culture medium, temperature, photoperiod and pH on mycelial growth and spore production of F. solani were investigated. In addition, effective fungicides were screened and the concentration ratios of fungicides were optimized using response surface methodology (RSM). The experimental results showed that sucrose was the optimum carbon source for the pathogen, and the optimum temperature and pH were 25°C and pH 7, respectively, while light did no significant effect. Effective fungicides were screened, among which difenoconazole showed the strongest inhibition with EC50 of 142.773 µg/mL. The optimum fungicide concentration scheme (difenoconazole, pyraclostrobin, and thiophanatemethyl at 395.42, 781.03, and 561.11 µg/mL, respectively) was obtained using response surface methodology (RSM) to improve the inhibition rate of 92.24 ± 0.34%. This study provides basic data for the pathogen characterization of B. striata white root rot and its potential fungicides in Sichuan, China. In addition, the optimal fungicide concentration ratios were obtained through response surface methodology (RSM) optimization, which significantly enhanced the fungicidal effect and provided a scientific basis for the future control of B. striata white root rot. [ABSTRACT FROM AUTHOR]

Succinate dehydrogenase inhibitor (SDHI) fungicides are the most commonly and effectively used class of fungicides for controlling gray mold. Among them, only boscalid has been registered in China for controlling grape gray mold, whereas isofetamid and pydiflumetofen are two new SDHI fungicides that have demonstrated high efficacy against various fungal diseases. However, the sensitivity of Botrytis cinerea isolates from vineyards in China to these three fungicides is currently unknown. In this study, the sensitivity of 55 B. cinerea isolates from vineyards to boscalid, isofetamid, and pydiflumetofen was determined, with the effective concentrations for inhibiting 50% of spore germination (EC50) values ranging from 1.10 to 393, 0.0300 to 42.0, and 0.0990 to 25.5 μg ml-1, respectively. The resistance frequencies for boscalid, isofetamid, and pydiflumetofen were 60.0, 7.2, and 12.8%, respectively. Three mutations (H272R, H272Y, and P225F) were detected in the SdhB subunit, with H272R being the most prevalent (75.7%), followed by H272Y (16.2%) and P225F (8.1%). All three mutations are associated with resistance to boscalid, and of them, H272R mutants exhibited high resistance. Only P225F and H272Y mutants exhibited resistance to isofetamid and pydiflumetofen, respectively. A weakly positive cross-resistance relationship was observed between boscalid and pydiflumetofen (r = 0.38, P < 0.05). Additionally, the H272R mutants showed no significant fitness costs, whereas the remaining mutants exhibited reduced mycelial growth (P225F) and sporulation (H272Y and P225F). These results suggest that isofetamid and pydiflumetofen are effective fungicides against B. cinerea in vineyards, but appropriate rotation strategies must be implemented to reduce the selection of existing SDHI-resistant isolates. [ABSTRACT FROM AUTHOR]

Macrofungi play important roles in the soil elemental cycle of terrestrial ecosystems. Fungal viruses are common in filamentous fungi, and some of them can affect the growth and development of hosts. However, the composition and evolution of macrofungal viruses are understudied. In this study, ninety strains of Trametes versicolor, Coprinellus micaceus, Amanita strobiliformis, and Trametes hirsuta were collected in China. Four mixed pools were generated by combining equal quantities of total RNA from each strain, according to the fungal species, and then subjected to RNA sequencing. The sequences were assembled, annotated, and then used for phylogenetic analysis. Twenty novel viruses or viral fragments were characterized from the four species of macrofungi. Based on the phylogenetic analysis, most of the viral contigs were classified into ten viral families or orders: Barnaviridae, Benyviridae, Botourmiaviridae, Deltaflexiviridae, Fusariviridae, Hypoviridae, Totiviridae, Mitoviridae, Mymonaviridae, and Bunyavirales. Of these, ambi-like viruses with circular genomes were widely distributed among the studied species. Furthermore, the number and overall abundance of viruses in these four species of macrofungi (Basidiomycota) were found to be much lower than those in broad-host phytopathogenic fungi (Ascomycota: Sclerotinia sclerotiorum, and Botrytis cinerea). By employing metatranscriptomic analysis in this study, for the first time, we demonstrated the presence of multiple mycoviruses in Amanita strobiliformis, Coprinellus micaceus, Trametes hirsute, and Trametes versicolor, significantly contributing to research on mycoviruses in macrofungi. [ABSTRACT FROM AUTHOR]

As one of the most frequently used components of traditional Chinese herbal medicine, the economic plant Fritillaria thunbergii Miq is widely grown in several provinces of China. The so-called "gray mold disease" of the plant that may lead to fatal economic loss is caused by the fungal pathogen Botrytis cinerea. Sensitive and rapid detection of fungal infections is highly desired as a preventive step to fight against the disease. In this study, we prepared a monoclonal antibody (McAb) against a pathogenic fungus using classic hybridoma technology. After analyzing the titer, sensitivity, specificity, type, and binding protein of the prepared McAbs, we developed a colloidal carbon competitive immunochromatographic test strip with the McAbs. Results showed that we successfully obtained two highly specific McAbs, IgG3 and IgG2a, against B. cinerea from hybridoma cell lines BcA4 and BcE4, respectively. The McAbs from BcA4 could bind a 25 kDa protein, while the antibodies from BcE4 could bind two proteins (53 and 340 kDa). The test strip prepared with antibodies against BcE4 reached a detection sensitivity of 6.25 μg/mL. The strips could be conveniently stored in a dry environment (≤ 4 °C) for > 6 months without any noticeable decrease in performance. The design was user-friendly, and all the steps required to perform the detection were sample preparation and sample loading. The results could be read directly within 15 min. The use of test strips enabled the detection of disease at a stage 4 days earlier than the traditional method. [ABSTRACT FROM AUTHOR]

Fluopyram, as a novel succinate dehydrogenase inhibitors (SDHIs) fungicide, was applied for controlling grey mould in China. In order to investigate the possible development of resistance development of Botrytis cinerea to fluopyram, Botrytis cinerea were collected from eight areas in Liaoning Province, and the sensitivities of these isolates were assessed by mycelium growth and the fitness and resistance mechanism of resistant isolates screened. The results showed that the sensitivity baseline of B. cinerea to fluopyram was (4.82 ± 1.49) μg/mL, and 5 low resistance isolates to fluopyram were detected. The fitness of resistant isolates showed a downward trend of several variables, such as mycelium growth, mycelium dry weight, sporulation and lesion diameter, which were significantly lower than those of sensitive isolates. Conidia germination did not differ significantly between sensitive and resistant isolates. There was no cross‐resistance between fluopyram and fludioxonil/boscalid/pyrimethanil/procymidone/carbendazim. The succinate dehydrogenase activity of resistant isolates was higher than that of sensitive isolates with fluopyram or not, and the inhibition of fluopyram on succinate dehydrogenase of sensitive isolates was greater than that of resistant isolates. Resistant isolates AS8 and AS14 carried the point mutation (N230I) in subunit B. These results provided that fluopyram belonged to a medium‐high resistance risk to B. cinerea. Information for managing resistance suggested that (1) the number of fluopyram applications should be limited to one per season and (2) fluopyram could be a valid alternative to fludioxonil, pyrimethanil, procymidone and carbendazim for the control of grey mould of tomato. [ABSTRACT FROM AUTHOR]

Edible fungi are not only delicious but are also rich in nutritional and medicinal value, which is highly sought after by consumers. As the edible fungi industry continues to rapidly advance worldwide, particularly in China, the cultivation of superior and innovative edible fungi strains has become increasingly pivotal. Nevertheless, conventional breeding techniques for edible fungi can be arduous and time-consuming. CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated nuclease 9) is a powerful tool for molecular breeding due to its ability tomediate high-efficiency and high-precision genome modification, which has been successfully applied to many kinds of edible fungi. In this review, we briefly summarized the working mechanism of the CRISPR/Cas9 system and highlighted the application progress of CRISPR/Cas9- mediated genome-editing technology in edible fungi, including Agaricus bisporus, Ganoderma lucidum, Flammulina filiformis, Ustilago maydis, Pleurotus eryngii, Pleurotus ostreatus, Coprinopsis cinerea, Schizophyllum commune, Cordyceps militaris, and Shiraia bambusicola. Additionally, we discussed the limitations and challenges encountered using CRISPR/Cas9 technology in edible fungi and provided potential solutions. Finally, the applications of CRISPR/Cas9 system for molecular breeding of edible fungi in the future are explored. [ABSTRACT FROM AUTHOR]

