First report of Colletotrichum gloeosporioides causing leaf spot on Cyclobalanopsis glauca in China

Cyclobalanopsis glauca (Thunb.) Oerst. is one of the most widely distributed species of evergreen broad-leaved tree in subtropical areas of China. It is also grown in Korea, Japan, and India. Because of its beautiful shape, C. glauca is commonly used for greening gardens and walkways. In July 2018, leaf spots on C. glauca were observed in Zhejiang province (Lishui, N: 28°26’ 6.75”;E: 119°54’11.22), China. About 70% of the trees were found to be diseased, with approximately 50% of leaves showing symptoms. The symptoms on C. glauca leaves initially appeared as small brown-yellow spots which gradually expanded, developing a light brown central and dark brown to black margin. The spots ranged from 4 to 15 mm in diameter. Ten symptomatic fragments measuring approximately 5×5 mm from each leaf were surface disinfested with 70% ethanol for 30 s, and then they were rinsed in sterile distilled water and placed on potato dextrose agar (PDA) medium at 25 °C in the dark for five days. Segments of colony perimeters were then transferred to new plates. The colonies initially produced white mycelia that later turned gray-white with pink and occasionally black dots scattered on the surface of the mycelium. Spores were aseptate, cylindrical, 8 to 15 μm in length, and 3 to 5 μm wide, most with rounded ends, a few with one apex round and the other fusiform, as described for Colletotrichum gloeosporioides (Penz.) Sacc. (Agostini et al. 1993). The internal transcribed spacer rDNA (ITS: MK758005) and two nuclear protein-coding genes (CHS: MK784770, ACT: MK784769) were amplified with ITS1/ITS4, CHS-79F/CHS-345, and ACT-512F/ACT-783R, respectively (Weir et al. 2012). The sequence had 99.61% identity to GQ485605 for ITS, 99.56% to GQ856782 for ACT, and 100% to GQ856733 for CHS of C. gloeosporioides CBS 953.97 in GenBank, respectively. To fulfill Koch’s postulates, spores (1×108) of the isolate were sprayed onto leaves of twelve 2-year-old C. glauca plants (at least six leaves per plant). The fungus was inoculated on one side of each leaf, and distilled water was used as a mock inoculated control on the other side. The plants were cultivated in the greenhouse to maintain high humidity and a temperature near 25 °C. After 9 days, 100% of the leaf halves that had been inoculated had symptoms identical to those observed on affected C. glauca leaves in the field, while no symptoms were observed on the mock inoculated half of each leaf. The fungus was reisolated from the symptoms and identified as C. gloeosporioides using techniques previously described. To our knowledge, this is the first report of C. gloeosporioides infecting C. glauca in China. This study will establish a foundation for the further study of C. gloeosporioides to address the disease effectively. References: Agostini, J. P., et al. 1993. Phytopathology. 82:1177. Weir, B. S., et al. 2012. Stud. Mycol. 73:115. This work was supported by the National Science Foundation for Young Scientists of China (31800035).

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First Report of Colletotrichum gloeosporioides Causing Leaf Spots on Smilax sieboldii in China

Plant Disease ◽

10.1094/pdis-06-17-0810-pdn ◽

2017 ◽

Vol 101 (12) ◽

pp. 2150-2150

Author(s):

J. N. Zhang ◽

L. M. Song ◽

W. X. Liang ◽

D. L. Li

Keyword(s):

Colletotrichum Gloeosporioides ◽

First Report ◽

Leaf Spots

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First Report of Leaf Spot of Sweet Basil Caused by Cercospora guatemalensis in Korea

Plant Disease ◽

10.1094/pdis-05-12-0436-pdn ◽

2012 ◽

Vol 96 (10) ◽

pp. 1580-1580

Author(s):

J. H. Park ◽

K. S. Han ◽

J. Y. Kim ◽

H. D. Shin

Keyword(s):

