scholarly journals Twig and Shoot Dieback of Citrus, a New Disease Caused by Colletotrichum Species

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 449
Author(s):  
Mario Riolo ◽  
Francesco Aloi ◽  
Antonella Pane ◽  
Magdalena Cara ◽  
Santa Olga Cacciola
Keyword(s):  
Mediterranean Region ◽  
Colletotrichum Gloeosporioides ◽  
Southern Italy ◽  
Sweet Orange ◽  
First Report ◽  
Colletotrichum Species ◽  
Rdna Its ◽  
Citrus Groves ◽  
Dieback Disease ◽  
The Mediterranean

(1) Background: This study was aimed at identifying the Colletotrichum species associated with twig and shoot dieback of citrus, a new syndrome occurring in the Mediterranean region and also reported as emerging in California. (2) Methods: Overall, 119 Colletotrichum isolates were characterized. They were recovered from symptomatic trees of sweet orange, mandarin and mandarin-like fruits during a survey of citrus groves in Albania and Sicily (southern Italy). (3) Results: The isolates were grouped into two distinct morphotypes. The grouping of isolates was supported by phylogenetic sequence analysis of two genetic markers, the internal transcribed spacer regions of rDNA (ITS) and β-tubulin (TUB2). The groups were identified as Colletotrichum gloeosporioides and C. karstii, respectively. The former accounted for more than 91% of isolates, while the latter was retrieved only occasionally in Sicily. Both species induced symptoms on artificially wound inoculated twigs. C. gloeosporioides was more aggressive than of C. karstii. Winds and prolonged drought were the factor predisposing to Colletotrichum twig and shoot dieback. (4) Conclusions: This is the first report of C. gloeosporioides and C. karstii as causal agents of twig and shoot dieback disease in the Mediterranean region and the first report of C. gloeosporioides as a citrus pathogen in Albania.

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

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 138-138 ◽  
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.

scholarly journals First Report of Dieback Disease on Cedars Caused by Diplodia seriata in China

Plant Disease ◽  
2014 ◽  
Vol 98 (9) ◽  
pp. 1279-1279 ◽  
Author(s):  
Z. J. Jiao ◽  
Y. C. Kan ◽  
S. L. Huang
Keyword(s):  
Morphological Characteristics ◽  
Its Sequences ◽  
Fluorescent Light ◽  
Foeniculum Vulgare ◽  
Diplodia Seriata ◽  
First Report ◽  
Rdna Its ◽  
Rdna Its Sequences ◽  
Dieback Disease ◽  
Pinus Spp