Brown spots occurring on potato leaves affect the normal growth of host plants. Recently, a new brown spot disease with some black dots was discovered on potato leaves in Dingxi, China. To confirm the causal agents of potato brown spots, the diseased lesions were collected and disinfected, and only one type of isolate, with football‐shaped conidia, was obtained from disinfected diseased leaves in three experimental fields. Pathogenicity tests of four representative isolates revealed that they can cause disease symptoms on 50%–75% of wounded and non‐wounded potato leaves. In addition, a typical isolate, DXPH, was identified based on morphological and molecular characteristics, and the colony and conidial characteristics were similar to those of Epicoccum sp. Multilocus sequence analysis showed that the internal transcribed spacer (ITS), RNA polymerase II second largest subunit (RPB2) and β‐tubulin (Tub2) genes of DXPH were 100%, 100% and 99% identical to the sequences of Epicoccum nigrum (CBS 140523), respectively. Additionally, antagonistic evaluation confirmed that the representative pathogenic strain DXPH showed greatest inhibition of the mycelial growth of Colletotrichum coccodes and Fusarium chlamydosporum in vitro, with antagonistic effects of 66.67% and 61.56%, respectively. Our findings provide evidence that E. nigrum can be pathogenic to potatoes in vivo in China, while retaining a biocontrol capacity on C. coccodes, Fusarium spp. and Botrytis cinerea in vitro, which will be helpful for the effective control of potato brown spot disease and management of the use of E. nigrum as a biological control agent. [ABSTRACT FROM AUTHOR]

Botrytis cinerea is a phytopathogenic fungus that causes serious damage to the agricultural industry by infecting various important crops. 2-allylphenol has been used in China as a fungicide for more than a decade, and it has been shown that is a respiration inhibitor. A series of derivatives of 2-allylphenol were synthesized and their activity against B. cinerea was evaluated by measuring mycelial growth inhibition. Results indicate that small changes in the chemical structure or the addition of substituent groups in the aromatic ring induce important variations in activity. For example, changing the hydroxyl group by methoxy or acetyl groups produces dramatic increases in mycelial growth inhibition, i.e., the IC50 value of 2-allylphenol decreases from 68 to 2 and 1 μg mL−1. In addition, it was found that the most active derivatives induce the inhibition of Bcaox expression in the early stages of B. cinerea conidia germination. This gene is associated with the activation of the alternative oxidase enzyme (AOX), which allows fungus respiration to continue in the presence of respiratory inhibitors. Thus, it seems that 2-allylphenol derivatives can inhibit the normal and alternative respiratory pathway of B. cinerea. Therefore, we believe that these compounds are a very attractive platform for the development of antifungal agents against B. cinerea. [ABSTRACT FROM AUTHOR]

Background: Gray mold caused by Botrytis cinerea is an airborne plant pathogen with a necrotrophic lifestyle that infects more than 200 crops worldwide. Florylpicoxamid is a second‐generation picolinamide fungicide inspired by a natural product. Florylpicoxamid targets the Qi site of the mitochondrial cytochrome bc1 complex and is currently being registered in China for the control of gray mold in a variety of crops. Although a broad spectrum of activity and attributes have been reported for florylpicoxamid, little is known about its effectiveness against gray mold or its protective and curative properties. Results: Florylpicoxamid exhibited substantial inhibitory activity against 12 tested species of plant‐pathogenic fungi, with effective concentration for 50% growth inhibition (EC50) values ranging from 0.017 to 2.096 μg ml−1. A total of 129 isolates of B. cinerea from ten regions were tested for their sensitivity to florylpicoxamid, and the mean EC50 value was 0.04 ± 0.017 μg ml−1. Furthermore, florylpicoxamid was observed to substantially inhibit all developmental stages of B. cinerea, with mycelial development, sclerotium germination, germ tube elongation and conidial germination being restrained with an EC50 value of 0.051 ± 0.0072, 0.012 ± 0.0069, 0.019 ± 0.0041 and 0.0062 ± 0.0007 μg ml−1, respectively. No cross‐resistance was observed between florylpicoxamid and quinone outside inhibitor (QoI), methyl benzimidazole carbamates or succinate dehydrogenase inhibitor. Florylpicoxamid also exhibited protective and curative activity against the development of B. cinerea infection in tests on tomato fruits. At application rates of 90, 112.5 and 135 g a.i. ha−1, florylpicoxamid was also observed to provide more‐effective control than boscalid (300 g a.i. ha−1). Conclusion: This study demonstrated that the novel fungicide florylpicoxamid exhibits strong inhibitory activity against B. cinerea, regardless of the resistance profiles of those isolates to tested fungicides with different modes of action. This makes florylpicoxamid a powerful new solution to optimize gray mold control and manage fungicide resistance. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Previous studies in Botrytis cinerea showed that resistance to methyl benzimidazole carbamates (MBCs) was mainly related to E198A/V/K and F200Y mutations of the β-tubulin gene, and El98V was the dominant mutation in the resistant subpopulation in Hubei Province of China, indicating that resistant mutations might influence fitness. However, little is known about the effect of each E198 A/V/K mutation on fitness. In this study, the fitness and competitive ability of isolates with E198A/V/K mutations were investigated. Results showed that E198A/V/K isolates and wild-type isolates shared similar fitness components in terms of virulence, sporulation, conidial germination, oxidative sensitivity, and sclerotial production and viability. However, slower mycelial growth at 4°C, higher sensitivity to 4% NaCl, and increased sclerotial production percentage at 4°C were observed in the isolates with E198V, E198K, and E198A mutations, respectively. Competitive analysis showed that the wild-type subpopulation became dominant after three disease cycles in the absence of fungicide selection pressure, whereas the resistant subpopulation seized the space of the sensitive subpopulation upon MBC application. Unexpectedly, the frequency of El98V isolates decreased dramatically after the first disease cycle with or without fungicide selection pressure. These results suggest that MBC-resistant isolates suffer little fitness penalty but possess competitive disadvantages in the absence of fungicide selection pressure. Under fungicide selection pressure. El98V isolates could not compete with E198A/K isolates. According to the current results, there is a great possibility that the El98V mutation will lose dominance in the future in China. [ABSTRACT FROM AUTHOR]

Grey mould, caused by Botrytis cinerea, is an increasingly destructive disease of ginseng (Panax ginseng) in China. However, the extent of variation in the morphological characteristics of fungal colonies, genetic background and pathogenicity of different strains of this pathogen remains unknown. In this study, we isolated and identified 102 isolates of B. cinerea from ginseng. Among these, the sclerotial phenotype was dominant, followed by the mycelial and conidial phenotypes, with the proportion of each phenotype in the pathogen population showing no obvious variance across three provinces. Isolates were separated into three groups with differing pathogenicity, based on the diameter of the lesions they caused in pathogenicity tests; moderate-pathogenicity isolates were dominant, followed by strong- and weak-pathogenicity isolates. Variation was observed in the pathogenicity of isolates from three provinces. The Nei's genetic diversity index and the Shannon's information index of isolates from Jilin province was highest, followed by those from Liaoning, while isolates from Heilongjiang displayed the lowest genetic diversity. Furthermore, most of the genetic variance was found within the geographically defined B. cinerea populations; the low-genetic variance among populations was probably counteracted by gene flow. Results from this study provide a base understanding of genetic and pathogenic variation in B. cinerea populations from the main ginseng-growing regions of China, which will be helpful for further research and control of grey mould of ginseng. [ABSTRACT FROM AUTHOR]

Tomato gray mold (TGM), caused by Botrytis cinerea, is a destructive disease of greenhouse tomatoes. Its control mainly depends on the application of chemical fungicides. In China, penthiopyrad has been registered for the management of TGM for about 3 years. In this study, the baseline sensitivity of B. cinerea to penthiopyrad was measured based on mycelial growth and spore germination, using 131 wild isolates collected from Hebei Province. The mean EC50 values 1.054 ± 0.633 mg/L (on mycelial growth) and 0.101 ± 0.037 mg/L (on conidia germination) were used as the baseline sensitivity. Isolates (187) of B. cinerea, sampled from eight regions in Hebei province during 2021 and 2022, were used for resistance studies by mycelial growth method. Based on the resistance factor, these isolates were considered: sensitive (=65 isolates), low (=39 isolates), moderate (=38 isolates), and high (=45 isolates) resistance. All 15 isolates from Raoyang were sensitive to penthiopyrad. Four mutation types in the sdhB subunit, namely H272R, N230I, P225F, and P225L, were associated with the resistance to penthiopyrad. A positive cross-resistance was also recorded between penthiopyrad and fluopyram, boscalid, or pydiflumetofen. These results provide useful information on the chemical control of TGM. [ABSTRACT FROM AUTHOR]