Leaf Spot ◽

Morphological Characteristics ◽

Its Region ◽

Culture Collection ◽

Distilled Water ◽

First Report ◽

Sweet Basil ◽

Organic Farm ◽

Leaf Spots ◽

Close Phylogenetic Relationship

Sweet basil, Ocimum basilicum L., is a fragrant herb belonging to the family Lamiaceae. Originated in India 5,000 years ago, sweet basil plays a significant role in diverse cuisines across the world, especially in Asian and Italian cooking. In October 2008, hundreds of plants showing symptoms of leaf spot with nearly 100% incidence were found in polyethylene tunnels at an organic farm in Icheon, Korea. Leaf spots were circular to subcircular, water-soaked, dark brown with grayish center, and reached 10 mm or more in diameter. Diseased leaves defoliated prematurely. The damage purportedly due to this disease has reappeared every year with confirmation of the causal agent made again in 2011. A cercosporoid fungus was consistently associated with disease symptoms. Stromata were brown, consisting of brown cells, and 10 to 40 μm in width. Conidiophores were fasciculate (n = 2 to 10), olivaceous brown, paler upwards, straight to mildly curved, not geniculate in shorter ones or one to two times geniculate in longer ones, 40 to 200 μm long, occasionally reaching up to 350 μm long, 3.5 to 6 μm wide, and two- to six-septate. Conidia were hyaline, acicular to cylindric, straight in shorter ones, flexuous to curved in longer ones, truncate to obconically truncate at the base, three- to 16-septate, and 50 to 300 × 3.5 to 4.5 μm. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora guatemalensis A.S. Mull. & Chupp (1,3). Voucher specimens were housed at Korea University herbarium (KUS). An isolate from KUS-F23757 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC43980). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 548 bp was deposited in GenBank (Accession No. JQ995781). This showed >99% similarity with sequences of many Cercospora species, indicating their close phylogenetic relationship. Isolate of KACC43980 was used in the pathogenicity tests. Hyphal suspensions were prepared by grinding 3-week-old colonies grown on PDA with distilled water using a mortar and pestle. Five plants were inoculated with hyphal suspensions and five plants were sprayed with sterile distilled water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 24 h and then transferred to a 25 ± 2°C greenhouse with a 12-h photoperiod. Typical symptoms of necrotic spots appeared on the inoculated leaves 6 days after inoculation, and were identical to the ones observed in the field. C. guatemalensis was reisolated from symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in Malawi, India, China, and Japan (2,3), but not in Korea. To our knowledge, this is the first report of C. guatemalensis on sweet basil in Korea. Since farming of sweet basil has recently started on a commercial scale in Korea, the disease poses a serious threat to safe production of this herb, especially in organic farming. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology & Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , May 5, 2012. (3) J. Nishikawa et al. J. Gen. Plant Pathol. 68:46, 2002.

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First Report of Leaf Spot Disease Caused by Colletotrichum gloeosporioides on Chinese Bean Tree in China

Plant Disease ◽

10.1094/pdis-03-12-0261-pdn ◽

2013 ◽

Vol 97 (1) ◽

pp. 138-138 ◽

Cited By ~ 1

Author(s):

B. Z. Fu ◽

M. Yang ◽

G. Y. Li ◽

J. R. Wu ◽

J. Z. Zhang ◽

...

Keyword(s):

