scholarly journals First Report of Colletotrichum tropicale Causing Anthracnose on Common Fig in Taiwan

Plant Disease ◽  
2021 ◽  
Author(s):  
Chung-hang Duan ◽  
Guan-ying Chen
Keyword(s):  
Manganese Superoxide Dismutase ◽  
Morphological Characteristics ◽  
Width Ratio ◽  
Conidial Suspension ◽  
Gene Sequences ◽  
First Report ◽  
Fungal Isolates ◽  
Common Fig ◽  
Colletotrichum Tropicale ◽  
Central Taiwan

Ficus carica L. known as common fig is one of the most profitable fruit crops in Taiwan. Their fruit are harvested for high-priced market. Common fig can be eaten fresh or dried and processed to make different food products. In September 2015, an anthracnose-like disease was widely observed on common fig fruit planted in an orchard in Lukang township (24°04'36" N, 120°27'15" E) in Changhua County, central Taiwan. Symptoms were sunken, water-soaked lesions covered with salmon-colored spore masses and were observed on all stages of fruit, especially when fruit was ripe. Four fungal isolates were collected from four diseased fruit of different plants in the same orchard. Conidia were spread on 2% water agar, and a single conidium was separated by a handmade glass needle. Fungal isolates were grown on potato dextrose agar (PDA) at 24 to 28°C with diffused light. All four strains produced white, aerial, and cottony mycelia covered with abundant salmon-colored conidial masses on PDA. The conidia were hyaline, single celled, round cylindrical on both ends, thin walled, and the contents guttulate. The sizes of conidia were 15.4 (18.5 to 13.1) × 4.73 (5.8 to 3.6) μm [average (max. to min.); length/width ratio = 3.25, n = 40]. DNA was isolated from the representative isolate FC1 and used for amplification of partial sequences of the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), β-tubulin 2 (TUB2), manganese-superoxide dismutase (SOD2), calmodulin (CAL), chitin synthase 1 (CHS-1) (Weir et al. 2012) and the intergenic region of apn2 and MAT1-2-1 gene (ApMat) genes (Sharma et al. 2013). A BLAST search against the NCBI database revealed that FC1 gene sequences [GenBank accession nos. MT192648 (ITS), MT155819 (GAPDH), MT199873 (ACT), MT199874 (TUB2), MT815916 (SOD2), MT815917 (CAL), MW684717 (CHS-1) and MT221652 (ApMat)] displayed 99.1, 98.2, 99.3, 99.6, 99.5, 100.0, 92.8 and 100.0% nucleotide identity to the respective gene sequences of Colletotrichum tropicale CBS 124949 (ICMP18653) (JX010264, JX010007, JX009489, JX010407, JX010329, JX009719, JX009870 and KC790728). Multilocus phylogenetic analysis performed with reference sequences showed that the isolate FC1 clustered with C. tropicale in accordance with BLAST results. A conidial suspension (1 × 106 conidia/mL) prepared from FC1 isolate was inoculated by spraying onto detached, ripe, healthy, non-wounded and surface-disinfected common fig fruit (cv. China, n = 4). Fruit sprayed with sterile water were used as control. Fruit were kept in a moist chamber (greater than 90% relative humidity, 24 to 28°C) for 24 h and then maintained in the lab for additional 5 days. The inoculated fruit developed lesions similar to the disease symptoms in the orchard. No symptom was observed on fruit treated with water. C. tropicale was re-isolated from symptomatic fruits and had similar morphological characteristics to FC1 isolate, thus fulfilling Koch’s postulates. The experiment was repeated once showing similar results. The FC1 isolate of C. tropicale with the identification number BCRC FU31436 has been deposited at Taiwan Bioresource Collection and Research Center. This fungus had previously been found on lotus and mango in Taiwan (Chen and Kirschner 2018; Wu et al. 2020), while the pathogenicity among the isolates from different origins is not yet known. To our knowledge, this is the first report of C. tropicale causing anthracnose on common fig fruit in Taiwan.

scholarly journals First report of Curvularia plantarum causing leaf spot on sweet potato (Ipomoea batatas) in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Jiahao Lai ◽  
Tongke Liu ◽  
Bing Liu ◽  
Weigang Kuang ◽  
Shuilin Song
Keyword(s):  
Sweet Potato ◽  
Molecular Identification ◽  
Leaf Spot ◽  
Ipomoea Batatas ◽  
Morphological Characteristics ◽  
Distilled Water ◽  
Gene Sequences ◽  
First Report ◽  
Potted Plants ◽  
Fungal Isolates