Cedars (Cedrus deodara (Roxb.) G. Don) are well known as evergreen ornamental trees widely used in horticulture in temperate climates. In March 2013, dieback symptoms were found on cedar trees in different locations (including the campus of Nanyang Normal University) in Nanyang (33°01′ N, 112°29′ E), a southwestern city of Henan Province, China. Characteristic symptoms included needle discoloration and defoliation, canker formation and gummosis on trunks and branches, browning and tissue necrosis under the bark as well as dieback of branches/trunks. Of 873 cedar trees investigated, 139 (16%) were symptomatic. A total of 21 Diplodia sp. isolates were obtained from 102 tissue pieces randomly sampled from the lesion margins of 31 affected trees with a conventional method for isolation of culturable fungal species from plant tissues. Monohyphal cultures were isolated from actively growing edges of colonies to purify the isolates. The purified isolates were grown on 2% water agar with sterilized stems of Foeniculum vulgare to induce their colonies to form pycnidia (4). Unmatured conidia were hyaline, aseptate, and turned light to dark brown with maturity. Mature conidia were aseptate (rarely uniseptate), ovoid with truncated or rounded base and obtuse apex, externally smooth, roughened on the inner surface, and 8 to 11 × 23 to 26 μm (n = 50). These morphological characteristics of the isolates agreed with those of Diplodia seriata (the anamorph of Botryosphaeria obtusa) (5). The rDNA-ITS sequences of two representative isolates (xs-01 and xs-06) were amplified with primers ITS1 and ITS4. PCR products were purified and ligated with PMD-19T vector for sequencing. The rDNA-ITS sequences were submitted to GenBank with accession nos. KJ463386 and KJ549774 for isolates xs-01 and xs-06, respectively, showing 100% identity with multiple isolates of D. seriata (HQ660463, KC461297, and KF535906). Koch's postulates were fulfilled in greenhouse tests on 2-year-old cedar plantlets inoculated by the two isolates. Ten plantlets were used for the inoculation tests for each of the isolates, and their trunks were wounded to a 2 mm depth with a sterilized cork borer (3 mm diameter). The wounds were inoculated by mycelial plugs cut from 7-day-old colonies grown on potato dextrose agar (PDA) plates and wrapped with Parafilm, and those inoculated with pure PDA plugs served as control. Inoculated plantlets were incubated in a greenhouse with alternating cycles of 14 h fluorescent light/10 h darkness under moist conditions for 30 to 60 days at 28°C. Nine of 20 inoculated plantlets developed needle discoloration and shoot blight symptoms similar to those observed on naturally infected cedar trees. The control plantlets remained symptomless during the incubation period. D. seriata cultures were constantly recovered from each diseased plantlet, indicating that the isolated D. seriata isolates were responsible for the disease. D. seriata has been reported as a phytopathogen causing dieback diseases worldwide on multiple woody plant species such as olive (4), mulberry (1), Pinus spp., and Picea glauca (2,3). To our knowledge, this is the first report of D. seriata causing dieback disease on cedars in China. References: (1) M. Arzanlou et al. Arch. Phytopathol. Plant Protect. 46:682, 2013. (2) T. Burgess et al. Appl. Environ. Microbiol. 67:354, 2001. (3) G. Hausner et al. Can. J. Plant Pathol. 21:256, 1999. (4) J. Kaliterna et al. Plant Dis. 96:290, 2012. (5) A. J. L. Phillips et al. Fungal Divers. 25:141, 2007.

scholarly journals First Report of Septoria Blight of Parsley Caused by Septoria petroselini in the Mediterranean Region of Turkey

Plant Disease ◽  
2003 ◽  
Vol 87 (1) ◽  
pp. 99-99 ◽  
Author(s):  
S. Kurt
Keyword(s):  
Mediterranean Region ◽  
Morphological Characteristics ◽  
Potato Dextrose Agar ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Sterile Water ◽  
First Report ◽  
Foliar Symptoms ◽  
Polyethylene Bags ◽  
The Mediterranean

During December 2001 to March 2002, Septoria blight of parsley was observed in approximately 500 ha of commercial parsley crops in Arsuz County, Hatay, in the Mediterranean Region of Turkey. Incidence of disease ranged from 42 to 80%. Symptoms included irregularly shaped, grayish brown spots (average 3 to 8 mm diameter) with a slightly darker brown margin of necrotic tissue that developed into tan-to-brown lesions surrounded by chlorotic halo on the leaves. Oval-shaped lesions were observed occasionally on petioles. Lesions contained erumpent, dark brown, flask-shaped pycnidia with the ostiole on the upper surface of the foliage. Thirty samples, consisting of diseased leaves and petioles of parsley, were collected from each field. Infected tissues were surface-sterilized in 1% NaOCl for 2 min, rinsed in sterile distilled water, placed on petri dishes containing potato dextrose agar (PDA), and incubated for 10 to 14 days at 25°C. The fungus formed long, multiseptate (0 to 4), hyaline, filiform conidia (14 to 29 μm × 0.5 to 1.9 μm), and short conidiophores within the pycnidia. Based on the morphological characteristics of the fungus, the pathogen was identified as Septoria petroselini Desm. (1). Monoconidial cultures of 18 isolates were prepared. Pathogenicity was confirmed by brush-inoculating slightly wounded foliage of 5- to 7- week-old parsley plants (cv. Kereviz yapragi) with a conidial suspension (106 conidia per ml of sterile water) of each isolate of S. petroselini. Control plants that were brush-inoculated with distilled water and inoculated plants were placed in clear polyethylene bags that were closed and incubated at 20°C for 48 h. The bags were removed, and plants were maintained in a dew chamber for 21 days at 65 to 70% relative humidity. Foliar symptoms developed 15 days after inoculation and appeared similar to lesions observed in the field. Yellowing and necrosis of leaves was also observed on >60% of inoculated plants. No lesions developed on the control plants. The pathogen was readily reisolated on PDA from inoculated plants. To our knowledge, this is the first report of Septoria blight of parsley in the Mediterranean Region of Turkey. Reference: (1) R. F. Cerkauskas and J. Uyenaka. Plant Dis. 74:1037, 1990.

