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Plant Disease Feb 2023The coconut (Cocos nucifera L., Arecaceae) is one of the most important tropical species used by humans. In Brazil, its cultivation has been expanding in the recent...
The coconut (Cocos nucifera L., Arecaceae) is one of the most important tropical species used by humans. In Brazil, its cultivation has been expanding in the recent years (Souza et al. 2020) and many diseases have emerged. The pestalotia spot, caused by Pestalotiopsis guepinii (Desm.), is a leaf disease of the coconut characterized by elliptic lesions with defined dark borders varying in size from 3 to 5 mm (Cardoso et al. 2003). In January of 2018, leaves with symptoms of pestalotia spot were obtained from ten year old coconut plants "dwarf variety" in a commercial planting in the city of Neópolis (10°20'S/36°42'W), Sergipe, Brazil. Disease incidence was 80% on 60 plants observed. Twenty samples of symptomatic tissues were collected and disinfested for 2 min in 1% sodium hypochlorite, washed in sterile water, placed on PDA (potato dextrose agar), and incubated at 25 ± 1°C with a 12-h photoperiod for 4 days. Five isolates were obtained, and pure cultures deposited in Phytopathogen Collection of the Federal University of Alagoas, accession numbers: COUFAL0240 to COUFAL0244. Seven day old colonies grown on PDA at 25°C, were whitish with aerial mycelium on the surface and abundant production of black conidiomata. Conidia were fusiform, straight to slightly curved with five cells, three median cells with brown coloring being the second and third being darker and the apical and basal cells, hyaline. Fifty conidia were measured and varied in size from 20.02-24.26 x 5.37-7.50 μm. The conidia presented two to four apical appendages and one basal appendage (Fig. S1). The morphological characteristics coincide with the Neopestalotiopsis foedans (Sacc. & Ellis), Maharachchikumbura et al. (2014). Molecular identification was conducted using partial nucleotide sequences from the ITS (ITS1/ITS4) region (GenBank no. MT605375 to MT605379) and from the genes TUB2 (Bt2a/Bt2B) (no. MT634202 to MT634206) and TEF-1α (526F/1567R) (no. MT634197 to MT634201). Besides that, the isolates grouped with the ex-type N. foedans species (CGMCC 3.9123) in a phylogenetic tree of Bayesian inference using concatenated sequences (Fig. S2). The pathogenicity was confirmed on seedling from coconut plants "dwarf variety" maintained in a greenhouse. Four plants were used, being one as a control. Spore suspensions of 106 conidia mL-1 was prepared from a 7 days old culture (cultivated at 25ºC). Inoculations were performed by spraying the conidial suspension on two whole leaves per plant (wounded and unwounded). In the control, sterilized distilled water was used. Plants were incubated at 25 ± 1°C and 100% relative humidity. Ten days after inoculation, depressed and necrotic lesions were observed in 100% on the inoculated leaves with wound. No symptoms observed on unwounded leaves, nor in the control treatment. To complete Koch's postulates, the N. foedans fungus was successfully re-isolated from the symptomatic leaves and identified phenotypically in optical microscope. Neopestalotiopsis foedans has already been reported in Calliandra haematocephala (Hassk), Neodypsis decaryi (Jum.), Rhizophora mangle (L.), Thuja occidentalis and Psidium guajava (L.) (Saccardo, 1882; Maharachchikumbura et al. 2014, Solarte et al. 2018). However, this is first report of N. foedans causing leaf spot in coconut in the world. The pestalotia spot is commonly observed in Brazil in C. nucifera and should be considered an important disease for this culture, as this can significantly reduce its photosynthetic area.
PubMed: 36726002
DOI: 10.1094/PDIS-12-22-2874-PDN -
Plant Disease Feb 2023Liquidambar formosana Hance, a deciduous tree, is widely cultivated in China for its ornamental and afforestation value (Yin et al. 2021). In July 2019, leaf spot...
