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International Journal of Microbiology 2018Anthracnose disease of avocado contributes to a huge loss of avocado fruits due to postharvest rot in Kenya. The causal agent of this disease has not been clear but...
Anthracnose disease of avocado contributes to a huge loss of avocado fruits due to postharvest rot in Kenya. The causal agent of this disease has not been clear but presumed to be as reported in other regions where avocado is grown. The fungus mainly infects fruits causing symptoms such as small blackish spots, "pepper spots," and black spots with raised margin which coalesce as infection progresses. Due to economic losses associated with the disease and emerging information of other species of fungi as causal agents of the disease, this study was aimed at identifying causal agent(s) of the disease. A total of 80 fungal isolates were collected from diseased avocado fruits in Murang'a County, the main avocado growing region in Kenya. Forty-six isolates were morphologically identified as spp. based on their cultural characteristics, mainly whitish, greyish, and creamish colour and cottony/velvety mycelia on the top side of the culture and greyish cream with concentric zonation on the reverse side. Their spores were straight with rounded end and nonseptate. Thirty-four isolates were identified as spp. based on their cultural characteristics: whitish grey mycelium with black fruiting structure on the upper side and greyish black one on the lower side and septate spores with 3-4 septa and 2 or 3 appendages at one end. Further molecular studies using ITS indicated , , and as the causal agents of anthracnose disease in avocado. However, with this being the first report, there is a need to conduct further studies to establish whether there is coinfection or any interaction thereof.
PubMed: 29681943
DOI: 10.1155/2018/4568520 -
Mycology Aug 2020A survey of the diversity and distribution of microfungi on leaf litter in Songkhla Province (Thailand) yielded two collections of pestalotiopsis-like fungi. Analyses...
A survey of the diversity and distribution of microfungi on leaf litter in Songkhla Province (Thailand) yielded two collections of pestalotiopsis-like fungi. Analyses of a combined ITS, TEF1-α and TUB2 sequence data matrix were applied to infer the phylogenetic position of these new isolates in . The phylogenies indicated that these two isolates were monophyletic and constituted a distinct lineage that perceived a taxonomic novelty in . This clade shared a close phylogenetic affinity with and . The comparison of morphological features with the phylogenetically closely related taxa are given and the new species is introduced as sp. nov. with comprehensive descriptions and illustrations herein.
PubMed: 33329926
DOI: 10.1080/21501203.2020.1801873 -
Current Medical Mycology Jun 2020Pestalotioid fungi are ubiquitous environmental molds that have received considerable attention in recent times not only because of their role as a plant pathogen but...
BACKGROUND AND PURPOSE
Pestalotioid fungi are ubiquitous environmental molds that have received considerable attention in recent times not only because of their role as a plant pathogen but also owing to their high frequency of retrieval from human diseases. Regarding this, the present study was conducted to investigate onychomycosis caused by pestalotioid fungi, commonly considered important phytopathogens causing grey blight disease in .
MATERIALS AND METHODS
A total of 122 agriculture workers were enrolled from Assam, India. Direct microscopic examination was carried out using 40% KOH to determine the presence of any fungal element. Further processing of the specimens for the isolation of fungi was performed using the standard protocol. In addition, the keratinolytic potential of the isolates was evaluated by means of the in vitro hair perforation test.
RESULTS
Out of 103 culture-positive samples, non-dermatophyte and dermatophyte molds constituted 82.52% (n=85) and 6.79% (n=7) of the samples, followed by yeasts (n=1, 0.9%) and sterile hyphae (n=10, 9.7%). With regard to the isolated non-dermatophyte molds (82.69%), 4 cases belonged to pestalotioid fungi, such as (n=1), (n=1), and (n=2). The keratinolytic activity of Pestalotiopsis species showed perforation by disrupting the hair cortex; furthermore, macroconidia were found to be present inside the human hair.