scholarly journals First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Ramie in China

Plant Disease ◽  
2010 ◽  
Vol 94 (12) ◽  
pp. 1508-1508 ◽  
Author(s):  
X. X. Wang ◽  
B. Wang ◽  
J. L. Liu ◽  
J. Chen ◽  
X. P. Cui ◽  
...  
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Morphological Characteristics ◽  
The Philippines ◽  
Herbaceous Plant ◽  
Commonwealth Mycological Institute ◽  
First Report ◽  
Perennial Herbaceous Plant ◽  
Rdna Its ◽  
Pathogenicity Tests ◽  
And Control

Ramie (Boehmeria nivea), usually called “China grass”, is a perennial herbaceous plant belonging to the family Urticaceae with recognized importance in the production of fibers. It is mainly planted in China and other Asian countries including the Philippines, India, South Korea, and Thailand. From June 2007 to September 2010, typical anthracnose symptoms were observed in cultivated ramie fields in HuBei, HuNan, JiangXi, and SiChuan provinces, China, with the diseased area estimated to be more than 10,000 ha. Ramie yield was reduced by 20% on average with up to 55% yield losses in some fields. Lesions were initially small, scattered, round, and gray with brown margin on leaves. As the disease progressed, irregular spots developed and expanded until the leaves withered. Initial lesions on stems were fusiform and expanded, causing the stem to break. Finally, the fibers ruptured. Five isolates (CS-1, CS-2, CS-3, CS-4, and CS-5) were used to evaluate cultural and morphological characteristics of the pathogen. On potato dextrose agar, all isolations initially developed white colonies with orange conidial mass and the colonies turned to gray or brown after 5 days of incubation. Twenty conidia and fifteen setae were measured. Conidia were single celled, colorless, straight, oval, obtuse at both ends, and 11 to 18 × 3 to 6 μm with an average of 14.89 × 4.32 μm. Conidiophores were dense and 11 to 22 × 4 to 5 μm with an average of 15.82 × 4.43 μm. Setae were few, dark brown, one to two septa, and 62 to 71 × 4 to 5 μm with an average of 65.13 × 4.46 μm. The pathogen was identified as Colletotrichum gloeosporioides on the basis of descriptions in Bailey and Jeger (1). Genomic DNA was extracted from the five isolates and sequences of rDNA-ITS with primers ITS1 and ITS4 were obtained (GenBank Accession Nos. GQ120479–GQ120483). Comparison with sequences in GenBank showed 99 to 100% similarity with C. gloeosporioides (Accession Nos. FJ515005, FJ459930, and HM016798). Pathogenicity tests were performed with the five isolates in the laboratory by spraying conidial suspensions (1 × 106 conidia/ml) onto upper and lower surfaces of 10 leaves of 10-day-old, 30-cm high plants. There were three replicate plants for each isolate. The inoculated plants were incubated with a 12-h photoperiod at 25 to 28°C and 90% relative humidity in an artificial climate chamber. Three days after inoculation, brown spots were observed on all inoculated leaves, but no symptoms were seen on water-treated control plants. Koch's postulates were fulfilled by reisolation of C. gloeosporioides from diseased leaves. Though in the revision of Colletotrichum by von Arx (4) and Sutton (3), C. boehmeriae, named based on host specificity, was cancelled, C. boehmeriae was regarded as a pathogen of ramie by some Chinese researchers (2). To our knowledge, this is the first report of C. gloeosporioides causing anthracnose of ramie in China. References: (1) J. A. Bailey and M. J. Jeger. Colletotrichum: Biology, Pathology and Control. CAB International, Wallingford, UK, 1992. (2) R. M. Li and H. G. Ma. J. Plant Prot. 20:83, 1993. (3) B. C. Sutton. Page 523 in: The Coelomycetes: Fungi Imperfecti with Pycnidia, Acervuli and Stromata. Commonwealth Mycological Institute, London, 1980. (4) J. A. von Arx. Phytopathol. Z. 29:413, 1957.