Leaf Spot ◽

Colletotrichum Gloeosporioides ◽

Disease Incidence ◽

Phylogenetic Analyses ◽

Morphological Characteristics ◽

Leaf Spot Disease ◽

First Report ◽

Spot Disease ◽

Rdna Its ◽

Its Sequence Analysis

Chinese bean tree, Catalpa fargesii f. duciouxii (Dode) Gilmour, is an ornamental arbor plant. Its roots, leaves, and flowers have long been used for medicinal purposes in China. During July 2010, severe outbreaks of leaf spot disease on this plant occurred in Kunming, Yunnan Province. The disease incidence was greater than 90%. The symptoms on leaves began as dark brown lesions surrounded by chlorotic halos, and later became larger, round or irregular spots with gray to off-white centers surrounded by dark brown margins. Leaf tissues (3 × 3 mm), cut from the margins of lesions, were surface disinfected in 0.1% HgCl2 solution for 3 min, rinsed three times in sterile water, plated on potato dextrose agar (PDA), and incubated at 28°C. The same fungus was consistently isolated from the diseased leaves. Colonies of white-to-dark gray mycelia formed on PDA, and were slightly brown on the underside of the colony. The hyphae were achromatic, branching, septate, and 4.59 (±1.38) μm in diameter on average. Perithecia were brown to black, globose in shape, and 275.9 to 379.3 × 245.3 to 344.8 μm. Asci that formed after 3 to 4 weeks in culture were eight-spored, clavate to cylindrical. The ascospores were fusiform, slightly curved, unicellular and hyaline, and 13.05 to 24.03 × 10.68 to 16.02 μm. PCR amplification was carried out by utilizing universal rDNA-ITS primer pair ITS4/ITS5 (2). Sequencing of the PCR products of DQ1 (GenBank Accession No. JN165746) revealed 99% similarity (100% coverage) with Colletotrichum gloeosporioides isolates (GenBank Accession No. FJ456938.1, No. EU326190.1, No. DQ682572.1, and No. AY423474.1). Phylogenetic analyses (MEGA 4.1) using the neighbor-joining (NJ) algorithm placed the isolate in a well-supported cluster (>90% bootstrap value based on 1,000 replicates) with other C. gloeosporioides isolates. The pathogen was identified as C. gloeosporioides (Penz.) Penz. & Sacc. (teleomorph Glomerella cingulata (Stoneman) Spauld & H. Schrenk) based on the morphological characteristics and rDNA-ITS sequence analysis (1). To confirm pathogenicity, Koch's postulates were performed on detached leaves of C. fargesii f. duciouxii, inoculated with a solution of 1.0 × 106 conidia per ml. Symptoms similar to the original ones started to appear after 10 days, while untreated leaves remained healthy. The inoculation assay used three leaves for untreated and six leaves for treated. The experiments were repeated once. C. gloeosporioides was consistently reisolated from the diseased tissue. C. gloeosporioides is distributed worldwide causing anthracnose on a wide variety of plants (3). To the best of our knowledge, this is the first report of C. gloeosporioides causing leaf spots on C. fargesii f. duciouxii in China. References: (1) B. C. Sutton. Page 1 in: Colletotrichum: Biology, Pathology and Control. CAB International. Wallingford, UK, 1992. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (3) J. Yan et al. Plant Dis. 95:880, 2011.

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First Report of Stem and Leaf Anthracnose on Blueberry Caused by Colletotrichum gloeosporioides in China

Plant Disease ◽

10.1094/pdis-11-12-1056-pdn ◽

2013 ◽

Vol 97 (6) ◽

pp. 845-845 ◽

Cited By ~ 1

Author(s):

C. N. Xu ◽

Z. S. Zhou ◽

Y. X. Wu ◽

F. M. Chi ◽

Z. R. Ji ◽

...

Keyword(s):