Sweet potato [Ipomoea batatas (L.) Lam], is an extremely versatile vegetable that possesses high nutritional values. It is also a valuable medicinal plant having anti-cancer, antidiabetic, and anti-inflammatory activities. In July 2020, leaf spot was observed on leaves of sweet potato in Nanchang, China (28°45'51"N, 115°50'52"E), which affected the growth and development of the crop and caused tuberous roots yield losses of 25%. The disease incidence (total number of diseased plants / total number of surveyed plants × 100%) was 57% from a sampled population of 100 plants in the field. Symptomatic plants initially exhibited small, light brown, irregular-shaped spots on the leaves, subsequently coalescing to form large irregular brown lesions and some lesions finally fell off. Fifteen small pieces (each 5 mm2) of symptomatic leaves were excised from the junction of diseased and healthy tissue, surface sterilized in 75% ethanol solution for 30 sec and 0.1% mercuric chloride solution for 2 min, rinsed three times with sterile distilled water and incubated on potato dextrose agar (PDA) plates at 28°C in darkness. A total of seven fungal isolates with similar morphological characteristics were obtained as pure cultures by single-spore isolation. After 5 days of cultivation at 28°C, dark brown or blackish green colonies were observed, which developed brown, thick-walled, simple, or branched, and septate conidiophores. Conidia were 18.28 to 24.91 × 7.46 to 11.69 µm (average 21.27 × 9.48 µm, n = 100) in size, straight or slightly curved, middle cell unequally enlarged, brown to dark brown, apical, and basal cells slightly paler than the middle cells, with three septa. Based on morphological characteristics, the fungal isolates were suspected to be Curvularia plantarum (Raza et al. 2019). To further confirm the identification, three isolates (LGZ1, LGZ4 and LGZ5) were selected for molecular identification. The internal transcribed spacer region (ITS), glyceraldehyde-3-phosphate-dehydrogenase (GAPDH), and translation elongation factor 1-alpha (EF1-α) genes were amplified and sequenced using primers ITS1/ITS4 (Peever et al. 2004), gpd1/gpd2 (Berbee et al. 1999), EF-983F/EF-2218R (Rehner and Buckley 2005), respectively. The sequences of ITS region of the three isolates (accession nos. MW581905, MZ209268, and MZ227555) shared 100% identity with those of C. plantarum (accession nos. MT410571-72, MN044754-55). Their GAPDH gene sequences were identical (accession nos. MZ224017-19) and shared 100% identity with C. plantarum (accession nos. MN264120, MT432926, and MN053037-38). Similarly, EF1-α gene sequences were identical (accession nos. MZ224020-22) and had 100% identity with C. plantarum (accession nos. MT628901, MN263982-83). A maximum likelihood phylogenetic tree was built based on concatenated data from the sequences of ITS, GAPDH, and EF-1α by using MEGA 5. The three isolates LGZ1, LGZ4, and LGZ5 clustered with C. plantarum. The fungus was identified as C. plantarum by combining morphological and molecular characteristics. Pathogenicity tests were conducted by inoculating a conidial suspension (106 conidia/ml) on three healthy potted I. batatas plants (five leaves wounded with sterile needle of each potted plant were inoculated). In addition, fifteen wounded leaves of three potted plants were sprayed with sterile distilled water as a control. All plants were maintained in a climate box (12 h light/dark) at 25°C with 80% relative humidity. All the inoculated leaves started showing light brown flecks after 7 days, whereas the control leaves showed no symptoms. The pathogenicity test was conducted three times. The fungus was reisolated from all infected leaves of potted plants and confirmed as C. plantarum by morphological and molecular identification, fulfilling Koch’s postulates. To our knowledge, this is the first report of C. plantarum causing leaf spot on sweet potato in China. The discovery of this new disease and the identification of the pathogen will contribute to the disease management, provide useful information for reducing economic losses caused by C. plantarum, and lay a foundation for the further research of resistance breeding.

scholarly journals First Report of Postharvest Blue Mold decay caused by Penicillium expansum on Lemon (Citrus limon) fruit in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Ibatsam Khokhar ◽  
Jianming Chen ◽  
Junhuan Wang ◽  
Yang Jia ◽  
Yanchun Yan ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Penicillium Expansum ◽  
Citrus Limon ◽  
Conidial Suspension ◽  
Blue Mold ◽  
Causal Organism ◽  
Lemon Fruit ◽  
First Report ◽  
Fungal Isolates

Lemon (Citrus limon) is one of the most important commercial (both dried and fresh) citrus fruits in China. In the spring of 2019, postharvest blue mold decay was observed at an incidence of 3-5% on lemon fruit at the local markets in Beijing, China. Fruit lesions were circular, brown, soft, and watery, and rapidly expanded at 25°C. To isolate the causal organism, small pieces (2 mm3) were cut from the lesions, surface-sterilized for 1 min in 1.5% NaOCl, rinsed three times with sterilized water, dried with sterile filter paper, placed onto potato dextrose agar (PDA) medium, and incubated at 25°C for 6 days. Eight morphologically similar single-colony fungal isolates were recovered from six lemon fruit. Colony surfaces were bluish-green on the upper surface and cream to yellow-brown one the reverse. Hyphae on colony margins were entirely subsurface and cream in color. Mycelium was highly branched, septate, and colorless, and conidiophores were 250 to 450 × 3.0 to 4.0 µm in size. Stipe of conidiophores were smooth-walled, bearing terminal penicilli, typically terverticillate or less commonly birverticillate, rami occurring singly, 16 to 23 × 3.0 to 4.0 µm, metulae in 3 to 6, measuring 12 to 15 × 3.0 to 4.0 µm. Phialides were ampulliform to almost cylindrical, in verticils of 5 to 8, measuring 8 to 11 × 2.5 to 3.2 µm with collula. Conidia were smooth-walled, ellipsoidal, measuring 3.0 to 3.5 × 2.5 to 3.0 µm. According to morphological characteristics, the fungus was identified as Penicillium expansum (Visagie et al. 2014). For molecular identification, genomic DNA of eight fungal isolates was extracted, regions of the beta-tubulin (TUB), and calmodulin (CAL) genes and ITS region, were amplified using Bt2a/Bt2b, CAL-228F/ CAL-737, and ITS1/ITS4 primers respectively. Obtained sequences of all isolates were identical to sequences of the representative isolate YC-IK12, which was submitted in the GenBank. BLAST results of YC-IK12 sequences (ITS; MT856700: TUB; MT856958: CAL; MT856959) showed 98 to 100% similarity with P. expansum accessions (NR-077154, LN896428, JX141581). For pathogenicity tests, 10 μl of conidial suspension (10 × 105 conidia/ml) from seven-day-old YC-IK12 culture was inoculated using a sterilized needle into the surface of each five asymptomatic disinfected lemons. As a control, three lemons were inoculated using sterile distilled water. All inoculated lemons were placed in plastic containers and incubated at 25°C for 7 days. Decay lesions, identical to the original observations, developed on all inoculated lemons, while control lemons remained asymptomatic. Fungus re-isolated from the inoculated lemon was identified as P. expansum on the basis morphology and Bt2a/Bt2b, CAL-228F/ CAL-737, and ITS1/ITS4 sequences. Previously, Penicillium spp. including P. expansum have been reported as post-harvest pathogens on various Citrus spp. (Louw & Korsten 2015). However, P. digitatum has been reported on lemons and P. expansum has been reported on stored Kiwifruit (Actinidia arguta), Malus, and Pyrus species in China (Tai, 1979; Wang et al. 2015). To our knowledge, this is the first report of blue mold caused by P. expansum on lemons in China. References Louw, J. P., Korsten, L. 2015. Plant Dis. 99:21-30. Tai, F.L. 1979. Sylloge Fungorum Sinicorum. Sci. Press, Acad. Sin., Peking, 1527 pages. 8097 Visagie, C.M. et al. 2014. Studies. Mycol.78: 343. Wang, C. W. et al. 2015. Plant Dis. 99:1037.

