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Plant Disease Jun 2024Psidium guajava L. is widely cultivated in southern China. In May 2021, guava scab on cv. Zhenzhu was observed in Zhanjiang (21.18° N, 110.21° E), Guangdong province,...
Psidium guajava L. is widely cultivated in southern China. In May 2021, guava scab on cv. Zhenzhu was observed in Zhanjiang (21.18° N, 110.21° E), Guangdong province, China. Guava scab was corky with ovoid or round lesions on the surfaces of green fruits. Gradually the lesions sunk. Disease incidence was estimated as 85% in 500 investigated plants in about 50 ha. Twenty diseased fruits were collected from twenty trees in the field. From each fruit the margin of the diseased tissues was cut into 2 mm × 2 mm pieces; surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, successively; and rinsed thrice with sterile water. The tissues were plated onto potato dextrose agar (PDA) medium and incubated at 28 ℃. Thirty-four isolates were obtained. Single-spore isolation method (Liu et al. 2021) was used to recover pure cultures of three isolates (PGNC-1, PGNC-2, and PGNC-3) . The colonies were initially white with cottony aerial mycelium at 7 days on PDA. Then, these colonies form black acervular conidiomata at 10 days. Conidia were clavate to fusiform, four-septate, straight or slightly curved, and measured 15.8 to 21.2 µm × 4.5 to 6.5 µm (n = 40). The three median cells were versicolored, whereas the basal and apical cells were hyaline. Conidia had a single basal appendage (4.5 to 5.5 µm long; n = 40) and three apical appendages (19.2 to 24.5 µm long; n = 40). The morphological characteristics of the isolates were consistent with the description of Neopestalotiopsis clavispora (Maharachchikumbura et al. 2012). Molecular identification was performed using PCR method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012). Sequences were generated from the isolates using primers for the rDNA ITS (ITS1/ITS4), TEF1-α (EF1-728F/EF1-986R), and β-tubulin (T1/βt2b) loci (Maharachchikumbura et al. 2012). The sequences of the isolates were submitted to GenBank (ITS, OQ996557 to OQ996559; TEF, OR101037 to OR101039; β-tubulin, OR100971 to OR100973). The sequences of the isolates were 100% identical to the type strain MFLUCC12-0281 (accession nos. JX398979, JX399014, and JX399045) through BLAST analysis. The isolates clustered with N. clavispora (MFLUCC12-0280 and MFLUCC12-0281). N. clavispora and Pestalotiopsis clavispora are synonyms. The pathogenicity was tested in vivo. Plants (cv. Zhenzhu) were grown ( 3 years old) in a quarantine orchard at 25 ℃ to 32 ℃ with 60 to 80% relative humidity in May 2022. Disease-free green fruits were inoculated. Sterile cotton balls were immersed in the spore suspension (1 × 105 per mL) and sterile distilled water (control) for about 15 s before they were fixed on the wounded fruits with transparent tape. Five fruits on one plant per isolate were inoculated. Five fruits on one plant severed as control. The test was performed thrice. Disease symptoms were found on the inoculated fruits after 20 days, whereas the controls remained healthy. The pathogen was re-isolated from infected fruits and was phenotypically identical to the original isolates thus fulfilling Koch's postulates. Neopestalotiopsis or Pestalotiopsis spp. were reported to be the causal agents of guava scab in Colombia and in Hawaii (Keith et al. 2006; Solarte et al. 2018). N. clavispora has been reported to cause disease in a broad range of hosts (Ge et al. 2009; Chen et al. 2018), but not in guava. This is the first report of N. clavispora causing guava scab in China. There would be no harvest if this disease is left unmanaged.
PubMed: 38885025
DOI: 10.1094/PDIS-11-23-2357-PDN -
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 Oct 2022Thunb., an evergreen shrub, is popular for landscaping in China. In 2021, leaf spot was observed on (about 150 trees) leaves with 40 to 50% disease incidence in...