Colletotrichum Gloeosporioides ◽

Morphological Characteristics ◽

Its Region ◽

Pathogenic Fungi ◽

Molecular Characteristics ◽

First Report ◽

Potted Plants ◽

Leaf Spots ◽

Pathogenicity Tests ◽

Highbush Blueberries

Blueberry (Vaccinium spp.) is becoming increasingly popular in China as a nutritional berry crop. With the expansion of blueberry production, many diseases have become widespread in different regions of China. In August of 2012, stem and leaf spots symptomatic of anthracnose were sporadically observed on highbush blueberries in a field located in Liaoning, China, where approximately 15% of plants were diseased. Symptoms first appeared as yellow to reddish, irregularly-shaped lesions on leaves and stems. The lesions then expanded, becoming dark brown in the center and surrounded by a reddish halo. Leaf and stem tissues (5 × 5 mm) were cut from the lesion margins and surface-disinfected in 70% ethanol for 30 s, followed by three rinses with sterile water before placing on potato dextrose agar (PDA). Plates were incubated at 28°C. Colonies were initially white, becoming grayish-white to gray with yellow spore masses. Conidia were one-celled, hyaline, and cylindrical with rounded ends, measuring 15.0 to 25.0 × 4.0 to 7.5 μm. No teleomorph was observed. The fungus was tentatively identified as Colletotrichum gloeosporioides (PenZ.) PenZ & Sacc. (teleomorph Glomerella cingulata (Stoneman) Spauld. & H. Schrenk) based on morphological characteristics of the colony and conidia (1). Genomic DNA was extracted from isolate XCG1 and the internal transcribed spacer (ITS) region of the ribosomal DNA (ITS1–5.8S-ITS2) was amplified with primer pairs ITS1 and ITS4. BLAST searches showed 99% identity with C. gloeosporioides isolates in GenBank (Accession No. AF272779). The sequence of isolate XCG1 (C. gloeosporioides) was deposited into GenBank (JX878503). Pathogenicity tests were conducted on 2-year-old potted blueberries, cv. Berkeley. Stems and leaves of 10 potted blueberry plants were wounded with a sterilized needle and sprayed with a suspension of 105 conidia per ml of sterilized water. Five healthy potted plants were inoculated with sterilized water as control. Dark brown lesions surrounded by reddish halos developed on all inoculated leaves and stems after 7 days, and the pathogen was reisolated from lesions of 50% of inoculated plants as described above. The colony and conidial morphology were identical to the original isolate XCG1. No symptoms developed on the control plants. The causal agent of anthracnose on blueberry was identified as C. gloeosporioides on the basis of morphological and molecular characteristics, and its pathogenicity was confirmed with Koch's postulates. Worldwide, it has been reported that blueberry anthracnose might be caused by C. acutatum and C. gloeosporioides (2). However, we did not isolate C. acutatum during this study. To our knowledge, this is the first report of stem and leaf anthracnose of blueberry caused by C. gloeosporioides in China. References: (1) J. M. E. Mourde. No 315. CMI Descriptions of Pathogenic Fungi and Bacteria. Kew, Surrey, UK, 1971. (2) N. Verma, et al. Plant Pathol. 55:442, 2006.

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First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Schefflera actinophylla in China

Plant Disease ◽

10.1094/pdis-12-12-1205-pdn ◽

2013 ◽

Vol 97 (7) ◽

pp. 998-998

Author(s):

J. Huang

Keyword(s):

Dna Sequence ◽

Species Complex ◽

Colletotrichum Gloeosporioides ◽

Conidial Suspension ◽

First Report ◽

Leaf Spots ◽

Black Spots ◽

Pathogenicity Tests ◽

Colletotrichum Gloeosporioides Species Complex ◽

And Control

In China, in mild to warm climates, Schefflera actinophylla is commonly grown as a decorative tree in gardens. When mature, it has bright red flowers in inflorescences with up to 20 racemes that develop in summer or early autumn. From 2008 to 2011, lesions were observed on young and mature leaves in several locations in Guangzhou, China. The first symptoms were circular, necrotic areas that usually developed into irregular, dry, brown to reddish brown or black spots. Spots often first appeared at or near the margins of leaves. Reproductive bodies of the pathogen appeared as black specks in leaf spots. Under a 10× magnification, black, needle-like fungal structures (setae) were observed in the centers of spots on the upper leaf surface. A fungus was isolated from the lesion and was identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. based on cultural characteristics and conidial morphology (1). The voucher isolates were deposited in the Institute of Plant Pathology, Zhongkai University of Agriculture and Engineering. C. gloeosporioides is a species complex (2) and there is a degree of unresolved aspects of taxonomy in this species complex. Cultures on potato dextrose agar (PDA) had aerial white mycelium that turned gray to grayish black after 10 days at 25°C and a 12-h photoperiod and produced salmon to orange conidial masses. Brown, 80 to 120 μm long setae were observed in the acervulus. Conidia 14.1 to 18.0 × 4.0 to 6.1 μm in size were hyaline, thin-walled, aseptate, granular inside, clavate to slightly navicular in shape with an obtuse apex and a truncate base. To identify the fungus, a 588-bp segment of the ITS1-5.8S-ITS2 rDNA region was amplified by PCR and sequenced. The DNA sequence was submitted to GenBank as KC207404. A BLAST search of the DNA sequence showed 99% identity with accessions AY266389.1, EF423519.1, and HM575258.1 of C. gloeosporioides. Pathogenicity tests were conducted under greenhouse conditions at 25 ± 2°C. A total of 15 leaves from three 1-year-old S. actinophylla plants were inoculated with mycelial PDA plugs that were placed on 0.5-cm2 leaf wounds and then wrapped with Parafilm. Control leaves were treated similarly except that they were inoculated with PDA plugs without the fungus. No symptoms developed on control leaves after 10 days. Foliar lesions on inoculated leaves closely resembled those observed in the field. C. gloeosporioides was reisolated consistently from inoculated leaves. Pathogenicity was also tested by spraying leaves of potted S. actinophylla plants about 30 cm in height with 10 ml of a conidial suspension (1 × 105 conidia/ml) prepared from 7-day-old PDA cultures grown at 25°C. Leaves sprayed with distilled water were used as controls. Three plants were inoculated in each of two experiments and were incubated at 25°C and 90% relative humidity in a growth chamber. Tiny brown spots started to develop on all inoculated leaves 5 days after inoculation and the progression of symptom development was similar to that observed in the field. Control leaves remained asymptomatic. C. gloeosporioides was reisolated from inoculated leaves. To my knowledge, this is the first report of C. gloeosporioides causing anthracnose on S. actinophylla in China. References: (1) B. C. Sutton. The genus Glomerella and its anamorph Colletotrichum. In: Colletotrichum Biology, Pathology and Control. CAB International, Wallingford, UK, 1992. (2) B. S. Weir et al. The Colletotrichum gloeosporioides species complex. Stud. Mycol. 73:115, 2012.