scholarly journals First Report of Colletotrichum viniferum Causing Ripe Rot of Grape Berry in Taiwan

Plant Disease ◽  
2021 ◽  
Author(s):  
Chung-hang Duan ◽  
Guan-ying Chen
Keyword(s):  
Morphological Characteristics ◽  
Wide Distribution ◽  
Grape Berry ◽  
Gene Sequences ◽  
Single Spore ◽  
First Report ◽  
Grape Berries ◽  
Fungal Isolates ◽  
Rainy Weather ◽  
Rot Disease

Grape (Vitis spp.) is one of the most profitable fruit crops in Taiwan because of its delicacy and high nutritious value. Fruits of grape are harvested two times a year (summer and winter). In July 2015, a ripe rot disease was observed on grape berries (cv. Black queen) planted in a vineyard in Erlin Township of Changhua County (23°53’19” N, 120°24’40” E). The problem caused great concerns to the vine farmers because of its wide distribution and serious damage on berries, especially in rainy weather. Symptoms observed on ripe and nearly ripe berries showed reddish brown, irregular lesions covered with salmon-colored spore masses. Four fungal isolates were single spore isolated from four diseased berries by a hand-made glass needle. Fungal isolates were grown on potato dextrose agar (PDA) at 24 to 28°C with diffused light. All four strains produced salmon-colored conidial masses with few whitish mycelia around the colony on PDA. The conidia were hyaline, single-celled, round cylindrical on both ends, thin-walled and the contents guttulate. The sizes of conidia were 13.0±0.2 (11.0 to 15.0) ×4.5±0.1 (3.0 to 5.0) μm (L/W ratio=3.0±0.1, n=40). DNA was isolated from GC9 and used for amplification of partial sequences of the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), β-tubulin (TUB2), chitin synthase 1 (CHS-1) and apn2/MAT1-2-1 (ApMAT) genes (Silva et al. 2012; Weir et al. 2012). A BLAST search against the NCBI database revealed that GC9 gene sequences (GenBank accession nos. MT613359 [ITS], MT648518 [GAPDH], MT815915 [ACT], MT648525 [TUB2], MW684718 [CHS-1], MT648530 [ApMAT]) displayed 99.6%, 100.0%, 99.5%, 99.5%, 99.2% and 100.0% nucleotide identity to the respective gene sequences of Colletotrichum viniferum GZAAS5.08601 (JN412804, JN412798, JN412795, JN412813, JX009413) and GZAAS5.08608 (KJ623242). Bayesian inference analysis (Noireung et al. 2012) of the concatenated sequences of ITS, GAPDH, ACT, CHS-1 and TUB2 revealed that isolate GC9 and C. viniferum GZAAS5.08601 were grouped in the same clade, which was clearly separated from the other five closely related species of Colletotrichum. Conidial suspensions (1 ×106 conidia/mL) were prepared from a mixture of the four isolates of C. viniferum and inoculated by spraying onto detached, ripe, healthy, nonwounded and surface-disinfected grape berries (cv. Kyoho, n=4). Four bunches of berries were sprayed with sterile water as control. Berries were kept in a moist chamber (>90% relative humidity, 24 to 28°C) for 24 h and maintained in the lab for additional 5 days. The inoculated fruit showed small light brown-colored spots, which eventually developed into brown, water-soaked lesions, similar to the symptoms in the vineyard. No symptom was observed on berries treated with water. C. viniferum was reisolated from symptomatic fruit, showing similar morphological characteristics to those collected from the field, thus fulfilling Koch’s postulates. The experiment was repeated once showing similar results. The GC9 isolate of C. viniferum with the identification number BCRC FU31518 has been deposited at Taiwan Bioresource Collection and Research Center. C. viniferum has been reported to infect grape in China, Korea, Brazil and Japan (Farr and Rossman 2021). To our knowledge, this is the first report of C. viniferum causing grape ripe rot in Taiwan.