scholarly journals First Report of Globisporangium ultimum Causing Pythium Damping-Off on Aleppo Pine in Algeria, Africa, and the Mediterranean Region

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1111-1111 ◽  
Author(s):  
F. Lazreg ◽  
L. Belabid ◽  
J. Sanchez ◽  
E. Gallego ◽  
J. A. Garrido-Cardenas ◽  
...  
Keyword(s):  
Mediterranean Region ◽  
Petri Dish ◽  
Pythium Ultimum ◽  
Aleppo Pine ◽  
Plant Diseases ◽  
Pot Experiment ◽  
Native Forest ◽  
Damping Off ◽  
First Report ◽  
The Mediterranean

Globisporangium ultimum (Trow) Uzuhashi, Tojo & Kakish. (syn. Pythium ultimum Trow, syn. P. ultimum Trow var. ultimum) is a known oomycetal species from Pythium s.l. causing damping-off and/or root rot on a great variety of plants throughout the world, including some pine species (Pinus L.) and conifers (2,3). Aleppo pine (Pinus halepensis Mill.) is a common native forest tree in the Mediterranean region. Pre- and post-emergence damping-off disease symptoms were observed during 2008 and 2009 in four forest nurseries from northwestern Algeria (Relizane, Sidi Belabes, and Tlemcen departments). This disease occurred under cool conditions, and Aleppo pines were significantly affected, reducing seedling emergence. Disinfected segments, about 5 mm in length, from decayed root and collar, were cultured on CMA at 25°C. This oomycetal species was identified based on the species description in Pythium keys (3,4). For the molecular identification, PCR was used to amplify the ITS region of Pythium isolates. It was amplified with the flanking primers ITS1 and ITS4, and these products were directly sequenced. Sequence data were compared to known sequences deposited in the NCBI non redundant database to confirm morphological identification. A BLAST search identified U3CR, U7CR, U1RT, U2CR, U4CR, U14CR, U7RT, and U17RT isolates (GenBank Accession Nos. JX191921, 22, 27, 29, 31, and 33 to 35, respectively) as G. ultimum based on 100% similarity with corresponding sequence of the reference isolate no. UZ056 MAFF240024 (AB468781) (3). Phytopathogenicity testing was conducted in a petri dish and pot experiment. In the petri dish experiment, a 3 mm diameter plug was transferred from a 7-day-old CMA colony to the center of a CMA petri dish, with three replicates per isolate, and three control plates were inoculated with sterile agar plugs. After 72 h, 10 Aleppo pine seeds were placed equally spaced to 1 cm from the edge of each plug. After 7 days at 22°C in the dark, germination inhibition (46.1 to 87.6%) and root growth inhibition (62.3 to 92.2%) were calculated. In the control plates, germination failure (13.4%) and root length (27.7 cm) were observed. For the pot experiment, inocula were produced by adding a 5 mm diameter plug from a 7-day-old CMA culture to a previously sterilized 500 ml flask containing 237.5 g sand, 12.5 g cornmeal, and 80 ml SDW. Nine-day-old inoculum was mixed with sterile soil at a rate of 1:3 (v:v). Inoculum was transferred to 500 ml pot, and 10 Aleppo pine seeds were planted, with three replicates per isolate, and three control pots were used. After 2 weeks, all of the isolates tested caused typical symptoms of Aleppo pine Pythium damping-off, the percentage of inoculated plants that became infected was 36.6 to 83.3%. In the control pots, no infected plants were observed. To our knowledge, this is the first report of G. ultimum causing damping-off on Aleppo pine in Algeria, Africa, and the Mediterranean Region. Before, Aleppo pine damping-off caused by G. ultimum was reported in Australia (1). References: (1) R. P. Cook and A. J. Dubé. Host-pathogen index of plant diseases in South Australia. SADA, Melbourne, Australia, 1989. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory. ARS, USDA, Bestville, MD. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , June 24, 2012. (3) S. Uzuhashi et al. Mycoscience 51:337, 2010. (4) A. J. van der Plaats-Niterink. Stud. Mycol. 21:1, 1981.

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