A method was established for the simultaneous determination of penthiopyrad, its main metabolite 1-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxamide (PAM), trifloxystrobin and its metabolite trifloxystrobin acid in tomato. The samples were extracted with acetic acid and acetonitrile, cleaned-up with anhydrous MgSO4, primary secondary amine (PSA) and GCB, and detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The linearities of penthiopyrad, PAM, trifloxystrobin and trifloxystrobin acid ranged from 0.025 to 2 mg/L, with R2 ı 0.9992. The average recoveries of the four compounds in tomato at different spiked levels were 88%-97%, with the relative standard deviations (RSD) less than 3.9%. The limits of quantification (LOQs) of the analytes were all 0.05 mg/kg. The supervised residue trials were carried out in 12 farm regions in China according to "Guideline for the Testing of Pesticide Residues in Crops". The 30% suspension concentrate of penthiopyrad and trifloxystrobin was sprayed twice with an interval of 7 days at the recommended dosage of 270 g a.i./hm2 at the early stage of Botrytis cinerea in tomato, and the recommended pre-harvest interval was 5 days. On the 5th and 7th day after the last application, the residues of penthiopyrad in tomato samples were below 0.26 mg/kg, and the residues of trifloxystrobin were below 0.33 mg/kg, which were lower than the corresponding MRLs set in China. The dietary risk assessment was carried out according to the results of residue field trials, dietary structure and toxicological data. The results showed that the national estimated daily intake (NEDI) of penthiopyrad and trifloxystrobin were 0.138 2 mg and 0.264 5 mg, respectively. The dietary risk quotient (RQ) of penthiopyrad and trifloxystrobin in tomato were less than 100%, which indicated that the application of the 30% suspension concentrate of penthiopyrad and trifloxystrobin under recommended Good Agricultural Practice (GAP) conditions would not pose an unacceptable risk to human health. [ABSTRACT FROM AUTHOR]

BACKGROUND: Gray mold caused by Botrytis cinerea Pers. is one of the most significant airborne diseases. It can infest a wide range of crops, causing significant losses in yield and quality worldwide. Pydiflumetofen, a new generation succinate dehydrogenase inhibitor (SDHI), is currently being registered in China to control gray mold in a variety of crops. The baseline sensitivity, resistance risk, and resistance mechanism of Botrytis cinerea to pydiflumetofen were assessed in this study. RESULTS: A total of 138 strains of B. cinerea from 10 different regions were tested for their sensitivity to pydiflumetofen, and the mean EC50 value was 0.0056 μg mL−1. Eight mutants were obtained by fungicide adaption from five sensitive parental isolates, and the resistance factor (RF) ranged from 51 to 135. The mutants exhibited strong adaptive traits in conidial production, conidial germination, and pathogenicity. Positive cross‐resistance was only observed between other SDHIs (i.e. boscalid, fluopyram, and isopyrazam). Two different types of pydiflumetofen‐resistant mutants were identified: point mutation P225L in sdhB and double mutation G85A and I93V in sdhC. The in vivo control efficacy of pydiflumetofen on the resistant mutants carrying P225L in sdhB as well as G85A and I93V in sdhC was significantly decreased to 52.62% and 32.27%, respectively. CONCLUSION: The fitness was significantly higher for all pydiflumetofen‐resistant mutants than the corresponding parental. Two types of point mutations, sdhB‐P225L and sdhC‐G85A and I93V, might confer resistance to pydiflumetofen in B. cinerea. A precautionary resistance management strategy should be implemented. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The bacterial genus Streptomyces is an important source of antibiotics, and genome mining is a valuable tool to explore the potential of microbial biosynthesis in members of this genus. This study reports an actinomycete strain 135, which was isolated from Qinghai-Tibet Plateau in China and displayed broad antimicrobial activity. The fermentation broth of strain 135 displayed strong antifungal activity (>70%) against Sclerotinia sclerotiorum , Botrytis cinerea , Valsa mali , Phytophthora capsici , Glomerella cingulata , Magnaporthe grisea , Bipolaris maydis , Exserohilum turcicum in vitro , meanwhile possessed significant preventive and curative efficacy against S. sclerotiorum , Gaeumannomyces graminis , and P. capsici on rape leaves (54.04 and 74.18%), wheat (90.66 and 67.99%), and pepper plants (79.33 and 66.67%). X-14952B showed the greatest antifungal activity against S. sclerotiorum and Fusarium graminearum which the 50% inhibition concentration (EC50) were up to 0.049 and 0.04 μg/mL, respectively. Characterization of strain 135 using a polyphasic approach revealed that the strain displayed typical features of the genus Streptomyces. 16S rRNA gene sequencing and phylogenetic analysis demonstrated that the isolate was most closely related to and formed a clade with Streptomyces huasconensis HST28T (98.96% 16S rRNA gene sequence similarity). Average nucleotide identity (ANI) and DNA-DNA hybridization (DDH) values in strain 135 and related type strains were both below the threshold of species determination (91.39 and 56.5%, respectively). OrthoANI values between strain 135 and related type strains are under the cutoff of determining species (<95%). The biosynthetic gene cluster (BGC) designated to X-14952B biosynthesis was identified through genome mining and the possible biosynthesis process was deduced. [ABSTRACT FROM AUTHOR]

Botrytis cinerea is a destructive plant pathogenic ascomycete that causes serious pre- and post-harvest losses worldwide. The novel sterol 14α-demethylase inhibitor (DMI) pyrisoxazole was recently registered for the control of tomato gray mold caused by B. cinerea in China. Baseline sensitivity of 110 B. cinerea isolates collected from nine provinces in China to pyrisoxazole was demonstrated, with a mean EC50 of 0.057 ± 0.029 μg/ml. Eleven stable mutants resistant to pyrisoxazole were generated via UV irradiation (RU-mutants) and spontaneous selection (RS-mutants) of conidia. The efficacy of pyrisoxazole against the resistant mutants was significantly lower than that of the sensitive isolates. Most of the pyrisoxazole- resistant mutants were less fit than the sensitive isolates, with reduced sporulation, conidia germination, sclerotium production, and pathogenicity, which was confirmed by the competitive ability test. Positive cross-resistance was only observed between pyrisoxazole and the DMIs tebuconazole and prochloraz, but not between pyrisoxazole and non-DMIs iprodione, procymidone, diethofencarb, fluazinam, pyrimethanil, or fludioxonil. A two-point mutation, at G476S and K104E in the RU-mutants, and a one point mutation, M231T, in the RS-mutants, were detected in the CYP51 protein of the resistant mutants. When exposed to pyrisoxazole, the induced expression level of CYP51 increased in the resistant isolates as compared to sensitive ones. Molecular docking suggested that G476S and M231T mutations both led to the loss of electrostatic interactions between CYP51 and pyrisoxazole, while no change was found with the K104E mutation. Thus, two point mutations on CYP51 protein combined with induced expression of its target gene appeared to mediate the pyrisoxazole resistance of B cinerea. [ABSTRACT FROM AUTHOR]

Maxim (EbM) is a perennial herb grown in China for traditional Chinese medicines. Grey mould symptoms were observed on EbM leaves in several fields in Hubei Province, China, from April to June in 2015, 2016 and 2017. V-shaped blights or concentric rings appeared initially on the basal leaves, followed by necrosis gradually spreading from the tips and margins to the entire leaf. Severely infected leaves were rolled or distorted and became brittle. A fungal isolate, MF468110, was recovered from diseased plants and identified as Botrytis cinerea based on its morphological features and sequence analysis of multiple genes. The colony on potato dextrose agar was initially white with abundant fluffy aerial mycelia and turned grey with numerous irregular black sclerotia. Sequence analysis of the G3PDH, RPB2 and HSP60 genes found high similarity with other reference strains representing the species B. cinerea. Pathogenicity tests showed that the symptoms were similar on EbM leaves after inoculation with a conidial suspension and the re-isolated fungi were morphologically similar to the isolates used for inoculation, indicating that the isolate MF468110 was pathogenic to EbM. This is the first report of B. cinerea causing grey mould on EbM in China. [ABSTRACT FROM AUTHOR]