Thunb., an evergreen shrub, is popular for landscaping in China. In 2021, leaf spot was observed on (about 150 trees) leaves with 40 to 50% disease incidence in Wanzhou urban forest (30°45'N; 108°27'E) of Chongqing, the infected plants were between 5 and 6 years old. The symptoms started to occur from June to July and approximately 30 to 40% of the leaves exhibited leaf spot symptoms from August to September. Initial symptoms appeared as yellow spots of 1.2 to 4.9 mm in diameter, and then expanded to become large and irregular lesions, having white center surrounded by a brown halo. Under humid conditions, black dots appeared in the central part of the spots. In later stage, split and fall of the tissues occurred from the infected spot. To identify the causal agent, infected tissues from 20 samples (from 5 trees) were cut into small pieces (5 mm), surface-sterilized for 30 s in 75% ethanol and 3 minutes in 3% sodium hypochlorite, rinsed three times in sterile water, placed onto potato dextrose agar (PDA) amended with streptomycin sulfate (50 μg/ml) and incubated at 25°C in dark conditions. Purified eight fungal colonies were white with undulating margins and light cream on the reverse side, measuring 85 mm diameter after 7 days, dark brown to black conidiomata were irregularly scattered and Conidia were observed in 20 days old colonies. Conidia were spindle-shaped, 4.5 to 6.8 × 15.2 to 23.5 μm (n=50), with 4 diaphragms, the three median cells were light to dark brown and the two end cells were colorless. 1 to 3 accessory filaments (5.2 to 22.5 μm long) protrude from theapical cell while a short stalk (3.5 to 5.5 μm long) was attached to the basal cell, these morphological features suggested that the isolates were most likely . sp. Eight colonies were confirmed to be identical based on morphological characteristics. For molecular identification, DNA was extracted from representative strains (YF-5, YF-13, YF-24). The internal transcribed spacer (ITS) region, β-tubulin (), the translation elongation factor-1 alpha gene (), genes were amplified using primers ITS5/ITS4, /, and /, respectively (White et al.1990; Glass & Donaldson 1995; O'Donnell & Cigelnik 1997; Carbone &, Kohn.1999). The sequences were deposited in NCBI GenBank YF-24, [ITS; ON204233: ; ON304156: ; ON400075]: YF-5, [ITS; OP379570: ; OP413495: ; OP413496]: YF-13, [ITS; OP379589: ; OP413494: ; OP413497]. Which revealed a 95% similarity to the NTUCC 18-067 [ITS; MT322086: ; MT321888: ; MT321987] ex-type sequences. Based on morphology and multilocus phylogenetic analysis, representative strains were identified as . For Koch's postulates, wiped the leaves of six healthy plants of (two-year-old) grown in pots with sterile water, 10 μL of spore suspension (10 spores/ mL) was brushed on five leaves per plant (three plants in total) with a sterile brush, and the other three plants were treated with sterile water instead of spore suspension as control, the plants were placed in a greenhouse at 28°C and 95±1% relative humidity. Seven days after inoculation, brown lesions appeared, similar to those observed in infected plants. Black dots surrounded by a brown halo reappear on the lesions after 12 days, whereas control plants remained healthy. culture was re-isolated from the infected leaves and identified using morphological characteristics and DNA sequence analysis. To our knowledge, can cause diseases on tea plants and has been found in Japan, Thailand and China, this is the first report of leaf spot infection of caused by in China. This disease is reducing the ornamental value of . Our results will contribute to the prevention and cure of leaf spot disease in .
PubMed: 36190304
DOI: 10.1094/PDIS-07-22-1722-PDN -
Plant Disease Aug 2022Nageia nagi (Thunb.) Kuntze is widely cultivated in China for its ornamental and economic value. In August 2019, a leaf spot was observed on N. nagi plants at the campus...
Nageia nagi (Thunb.) Kuntze is widely cultivated in China for its ornamental and economic value. In August 2019, a leaf spot was observed on N. nagi plants at the campus of Jiangxi Agricultural University (28°45'56″N, 115°50'21″E). Disease incidence was about 35%, and the diseased leaf rate was above 40%. The early symptoms were small spots on the edge or tip of the leaves. The spots gradually expanded and became reddish-brown, eventually developing large irregular lesions. Leaf pieces (5 × 5 mm) from the lesion borders were surfaced sterilized in 70% ethanol for 30 s, followed by 2% NaOCl for 1 min, and then rinsed three times with sterile water. Tissues were placed on potato dextrose agar (PDA) and incubated at 25°C (Zhang et al. 2021). Pure cultures were obtained by transferring hyphal tips to new PDA plates. Twenty-six isolates of Colletotrichum ssp. were obtained (isolation frequency about 82%). Three representative single-spore isolates (ZB-1, ZB-3, and ZB-7) were used for morphological studies and phylogenetic analyses. Colonies on PDA medium of the three isolates were white to gray in color with cottony mycelia. Conidia were single-celled, straight, hyaline, cylindrical, clavate, and measured 14.1-17.9 ×4.4-6.8 µm (15.6 ± 1.2 × 5.4 ± 0.3 µm, n = 100). Appressoria were brown to dark brown, ovoid to clavate, slightly irregular to irregular, and ranged from 5.7-9.3 × 4.6-6.9 µm (7.8 ± 0.2 × 5.6 ± 0.3 µm, n=100). Morphological features were similar to Colletotrichum siamense complex (Weir et al. 2012). The internal transcribed spacer (ITS) regions, actin (ACT), calmodulin (CAL), β-tubulin 2 (TUB2), chitin synthase (CHS-1), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were amplified from genomic DNA for the three isolates using primers ITS1/ITS4, ACT-512F/ACT-783R, CL1/CL2, T1/Bt2b, CHS-79F/CHS-354R and GDF/GDR (Weir et al. 2012), respectively. Sequences of them deposited in GenBank under nos. OL826760 - OL826762 (ITS), OL830205 - OL830207 (ACT), OL830196 - OL830198 (GAPDH), OL830193 - OL830195 (TUB2), OL830199 - OL830201 (CHS-1), and OL830202 - OL830204 (CAL). A Blast search of GenBank showed that ITS, ACT, GAPDH, TUB2, CHS-1, and CAL sequences of the three isolates were identical to Colletotrichum siamense at a high level (Table 1). 