scholarly journals First Report of Foliar and Stem Blight on Sunflower Caused by Alternaria helianthiinficiens in Croatia

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1698-1698 ◽  
Author(s):  
K. Vrandečić ◽  
D. Jurković ◽  
J. Ćosić ◽  
I. Stanković ◽  
A. Vučurović ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Pathogenic Fungus ◽  
Morphological Characteristics ◽  
Its Region ◽  
Nucleotide Identity ◽  
Oilseed Crop ◽  
Conidial Suspension ◽  
First Report ◽  
Stem Blight ◽  
Detached Leaves

Sunflower (Helianthus annus L.) is the most important oilseed crop in Croatia. In August 2009, in six localities of eastern Croatia, severe foliar and stem blight symptoms were observed on several genotypes with disease incidence ranging from 10 to 50%. At the initial stage of the infection, irregular to oval, brown spots different in size, surrounded by a chlorotic halo, appeared on the leaves that gradually became enlarged and coalesced, and whole leaves turned yellow and necrotic, followed by defoliation. Lesions on the stems were light to dark brown, randomly distributed, rounded and tapered on the ends; later becoming large and elongated causing stem breakage. Tissue within the lesion was reddish on the cross section. To determine the causal agent, small pieces of symptomatic leaves and stem tissue of sunflower were surface disinfested and placed on potato dextrose agar. A total of 17 isolates from leaves as well as six from stems were obtained and all formed cottony, dark olivaceous to black colonies under 12 h of fluorescent light per day. All isolates formed uniform solitary, pale brown to brown, long ovoid conidia with five to eight transverse and one to two longitudinal septa. The conidia of all isolates were slightly constricted at the transverse septa, measuring 55 to 90 × 14 to 20 μm. Based on the morphological characteristics, the pathogen was identified as Alternaria helianthiinficiens E.G. Simmons, Walcz & R.G. Roberts (4). The pathogenicity was tested with one representative isolate (Alt5) by injection of a conidial suspension (106 conidia/ml) into stems of 20 healthy sunflower seedlings and by spraying 20 non-wounded detached leaves with a suspension of spores. Small necrotic spots on all inoculated seedlings and leaves formed 5 and 9 days after inoculation, respectively. The control sunflower seedlings and detached leaves, inoculated with sterile water, showed no reactions. The identity of isolate Alt5 was futher confirmed by amplification and sequencing of the internal transcribed spacer (ITS) region of rDNA. Because there are no available corresponding ITS sequences of A. helianthiinficiens in the GenBank, reference type strain CBS 208.86 (publicly purchased, CBS, Utrecht, Netherlands) was also sequenced in this study. Total DNA was extracted directly from fungal mycelium and PCR amplification and sequencing were performed with primers ITS1F/ITS4. Sequence analysis of ITS region revealed 100% nucleotide identity between isolate Alt5 (GenBank Accession No. JX101648) and isolate CBS 208.86 (GenBank Accession No. JX101649). The nucleotide identity of both isolates compared with A. helianthi (HM449991), another sunflower pathogenic fungus, was only 80%. A. helianthiinficiens has previously been reported on sunflower in Hungary and the USA (3), Serbia (1), and Korea (2). However, to our knowledge, this is the first report of A. helianthiinficiens occurrence in Croatia as a new and harmful parasite of sunflower, illustrating an expansion of its geographical range and underscoring the need for phytosanitary control because it is a seedborne fungus. References: (3) M. Aćimović and N. Lačok. Helia 14:129, 1991. (4) H. S. Cho and S. H. Yu. Plant Pathol. J. 16:331, 2000. (2) E. G. Simmons. Mycotaxon 25:203, 1986. (1) E. G. Simmons. Alternaria: An Identification Manual. CBS Fungal Biodiversity Centre, Utrecht, the Netherlands, 2007.

scholarly journals First Report of Leaf Blight Caused by Septoria allii on Garlic Chives in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 147-147
Author(s):  
J. H. Park ◽  
S. E. Cho ◽  
K. S. Han ◽  
H. D. Shin
Keyword(s):  
Disease Incidence ◽  
Morphological Characteristics ◽  
Its Region ◽  
Leaf Blight ◽  
Plant Diseases ◽  
Cultivated Plants ◽  
Sequence Information ◽  
Conidial Suspension ◽  
Korean Society ◽  
First Report