Botrytis cinerea is one of the most destructive pathogens worldwide. It can damage over 200 crops, resulting in significant yield and quality losses. Cyclobutrifluram, a new generation of succinate dehydrogenase inhibitors, exhibits excellent inhibitory activity against B. cinerea. However, the baseline sensitivity and resistance of B. cinerea to cyclobutrifluram remains poorly understood. This study was designed to monitor the sensitivity frequency distribution, assess the resistance risk, and clarify the resistance mechanism of B. cinerea to cyclobutrifluram. The baseline sensitivity of B. cinerea isolates to cyclobutrifluram was 0.89 μg/mL. Cyclobutrifluram-resistant B. cinerea populations are present in the field. Six resistant B. cinerea isolates investigated in this study possessed enhanced compound fitness index compared to the sensitive isolates according to mycelial growth, mycelial dry weight, conidiation, conidial germination rate, and pathogenicity. Cyclobutrifluram exhibited no cross-resistance with tebuconazole, fludioxonil, cyprodinil, or iprodione. Sequence alignment revealed that BcSDHB from cyclobutrifluram-resistant B. cinerea isolates had three single substitutions (P225F, N230I, or H272R). Molecular docking verified that these mutations in BcSDHB conferred cyclobutrifluram resistance in B. cinerea. In conclusion, the resistance risk of B. cinerea to cyclobutrifluram is high, and the point mutations in BcSDHB (P225F, N230I, or H272R) confer cyclobutrifluram resistance in B. cinerea. This study provided important insights into cyclobutrifluram resistance in B. cinerea and offered valuable information for monitoring and managing cyclobutrifluram resistance in the future. [Display omitted] • Baseline sensitivity of B. cinerea to cyclobutrifluram was established. • The resistance risk of cyclobutrifluram in B. cinerea was high. • Point mutations in BcSDHB were associated with the cyclobutrifluram resistance in B. cinerea. [ABSTRACT FROM AUTHOR]

Botrytis cinerea in China. One hundred fifty-seven isolates of B. cinerea in China. One hundred fifty-seven isolates of B. cinerea were collected from tomato greenhouses in 14 cities of Liaoning Province from 2016 to 2021 and examined for sensitivity to pyrisoxazole, with a mean EC 50 value of 0.151 μg/ml. Three highly resistant isolates, XD-5, DG-4, and GQ-3, were screened, and the EC 50 values were 0.734, 0.606, and 0.639 μg/ml with corresponding resistance factors of 12.88, 10.63, and 11.21, respectively. Compared with field-sensitive strains, the highly resistant isolate XD-5 exhibited fitness defects in traits, including mycelial growth, conidial production, and pathogenicity, but DG-4 and GQ-3 did not experience fitness costs. Positive cross-resistance was observed only between pyrisoxazole and the DMIs tebuconazole and prochloraz but not between pyrisoxazole and the non-DMIs iprodione, procymidone, pyrimethanil, fludioxonil, fluazinam, and fluopyram. Sequence alignment of the CYP51 gene indicated that three point mutations were observed in the highly resistant mutant, namely, V24I in XD-5, G461S in GQ-3, and R464K in DG-4. When exposed to pyrisoxazole, the induced expression levels of the ABC transporter AtrD and MFS transporter Mfs1 increased in the resistant isolates compared with those in the sensitive isolates, whereas the expression level of the CYP51 gene did not change significantly. Molecular docking suggested that the G461S and R464K mutations both led to a decrease in the binding energy between CYP51 and pyrisoxazole, whereas no change was found with the V24I mutation. Thus, two point mutations in the CYP51 protein combined with induced expression of the Mfs1 and AtrD genes appeared to mediate the pyrisoxazole resistance of the highly resistant mutants DG-4 and GQ-3, while the overexpression of the Mfs1 and AtrD genes was responsible for the highly resistant mutant XD-5., Competing Interests: The author(s) declare no conflict of interest.

Botrytis cinerea is an important pathogen of vegetable and fruit crops but little is known about its population structure and genetics in China. We hypothesized that the geographic populations of B. cinerea in China would be genetically differentiated by host, geographic location, and/or year. In this study, we collected 393 B. cinerea isolates representing 28 populations from tomato, cherry, and nectarine from 2006 to 2014 in China. The isolates were analyzed using 14 microsatellite markers, including six new markers that provided more genotyping power than the eight previously published loci. We also investigated the B. cinerea population structure and inferred its mode of reproduction and dispersal based on genotype data. High genotypic diversity was detected in all populations, and clonal reproduction was dominant. Southern China populations harbored more genotypes than northern populations. Differentiation by host plant was evident. Between 2011 and 2012, genotypes changed only slightly among years for Liaoning populations, but they changed substantially among years for the Shanghai and Fujian populations. Clonal dispersal was detected and the farthest dispersal distance was estimated to be about 1,717 km. Two high-frequency genotypes were widely distributed in more than 10 populations and across several years. Our results provide useful, novel information for plant breeding programs and control of B. cinerea in China. [ABSTRACT FROM AUTHOR]

Gray mold caused by Botrytis cinerea has become an important limiting factor for tree peony production. Currently, chemical control is still the main means of managing the disease in China. The objective of this study was to test fungicides with different mechanisms of action in controlling B. cinerea on tree peony. The inhibitory efficacy of five fungicides on four asexual stages was measured in the petri dish containing culture medium amended with a tested fungicide at various concentrations. The results showed that carbendazim had the strongest inhibition effect against all four stages of B. cinerea, with the EC50 values of 0.1037, 0.0563, 0.5578, and 0.0797 mg·L-1, respectively. The inhibitory effect of diethofencarb was only slightly less than that of carbendazim on conidia production, germination, and germ tube elongation. The inhibitory effect of procymidone was second only to that of carbendazim on colony expansion. The results indicated that carbendazim and diethofencarb could be used as protective fungicides to spray in the early stage of disease occurrence to inhibit conidia germination and germ tube elongation, so as to reduce the infection rate of B. cinerea and prevent disease occurrence. Carbendazim, procymidone, and diethofencarb mainly inhibit the reinfection of B. cinerea by inhibiting the growth of mycelium and the production of conidia, so they could be used as control fungicides during the occurrence phase of the disease. [ABSTRACT FROM AUTHOR]

Grey mould, caused by the fungal pathogen Botrytis cinerea, is one of the most devastating tomato diseases, and the control of this disease is mainly by the application of chemicals. In this study, 512 isolates of B. cinerea were collected from tomato grown in greenhouses at 10 locations in 10 cities of Hebei Province from 2011 to 2016 and tested for their sensitivities to carbendazim (Car), diethofencarb (Die), iprodione (Ipr) and pyrimethanil (Pyr). Of these tested isolates, 95.7%, 95.2%, 31.6% and 89.4% were resistant to Car, Die, Ipr and Pyr, respectively. There were nine fungicide‐resistant phenotypes in the tested isolates. CarRPyrRDieRIPRS and CarRPyrRDieRIPRR were the most common phenotypes, accounting for 59.6%, and 31.1% of the tested isolates, respectively. The field trials showed that the control efficacies (CE) of carbendazim + diethofencarb (WP, 25% + 25%), pyrimethanil (EC, 40%) and iprodione (WP, 50%) at the recommended doses were 22.75%–29.23%, 58.44%–64.19% and 61.02%–65.17%, respectively, significantly lower than those of boscalid (WG, 50%) and pyrisoxazole (EC, 25%). The resistance management trial conducted from 2015 to 2017 indicated that the CE of tomato grey mould in the experimental fields was higher than 90% and the sensitivity to carbendazim, diethofencarb and pyrimethanil of B. cinerea isolates from the experimental fields increased on a yearly basis. These results showed that the frequency of resistance to Car, Die, Ipr and Pyr was high, and these four fungicides could not effectively control tomato grey mould. Tomato grey mould could be controlled by using biopesticides and newly synthesized fungicides with different modes of action. Our findings would be useful in designing and implementing fungicide resistance management spray programmes for the control of tomato grey mould. [ABSTRACT FROM AUTHOR]

• Our work will extend applicable field of allicin. • Application of allicin increased the activities of SOD, CAT and POD in tomato leaves. • Allicin was a promising natural compound to control M. incognita and B. cinerea. Allicin (diallyl thiosulfinate) is the key natural antimicrobial compound of garlic. Extensive studies have been conducted to understand the effects of allicin in medicine; however, little information is currently available in China about its effects on root-knot nematodes, plant pathogens, plant growth and yield. Laboratory and greenhouse experiments were conducted to evaluate the potential of allicin to control Meloidogyne incognita and Botrytis cinerea in tomato, and its effect on tomato plant growth and yield. The responses of antioxidant enzyme activity to allicin application were also investigated. Results from the laboratory experiments showed that allicin exhibited effective inhibition against M. incognita and B. cinerea , with the median lethal concentration (LC 50) of 18.23 and 14.11 mg active ingredient (ai) L−1, respectively. In the greenhouse experiments, allicin not only had an active effect on tomato growth but also showed excellent efficacy to control M. incognita and B. cinerea , resulting in increased tomato yield. Application of allicin also significantly increased the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in tomato leaves compared with the untreated control. Results from this study indicated that allicin was a promising natural compound to control M. incognita and B. cinerea in tomato, providing a potential substitute to synthetic chemical compounds for control of the root-knot nematodes and gray mold of tomato. [ABSTRACT FROM AUTHOR]