scholarly journals First Report of Colletotrichum fructicola Causing Anthracnose on Indian Jujube (Ziziphus mauritiana) in Taiwan

Plant Disease ◽  
2021 ◽  
Author(s):  
Chung-hang Duan ◽  
Guan-ying Chen
Keyword(s):  
Morphological Characteristics ◽  
Ziziphus Mauritiana ◽  
Conidial Suspension ◽  
Gene Sequences ◽  
Great Loss ◽  
First Report ◽  
Jujube Fruit ◽  
Colletotrichum Fructicola ◽  
Diseased Fruit ◽  
Indian Jujube

Ziziphus mauritiana Lamarck known as Indian jujube is one of the most popular and delicious fruit crops in Taiwan. This crop is mainly planted in southern Taiwan and their fruit are harvested for providing fresh fruit. In March 2015, an anthracnose-like disease was observed on Indian jujube fruit (cv. Candied date) planted in an orchard in Yanchao District (22°46'33" N, 120°21'37" E) in Kaohsiung City. The disease was quickly distributed around the orchard after rain and caused great loss (around 40% of fruit infected). The diseased fruit would completely rot and lose its market value. Symptoms could be observed on all the developmental stages of fruit. On ripe fruit, symptoms were round, brown, water-soaked lesions covered with salmon-colored spore masses. Four fungal isolates from diseased fruit in the same orchard were collected by single spore isolation with hand-made glass needle. They were grown on potato dextrose agar (PDA) at 24 to 28°C with diffused light. All four strains produced white to gray, aerial, and cottony mycelia scattered with abundant salmon-colored conidial mass on the center of the colony on PDA. The conidia were hyaline, single celled, round cylindrical on both ends, thin walled, and the contents guttulate. The sizes of conidia were 15.2 (17.5 to 13.0) × 5.0 (5.5 to 4.5) μm (length/width ratio = 3.03, n = 40). DNA was isolated from JC1 and used for amplification of partial sequences of the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), β-tubulin 2 (TUB2), chitin synthase 1 (CHS-1), manganese-superoxide dismutase (SOD2) and the intergenic region of apn2 and MAT1-2-1 gene (ApMat) genes (Silva et al. 2012; Weir et al. 2012). A BLAST search against the NCBI database revealed that JC1 gene sequences [GenBank accession nos. MT197188 (ITS), MT199871 (GAPDH), MT199872 (ACT), MT199870 (TUB2), MT815918 (CHS-1), MT815919 (SOD2) and MT221653 (ApMat)] displayed 100.0, 100.0, 99.1, 100.0, 99.7, 99.5 and 99.8% nucleotide identity to the respective gene sequences of Colletotrichum fructicola ICMP 18581 (JX010165, JX010033, FJ907426, JX010405, JX009866, JX010327, and JQ807838). Conidial suspension (1 × 106 conidia/mL) was prepared from JC1 isolate of C. fructicola and inoculated by spraying onto detached, ripe, healthy, non-wounded and surface-disinfected jujube fruit (cv. Candied date, n = 4). Four control fruit were sprayed with sterile water. Fruit were kept in a moist chamber (greater than 90% relative humidity, 24 to 28°C) for 24 h and maintained in the lab for additional 5 days. The inoculated fruit initially showed small light-colored spots in 5 to 7 days, which eventually developed into brown, sunken, water-soaked lesions 8 to10 days after inoculation, similar to the symptoms in the orchard. C. fructicola was re-isolated from symptomatic fruit showing similar morphological characteristics to those collected from the field, thus fulfilling Koch’s postulates. No symptom was observed on fruit treated with water and no pathogen was re-isolated. The experiment was performed twice. The JC1 isolate of C. fructicola with the identification number BCRC FU31437 has been deposited at Taiwan Bioresource Collection and Research Center. This pathogen has been found in many plant species in various countries (Weir et al. 2012). To our knowledge, this is the first report of C. fructicola causing Indian jujube fruit anthracnose in Taiwan and worldwide.

scholarly journals First Report of Anthracnose Caused by Colletotrichum theobromicola on Barbados Cherry (Malpighia emarginata) in Brazil

Plant Disease ◽  
2014 ◽  
Vol 98 (9) ◽  
pp. 1272-1272 ◽  
Author(s):  
C. A. D. Bragança ◽  
A. F. Nogueira Junior ◽  
F. Rogério ◽  
N. S. Massola
Keyword(s):  
Nutritional Value ◽  
Morphological Characteristics ◽  
Fluorescent Light ◽  
Width Ratio ◽  
Conidial Suspension ◽  
First Report ◽  
Colletotrichum Species ◽  
Malpighia Emarginata ◽  
Tropical America ◽  
Length Width