CONCLUSION
A high rate of NDM isolation may be attributed to constant exposure to adverse environmental and occupational hazards. This study highlighted the importance of "pestalotioid fungi" as the rare etiologic agent of onychomycosis. Another remarkable finding was the keratinolytic potential of species, which is unique in this study.
PubMed: 33628978
DOI: 10.18502/CMM.6.2.2839 -
Interactions between abundant fungal species influence the fungal community assemblage on limestone.PloS One 2017The assembly of fungal communities on stone materials is mainly influenced by the differential bioreceptivity of such materials and environmental conditions. However,...
The assembly of fungal communities on stone materials is mainly influenced by the differential bioreceptivity of such materials and environmental conditions. However, little is known about the role of fungal interactions in the colonization and establishment of fungal species. We analyzed the effects of intra- and interspecific interactions between 11 species of fungi in oligotrophic and copiotrophic media and on limestone coupons. In a previous study, these species were the most frequently isolated in the epilithic biofilms of limestone walls exposed to a subtropical climate. In the culture media, we found a greater frequency of intra- and interspecific inhibitory effects in the oligotrophic medium than in the copiotrophic medium. On the limestone coupons, all fungi were able to establish; however, the colonization success rate varied significantly. Cladosporium cladosporioides had a less extensive colonization in isolation (control) than in dual interactions (coexistence) with other species. Phoma eupyrena exhibited the highest colonization success rate and competitive dominance among all tested species. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses revealed that Pestalotiopsis maculans and Paraconiothyrium sp. produced calcium oxalate crystals during their growth on coupon surfaces, both in isolation and in dual interactions. Our results demonstrate that interactions between abundant fungal species influence the fungal colonization on substrates, the biomineralization and the fungal community assemblage growing in limestone biofilms.
Topics: Calcium Carbonate; Culture Media; Fungi; Microscopy, Electron, Scanning; Species Specificity; X-Ray Diffraction
PubMed: 29211748
DOI: 10.1371/journal.pone.0188443 -
Plant Disease Oct 2022Chinese figwort ( Hemsl.) is an important annual herb and its dried root tubers are used as a traditional Chinese herbal medicine. In May 2021, a disease with stem rot...
Chinese figwort ( Hemsl.) is an important annual herb and its dried root tubers are used as a traditional Chinese herbal medicine. In May 2021, a disease with stem rot symptoms on was observed at three randomly selected fields (~0.67 ha per field) in Nanchuan district (28.93°N, 107.27°E) of Chongqing, China. Disease incidence was estimated between 10% and 17% based on calculating the proportion of symptomatic plants. Initially, watery dark brown spots appeared on the epidermis of the stem. Then the spots expanded into spindle or strip shape, and the center of lesions were sunken, constricted and rotted finally (Figure 1A and Figure 1B). Leaves turned yellow and the plants wilted (Figure 1C). The infected parts of the stem broke easily and became brittle. The number of daughter buds used for reproduction was reduced by more than 24% and the production of root tubers decreased by more than 3%. Twelve stems with typical rot symptoms were sampled from the three fields for further investigation. Infested tissue fragments (4×4 mm) were surface sterilized with 75% ethanol for 30s and 2% sodium hypochlorite for 2 minutes in turn, finally, were rinsed 4 times with sterilized water. The disinfected tissue were air-dried and transferred onto potato dextrose agar (PDA) in the dark for 6 days at 25℃. The resulting fungal colonies were isolated by the single-spore isolation technique (Fang. 1998). Six different fungal colonies were