Grey mould, caused by the fungus Botrytis cinerea Pers ex Fr., is a very destructive and important disease worldwide. Fluazinam is a phenylpyridinamine fungicide with broad‐spectrum activities. The baseline sensitivity of B. cinerea to fluazinam is yet to be established in Henan Province, China. In this study, a total of 117 field isolates of B. cinerea were collected from 49 commercial greenhouses in different locations of Henan Province, in 2016, and the sensitivities of these isolates to fluazinam were determined based on mycelial growth. The effective concentration for 50% (EC50) values ranged from 0.0038 to 0.0441 μg/ml, and the mean EC50 value was 0.0201 ± 0.0081 μg/ml for mycelial growth. The frequency distribution range presented a unimodal curve. To define the cross‐resistance relationships, the linear correlation coefficients of the EC50 values between fluazinam and carbendazim, procymidone, pyrimethanil or boscalid were analysed. The results showed that no correlation was observed between fluazinam and the other tested fungicides. These results provide important information to growers for the prevention and control of grey mould. [ABSTRACT FROM AUTHOR]

Gray mold, caused by the fungus Botrytis cinerea , is one of the most important plant diseases worldwide that is prone to developing resistance to fungicides. Currently, the phenylpyrrole fungicide fludioxonil exhibits excellent efficacy in the control of gray mold in China. In this study, we detected the fludioxonil resistance of gray mold disease in Shouguang City of Shandong Province, where we first found fludioxonil-resistant isolates of B. cinerea in 2014. A total of 87 single spore isolates of B. cinerea were obtained from cucumbers in greenhouse, and 3 of which could grow on PDA plates amended with 50 μg/mL fludioxonil that was defined as high-level resistance, with a resistance frequency of 3.4%. Furthermore, the 3 fludioxonil-resistant isolates also showed high-level resistance to the dicarboximide fungicides iprodione and procymidone. Sequencing comparison revealed that all the 3 fludioxonil-resistant isolates had a point mutation at codon 1158, GAC (Asp) → AAC (Asn) in the histidine kinase Bos1, which was proved to be the reason for fludioxonil resistance. In addition, the fludioxonil-resistant isolates possessed an impaired biological fitness compared to the sensitive isolates based on the results of mycelial growth, conidiation, virulence, and osmotic stress tolerance determination. Taken together, our results indicate that the high-level resistance to fludioxonil caused by the Bos1 point mutation (D1158N) has emerged in the field gray mold disease, and the resistance risk is relatively high, and fludioxonil should be used sparingly. [Display omitted] • The high levels of fludioxonil resistance was detected in gray mold disease in the greenhouse of China. • The new point mutation (D1158N) in histidine kinase Bos1 confers high-level resistance to fludioxonil. • The development of fludioxonil resistance is accompanied by fitness penalty. [ABSTRACT FROM AUTHOR]

This study assessed the fenhexamid sensitivity of 143 Botrytis cinerea isolates collected from greenhouse strawberries in five regions of China between 2012 and 2013, and identified four isolates with moderate levels of resistance: two from the Xinjiang Uygur Autonomous Region and two from Hebei Province. The baseline fenhexamid sensitivity of B. cinerea exhibited a unimodal distribution with a mean EC50 value of 0.20 ± 0.10 μg/ml ( SD). The EC50 values of the fenhexamid-resistant isolates ranged from 0.05 to 0.40 μg/ml. Molecular analysis of the fenhexamid target gene erg27 revealed that the resistant isolates collected from Xinjiang (163-6 and 163-22) contained three mutations that led to amino acid changes (V365A, E368D and A378T) known to be associated with fenhexamid resistance, but that the isolates from Hebei lacked any mutations, indicating that an alternative mechanism could be responsible for their resistance. Most of the biological characteristics of the fenhexamid-resistant isolates, such as mycelial growth, sclerotia production and pathogenicity, did not significantly differ from those of the sensitive ones ( p ≤ .05), but it was noted that some of the resistant isolates exhibited reduced rates of sporulation and spore germination. In addition, the resistant isolates exhibited lower osmotic sensitivity than the sensitive ones. The study found no evidence of cross-resistance with other fungicides, but that there was negative cross-resistance with procymidone, iprodione, carbendazim and pyraclostrobin, which indicates that the inclusion of these fungicides within an integrated pest management ( IPM) programme could help to minimize the risk of fenhexamid resistance developing in B. cinerea. [ABSTRACT FROM AUTHOR]

Fluxapyroxad, a type of succinate dehydrogenase inhibitor fungicide, has been used to control the growth of gray mold on strawberry for more than 5 years in China. Selection for resistance to the causal agent Botrytis cinerea became a threat to the efficacy of fluxapyroxad. In total, 160 B. cinerea isolates collected from Shanghai during 2020 and 2021 were tested for their resistance to fluxapyroxad using mycelial growth inhibition. The results indicated that the curve of baseline sensitivity was unimodal, with an approximately normal distribution and a mean effective concentration of the fungicide that inhibited growth by 50% (EC 50 ) of 0.18 ± 0.01 μg/ml. In total, 27.78 and 48.57% of isolates were resistant to fluxapyroxad in 2020 and 2021, respectively, where the lowest EC 50 value of mycelial growth inhibition was 0.03 μg/ml and the highest value was 51.3 μg/ml. Resistance mechanism analysis showed that the succinate dehydrogenase subunit B ( SdhB ) N230I mutation could lead to resistance and P225F mutation could lead to higher resistance. These data suggest that the resistance frequency of B. cinerea isolates to fluxapyroxad increased in 2021 compared with 2020, which requires appropriate fungicide rotation strategies to be implemented in order to control gray mold on strawberry in the future., Competing Interests: The author(s) declare no conflict of interest.

Grey mould, caused by Botrytis cinerea Pers ex Fr., is one of the most common diseases of tomato worldwide. Fludioxonil belongs to the phenylpyrrole fungicides, which have high activity against B. cinerea. The sensitivity of fludioxonil was evaluated on the basis of the level of inhibition of mycelium growth in 274 B. cinerea isolates collected from different locations (untreated with this fungicide) in Henan Province, China. The EC50 values for fludioxonil ranged from 0.0033 to 0.0415 mg/l, and the average EC50 values were 0.0156 ± 0.0078 mg/l. Three fludioxonil-resistant mutants were obtained by subculturing fludioxonil-sensitive wild-type isolates on continuously increasing fludioxonil concentrations. For the cross-resistance assay, fludioxonil revealed positive cross-resistance with procymidone but did not reveal cross-resistance with pyrimethanil, boscalid and trifloxystrobin. Mycelial growth, conidial production, hyphal dry weight and pathogenicity were diminished significantly between the fludioxonil-resistant mutants and their sensitive wild-type parental isolates. This study shows for the first time that fludioxonil-resistant isolates of B. cinerea are still not present in Henan Province because this fungicide is an attractive and effective fungicide for chemical control. Recommendations can be made to growers to use fludioxonil to control grey mould and to consider the potential moderate resistance risk of using this fungicide. [ABSTRACT FROM AUTHOR]

Okra ( Abelmoschus esculentus), or Lady's finger, is a plant originating from Africa and is grown as a multipurpose crop in Asia, America and Europe nowadays. Grey mould disease was observed on okras in several okra fields in Ledong County, Hainan Province, and Shunyi District, Beijing City, during September to December in 2014 with the incidence varying from 20 to 55%. To identify the pathogen, the detailed morphological, cultural characteristics, pathogenicity test along with the DNA sequences for four gene regions ITS, G3PDH, HSP60 and RPB2 of our isolate were compared with those of some previously reported Botrytis cinerea and other similar species of the genus Botrytis. Results suggested this is the first report of grey mould disease on Abelmoschus esculentus caused by Botrytis cinerea in China. [ABSTRACT FROM AUTHOR]