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 ZB-1, ZB-3, and ZB-7 in the clade of C. siamense. Based on the multi-locus phylogeny and morphology, three isolates were identified as C. siamense. The pathogenicity of three isolates was tested on six N. nagi plants (three for inoculation, three for controls), which were grown in the field. Six healthy leaves were wounded with a sterile needle and inoculated with 10 µL of conidial suspension (1 × 106 conidia/mL) per plant. Healthy leaves were inoculated with ddH2O as a control by the same method. All the inoculated leaves were covered with plastic bags to keep a high-humidity environment for 2 days. The experiment was repeated three times. All the inoculated leaves showed similar symptoms to those observed in the field, whereas control leaves were asymptomatic for 8 days. C. siamense was reisolated from the lesions, whereas no fungus was isolated from control leaves. Up to now, Cephleuros virescens, Pestalotiopsis longisetula, Alternaria tenuissima, A. alternate, and Phoma glomerata could infect N. nagi (Zhou et al. 2015; Zhang et al. 2016), and cause leaf spots in China. To our knowledge, this is the first report of C. siamense causing leaf spots on N. nagi worldwide. This work provided crucial information for epidemiologic studies and appropriate control strategies for this newly emerging disease.
PubMed: 35947012
DOI: 10.1094/PDIS-06-22-1417-PDN -
Plant Disease Apr 2022× Z.J. Ye, J.J. Zhang & S.H. Pan is a hybrid of and . It can adapt to various site conditions and has a good saline-alkali tolerance, which is a unique tree species...
× Z.J. Ye, J.J. Zhang & S.H. Pan is a hybrid of and . It can adapt to various site conditions and has a good saline-alkali tolerance, which is a unique tree species in eastern China. In August 2020, a red foliage blight with an incidence of 70% (105/150 plants) was found on the leaves of × in a nursery, Shanghai, China (121°21'12"E, 31°41'56"N). It developed from apical leaves of branches downwards. The infected leaves became reddish brown and withered. Fresh specimens were collected from 3 infected trees. Small samples (3-4 mm) from lesion margins were sterilized, plated on potato dextrose agar (PDA) and incubated at 25°C. Nine isolates of the same fungus were obtained. Three representative isolates (DFS1-3, DFS1-8, and DFS1-9) were used for morphological and molecular studies and deposited in the China's Forestry Culture Collection Center (cfcc57401 to cfcc57403). The colonies of three isolates on PDA grew fast, covering the entire plate with white cottony mycelia in 7 days. Acervuli of DFS1-3 were 618-996 × 586-945 µm (n = 50). Conidiogenous cells were 4.4-9.8 µm (n = 50) long. Conidia were 5-celled, clavate to fusiform, smooth, 19-24 × 6.4-8.8 µm (n = 50). 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 (3.4-8 µm long; n = 50), and 2-3 apical appendages (15-30 µm long; n = 50), filiform. The morphological characters of DFS1-8 and DFS1-9 were almost identical to DFS1-3. Based on morphological studies, the isolates were sp.. The DNA of 3 isolates was extracted. The internal transcribed spacer region (ITS), β-tubulin 2 () and translation elongation factor 1-alpha () loci were amplified using the primer pairs ITS1/ITS4, T1/Bt-2b, EF1-728F/EF-2. BLAST result showed that ITS of the three isolates were identical to sp. at a high level (greater than 99%), and , were highly similar with sp. (greater than 99%). The sequences were deposited in GenBank [Accession Nos. OM188301 and OM222696 to OM222697 for DFS1-3; OM188303 and OM222698 to OM222699 for DFS1-8; OM188302 and OM222700 to OM222701 for DFS1-9]. 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 (ITS, , ) clustered 3 isolates together with including type isolate (MFLUCC 12-0281). Based on the morphology and phylogeny, the fungus was . To confirm pathogenicity, 9 healthy 2-yr-old seedlings, and 10 leaves per seedling were wounded with a sterile needle and inoculated with conidial suspension (10 conidia/mL). Three control plants were sprayed with sterile water. Seedlings were covered with plastic bags after inoculation and kept in a greenhouse at 25 ± 2°C and RH 80%. Seven days after inoculation, all inoculated leaves were reddish brown and withered like those observed in the field, whereas the control plants remained symptomless. was successfully reisolated from the infected tissues. This pathogen has been reported to cause leaf blight on many other hosts, such as and macadamia, but in recent years, the disease has also been reported on flowers, such as Anthurium. It has not been reported on and . This is the first report of infecting × in the world. These data will help select appropriate fungicides for managing this newly emerging disease.