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First Report of Soft Rot on Dendrobium officinale caused by Epicoccum sorghinum in China

Plant Disease ◽

10.1094/pdis-04-21-0866-pdn ◽

2021 ◽

Author(s):

Caiyun Xiao ◽

Rongyu Li ◽

Xingchen Song ◽

Xujun Tian ◽

Qijun Zhao

Keyword(s):

Internal Transcribed Spacer ◽

Elongation Factor ◽

Morphological Characteristics ◽

Reference Value ◽

Soft Rot ◽

Dendrobium Officinale ◽

First Report ◽

Rdna Its ◽

And Control ◽

Internal Transcribed Spacer Rdna

In recent years, soft rot is one of the most serious diseases in the production of Dendrobium officinale. In this study, we took the diseased plants of Dendrobium officinale in Guizhou as samples, through Koch's rule and sequence analysis of rDNA internal transcribed spacer (rDNA-ITS), calmodulin (cmdA), the second largest subunit of RNA polymerase Ⅱ (RPB2), elongation factor EF-1 α and β-tubulin (β-Tub), it was determined that the pathogen of Dendrobium officinale soft rot was sorghum accessory cocci. This is our first report on the soft rot of Dendrobium officinale caused by Epicoccum sorghinum in China. The morphological characteristics of the pathogen shown in the study will have a certain reference value for the prevention and control of the soft rot of Dendrobium officinale in the future.

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First Report of Colletotrichum siamense Causing Anthracnose on Zinnia elegans Jacq. in China

Plant Disease ◽

10.1094/pdis-04-20-0803-pdn ◽

2020 ◽

Author(s):

Wen Li ◽

Yue-qiu He ◽

Tao Fu ◽

Li Lin ◽

Feng Liu ◽

...

Keyword(s):