isolated (X1-X6) and Koch's postulates were conducted to verify the pathogenicity of individual isolates. The stem surfaces of 8 months old plants were sterilized with 75% ethanol for 30 s, rinsed three times with sterilized water, and stabbed with a sterilized needle. Conidial from the fungal colonies grown on PDA plate were harvested by filtration through five layers of sterilized absorbent gauze. Conidial concentration was then adjusted to 106 conidia per mL. 10 μL of conidial suspension was sprayed on stems injured with a sterile syringe. For each isolate, 6 plants were inoculated. Stems inoculated with sterilized water were used as a blank control. All plants were all put in a growth chamber at 28℃ with 75 to 80% relative humidity under a 12 h photoperiod for 15 days. The pathogenicity test was repeated once. After 13 days, the stems inoculated with X3 showed the same rot symptoms as we observed in the fields (Figure 1D) whereas the control stems remained symptomless (Figure 1E). The fungus re-isolated from the plants showing 100% symptoms had a similar morphology than X3 as described below. At the same time, the stems inoculated with X1, X2, X4, X5 and X6 showed no sign of rot. After culturing on PDA for 9 days under 25℃ in dark, isolate X3 grew all over the dish with white or pale pink pigmentation in the center (Figure 1F). Macroconidia were produced on synthetic low nutrient agar (SNA) plates, which showed sickle or spindle, 3 septate, straight to slightly curved with a foot-shaped basal cell, ranging from 17.595~44.88 × 2.04~3.315 μm (n=30). Microconidia were oval, elliptical or reniform, 0 to 1 septate, 3.06~12.75 ×1.785~2.805 μm (n=30) in size (Figure 1G). Phialides of conidiophores were cylindrical, short and monophialides or polyphialides (Figure 1H). Chlamydospores were found terminal or cluster with round or oblong (Figure 1I). These morphological characteristics described as (Skovgaard et al. 2003). For molecular identification, the ribosomal internal transcribed spacer (), translation elongation factor 1-alpha (), RNA polymerase II subunit 1 (), the largest subunit of RNA polymerase Ⅱ gene sequences () and the mitochondrial small subunit rDNA () genes were amplified with primers V9G /ITS4 (Hoog et al. 1998; White et al. 1990), EF1-668F /EF1-1251R (Alves et al. 2008), Fa/G2R (O'Donnell et al. 2010), 5f2/7cr (Liu et al. 1999; O'Donnell et al. 2010) and NMS1/NMS2 (Li et al. 1994). The sequences of isolate X3 were deposited in GenBank (MZ571935 (), MZ576201 (), MZ882396 (), MZ882397 () and MZ867716 ()). All sequences were revealed more than 99.8% sequence identity with reported sequences of (GenBank accession No: KY630717, JF740838, KU171680, KU171700 and MK439851). Based on the optimal nucleotide replacement model SYM of multi-gene series sequence matrix, the system development tree was constructed. Results showed the strain X3 and those of (Isolates numbers were NRRL 28387, MRC 2566, MRC 2564 and CZ3-5-6) were clustered into the same evolutionary branch with a post-mortem probability of 0.996 (Figure 2). According to the morphology, molecular identification and phylogenetic analysis based on the concatenated of and genes sequences, the isolated X3 was identified as . The ITS sequences of X1, X2, X4, X5 and X6 showed homology exceeding 97.1% to (MH931273), (MH858371), sp. (JX179237), (EF026129) and (EU552147), respectively, suggested the five strains to be these species possibly. GeneBank accession number of X1, X2, X4, X5 and X6 was OM074010, OM074011, OM074013, OM074015 and OM074018, respectively. To our best knowledge, this is the first report of infecting in China. Stem rot caused by is a severe threat to Chinese figwort cultivation, and identification of this pathogen is important for effective disease management and control.
PubMed: 36222729
DOI: 10.1094/PDIS-09-21-1896-PDN -
PloS One 2018Pestalopezia brunneopruinosa, the type species of Pestalopezia in Leotiomycetes, produces typical cup-shaped ascomata. Because its asexual morph has conidia comprised of...