Barbados cherry, also called acerola, is a fruit originated from tropical America that is well-known for its high content of vitamin C and nutritional value. Anthracnose is one of the most common diseases on Barbados cherry. In Brazil, this disease is associated with Colletotrichum gloeosporioides sensu lato (2). In 2012, necrotic and sunken spots were observed on Barbados cherry fruit (cv. Rubra) in Sao Paulo State, Brazil, from which a Colletotrichum species was isolated on potato dextrose agar (PDA). The isolate was grown on PDA at 25°C and 12-h photoperiod under fluorescent light. The colony was gray on the upper surface and the reverse part was dark gray. Conidia (n = 50) were cylindrical to subcylindrical, hyaline, and 12 to 15 (avg. 12.7) × 3.8 to 5.9 (avg. 4.3) μm. Conidia length/width ratio was 2 to 3.6. Pathogenicity was confirmed on Barbados cherry fruit. Inoculation was carried out by depositing 40-μl droplets of a conidial suspension (1 × 105 conidia ml−1) on fruit wounded with a sterilized needle and on non-wounded fruit. Fruit were incubated in a moist chamber at 25°C. First symptoms appeared 3 and 5 days after inoculation on wounded and non-wounded fruit, respectively. No symptoms were observed on control fruit inoculated with water. Six isolates recovered from inoculated fruit showed the same morphological characteristics of the previous isolate. The DNA of the fungus was extracted by a CTAB protocol (1) and the sequences of ITS, GAPDH, ACT, CHS-1, TUB, and CAL genes (4) were generated. Sequences were used in BLAST searches in GenBank and were 100% similar to C. theobromicola, except for GAPDH. The ITS (KC566724) and CAL (KC566437) sequences matched strain ICMP 17099 (JX010285 and JX009588, respectively) with 100% identity. The BTUB (KC566148), GAPDH (KC566578), ACT (KC566870), and CHS-1(KC566292) sequences matched with the strains ICMP 18649 (JX010447, 100% identity), ICMP 17099 (JX009957, 99% identity, 1 pb), ICMP 18567 (JX009457, 100% identity), and ICMP 18613 (JX009771, 100% identity), respectively. The sequences were also compared with authentic culture of C. gloeosporioides (IMI 356878) and the identities were: ITS 99% (JX010148), CAL 91% (JX009729), BTUB 90% (JX010445), GAPDH 83% (GU174561), ACT 93% (JX009494), and CHS-1 98% (JX009747). Based on the multi-gene sequencing, the isolate was identified as C. theobromicola. C. theobromicola was described in 2010 (3) and it is considered as a widely distributed species occurring on different hosts in tropical and subtropical regions (4). This report shows the necessity of the identification of Colletotrichum species from tropical fruits to elucidate the etiology of anthracnose diseases of which C. gloeosporioides sensu lato is considered to be the causal agent. To our knowledge, this is the first report of C. theobromicola on Barbados cherry. References: (1) M. G. Murray and W. F. Thompson. Nucleic Acids Res. 8:4321, 1980. (2) R. Ritzinger et al. Acerola em Foco 13:1, 2007. (3) E. I. Rojas et al. Mycologia 102:1318, 2010. (4) B. S. Weir et al. Stud. Mycol. 73:115, 2012.

scholarly journals First Report of Colletotrichum cereale Causing Anthracnose on Avena nuda in China

Plant Disease ◽  
2020 ◽  
Author(s):  
Na Zhao ◽  
Junyu Yang ◽  
Xiaoli Fang ◽  
lingrui Li ◽  
Hongfei Yan ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Causal Agent ◽  
Post Inoculation ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Single Spore ◽  
First Report ◽  
Fungal Isolates ◽  
Colletotrichum Cereale ◽  
Avena Nuda

Naked oats (Avena nuda L.) is rich in protein, fat, vitamin, mineral elements and so on, and is one of the world's recognized cereal crops with the highest nutritional and healthcare value. In July 2019, leaf spot was detected on A. nuda in Zhangbei experimental station of Hebei Agricultural University. The incidence of disease is 10% to 20%. The symptoms were similar to anthracnose disease, the infected leaves had fusiform or nearly fusiform yellowish-brown spots, yellow halo around the spots. Numerous acervuli with black setae diagnostic of fungi in the genus Colletotrichum were present on necrotic lesions. To identify the pathogen, ten symptomatic leaves were collected, and only one disease spot was isolated from each leaf. Small square leaf pieces (3 to 5 mm) were excised from the junction of diseased and healthy tissues with a sterile scalpel and surface disinfested with 75% alcohol for 30s, 0.1% corrosive sublimate for 1 min, rinsed three times in sterile water. Plant tissues were then transferred on potato dextrose agar (PDA), and incubated at 25°C for 7 days. Two fungal isolates were obtained and purified by single-spore isolation method. All fungi have the same morphology and no other fungi were isolated. The aerial mycelium was gray black. The conidia were colorless and transparent, falcate, slightly curved, tapered toward the tips, and produced in acervuli with brown setae. The length and width of 100 conidia were measured and size ranged from 1.86 to 3.84 × 8.62 to 29.81 μm. These morphological characteristics were consistent with the description of Colletotrichum cereale (Crouch et al. 2006). To further assess the identity of the species, the genomic DNA of two fungal isolates (LYM19-4 and LYM19-10) was extracted by a CTAB protocol. The ribosomal DNA internal transcribed spacer (ITS) region as well as, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), and the beta-tubulin 2 (Tub2) partial genes were amplified and sequenced with primers ITS4/5, GDF/GDR, ACT-512F/ACT-783R, and T1/Bt2b, respectively (Carbone et al. 1999; Templeton et al. 1992; O'Donnell et al. 1997; Glass et al. 1995). The sequences of the ITS-rDNA region (MW040121, MW040122), the GAPDH sequences (MW052554, MW052555), the ACT sequences (MW052556, MW052551) and the Tub2 sequences (MW052552, MW052553) of the two single-spore isolates were more than 99% identical to C. cereale isolate CGMCC3.15110 (JX625159, KC843517, KC843534 and JX625186). Maximum likelihood tree based on concatenated sequences of the four genes were constructed using MEGA7. The results showed the strains isolated from A. nuda were closely related to C. cereale, as supported by high bootstrap values. A pathogenicity test of the C. cereale isolates was performed on first unfolding leaves of A. nuda. Koch's postulates were carried out with isolates by spraying a conidial suspension of 106 conidia/mL on leaves of healthy A. nuda. Four replicated pots were inoculated at a time, 10 leaves each pot, while sterile distilled water was used as the control. All treated plants were placed in a moist chamber (25°C, 16-h light and 8-h dark period). Anthracnose symptoms developed on the inoculated plants 7 days post inoculation while all control plants remained healthy. Microscopic examination showed the surface of infected leaves had the same acervuli, setae, and conidia as the original isolate. The pathogenicity test was repeated three times. C. cereale was previously reported as the causal agent of anthracnose on feather reed grass in US (Crouch et al. 2009). To our knowledge, this is the first report of C. cereale as the causal agent of A. nuda anthracnose in China.