Liquidambar formosana Hance, a deciduous tree, is widely cultivated in China for its ornamental and afforestation value (Yin et al. 2021). In July 2019, leaf spot symptoms were observed with 20 to 30% disease incidence in Li shan forest farm (27°19'27.2″N, 115°32'51.08″E) in Ji'an city, Jiangxi province, China. Initial disease symptoms were small spots, which enlarged and circular to irregular, gray in the center, and dark brown to black circular on the lesion margin. Leaf pieces (5 × 5 mm) from the lesion borders were surfaced and sterilized in 70% ethanol for 30 s, followed by 2% NaOCl for 1 min, and then rinsed three times with sterile water (Si et al. 2022). Tissues were placed on potato dextrose agar (PDA) and incubated at 25°C. Pure cultures were obtained by monosporic isolation, and the representative isolates, FX-2, FX-5, and FX-9 were used for morphological studies and phylogenetic analyses. The colonies of three isolates on PDA grew fast, covering the entire plate with white cottony mycelia with black acervuli after 8 to 10 days. Conidia were 5-celled, clavate to fusiform, smooth, 19.6-24.2 × 6.2-8.5 μm (n = 100). The 3 median cells were dark brown to olivaceous, central cell was darker than other 2 cells, and the basal and apical cells were hyaline. All conidia developed one basal appendage (3.5-8.2 μm long; n = 100), and 2-3 apical appendages (18-31 μm long; n = 100), filiform. Morphological features were similar to Neopestalotiopsis sp. (Maharachchikumbura et al. 2014). The internal transcribed spacer (ITS) regions, β-tubulin 2 (TUB2) and translation elongation factor 1-alpha (TEF1-α) were amplified from genomic DNA for the three isolates using primers ITS1/ITS4, T1/Bt-2b, EF1-728F/EF-2 (Maharachchikumbura et al. 2014), respectively. All sequences were deposited into GenBank (ITS, ON622512- ON622514; TUB2, ON676532 - ON676534; TEF1-α, ON676529 - ON676531). A maximum likelihood and Bayesian posterior probability analyses using IQtree v. 1.6.8 and Mr. Bayes v. 3.2.6 with the concatenated sequences placed FX-2, FX-5, and FX-9 in the clade of N. clavispora. Based on the multi-locus phylogeny and morphology, three isolates were identified as N. clavispora. To confirm pathogenicity, 10 healthy 2-year-old seedlings, and 5 leaves per seedling were wounded with a sterile needle (Φ=0.5 mm) and inoculated with 200 μL conidial suspension per leaf(106 conidia/mL). Ten control plants were inoculated with ddH2O. All the inoculated leaves were covered with plastic bags and kept in a greenhouse at 26 ± 2 °C and RH 70%. All the inoculated leaves showed similar symptoms to those observed in the field, whereas control leaves were asymptomatic for 8 days. N. clavispora was reisolated from the lesions, whereas no fungus was isolated from control leaves. N. clavispora can cuase leaf diseases in a variety of hosts, including × Taxodiomeria peizhongii (Zhang et al. 2022), Macadamia integrifolia (Qiu et al. 2020), Dendrobium officinale (Cao et al. 2022). N. cocoes, N. chrysea, Pestalotiopsis neglecta and P. neolitseae were also reported to infect L. formosana (Fan et al. 2021). However, this is the first report of N. clavispora infecting L. formosana in China. This work provided crucial information for epidemiologic studies and appropriate control strategies for this newly emerging disease.
PubMed: 36724035
DOI: 10.1094/PDIS-12-22-2825-PDN -
Scientific Reports Jan 2023Synthetic fungicides are necessary evil in crop production, their usage cannot be neglected or abandoned but must be alternated/supplemented with other control measures...
Synthetic fungicides are necessary evil in crop production, their usage cannot be neglected or abandoned but must be alternated/supplemented with other control measures such as cultural, host resistance and biocontrol methods to reduce their detrimental effect on the environment and living organisms. A bioproduct (wood vinegar) was evaluated against oil palm seedling pathogens at CSIR-Oil Palm Research Institute, Kusi at different concentrations and compared with an inorganic fungicide at the manufacturer's recommended dosage. Disease pathogens were isolated from collected diseased leaf samples and pure cultures were established on cPDA. PDA was amended with wood vinegar ranging from 0 to 3.35% and 0.1%v/v of carbendazim as a positive control. Daily colony growth was measured in two diagonal lengths and averages of day 6 and day 7 were used to calculate the inhibition percentage for both pathogens. 11 mm/day was the lowest average growth rate recorded for 2.68% v/v of wood vinegar and 14.17 mm/day on control plate of Curvularia species. There was no significant difference between 0.1%v/v carbendazim, 2.68 and 3.35% v/v against Curvularia species whilst significantly, there was difference between 0.1%v/v carbendazim and 2.68 and 3.35%v/v of wood vinegar against Pestalotiopsis species.