PubMed: 35394337
DOI: 10.1094/PDIS-02-22-0444-PDN -
Microbiological Research Nov 2020Diseases in plants are mostly caused by fungi. Fungal interactions with the host can be either biotrophic, necrotrophic or hemibiotrophic. Synergistic polymicrobial...
Diseases in plants are mostly caused by fungi. Fungal interactions with the host can be either biotrophic, necrotrophic or hemibiotrophic. Synergistic polymicrobial interactions have been recently recognized that can also attribute to the occurrence of complex plant diseases. Tea is one of the most widely consumed beverages worldwide, although tea plants are affected by many different diseases causing a significant reduction in global tea production. Blister blight is one such serious and damaging leaf disease of tea. An assessment of blister blight disease was carried out at the tea development center in Umsning, Meghalaya. A considerable number of tea varieties showed characteristic blister blight symptoms that ranged from preliminary yellow spots in the upper leaf surface, matured white sporulating blisters in the lower leaf surface, and delayed brown necrotic lesions throughout the surfaces of the leaves. A total of 42 isolates, 15 from initial, 15 from mature, and 12 from necrotic stages were isolated from the symptomatic leaf samples. Pestalotiopsis and Nigrospora were the two fungi incessantly isolated from the diseased leaves. Colony characteristics that included colony, hyphal, and spore morphologies were examined and mycelial accumulation, sporulation, and sporal germination were determined for all the isolates of Pestalotiopsis and Nigrospora. Molecular analysis based on ITS-RFLP was performed for identification and genetic variability. In vitro pathogenicity assay revealed that Pestalotiopsis spp. and Nigrospora sp. developed distinct characteristics symptoms on greenhouse acclimated TV17 tea clones. To our knowledge, this is the first report of the prevalence of tea blister blight disease in Meghalaya and it is an initial attempt to identify fungal pathogens during different stages of blister blight disease.
Topics: Ascomycota; Camellia sinensis; Genes, rRNA; Hyphae; India; Phylogeny; Plant Diseases; Plant Leaves; Transcription Factors
PubMed: 32799070
DOI: 10.1016/j.micres.2020.126561 -
Plant Disease Jul 2023Photinia bodinieri Lévl. is an evergreen broadleaf species widely cultivated in subtropical China as an ornamental value (Zhang et al. 2018). In July 2021, leaf spot...