scholarly journals First Report of Colletotrichum boninense Causing Anthracnose on Pepper in Brazil

Plant Disease ◽  
2009 ◽  
Vol 93 (1) ◽  
pp. 106-106 ◽  
Author(s):  
H. J. Tozze ◽  
N. M. Massola ◽  
M. P. S. Câmara ◽  
R. Gioria ◽  
O. Suzuki ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Hypodermic Needle ◽  
Molecular Characteristics ◽  
Width Ratio ◽  
Conidial Suspension ◽  
Rio Grande Do Sul ◽  
First Report ◽  
Potted Plants ◽  
Length Width ◽  
Orange Color

Colletotrichum boninense was isolated from pepper (Capsicum annuum) fruits (cv. Amanda) with preharvest anthracnose symptoms collected in the Brazilian states of Rio Grande do Sul and São Paulo in July of 2005. In the field, the disease affected mature fruits and leaves with an incidence near 25%. Typical symptoms in fruits were circular, sunken lesions with orange spore masses in a dark center. Three single conidia isolates were obtained from infected fruits. When grown on potato dextrose agar at 25°C with a 12-h photoperiod, these isolates produced white colonies with a cream-to-orange color in the opposite side, but no sclerotia. Conidia were cylindrical, had obtuse ends and a hilum-like low protuberance at the base, and measured 13.5 to 15.5 × 4.6 to 5.1 μm. Conidial length/width ratio was 2.8 to 3.0. These morphological characteristics are consistent with the description of C. boninense (1). To confirm pathogen identity, the internal transcribed spacer rRNA region was sequenced (GenBank Accession Nos. FJ010199, FJ010200, and FJ010201) and compared with the same region of C. boninense (GenBank Accession No. DQ286160.1). Similarity between these sequences was 98 to 99%. The pathogenicity of the three isolates was determined on pepper fruits cv. Amanda. Attached as well as detached fruits from potted plants were inoculated. Inoculation was performed by depositing 40-μl droplets of a suspension (105 conidia per ml) on the surfaces of nonwounded (detached n = 5; attached n = 5) and wounded (detached n = 5; attached n = 5) fruits with a sterilized hypodermic needle. Incubation took place in a moist chamber for 12 days at 25°C with a 12-h photoperiod. Inoculation of control fruits was similar in procedure and number to that of test fruits, except sterile distilled water was used instead of the conidial suspension. Symptoms, observed in wounded and nonwounded test fruits 3 to 5 days after inoculation, were characterized by necrotic, sunken zones containing acervuli, black setae, and orange spore masses. Control fruits presented no symptoms. Pathogens reisolated from infected fruits showed the same morphological and molecular characteristics of the isolates previously inoculated. To our knowledge, this is the first report of C. boninense infecting pepper in Brazil. Reference: (1) J. Moriwaki et al. Mycoscience 44:47, 2003.

scholarly journals First Report of Flyspeck Caused by Zygophiala wisconsinensis on Sweet Persimmon Fruit in Korea

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 616-616 ◽  
Author(s):  
J. Kim ◽  
O. Choi ◽  
J.-H. Kwon
Keyword(s):  
Disease Incidence ◽  
Morphological Characteristics ◽  
Its Rdna ◽  
Control Treatment ◽  
Diospyros Kaki ◽  
Distilled Water ◽  
First Report ◽  
Persimmon Fruit ◽  
Fungal Isolates ◽  
Agar Disc