Topics: Seedlings; Organic Agriculture; Fungicides, Industrial; Palm Oil
PubMed: 36690688
DOI: 10.1038/s41598-023-27972-y -
Microorganisms Jan 2023Fungal endophytes are friendly microorganisms that colonize plants and are important in the interactions between plants and their environment. They generate valuable...
Fungal endophytes are friendly microorganisms that colonize plants and are important in the interactions between plants and their environment. They generate valuable secondary metabolites that are valuable to both plants and humans. Endophytic fungi with bioactivities were isolated from the leaves of the medicinal plant . An efficient isolate was selected and identified as based on nucleotide sequencing of the internal transcribed spacer region (ITS 1-5.8S-ITS 2) of the 18S rRNA gene (NCBI accession number OP529850); the 564 bp had 99 to 100% similarity with MH860161.1, AY682935.1, KP689121.1, and MG572407.1, according to the BLASTn analysis, following preliminary phytochemical and antifungal screening. The biological activities of this fungus' crude ethyl acetate (EtOAc) extract were assessed. With an efficient radical scavenging activity against 2,2'-diphenyl-1-picrylhydrazyl and an IC value of 36.6 µg mL, extract has shown its potential as an antioxidant. Moreover, it displayed notable cytotoxic effects against MCF-7 (breast carcinoma, IC = 22.4 µg mL), HeLa (cervical carcinoma, IC = 28.9 µg mL) and HepG-2 (liver carcinoma, IC = 28.9 µg mL). At 10 µg mL, EtOAc demonstrated significant DNA protection against hydroxyl radical-induced damage. Based on FT-IR and GC-MS spectral analysis, it was detected that the EtOAc of product contains multiple bioactive functional groups. Subsequently, this validated the features of major different potent compounds; tolycaine, 1H-pyrazol, 1,3,5-trimethyl-, eugenol, 2,5-cyclohexadiene-1,4-dione, 2,6-bis(1,1-dimethyl), and bis(2-ethylhexyl) phthalate. Since these compounds are biologically relevant in various aspects, and distinct biological activities of fungal extract were acceptable in vitro, this suggests that endophytic fungus may be a viable source of bioactive natural products. This could be a good starting point for pharmaceutical applications.
PubMed: 36677409
DOI: 10.3390/microorganisms11010117 -
Foods (Basel, Switzerland) Jan 2023Diacylglycerol (DAG) production by microbial fermentation has broad development prospects. In the present study, five endophytic fungi which could accumulate DAG were...
Diacylglycerol (DAG) production by microbial fermentation has broad development prospects. In the present study, five endophytic fungi which could accumulate DAG were screened from by using potato dextrose agar plate and flask cultivation in potato dextrose broth culture medium. The strains were biologically identified based on morphological features and semi-quantitative PCR. The identification results indicated that the five strains belonged to different genera: ( coded as MLP41), ( coded as MLG23), ( coded as MLY23), ( coded as MLY31W), and ( coded as MLGP11). The crude lipids from the strains and their corresponding triacylglycerol, 1,2-DAG, and 1,3-DAG fractions separated via thin-layer chromatography were mainly composed of palmitic acid, stearic acid, oleic acid, and linoleic acid, which in total accounted for higher than 94% of the content. The effects of fermentation conditions on the DAG productivity were discussed, and the yields of DAG were determined based on the H NMR spectra of crude lipids. The highest total DAG yields of , , , , and were 112.28, 126.42, 189.87, 105.61, and 135.56 mg/L, respectively. had the strongest potential to produce DAG. The results showed that this may be a new promising route for the production of DAG via fermentation by specific endophytic fungi, such as .
PubMed: 36673491
DOI: 10.3390/foods12020399 -
BioMed Research International 2022Plant species are known to harbor large number of endophytes, which stays in plant tissues as symbionts. These endophytes secrete large array of bioactive compounds that...