Phylogenetic Trees ◽

Colletotrichum Gloeosporioides ◽

Disease Incidence ◽

Morphological Characteristics ◽

Zinnia Elegans ◽

Likelihood Method ◽

Distilled Water ◽

First Report ◽

Colletotrichum Siamense ◽

Leaf Tissues

Zinnia elegans (syn. Zinnia violacea), known as common zinnia, is one of the most spectacular ornamental plants in the family Asteraceae. Zinnia plants are widely cultivated in China for their impressive range in flower colours and profuse bloom over a long period. In April 2019, Zinnia plants grown in Ningbo Botanical Garden (29°56′57″N, 121°36′20″E) were found to have many circular necrotic lesions. In the early infection stage, the lesions appeared as small circular specks which developed later into large spots (15 to 32 mm diameter). Typical symptoms appeared to be grayish white centers with a chlorotic edges and disease incidence reached approximately 80% of plants in the affected field. Moreover, the growth of Zinnia plants was seriously affected by the disease. To identify the causative pathogen associated with the disease, 10 symptomatic leaves were collected from ten different Zinnia plants. Leaf tissues were cut from the lesion margins, surface sterilized with 75% ethanol for 30 seconds and rinsed three times in sterile distilled water. The leaf tissues were then dipped into 10% sodium hypochlorite for 2-3 minutes, washed three times in distilled water and dried on a sterile filter paper. After drying, the surface-sterilized leaf discs were transferred to potato dextrose agar (PDA) plates and incubated at 28°C for 2 to 3 days under the 12 h photoperiod. A total of ten pure fungal isolates were obtained and all the isolates displayed the same colony structure. Afterwards, three pure strains were randomly selected (F1, F3 and F5) for further study. The fungal colonies showed gray to brownish aerial mycelia with pink-colored masses of conidia. Conidia were one-celled, hyaline, cylindrical to subcylindrical, spindle-shaped with obtuse ends, measuring from 15.6 to 17.3 × 4.6 to 5.1 μm with both ends rounded. These morphological characteristics were consistent with the description of Colletotrichum gloeosporioides complex (Weir et al. 2012). The identity of a representative isolate, F3, was confirmed by a multilocus approach. Genomic DAN of isolate F3 was extracted and partial sequences of actin (ACT), chitin synthase (CHS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ribosomal internal transcribed spacer (ITS), manganese-superoxide dismutase (SOD2) , glutamine synthatase (GS), beta-tubulin (TUB2) and calmodulin (CAL) were amplified and sequenced as previously described (Weir et al. 2012). These nucleotide sequences were deposited in GenBank (accession MN972436 to MN972440, and MT266559 to MT266561; all sequences in FASTA format are shown (Supplementary S1). BLAST analysis of ITS, ACT, CHS, GAPDH and GS sequences from the F3 isolate revealed similarity to C. gloeosporioides voucher strain ZH01 with 100%, 100%，99%, 99% and 99% identity, respectively. SOD, TUB2 and CAL sequences showed similarity to C. siamense with 100%, 100% and 100% identity, respectively. The phylogenetic trees were constructed by Maximum Likelihood method (ML) using JTT model implemented in the MEGA 7. Results inferred from the concatenated sequences (ACT, CHS, GAPDH, ITS, SOD, GS, TUB2 and CAL) placed the isolate F3 within the C. siamense cluster (Supplementary S2). To confirm pathogenicity of the fungus, Koch’s postulates were conducted by spraying 20 Zinnia plants (60-day-old) with a 1 × 106 conidia/ml suspension. Plants were maintained in the growth chamber at 25°C and 85% relative humidity. After 10 to 15 days, symptoms were observed on all inoculated leaves and resembled those observed in the field, whereas the control plants remained asymptomatic. Here, C. siamense was isolated only from the infected Zinnia leaves and identified by morphological and gene sequencing analyses. C. siamense has been reported in many crops in China (Yang et al. 2019; Chen et al. 2019; Wang et al. 2019). However, to our knowledge, this is the first report of anthracnose caused by C. siamense on Zinnia elegans in China. References Chen, X., Wang, T., Guo, H., Zhu, P. K., and Xu, L. 2019. First report of anthracnose of Camellia sasanqua caused by Colletotrichum siamense in China. Plant Dis. 103:1423-1423. Wang, Y., Qin, H. Y., Liu, Y. X., Fan, S. T., Sun, D., Yang, Y. M., Li, C. Y., and Ai, J. 2019. First report of anthracnose caused by Colletotrichum siamense on Actinidia arguta in China. Plant Dis. 103:372-373. Weir, B. S., Johnston, P. R., and Damm, U. 2012. The Colletotrichum gloeosporioides species complex. Stud. Mycol. 73: 115-180. Yang, S., Wang, H. X., Yi, Y. J., and Tan, L. L. 2019. First report that Colletotrichum siamense causes leaf spots on Camellia japonica in China. Plant Dis. 103:2127-2127.