Tomato gray mold (TGM), a worldwide destructive disease, is caused by Botrytis cinerea , and fungicide treatments are effective for its control. Pydiflumetofen is a new fungicide of succinate dehydrogenase inhibitors. In this research, 153 B. cinerea isolates were collected from eight different cities in Hebei Province from 2015 to 2017. The sensitivity of these 153 isolates to pydiflumetofen was determined by spore germination assays and mycelial growth rate assays. The results indicated that for these tested isolates, the EC 50 values of pydiflumetofen ranged from 0.0036 to 0.0822 mg/L (on conidia germination), and 0.0287–1.2659 mg/L (on mycelial growth rate), with average EC 50 values of 0.0327 ± 0.0213 mg/L and 0.3717 ± 0.2744 mg/L, respectively. The frequency distribution of the sensitivity of these 153 isolates to pydiflumetofen was a continuous single-peak curve, and could be used as the baseline for testing the sensitivity of B. cinerea to pydiflumetofen. No cross-resistance existed between pydiflumetofen and the other six botryticides such as diethofencarb, pyrimethanil, iprodione, pyrisoxazole, and fludioxonil, apart from fluopyram. The control efficacy of pydiflumetofen against TGM was determined using detached leaves and in field trials. Pydiflumetofen exhibited good control efficacy against TGM and the preventive effect was better than the curative effect. In the field trials, the control efficacy of pydiflumetofen against TGM was higher than 80%, both on leaves and fruits, at doses of 120, 160 and 200 g a.i./ha. It was significantly better than pyrimethanil. This study showed that pydiflumetofen had high activity and could effectively control the prevalence of TGM, but it should be administered carefully. • Establishment the baseline-sensitivity of Botrytis cinerea to pydiflumetofen. • Clarify the cross-resistance relationship between pydiflumetofen and other six botryticides. • Pydiflumetofen has good preventive-activity and curative-activity on TGM. • Pydiflumetofen is an excellent fungicide for controlling TGM. [ABSTRACT FROM AUTHOR]

One hundred and eight isolates of Botrytis cinerea from greenhouse cucumber and tomato in two locations in Jiangsu Province (Nanjing and Huaiyin) and one location in Shandong Province were tested for their sensitivities to the four fungicides commonly used in China. Isolates with resistance to all four fungicides-carbendazim, diethofencarb, procymidone, and pyrimethanil (CarRDieRPrcRPyrR)-were found in all three regions in this study. High frequencies (52 and 53%) of resistance to all four fungicides were observed among the 62 isolates collected in Nanjing and the 36 isolates collected in Huaiyin in Jiangsu Province. The 10 isolates from Shandong Province were all resistant to the four fungicides. Pathogenicity and sporulation in vivo, and mycelial growth, sporulation, spore germination, and osmotic sensitivity to NaCI in vitro, were similar for the group of quadruple-resistant and wild-type isolates (P > 0.05). In the present study, the complete two-component histidine kinase gene (Bosi) was sequenced for 10 procymidone-resistant and 3 procymidone-sensitive B. cinerea isolates. Isolates representing four different procymidone-resistant phenotypes (CarRDieRPrcRPyrR, CarRDieRPrcRPyrR, CarRDieRPrcRPyrR, and CarRDieRPrcRPyrR) all had nucleic acid point mutations resulting in amino acid changes at position 369 (change from glutamine to proline) as well as at amino acid position 373 (asparagine to serine) in the Bosi gene. [ABSTRACT FROM AUTHOR]

The article presents a study which uses point mutation to transform the ß-tubulin gene of Botrytis cinerea into Fusarium graminearum and identify if transformants were resistant to technical-grade carbendazim (MBC). It states that the Shenyang Academy of Chemistry and Industry in Shenyang, Liaoning Sheng, China has provided the MBC for testing. The results show that the gene could not manifest its effect in the F. graminearum due to the sensitivity of MBC transformants.

The article reports on the result of the study conducted on the biochemical mechanism of 2-allyphenol inhibiting Botrytis cinerea in China. It includes the use of the obtained 2-allylphenol from the Research Center of Agric-bionic Engineering and Technology of Shandong Province, China. Result of the study suggests that 2-allyphenol induces cyanide-resistant respiration causing ATP decrease and inhibits respiration through an unidentified mechanism.

Botrytis cinerea , the fungal pathogen that causes grey mold in many crops, including the herbal medicinal plant ginseng (Panax ginseng), frequently exhibits multi-resistance. In this study, the sensitivity of 102 ginseng B. cinerea isolates collected from 11 ginseng growing regions in Jilin, Liaoning and Heilongjiang Provinces of China in 2018 and 2019 was examined. A total of 100%, 72.55% and 76.47% of the isolates were resistant to carbendazim (C), pyrimethanil (P) and iprodione (I), respectively. Four fungicide resistance patterns, including CRPRIR, CRPSIR, CRPRIS and CRPSIS, were identified, comprising 58.82%, 17.65%, 13.73% and 9.80%, respectively. The frequency and level of resistance of the isolates resistant to pyrimethanil and iprodione clearly varied among ginseng growing regions and lack significant cross-resistance. The geographic origins lacked any apparent correlation to pathogenicity, while the pathogenicity of isolates with the SC and M phenotypes was clearly higher than those with the SP phenotype. All the isolates resistant to carbendazim harbored a point mutation of E198A (Glu→Ala), E198V (Glu→Val), or E198K (Glu→Lys) at codon 198 in the β-tubulin gene, while isolates resistant to iprodione harbored a point mutation of I365S (Ile→Ser) or I365N (Ile→Asn) at codon 365, or point mutations of Q369P (Gln→Pro) + N373S (Asn→Ser) at codons 369 and 373 in the BcOS -1 gene. The patterns of point mutations in these genes closely correlated with the geographic origins, and the resistance of isolates that had the Q369P + N373S mutations was higher than those that had the I365S and I365N mutations. All these results provide a relatively clear understanding of the multi-resistance and molecular mechanism of B. cinerea isolates from ginseng growing regions in China. The variation in pathogenicity and the fungicide resistance of these isolates was revealed, which will help to establish a more effective strategy to control ginseng grey mold. • B. cinerea isolates from ginseng growing regions of China shown marked resistance to carbendazim, pyrimethanil and iprodione. • The pathogenicity of B. cinerea isolates was unrelated to their geographic origin but correlated with colonial phenotype. • E198A and E198V were predominated for carbendazim resistance, Q369P + N373S more resistant to iprodione than I365S and I365N. • The patterns of point mutations of B. cinerea isolates closely correlated with their geographic origins. [ABSTRACT FROM AUTHOR]

Gastrodia elata Blume is a valuable Chinese herbal medicine. G. elata flower tissue with symptoms of gray mold was collected in June 2021 at the G. elata breeding base in Dejiang County and Qixingguan County, Guizhou Province. Botrytis cinerea was isolated from the symptomatic flowers, and the fungus was identified based on morphological characteristics and phylogenetic analyses of the ITS, HSP60, and RPB2 sequences. The pathogenicity test revealed B. cinerea as responsible for causing flower gray mold identified on G. elata. To our knowledge, this is the first report of B. cinerea causing gray mold in G. elata flowers. These findings thus provide a basis for further research on the management of flower gray mold of G. elata. • Gastrodia elata Blume is a valuable Chinese herbal medicine. • G elata is well-distributed throughout China and contributes highly to the economy. • G elata is affected by tuber rot disease, fungal infections, white sclerosis etc. • We identified gray mold in G elata at the flowering stage. • Ours is the first study to report the causative agent as Botrytis cinerea. [ABSTRACT FROM AUTHOR]

Bursaphelenchus chengi sp. n. is described and illustrated. Dauer juveniles were isolated from imported wood packaging materials from Taiwan to Nanjing Port, China. Bursaphelenchus chengi sp. n. was reared and maintained on Petri dish cultures of the fungus Botrytis cinerea. The new species is characterised by the medium body size in both sexes, the presence of only two incisures in the lateral field and the robust and strongly curved spicules. The spicule lamina is angular distally, the rostrum digitate and the condylus rounded. The tail is arcuate with a pointed terminus. The bursa is usually truncate with the posterior margin indented in some specimens or rounded with a fine axial point. Females have a small vulval flap formed by a short extension of the cuticle of the anterior lip, and a conical tail that gradually tapers to an almost straight or slightly recurved, pointed or rounded terminus. Because of the presence of two lateral lines, similar spicule shape, tapering female tail and the presence of a small vulval flap, B. chengi sp. n. should be grouped in the abietinus-group sensu Braasch. together with B. abietinus, B. antoniae, B. hellenicus, B. hylobianum and B. rainulfi. ITS-RFLP profiles support the proposal of the new species, and phylogenetic analysis of the 28S rDNA D2/D3 domain sequence places it close to B. antoniae and other species of the abietinus-group. [ABSTRACT FROM AUTHOR]

Twenty-one strains of Botrytis cinerea isolated from 13 species of plants grown in China were compared for pathogenicity on Brassicci napus, mycelial growth on potato dextrose agar, and presence of double-stranded (ds)RNA. The results showed that the strain CanBc-1 was severely debilitated in pathogenicity and mycelial growth, compared with the 20 virulent strains. A dsRNA of approximately 3.0 kb in length was detected in CanBc-1 and 4 hypovirulent single-conidium (SC) isolates of CanBc-1, but was not detected in the 20 virulent strains of B. cinerea and 4 virulent SC isolates of CanBc-1. Results of the horizontal transmission experiment showed that the hypovirulent trait of CanBc-1 was transmissible and the 3.0-kb dsRNA was involved in the transmission of hypovirulence. Analysis of a 920-bp cDNA sequence generated from the 3.0-kb dsRNA of CanBc-1 indicated that the dsRNA element was a mycovirus, designated as B. cinerea debilitation-related virus (BcDRV). Further analyses showed that BcDRV is closely related to Ophiostoma Initovirus 3b infecting O. novo-ulmi, the causal agent of Dutch elm disease. Mitochondria and cytoplasm in hyphal cells of CanBc-1 became degenerated, compared with the virulent isolate CanBc-1c-66 of B cinerea. This is the first report on the occurrence of Mitovirus-associated hypovirulence in B. cinerea. [ABSTRACT FROM AUTHOR]