Plant species are known to harbor large number of endophytes, which stays in plant tissues as symbionts. These endophytes secrete large array of bioactive compounds that have potency against certain diseases with no side effects. We have collected leaf samples of the plant from the Pakistan Forest Institute, Khyber Pakhtunkhwa, Pakistan for the isolation of beneficial endophytes. The strains isolated from the leaves of were coded with MOL and tested for antimicrobial, antifungal, germicidal, phytotoxic, insecticidal, cytotoxic, and anti-inflammatory activities. The isolates, MOL1, MOL16, MOL19, and MOL21, possessed antibacterial activity against , whereas MOL7 inhibited 55% of the growth of . MOL3 inhibited the growth of , S. , and . The strains, MOL1 and MOL7, showed antifungal activity against and , while the strains, MOL11 and MOL17, showed activity against . The isolates, MOL3, MOL7, MOL9, MOL15, MOL17, MOL18, and MOL19, inhibited the growth of (duckweed) at 100 g/ml. MOL2 exhibited strong activity in the brine shrimp assay, while MOL1, MOL2, MOL5, MOL6, MOL12, MOL17, MOL19, and MOL20 showed insecticidal, and MOL3 demonstrated larvicidal and antileishmanial activity. The isolated potent endophytes were identified as , through morphological and microscopic characteristics of the colonies.
Topics: Antifungal Agents; Moringa oleifera; Staphylococcus aureus; Escherichia coli; Microbial Sensitivity Tests; Fungi; Anti-Infective Agents; Plant Leaves; Endophytes
PubMed: 36567913
DOI: 10.1155/2022/2461021 -
Caryophyllene sesquiterpenoids with various ring systems from the fungus Pestalotiopsis chamaeropis.Phytochemistry Mar 2023Six undescribed caryophyllene sesquiterpenoids named pestalotiopsins O-T, along with eight known analogues, were obtained from the fungus Pestalotiopsis chamaeropis....
Six undescribed caryophyllene sesquiterpenoids named pestalotiopsins O-T, along with eight known analogues, were obtained from the fungus Pestalotiopsis chamaeropis. Their structures and absolute configurations were assigned by NMR spectroscopic analyses, HRESIMS, single-crystal X-ray diffraction, electronic circular dichroism (ECD) calculations, Mo(OAc)-induced ECD, and chemical derivatization. Pestalotiopsin P represents the first example of a caryophyllene sesquiterpenoid possessing an oxatricyclo [7.2.2.0]tridecane decorated with a rare bridgehead double bond, while pestalotiopsin Q has an oxatricyclic [6.3.1.0]dodecane skeleton with an unusual ether bridge between C-1 and C-5. These undescribed caryophyllene sesquiterpenoids were screened for their cytotoxic and anti-inflammatory activities.
Topics: Molecular Structure; Sesquiterpenes; Fungi
PubMed: 36566821
DOI: 10.1016/j.phytochem.2022.113569 -
Microorganisms Dec 2022Lipases (EC 3.1.1.3) are hydrolases that catalyze triglycerides hydrolysis in free fatty acids and glycerol. Among the microorganisms that produce lipolytic enzymes, the...
Lipases (EC 3.1.1.3) are hydrolases that catalyze triglycerides hydrolysis in free fatty acids and glycerol. Among the microorganisms that produce lipolytic enzymes, the entophytic fungi stand out. We evaluated 32 fungi of different genera, Pestalotiopsis, Aspergillus, Trichoderma, Penicillium, Fusarium, Colletotrichum, Chaetomium, Mucor, Botryodiplodia, Xylaria, Curvularia, Neocosmospora and Verticillium, isolated from Euterpe oleracea Mart. (Açaizeiro) from the Brazilian Amazon for lipase activity. The presence of lipase was evidenced by the deposition of calcium crystals. The endophytic Pestalotiopsis sp. (31) and Aspergillus sp. (24) with Pz 0.237 (++++) and 0.5 (++++), respectively, were the ones that showed the highest lipolytic activity in a solid medium. Lipase activity was rated in liquid medium, in a different range of temperatures (°C), pH and time (days). The values obtained in the production of lipase by the endophytic fungi were 94% for Pestalotiopsis sp. (31) and 93.87% for Aspergillus sp. (24). Therefore, it is emphasized that the endophytic fungus isolated the E. oleracea palm may be a potential candidate to produce enzymes of global commercial interest.
PubMed: 36557647
DOI: 10.3390/microorganisms10122394 -
Plant Disease Jul 2023Recently, the Florida strawberry industry faced unprecedented outbreaks of an emerging disease caused by the fungus spp. Currently, there are no fungicides labeled to...