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First Report of Brown Blight Disease Caused by Colletotrichum gloeosporioides on Camellia sinensis in Anhui Province, China

Plant Disease ◽

10.1094/pdis-08-13-0896-pdn ◽

2014 ◽

Vol 98 (2) ◽

pp. 284-284 ◽

Cited By ~ 16

Author(s):

M. Guo ◽

Y. M. Pan ◽

Y. L. Dai ◽

Z. M. Gao

Keyword(s):

Camellia Sinensis ◽

Colletotrichum Gloeosporioides ◽

Tea Plant ◽

Anhui Province ◽

Molecular Characteristics ◽

Fluorescent Light ◽

Distilled Water ◽

Conidial Suspension ◽

First Report ◽

Twig Blight

Yellow Mountain fuzz tip, a cultivar of Camellia sinensis (L.) Kuntze, is commonly grown in the Yellow Mountain region in Anhui Province of China. During 2011 to 2012, leaf and twig blight on tea plants occurred from July to September in growing regions. Symptoms of blight on leaves of infected plants were detected in 30 to 60% of the fields visited and up to 500 ha were affected each year. Symptoms began as small, water-soaked lesions on young leaves and twigs and later became larger, dark brown, necrotic lesions, 1 to 3 mm in diameter on leaves and 2 to 5 mm long on twigs. To determine the causal agent, symptomatic leaf tissue was collected from plants in Gantang and Tangkou townships in September 2012. Small pieces of diseased tea leaves and twigs were surface-disinfested in 2% NaClO for 3 min, rinsed twice in distilled water, plated on potato dextrose agar, and incubated at 28°C for 5 days. Eleven isolates were recovered and all cultures produced white-to-gray fluffy aerial hyphae and were dark on the reverse of the plate. The hyphae were hyaline, branching, and septate. Setae were 2- to 3-septate, dark brown, acicular, and 78.0 to 115.0 μm. Conidiogenous cells were hyaline, short, branchless, cylindrical, and 11.3 to 21.5 × 4.2 to 5.3 μm. Conidia were hyaline, aseptate, guttulate, cylindrical, and 12.5 to 17.3 × 3.9 to 5.8 μm. Appresoria were ovate to obovate, dark brown, and 8.4 to 15.2 × 7.8 to 12.9 μm. DNA was amplified using the rDNA-ITS primer pair ITS4/ITS5 (3), glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH) primer pair GDF/GDR (2) and beta-tubulin 2 gene (Tub2) primer pair Btub2Fd/Btub4Rd (4). Sequences (GenBank Accession Nos. KC913203, KC913204, and KC913205) of the 11 isolates were identical and revealed 100% similarity to the ITS sequence of strain P042 of Colletotrichum gloeosporioides (EF423527), 100% identity to the GAPDH of isolate C07009 of C. gloeosporioides (GU935860), and 99% similarity to Tub2 of isolate 85 of C. gloeosporioides (AJ409292), respectively. Based on the above data, the 11 isolates were identified as C. gloeosporioides (Penz.) Penz. & Sacc. To confirm pathogenicity, Koch's postulate was performed and 4 ml of conidial suspension (1 × 105 conidia/ml) of each of the 11 isolates was sprayed on five leaves and five twigs per plant on four 12-month-old Yellow Mountain fuzz tip plants. Control plants were sprayed with distilled water. The inoculated plants were maintained at 28°C in a greenhouse with constant relative humidity of 90% and a 12-h photoperiod of fluorescent light. Brown necrotic lesions appeared on leaves and twigs after 7 days, while the control plants remained healthy. The experiments were conducted three times and the fungus was recovered and identified as C. gloeosporioides by both morphology and molecular characteristics. Tea plant blight caused by C. gloeosporioides was identified in Brazil (1), but to our knowledge, this is the first report of C. gloeosporioides causing tea leaf and twig blight on Yellow Mountain fuzz tip plants in Anhui Province of China. References: (1) M. A. S. Mendes et al. Page 555 in: Embrapa-SPI/Embrapa-Cenargen, Brasilia, 1998. (2) M. D. Templeton et al. Gene 122:225, 1992. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (4) J. H. C. Woudenberg et al. Persoonia 22:56, 2009.