Sweet persimmon (Diospyros kaki L.), a fruit tree in the Ebenaceae, is cultivated widely in Korea and Japan, the leading producers worldwide (2). Sweet persimmon fruit with flyspeck symptoms were collected from orchards in the Jinju area of Korea in November 2010. The fruit had fungal clusters of black, round to ovoid, sclerotium-like fungal bodies with no visible evidence of a mycelial mat. Orchard inspections revealed that disease incidence ranged from 10 to 20% in the surveyed area (approximately 10 ha) in 2010. Flyspeck symptoms were observed on immature and mature fruit. Sweet persimmon fruit peels with flyspeck symptoms were removed, dried, and individual speck lesions transferred to potato dextrose agar (PDA) and cultured at 22°C in the dark. Fungal isolates were obtained from flyspeck colonies on 10 sweet persimmon fruit harvested from each of three orchards. Fungal isolates that grew from the lesions were identified based on a previous description (1). To confirm identity of the causal fungus, the complete internal transcribed spacer (ITS) rDNA sequence of a representative isolate was amplified and sequenced using primers ITS1 and ITS4 (4). The resulting 552-bp sequence was deposited in GenBank (Accession No. HQ698923). Comparison with ITS rDNA sequences showed 100% similarity with a sequence of Zygophiala wisconsinensis Batzer & Crous (GenBank Accession No. AY598855), which infects apple. To fulfill Koch's postulates, mature, intact sweet persimmon fruit were surface sterilized with 70% ethanol and dried. Three fungal isolates from this study were grown on PDA for 1 month. A colonized agar disc (5 mm in diameter) of each isolate was cut from the advancing margin of a colony with a sterilized cork borer, transferred to a 1.5-ml Eppendorf tube, and ground into a suspension of mycelial fragments and conidia in a blender with 1 ml of sterile, distilled water. The inoculum of each isolate was applied by swabbing a sweet persimmon fruit with the suspension. Three sweet persimmon fruit were inoculated per isolate. Three fruit were inoculated similarly with sterile, distilled water as the control treatment. After 1 month of incubation in a moist chamber at 22°C, the same fungal fruiting symptoms were reproduced as observed in the orchards, and the fungus was reisolated from these symptoms, but not from the control fruit, which were asymptomatic. On the basis of morphological characteristics of the fungal colonies, ITS sequence, and pathogenicity to persimmon fruit, the fungus was identified as Z. wisconsinensis (1). Flyspeck is readily isolated from sweet persimmon fruit in Korea and other sweet persimmon growing regions (3). The exposure of fruit to unusual weather conditions in Korea in recent years, including drought, and low-temperature and low-light situations in late spring, which are favorable for flyspeck, might be associated with an increase in occurrence of flyspeck on sweet persimmon fruit in Korea. To our knowledge, this is the first report of Z. wisconsinensis causing flyspeck on sweet persimmon in Korea. References: (1) J. C. Batzer et al. Mycologia 100:246, 2008. (2) FAOSTAT Database. Retrieved from http://faostat.fao.org/ , 2008. (3) H. Nasu and H. Kunoh. Plant Dis. 71:361, 1987. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, Inc., New York, 1990.

scholarly journals First Report of Leaf Blight of Japanese Yew Caused by Pestalotiopsis microspora in Korea

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 691-691 ◽  
Author(s):  
Y. H. Jeon ◽  
W. Cheon
Keyword(s):  
Dna Sequences ◽  
Apical Cell ◽  
Morphological Characteristics ◽  
Leaf Blight ◽  
Economic Damage ◽  
Leaf Margin ◽  
Conidial Suspension ◽  
First Report ◽  
Pestalotiopsis Microspora ◽  
Large Trees

Worldwide, Japanese yew (Taxus cuspidata Sieb. & Zucc.) is a popular garden tree, with large trees also being used for timber. In July 2012, leaf blight was observed on 10% of Japanese yew seedling leaves planted in a 500-m2 field in Andong, Gyeongsangbuk-do Province, South Korea. Typical symptoms included small, brown lesions that were first visible on the leaf margin, which enlarged and coalesced into the leaf becoming brown and blighted. To isolate potential pathogens from infected leaves, small sections of leaf tissue (5 to 10 mm2) were excised from lesion margins. Eight fungi were isolated from eight symptomatic trees, respectively. These fungi were hyphal tipped twice and transferred to potato dextrose agar (PDA) plates for incubation at 25°C. After 7 days, the fungi produced circular mats of white aerial mycelia. After 12 days, black acervuli containing slimy spore masses formed over the mycelial mats. Two representative isolates were further characterized. Their conidia were straight or slightly curved, fusiform to clavate, five-celled with constrictions at the septa, and 17.4 to 28.5 × 5.8 to 7.1 μm. Two to four 19.8- to 30.7-μm-long hyaline filamentous appendages (mostly three appendages) were attached to each apical cell, whereas one 3.7- to 7.1-μm-long hyaline appendage was attached to each basal cell, matching the description for Pestalotiopsis microspora (2). The pathogenicity of the two isolates was tested using 2-year-old plants (T. cuspidata var. nana Rehder; three plants per isolate) in 30-cm-diameter pots filled with soil under greenhouse conditions. The plants were inoculated by spraying the leaves with an atomizer with a conidial suspension (105 conidia/ml; ~50 ml on each plant) cultured for 10 days on PDA. As a control, three plants were inoculated with sterilized water. The plants were covered with plastic bags for 72 h to maintain high relative humidity (24 to 28°C). At 20 days after inoculation, small dark lesions enlarged into brown blight similar to that observed on naturally infected leaves. P. microspora was isolated from all inoculated plants, but not the controls. The fungus was confirmed by molecular analysis of the 5.8S subunit and flanking internal transcribed spaces (ITS1 and ITS2) of rDNA amplified from DNA extracted from single-spore cultures, and amplified with the ITS1/ITS4 primers and sequenced as previously described (4). Sequences were compared with other DNA sequences in GenBank using a BLASTN search. The P. microspora isolates were 99% homologous to other P. microspora (DQ456865, EU279435, FJ459951, and FJ459950). The morphological characteristics, pathogenicity, and molecular data assimilated in this study corresponded with the fungus P. microspora (2). This fungus has been previously reported as the causal agent of scab disease of Psidium guajava in Hawaii, the decline of Torreya taxifolia in Florida, and the leaf blight of Reineckea carnea in China (1,3). Therefore, this study presents the first report of P. microspora as a pathogen on T. cuspidata in Korea. The degree of pathogenicity of P. microspora to the Korean garden evergreen T. cuspidata requires quantification to determine its potential economic damage and to establish effective management practices. References: (1) D. F. Farr and A. Y. Rossman, Fungal Databases, Syst. Mycol. Microbiol. Lab. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ (2) L. M. Keith et al. Plant Dis. 90:16, 2006. (3) S. S. N. Maharachchikumbura. Fungal Diversity 50:167, 2011. (4) T. J. White et al. PCR Protocols. Academic Press, San Diego, CA, 1990.