Photinia bodinieri Lévl. is an evergreen broadleaf species widely cultivated in subtropical China as an ornamental value (Zhang et al. 2018). In July 2021, leaf spot symptoms were observed on the campus of Jiangxi Agricultural University (28°45'56″N, 115°50'21″E), Jiangxi province, China. The spots were circular to irregular, gray in the center, and dark brown on the lesion margin. The disease incidence was estimated 15%. Leaf pieces (5 × 5 mm) from the lesion borders were surface-sterilized in 70% ethanol for 30 s, followed by 2% NaOCl for 1 min, and then rinsed three times with sterile water. Tissues were placed on potato dextrose agar (PDA) and incubated at 25°C in the dark. Pure cultures were obtained by monosporic isolation, and the representative isolates, SN-3, SN-7, and SN-11 were used for morphological studies and phylogenetic analyses. The colonies of three isolates grown on PDA were white, cottony, and exhibited flocculent, contained undulate edges with dense aerial mycelium on the surface. Conidia were 5-celled, clavate to fusiform, smooth, 18.2-24.3 × 5.5-8.4 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. Conidia developed filiform appendages; one basal appendage (3.3-8.2 μm long; n = 100), and 2-3 apical appendages (16-29 μm long; n = 100). Morphological features were similar to Neopestalotiopsis sp. (Maharachchikumbura et al. 2014). Portions of internal transcribed spacer (ITS) regions, β-tubulin 2 (TUB2) and translation elongation factor 1-alpha (TEF1-α) genes 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, OQ572345 - OQ572347; TUB2, OQ597847 - OQ597849; TEF1-α, OQ597844 - OQ597846). 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 SN-3, SN-7, and SN-11 in the clade of N. clavispora. Based on the multi-locus phylogeny and morphology, three isolates were identified as N. clavispora. Pathogenicity of the three isolates was verified on nine disease-free 7-year-old Photinia bodinieri plants, which were grown in the field. Two healthy leaves per plant were wounded with two pricks using a sterile needle (Φ=0.5 mm) and inoculated with 20 μL conidial suspension per leaf (106 conidia/mL). Another nine control plants were inoculated with sterile water. 36 leaves were used for the pathogenicity test of three isolates. All leaves were covered with plastic bags to maintain a humid environment for 2 days. The inoculated leaves showed similar symptoms to those observed in the field, whereas control leaves were asymptomatic after 10 days. The fungi were consistently reisolated only from the inoculated and symptomatic leaves, fulfilling Koch's postulates. N. clavispora can cause leaf diseases in a variety of hosts, including Kadsura coccinea (Xie et al. 2018), Photinia serratifolia (Yang et al. 2018), Camellia chrysantha (Zhao et al. 2020). Photinia spp. is an excellent landscape gardening plant, threatened with grey blight (Pestalotiopsis microspore) (Ye et al. 2022), anthracnose (Colletotrichum sp.) (Guan et al. 2013). However, this is the first report of N. clavispora infecting Photinia bodinieri in China. This work provided crucial information for epidemiologic studies and appropriate control strategies for this newly emerging disease.
PubMed: 37467128
DOI: 10.1094/PDIS-06-23-1108-PDN -
Frontiers in Microbiology 2018() is one of dominant pathogenic fungi causing rotten disease in harvested Chinese olive ( Lour.) fruits. The purposes of this study were to evaluate the antifungal...
() is one of dominant pathogenic fungi causing rotten disease in harvested Chinese olive ( Lour.) fruits. The purposes of this study were to evaluate the antifungal activities of ginger oleoresin (GO) against and to illuminate the underlying action mechanisms. The assays indicate that GO exhibited strong antifungal activity against mycelial growth of , and with 50%-inhibition concentration ( ) and 90%-inhibition concentration ( ) at 2.04 μL GO and 8.87 μL GO per mL propylene glycol, respectively, while the minimal inhibitory concentration (MIC) and minimal fungicidal concentration were at 10 μL GO and 30 μL GO per mL propylene glycol, respectively. Spore germination of was inhibited by GO in a dose-dependent manner, and with 100% inhibition rate at the concentration of 8 μL GO per mL propylene glycol. Compared to the control, the cellular membrane permeability of increased due to severe leakage of intercellular electrolytes, soluble proteins, and total sugars with the treatments ( , ) by GO during incubation. In addition, analysis of fatty acid contents and compositions in cellular membrane by GC-MS indicated that GO could significantly promote the degradation or peroxidation of unsaturated fatty acids in , resulting in the enhancement of membrane fluidity. Moreover, observations of microstructure further showed the damage to plasma membrane and morphology of caused by GO, which resulted in distortion, sunken and shriveled spores and mycelia of the pathogen. Furthermore, assay confirmed that over 3 MIC GO treatments remarkably suppressed disease development in inoculated-Chinese olive fruit. These results demonstrate that owing to its strong antifungal activity, GO can be used as a promising antifungal agent to inhibit the growth of pathogenic fungi in Chinese olives.
PubMed: 30425698
DOI: 10.3389/fmicb.2018.02583 -
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 -
Frontiers in Microbiology 2021Three new secondary metabolites pestalothenins A-C (-), including two new humulane-derived sesquiterpeniods ( and ) and one new caryophyllene-derived sesquiterpeniod (),...
Three new secondary metabolites pestalothenins A-C (-), including two new humulane-derived sesquiterpeniods ( and ) and one new caryophyllene-derived sesquiterpeniod (), together with five known compounds (-) were isolated from the crude extract of the plant endophytic fungus (N635). Their structures were elucidated by the extensive analyses of HRESIMS and NMR spectroscopic data. The absolute configurations of - were determined by comparison of experimental and calculated electronic circular dichroism (ECD) spectra. The cytotoxic effects of these compounds were evaluated . Compound showed moderate cytotoxicity against T24 and MCF7 cell lines. In addition, compounds - were also evaluated for antibacterial activity.
PubMed: 33868199
DOI: 10.3389/fmicb.2021.641504