Between 2004 and 2006, 228 isolates of Botrytis cinerea from two regions in China were characterized for baseline sensitivity to boscalid, a new active ingredient that interferes with succinate ubiquinone reductase in the electron transport chain. The isolates showed similar sensitivity in different years and regions. Baseline sensitivities were distributed as unimodal curves with mean EC50 values of 1·07 (± 0·11) and 0·42 (± 0·05) mg L−1 for inhibition of mycelial growth and conidial germination, respectively. Laboratory studies were conducted to evaluate the risk of development of resistance to boscalid. Boscalid-resistant mutants were obtained by UV-treatment at lower frequencies and with smaller resistance factors than pyrimethanil-resistant mutants. All boscalid-resistant mutants were also significantly more sensitive to Qo inhibitors than their wild-type parents and showed reduced sporulation in vitro and pathogenicity on aubergine leaves. The results suggested that the risk of resistance developing for boscalid was lower than for pyrimethanil. However, as B. cinerea is a high-risk pathogen, appropriate precautions against resistance development should be taken. Synergism between the activity of boscalid and that of kresoxim-methyl was observed. [ABSTRACT FROM AUTHOR]

The transcription factor WRKY33 is a vital regulator of the biological process of the necrotrophic fungus Botrytis cinerea ( B. cinerea ). However, its specific regulatory mechanism remains to be further investigated. In non-heading Chinese cabbage (NHCC, Brassica campestris (syn. Brassica rapa ) ssp. Chinensis ), our previous study showed that BcWRKY33A is induced not only by salt stress, but also by B. cinerea infection. Here, we noticed that BcWRKY33A is expressed in trichomes and confer plant defense resistance. Disease symptoms and qRT-PCR analyses revealed that BcWRKY33A -overexpressing and -silencing lines were less and more severely impaired, respectively, than wild type upon B. cinerea treatment. Meanwhile, the transcripts' abundance of indolic glucosinolates' (IGSs) biosynthetic genes is consistent with plants' B. cinerea tolerance. Identification and expression pattern analysis of BcMYB51s showed that BcMYB51-3 has a similar trend to BcWRKY33A upon B. cinerea infection. Moreover, BcWRKY33A directly binds to the BcMYB51-3 promoter, which was jointly confirmed by Y1H, dual-LUC, and EMSA assays. The importance of MYB51, the homolog of BcMYB51-3, in the BcWRKY33A-mediated B. cinerea resistance was also verified using the TRV-based VIGS system. Overall, our data concludes that BcWRKY33A directly activates the expression of BcMYB51-3 and downstream IGSs' biosynthetic genes, thereby improving the B. cinerea tolerance of NHCC plants.

[Display omitted] • We remarkably increase the potency of osthole derivatives against the resistant phytopathogenic fungi. • We have simplified the structure of osthole and obtained the potent osthole derivatives C 4. • We indicated that the cell membrane of fungi is the key action site of C 4. Plant pathogenic fungi decrease the quality and productivity of plant production. The botanical fungicides have better biocompatibility and rapid biodegradation, little or no cross resistance, and the structural diversity, and thus are beneficial to deal with plant fungal diseases. Osthole has been widely used as the commercial botanical fungicide against powdery mildew in China. In this article, a series of osthole derivatives were synthesized, which respectively contain different substituents on the benzene ring, at the C8-position and pyrone ring. All the target compounds were evaluated in vitro for their antifungal activity against resistant phytopathogenic fungi. Colletotrichum fragariae, Strawberry Botrytis Cinerea, Kiwifruit Botrytis Cinerea, Kiwifruit brown Rots, which are common in fruit fungal diseases. The compound C 4 was identified as the most promising candidate with the EC 50 values at 38.7 µg/mL against Colletotrichum Fragariae, 14.5 µg/mL against Strawberry Botrytis Cinerea and 24.3 µg/mL against Kiwifruit Botrytis Cinerea , respectively, whereas the antifungal activity against resistant phytopathogenic fungi. of osthole is too low to be used (EC 50 > 400 ppm). The results of mycelial relative conductivity determination, PI uptake and fluorescence spectroscopy indicated that the cell membrane of fungi is the key action site of C 4. Besides, C 4 has the potent inhibitory activity against both of plant and human pathogenic bacteria. Our studies showed that C 4 was worthy for further attention as a promising botanical fungicide candidate in crop protection. [ABSTRACT FROM AUTHOR]

Polygonatum sibiricum is a traditional Chinese medicinal herb and can also be used as tea and ornamental plant. During 2016 to 2018, a disease with symptoms similar to gray mold was extensively observed on leaves of P. sibiricum in the Sichuan Province of China. The pathogen was isolated from the diseased plants and identified as Botrytis cinerea based on the morphological features and Internal transcribed spacer (ITS), DNA dependent RNA polymerase subunit II gene (RPB2), heat-shock protein 60 gene (HSP60) and ATP-dependent RNA helicase DBP7 gene (MS547) all of which showed 99.89%–99.91% identities to the reported B. cinerea strains. Pathogenicity was confirmed through inoculation experiments fulfilling Koch's postulates. To our knowledge, this is the first report of B. cinerea causing gray mold disease on P. sibiricum in China. • This research first reported the occurrence of a gray mold of Polygonatum sibiricum in China. • The pathogen fungus was isolated and identified as B. cinerea. • Pathogenicity tests confirmed Botrytis cinerea was virulent to P. sibiricum. [ABSTRACT FROM AUTHOR]

Botrytis cinerea is a destructive necrotrophic pathogen that can infect many plant species. The control of gray mold mainly relies on the application of fungicides, and the fungicide fludioxonil is widely used in China. However, the field fungicide resistance of B. cinerea to this compound is largely unknown. In this study, B. cinerea isolates were collected from different districts of Shanghai province in 2015–2017, and their sensitivity to fludioxonil was determined. A total of 65 out of 187 field isolates (34.76%) were found to be resistant to fludioxonil, with 36 (19.25%) showing high resistance and 29 (15.51%) showing moderate resistance. Most of these resistant isolates also showed resistance to iprodione, and some developed resistance to fungicides of other modes of action. AtrB gene expression, an indicator of MDR1 and MDR1h phenotypes, was not dramatically increased in the tested resistant isolates. Biological characteristics and osmotic sensitivity investigations showed that the fitness of resistant isolates was lower than that of sensitive ones. To investigate the molecular resistance mechanisms of B. cinerea to fludioxonil, the Bos1 amino acid sequences were compared between resistant and sensitive isolates. Resistant isolates revealed either no amino acid variations or the mutations I365S, I365N, Q369P/N373S, and N373S. [ABSTRACT FROM AUTHOR]

Gray mold, caused by the fungus Botrytis cinerea Pers ex Fr., is one of the most destructive spoilage diseases, severely affecting tomato production in Henan Province, China. Spraying fungicides from the flowering to the harvest stage is a necessary measure to reduce losses associated with B. cinerea infection. However, B. cinerea has developed resistance to fungicides in many countries. Boscalid is a succinate dehydrogenase inhibitor (SDHI) fungicide and was registered for the control of gray mold. In this study, a total of 269 B. cinerea isolates were collected from tomato in commercial greenhouses in different locations of Henan Province in 2014 and 2015. The sensitivity and resistance of B. cinerea field isolates were determined based on mycelial growth. The effective concentration 50 ranged from 0.11 to 15.92 µg/ml and 0.16 to 8.54 µg/ml, in 2014 and 2015, respectively. The frequency of low resistance to boscalid was 12.6 and 7.6%, and moderate resistance was 2.7 and 1.3% in 2014 and 2015, respectively. No highly resistant isolates were found in Henan Province, China. Mycelial growth, mycelial dry weight, spore production, and pathogenicity were not significantly different between resistant and sensitive phenotypes of the B. cinerea isolates. The results of cross-resistance testing showed no correlation between boscalid and carbendazim, procymidone, pyrimethanil, fluazinam, or fluopyram. In this study, the succinate dehydrogenase genes B ( sdhB ), C ( sdhC ), and D ( sdhD ) were analyzed and compared in sensitive and low-resistance and moderately resistant B. cinerea isolates to boscalid. Results showed that point mutations occurred simultaneously at sdhC amino acid positions 85 (G85A), 93 (I93V), 158 (M158V), and 168 (V168I) in 4 out of 10 sensitive isolates and 23 of 26 low-resistance and 5 of 5 moderately resistant B. cinerea isolates to boscalid. No point mutations were found in the sdhB and sdhD genes of all isolates. Furthermore, no point mutations were found in sdhB , sdhC , and sdhD genes in 3 of 26 low-resistance B. cinerea isolates to boscalid. Therefore, we speculate that the simultaneous point mutations in the sdhC gene may not be related to the resistance of B. cinerea to boscalid. These results suggested that there might be a substitution mechanism for the resistance of B. cinerea to the SDHI fungicide boscalid.