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First Report of Colletotrichum gloeosporioides Causing Leaf Spots on Rubia cordifolia in Qingdao, China

Plant Disease ◽

10.1094/pdis-02-20-0292-pdn ◽

2020 ◽

Vol 104 (10) ◽

pp. 2733-2733

Author(s):

Si-Fu Tang ◽

Ling-Ling Tan

Keyword(s):

Colletotrichum Gloeosporioides ◽

Rubia Cordifolia ◽

First Report ◽

Leaf Spots

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First report of Alternaria alternata causing Alternaria leaf spot of Fig in Pakistan

Plant Disease ◽

10.1094/pdis-05-21-0963-pdn ◽

2021 ◽

Author(s):

Hafiz Arslan Anwaar ◽

Rashida Atiq ◽

Sobia Chohan ◽

Amjad Saeed ◽

Muqaddas Tanveer Cheema ◽

...

Keyword(s):

Alternaria Alternata ◽

Leaf Spot ◽

Its Rdna ◽

Tween 20 ◽

Distilled Water ◽

Conidial Suspension ◽

Fungal Isolation ◽

First Report ◽

Leaf Spots ◽

Fruit Disease

Fig (Ficus carica) is a species of flowering plants within the mulberry family. During June 2020, leaf spots were observed on several fig plants (31°26'15.0"N 73°04'25.6"E) at the University of Agriculture, Faisalabad, Pakistan. Early symptoms were small, oval to circular, light brown, sunken spots that were uniformly distributed on the leaves. Spots gradually enlarged and coalesced into circular to irregular dark brown to black spots that could be up to 3cm diam. with no or small sized fruit. Disease incidence was approximately 25%. To identify the causal agent of the disease, 15 symptomatic leaves were collected. Small pieces from all diseased samples were removed from the margin between healthy and diseased tissues were surface disinfested in 70% ethanol for 2 min, rinsed three times with sterile distilled water, plated on Potato dextrose agar and incubated at 25 ± 2°C with a 12-h photoperiod. Fungal isolation on PDA medium frequency was 95% from diseases leaves. Morphological observations were made on 7- day- old single-spore cultures. The colonies initially appeared light grayish which turned sooty black in color. All fungal isolates were characterized by small, short-beaked, multicellular conidia. The conidia were ellipsoidal or ovoid and measured 9 to 25 μm × 5 to 10 μm (n = 40) with longitudinal and transverse septa. The morphological characters matched those of Alternaria alternata (Simmons et al. 2007). Genomic DNA of a representative isolate (FG01-FG03) was extracted using DNAzol reagent (Thermo Fisher Scientific MA, USA) and PCR amplification of the internal transcribed spacer (ITS) rDNA region, was performed with primers ITS1/ITS4 (White et al. 1990), partial RNA polymerase II largest subunit (RPB2) with RPB2-5F/RPB2-7cR (Liu et al. 1999) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene regions was performed with gpd1/gpd2 (Berbee et al. 1999). The obtained sequences were deposited in GenBank with accession numbers MW692903.1 to MW692905.1 for ITS-rDNA gene, MZ066731.1 to MZ066733.1 for RPB2 and MZ066728.1 to MZ066730.1 for GAPDH. BLASTn analysis showed 100% identity with the submitted sequences of A. alternata for ITS rDNA, RPB2, and GAPDH. To confirm pathogenicity, 2-month-old 15 healthy potted F. carica plants were sprayed at true leaf stage with conidial suspension by using an atomizer in a greenhouse. Each representative A. alternata isolate (FG01-FG03) was inoculated on every three plants with conidial suspensions (106 conidia/ml; obtained from 1-week-old cultures) amended with 0.1% (vol/vol) of Tween 20 until runoff (1.5 to 2 ml per plant) whereas, three control plants were sprayed with sterile distilled water amended with 0.1% Tween 20. All plants were incubated at 25 ± 2°C in a greenhouse, and the experiment was conducted twice. After 10 days of inoculation, each isolate induced leaf spots similar to typical spots observed in the field, whereas the control plants remained symptomless. The fungus was re-isolated from symptomatic tissues and reisolation frequency was 100%. Re-isolated fungal cultures were again morphologically and molecularly identical to A. alternata, thus fulfilling Koch’s postulates. Previously, A. alternata has been reported cause fruit disease of fig in Pakistan and California, USA (Alam et al. 2021; Latinović et al. 2014). To our knowledge, this is the first report of A. alternata causing leaf spot on common fig in Pakistan. In Pakistan, fig is widely grown for drying, and this disease may represent a threat to fig cultivation.

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