scholarly journals First report of Coniella castaneicola causing leaf blight on blueberry (Vaccinium virgatum) in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Jiahao Lai ◽  
Guihong Xiong ◽  
Bing Liu ◽  
Weigang Kuang ◽  
Shuilin Song
Keyword(s):  
Molecular Identification ◽  
Morphological Characteristics ◽  
Leaf Blight ◽  
Yield Potential ◽  
Effective Control ◽  
Economic Losses ◽  
Distilled Water ◽  
First Report ◽  
Fungal Isolates ◽  
Blight Disease

Blueberry (Vaccinium virgatum), an economically important small fruit crop, is characterized by its highly nutritive compounds and high content and wide diversity of bioactive compounds (Miller et al. 2019). In September 2020, an unknown leaf blight disease was observed on Rabbiteye blueberry at the Agricultural Science and Technology Park of Jiangxi Agricultural University in Nanchang, China (28°45'51"N, 115°50'52"E). Disease surveys were conducted at that time, the results showed that disease incidence was 90% from a sampled population of 100 plants in the field, and this disease had not been found at other cultivation fields in Nanchang. Leaf blight disease on blueberry caused the leaves to shrivel and curl, or even fall off, which hindered floral bud development and subsequent yield potential. Symptoms of the disease initially appeared as irregular brown spots (1 to 7 mm in diameter) on the leaves, subsequently coalescing to form large irregular taupe lesions (4 to 15 mm in diameter) which became curly. As the disease progressed, irregular grey-brown and blighted lesion ran throughout the leaf lamina from leaf tip to entire leaf sheath and finally caused dieback and even shoot blight. To identify the causal agent, 15 small pieces (5 mm2) of symptomatic leaves were excised from the junction of diseased and healthy tissue, surface-sterilized in 75% ethanol solution for 30 sec and 0.1% mercuric chloride solution for 2 min, rinsed three times with sterile distilled water, and then incubated on potato dextrose agar (PDA) at 28°C for 5-7 days in darkness. Five fungal isolates showing similar morphological characteristics were obtained as pure cultures by single-spore isolation. All fungal colonies on PDA were white with sparse creeping hyphae. Pycnidia were spherical, light brown, and produced numerous conidia. Conidia were 10.60 to 20.12 × 1.98 to 3.11 µm (average 15.27 × 2.52 µm, n = 100), fusiform, sickle-shaped, light brown, without septa. Based on morphological characteristics, the fungal isolates were suspected to be Coniella castaneicola (Cui 2015). To further confirm the identity of this putative pathogen, two representative isolates LGZ2 and LGZ3 were selected for molecular identification. The internal transcribed spacer region (ITS) and large subunit (LSU) were amplified and sequenced using primers ITS1/ITS4 (Peever et al. 2004) and LROR/LR7 (Castlebury and Rossman 2002). The sequences of ITS region (GenBank accession nos. MW672530 and MW856809) showed 100% identity with accessions numbers KF564280 (576/576 bp), MW208111 (544/544 bp), MW208112 (544/544 bp) of C. castaneicola. LSU gene sequences (GenBank accession nos. MW856810 to 11) was 99.85% (1324/1326 bp, 1329/1331 bp) identical to the sequences of C. castaneicola (KY473971, KR232683 to 84). Pathogenicity was tested on three blueberry varieties (‘Rabbiteye’, ‘Double Peak’ and ‘Pink Lemonade’), and four healthy young leaves of a potted blueberry of each variety with and without injury were inoculated with 20 μl suspension of prepared spores (106 conidia/mL) derived from 7-day-old cultures of LGZ2, respectively. In addition, four leaves of each variety with and without injury were sprayed with sterile distilled water as a control, respectively. The experiment was repeated three times, and all plants were incubated in a growth chamber (a 12h light and 12h dark period, 25°C, RH greater than 80%). After 4 days, all the inoculated leaves started showing disease symptoms (large irregular grey-brown lesions) as those observed in the field and there was no difference in severity recorded between the blueberry varieties, whereas the control leaves showed no symptoms. The fungus was reisolated from the inoculated leaves and confirmed as C. castaneicola by morphological and molecular identification, fulfilling Koch’s postulates. To our knowledge, this is the first report of C. castaneicola causing leaf blight on blueberries in China. The discovery of this new disease and the identification of the pathogen will provide useful information for developing effective control strategies, reducing economic losses in blueberry production, and promoting the development of the blueberry industry.

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