Gray mold caused by Botrytis cinerea is one of the most important diseases in tomato. It can be controlled effectively by demethylation inhibitor (DMI) fungicides, but their resistance status after long-term use in the field is unclear. The baseline sensitivity to difenoconazole of 142 B. cinerea isolates from China with no history of DMI usage was characterized, with a mean effective concentration for 50% mycelial growth inhibition (EC 50 ) of 0.97 ± 0.50 μg/ml. EC 50 values for difenoconazole sensitivity of another 248 isolates collected in 2011 and 2016 ranged from 0.04 to 11.99 μg/ml, and the frequency of difenoconazole sensitivity formed a nonnormal distribution curve. Detached fruit studies revealed that isolates with EC 50 values of approximately 6.00 μg/ml were not controlled effectively. The mean EC 50 of the resistant isolates changed from 6.74 to 8.65 μg/ml between 2011 and 2016. Positive cross-resistance was only observed between difenoconazole and two DMIs. One dual resistant isolate and one triple resistant isolate were found among the difenoconazole-resistant isolates collected in 2016, associated with point mutations in corresponding target proteins of the fungicides azoxystrobin and fludioxonil. This indicated that B. cinerea not only showed higher difenoconazole resistance levels but gradually changed from single to multiple fungicide resistance over time. No amino acid variation was found in the CYP51 protein. In the absence of difenoconazole, the relative expression of CYP51 was not significantly different in sensitive and resistant isolates. Induced expression of CYP51 is an important determinant of DMI resistance in B. cinerea from tomato. However, nucleotide variants found in the upstream region had no association with the fungicide resistance phenotype. These results will be helpful for the management of B. cinerea in the field.

This study characterized a single-stranded circular DNA virus in Botrytis cinerea-namely, Botrytis cinerea genomovirus 1 (BcGV1). The genome of BcGV1 was 1710 nucleotides (nts) long, possessing two ORFs, encoding a putative replication initiation protein (Rep) and a hypothetical protein. The Rep contained seven conserved motifs. The two ORFs were separated by two intergenic regions; the large intergenic region (LIR) contained 259 nts while the small intergenic region (SIR) contained 95 nts. A nonanucleotide, TAACAGTAC, in the LIR was predicted to be associated with the initiation of viral replication. Based on the phylogenetic tree constructed by Reps, BcGV1 belongs to the family Genomoviridae, forming an independent branch, indicating that BcGV1 may belong to a new genus. BcGV1 could be detected in 6.7% of tested B. cinerea strains, suggesting that BcGV1 may be widely distributed in the Chinese B. cinerea population., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Gray mold caused by Botrytis cinerea is a fungal disease that critically threatens agricultural production, and carbendazim was the first fungicide used to control B. cinerea . However, B. cinerea developed serious resistance to carbendazim, and this fungicide has thus rarely been used in the past decade in China. Due to the extended discontinuation of carbendazim use, the evolution of the resistance of B. cinerea to carbendazim in recent years is unclear, and whether carbendazim can effectively control gray mold is largely unknown. Therefore, this study determined the sensitivity of 407 B. cinerea isolates collected from 2014 to 2018 to carbendazim and the ability of carbendazim to control gray mold in the field. The results showed that the frequency of B. cinerea isolates resistant to carbendazim remained above 95%. Three different mutation types responsible for the resistance of B. cinerea to carbendazim were identified at codon 198 in the β-tubulin gene sequence: E198V (changed from GAG to GTG), E198A (changed from GAG to GCG), and E198K (changed from GAG to AAG). Over the last 5 years, E198V was the major mutation. However, an analysis of its evolution revealed that the percentage of the E198V mutation declined after 2017 to 56.5% in 2018. In addition, the proportion of isolates with the E198K mutation decreased over time, and no isolates with this mutation were found in either 2017 or 2018. The proportion of the E198A mutation increased over the 5-year test period to reach 43.5% in 2018. Furthermore, three greenhouse experiments demonstrated that carbendazim has lost its ability to control gray mold. We attribute the above findings to our results showing that the carbendazim-resistant isolates had no fitness penalties compared with the carbendazim-sensitive isolates for sporulation and mycelial growth. In particular, the E198A mutant isolates exhibited a strong ability to sporulate, suggesting that the E198A mutation might become dominant in the future. Interestingly, the results showed that carbendazim-sensitive isolates could be easily controlled by four conventional fungicides, namely boscalid, procymidone, iprodione, and pyrimethanil, with mean EC 50 values of 0.71 ± 0.2 mg liter -1 , 1.33 ± 0.39 mg liter -1 , 0.59 ± 0.33 mg liter -1 , and 6.02 ± 3.02 mg liter -1 , respectively. In conclusion, carbendazim has lost its application value and is ineffective for the control of gray mold.

The gray mold caused by Botrytis cinerea has a significant impact on tomato production throughout the world. Although the synthetic fungicide fludioxonil can effectively control B. cinerea , there have been several reports of resistance to this fungicide. This study indicated that all of the fludioxonil-resistant strains tested, including one field-resistant isolate and four laboratory strains, had reduced fitness relative to sensitive isolates. In addition to having reduced growth, sporulation, and pathogenicity, the resistant strains were more sensitive to osmotic stress and had significantly ( P < 0.05) higher peroxidase activity. BOs1, a kinase in the high-osmolarity glycerol stress response signal transduction pathway, is believed to harbor mutations related to fludioxonil resistance. Sequence analysis of their BOs1 sequences indicated that the fludioxonil-resistant field isolate, XXtom1806, had four point mutations resulting in four amino acid changes (I365S, S531G, T565N, and T1267A) and three amino acids (I365S, S531G, and T565N) in the histidine kinases, adenylyl cyclases, methyl-accepting chemotaxis receptors, and phosphatases domain, which associated with fludioxonil binding. Similarly, two of the laboratory strains, XXtom-Lab1 and XXtom-Lab4, had three (Q846S, I1126S, and G415D) and two (P1051S and V1241M) point mutations, respectively. A third strain, XXtom-lab3, had a 52-bp insertion that included a stop codon at amino acid 256. Interestingly, the BOs1 sequence of the fourth laboratory strain, XXtom-lab5, was identical to those of the sensitive isolates, indicating that an alternative resistance mechanism exists. The study also found evidence of positive cross-resistance between fludioxonil and the dicarboximide fungicides procymidone and iprodione, but no cross-resistance was detected with any other fungicides tested, including boscalid, carbendazim, tebuconazole, and fluazinam.

Trichoderma species are a group of fungi which is widely distributed in major terrestrial ecosystems; they are also commonly used as biocontrol agents for many plant diseases. A virus, namely Trichoderma harzianum hypovirus 1 (ThHV1), was identified in T. harzianum isolate T-70, and also infected isolate T-70D, together with its defective RNA (ThHV1-S). The ThHV1 genome possessed two Open Reading Frames (ORFs), namely ORF1 and ORF2. The start codon of ORF2 overlapped with the stop codon of ORF1 in a 43 nt long region. The polypeptide encoded by ORF2 of ThHV1 shared sequence similarities with those of betahypoviruses, indicating that ThHV1 is a novel member of Hypoviridea. Isolate T-70D, carrying both ThHV1 and ThHV1-S, showed abnormal biological properties, notably a decreased mycoparasitism ability when compared with isolate T-70. Both ThHV1 and ThHV1-S could be vertically transmitted to conidia and horizontally transmitted to T. harzianum isolate T-68 and T. koningiopsis T-51. The derivative strains carrying both ThHV1 and ThHV1-S showed decreased mycoparasitism ability, whereas strains carrying ThHV1 alone were normal, indicating that ThHV1-S is closely associated with the decreased mycoparasitism ability of T. harzianum isolate T-70D. ThHV1 was widely detected in isolates of T. harzianum, T. koningiopsis and T. atroviride originating from soil of China. Therefore, viruses in fungal biocontrol agents may also be a factor associated with the stability of their application. [ABSTRACT FROM AUTHOR]