Recently, the Florida strawberry industry faced unprecedented outbreaks of an emerging disease caused by the fungus spp. Currently, there are no fungicides labeled to control this disease in the United States and the efficacy of single- and multisite fungicides is unknown. Therefore, this study aimed to determine the in vitro sensitivity of spp. isolates to fungicides with different modes of action and to evaluate the efficacy of these products on detached fruit and in the field. In preliminary in vitro tests, 30 commercially available fungicides were screened using discriminatory doses. The effective concentration that inhibited mycelial growth by 50% was determined for the most effective single-site fungicides. Four field experiments were conducted during the 2019-20, 2020-21, and 2021-22 seasons to determine product efficacy in managing the disease. The single-site fungicides fludioxonil, fluazinam, and sterol demethylation inhibitors, and the multisite fungicides captan, thiram, and chlorothalonil were the most effective in inhibiting pathogen growth and suppressing disease development. Conversely, products in Fungicide Resistance Action Committee (FRAC) groups 1 (methyl benzimidazole carbamate) and 7 (succinate-dehydrogenase inhibitors), except for benzovindiflupyr, were not effective against spp. Resistance to fungicides from FRAC group 11 (e.g., azoxystrobin) was confirmed by the presence of the G143A mutation in the gene together with inoculation tests and field trials. Our results provide information to support or discourage the registration of fungicides to manage Neopestalotiopsis fruit rot and leaf spot in strawberry production.
Topics: Fragaria; Fungicides, Industrial; Captan; Mutation; Xylariales
PubMed: 36541878
DOI: 10.1094/PDIS-08-22-1929-RE -
World Journal of Microbiology &... Dec 2022Gray blight, a fungal disease caused by Pestalotiopsis-like species, is a widespread disease affecting tea crop (Camellia sinensis (L.) Kuntze) in many tea-growing...
Gray blight, a fungal disease caused by Pestalotiopsis-like species, is a widespread disease affecting tea crop (Camellia sinensis (L.) Kuntze) in many tea-growing countries, including India, resulting in huge losses in tea production. In India, several studies have been conducted to understand the fungal diseases of tea crop, but gray blight has not been well described in major tea growing areas such as in North Bengal, based on its geographic distribution, molecular analysis, or pathogenicity, and even fungicide resistance. The objective of this study was to identify and characterize the causative agents of gray blight disease in symptomatic leaf sample of tea crop collected from 27 tea gardens located in North Bengal, India and to evaluate some common fungicides against them in order to understand the resistance mechanism. In this study, we characterized Pestalotiopsis-like species based on the phylogenies of DNA sequences (internal transcribed spacers) and assessment of conidial characteristics. The study revealed that out of 27 isolates of gray blight pathogens, 17 belonged to the genus Pseudopestalotiopsis (Ps.), six isolates were Neopestalotiopsis, and four were Pestalotiopsis. Two novel species, Ps. thailandica and N. natalensis were introduced through this study. The most frequently isolated genus from C. chinensis was Pseudopestalotiopsis. Pathogenicity tests showed that the isolates displayed significantly different virulence when inoculated onto wounded tea leaves and the mycelial growth rate was positively correlated with pathogenicity (P < 0.01). Based on the 13 ISSR (Inter Simple Sequence Repeat) markers used and principal coordinate analysis, it was found that isolates were very diverse. Out of 27 isolates, IND0P2, DLG0P10, and BHAT0P11 isolates were insensitive against both MBC + M3 (Carbendazim + Mancozeb) and DMI (Hexaconazole) fungicides, while isolates SANY0P18, PAHG0P19, RANG0P24, and SING0P25 were insensitive only against MBC + M3 fungicide. Further, these insensitive isolates were grouped into separate clusters by ISSR, indicating their distinctiveness. However, all the evaluated isolates were susceptible to M1 (copper oxychloride) and another DMI (propiconazole) fungicides. Therefore, to manage gray blight, fungicide resistance management strategies as recommended by Fungicide Resistance Action Committee should be implemented.
Topics: Fungicides, Industrial; Pestalotiopsis; Plant Diseases; Camellia sinensis; Xylariales; Tea
PubMed: 36469148
DOI: 10.1007/s11274-022-03474-3