Pestalopezia brunneopruinosa, the type species of Pestalopezia in Leotiomycetes, produces typical cup-shaped ascomata. Because its asexual morph has conidia comprised of five cells including apical and basal appendages and three pigmented median cells, it was first described as Pestalotia gibbosa, which belongs to Sordariomycetes. This contradiction has not been resolved due to the difficulty in isolating this fungus in culture. In this study, we isolated separate strains from the sexual morph and the asexual morph for molecular analysis. Phylogenetic trees of Sporocadaceae based on internal transcribed spacer, partial β-tubulin, and partial translation elongation factor 1-alpha sequence datasets revealed that both strains fall into the same taxon, in a clade in Pestalotiopsis sensu stricto alongside P. gaultheriae and P. spathulata. We provide the first evidence that fungi producing cup-shaped ascomata in Pestalotiopsis belong to Sordariomycetes, and we have proposed the transfer of Pestalopezia brunneopruinosa to Pestalotiopsis gibbosa.
Topics: Ascomycota; Fungal Proteins; Phylogeny; Tubulin
PubMed: 29949577
DOI: 10.1371/journal.pone.0197025 -
Frontiers in Microbiology 2021Eight rhizospheric bacteria were isolated from the organic paddy fields of Sikkim, India, and identified as KSB, SRD, YMA7, SRB, sp. ARA, COW3, PSB2, and PSB1....
Isolation, Characterization, and Evaluation of Native Rhizobacterial Consortia Developed From the Rhizosphere of Rice Grown in Organic State Sikkim, India, and Their Effect on Plant Growth.
Eight rhizospheric bacteria were isolated from the organic paddy fields of Sikkim, India, and identified as KSB, SRD, YMA7, SRB, sp. ARA, COW3, PSB2, and PSB1. They showed plant growth-promoting attributes in rice and have bio-control potential against phytopathogen of large cardamom (). SRD showed production of indole acetic acid and ammonia and solubilization of phosphate and potassium and also possessed nitrogen fixation potential. It showed antagonistic activity against two other plant pathogens of large cardamom, viz., and sp., under conditions. The liquid bacterial consortium was prepared using the bacterial strains SRB, PSB1, and COW3 (Consortia-1); PSB2, SRD, and COW3 (Consortia-2); and COW3, KSB, and YMA7 (Consortia-3) to increase the growth and yield of rice plants under organic farming conditions. Greenhouse and field studies showed that the Consortia-3 had the highest plant growth-promoting activity. Consortia-3 demonstrated better agronomic performance in terms of root length (9.5 cm),number of leaflets per plant (5.3), grains per panicle (110.6), test grain weight (27.4 g), dry root weight per plant (0.73 g), and total dry biomass per plant (8.26 g).
PubMed: 34552571
DOI: 10.3389/fmicb.2021.713660 -
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 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 -
Plants (Basel, Switzerland) Apr 2021Three pathogenic fungi of blueberry ( spp.) responsible for dieback disease, identified as , and , were isolated in the northwestern region of the state of Michoacán,...
Three pathogenic fungi of blueberry ( spp.) responsible for dieback disease, identified as , and , were isolated in the northwestern region of the state of Michoacán, Mexico. The mycelial growth in vitro of these fungi was inhibited by extracts from , and , medicinal plants collected in Sahuayo, Michoacán, Mexico. The extracts showed different degrees of inhibition; the most effective were: M5L extract from and M6LFr extract from , both of which inhibited 100% of the mycelial growth of and ; and M4LS extract from , which inhibited 100% of the mycelial growth of the three pathogens. The extracts were fractionated by thin layer and column chromatography, and the most active fractions were analyzed by gas chromatography-mass spectrometry. The major compounds identified in extract were Phytol and α-Sitosterol. The compounds identified in were Toluene and Benzene, 1,3-bis(3-phenoxyphenoxy)-. In , the compound identified was Hexanedioic acid, bis(2-ethylhexyl) ester. These results show the potential of , and as a source of antifungal compounds.
PubMed: 33922510
DOI: 10.3390/plants10050852