Garlic chives, Allium tuberosum Roth., are widely cultivated in Asia and are the fourth most important Allium crop in Korea. In June 2011, a leaf blight of garlic chives associated with a Septoria spp. was observed on an organic farm in Hongcheon County, Korea. Similar symptoms were also found in fields within Samcheok City and Yangku County of Korea during the 2011 and 2012 seasons. Disease incidence (percentage of plants affected) was 5 to 10% in organic farms surveyed. Diseased voucher specimens (n = 5) were deposited at the Korea University Herbarium (KUS). The disease first appeared as yellowish specks on leaves, expanding to cause a leaf tip dieback. Half of the leaves may be diseased within a week, especially during wet weather. Pycnidia were directly observed in leaf lesions. Pycnidia were amphigenous, but mostly epigenous, scattered, dark brown to rusty brown, globose, embedded in host tissue or partly erumpent, separate, unilocular, 50 to 150 μm in diameter, with ostioles of 20 to 40 μm in diameter. Conidia were acicular, straight to sub-straight, truncate at the base, obtuse at the apex, hyaline, aguttulate, 22 to 44 × 1.8 to 3 μm, mostly 3-septate, occasionally 1- or 2-septate. These morphological characteristics matched those of Septoria allii Moesz, which is differentiated from S. alliacea on conidial dimensions (50 to 60 μm long) (1,2). A monoconidial isolate was cultured on potato dextrose agar (PDA). Two isolates have been deposited in the Korean Agricultural Culture Collection (Accession Nos. KACC46119 and 46688). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1/ITS4 primers and sequenced. The resulting sequence of 482-bp was deposited in GenBank (JX531648 and JX531649). ITS sequence information was at least 99% similar to those of many Septoria species, however no information was available for S. allii. Pathogenicity was tested by spraying leaves of three potted young plants with a conidial suspension (2 × 105 conidia/ml), which was harvested from a 4-week-old culture on PDA. Control leaves were sprayed with sterile water. The plants were placed in humid chambers (relative humidity 100%) for the first 48 h. After 7 days, typical leaf blight symptoms started to develop on the leaves of inoculated plants. S. allii was reisolated from the lesions of inoculated plants, confirming Koch's postulates. No symptoms were observed on control plants. The host-parasite association of A. tuberosum and S. allii has been known only from China (1). S. alliacea has been recorded on several species of Allium, e.g. A. cepa, A. chinense, A. fistulosum, and A. tuberosum from Japan (4) and A. cepa from Korea (3). To the best of our knowledge, this is the first report of S. allii on garlic chives. No diseased plants were observed in commercial fields of garlic chives which involved regular application of fungicides. The disease therefore seems to be limited to organic garlic chive production. References: (1) P. K. Chi et al. Fungous Diseases on Cultivated Plants of Jilin Province, Science Press, Beijing, China, 1966. (2) P. A. Saccardo. Sylloge Fungorum Omnium Hucusque Congnitorum. XXV. Berlin, 1931. (3) The Korean Society of Plant Pathology. List of Plant Diseases in Korea, Suwon, Korea, 2009. (4) The Phytopathological Society of Japan. Common Names of Plant Diseases in Japan, Tokyo, Japan, 2000.

scholarly journals First report of fruit blight caused by Alternaria alternata on sesame in Northeast China

Plant Disease ◽  
2021 ◽  
Author(s):  
Hongsen Cheng ◽  
De Xue Gao ◽  
Huijie Sun ◽  
Yanbin Na ◽  
Jing Xu
Keyword(s):  
Alternaria Alternata ◽  
Morphological Characteristics ◽  
Its Region ◽  
Liaoning Province ◽  
Oilseed Crop ◽  
Distilled Water ◽  
Conidial Suspension ◽  
First Report ◽  
Health Products ◽  
Blight Disease

Sesame (Sesamum indicum L.) is an important oilseed crop in China and it is also used in food and health products. In August of 2019, a blight sesame fruit was observed in a field of Liaoyang city, Liaoning province of China. Initial disease symptoms consisted of brown or dark brown spots on fruit. With time, lesions coalesced and the whole fruit turned dark brown or black. Most of the diseased fruit had thin and small, deformed, necrotic, hardened cracked epidermal lesions. Lesions were also produced on stem and petioles leading to leaf abscission. The disease results in premature fruit death, and in turn, considerable yield losses. To determine the causal agent, symptomatic fruit with developing lesions were collected, and surface sterilized in 2% NaClO for 3 min, rinsed three times in distilled water, and plated onto PDA medium. After incubation at 25°C for 5 days, a dark olivaceous fungus with abundant, branched, brown to black, and septate hyphae was consistently isolated. Twenty single spores were separated with an inoculation needle under stereomicroscope. The conidia were in chains, brown, obclavate, ovoid or ellipsoid, with 1-6 transverse septa and 0-4 longitudinal or oblique septa 12.5 to 45 × 6.5 to 14.5 μm in size. Conidiophores were septate, light brown to olive brown, measuring 22-60 μm × 2-4 μm. The morphological characteristics of the 20 isolates all matched the description of Alternaria alternata (Simmons, 2007). The internal transcribed spacer (ITS) region of rDNA of 15 isolates was amplified using primers ITS1/ITS4 (White et al. 1990) and EF1-728F/EF1-986R (Carbone et al. 1999) and sequenced. Identical sequences were obtained and the sequence of the isolate ZMHG12 was submitted to GenBank (Accession no. MW418181 and MW700316). BLAST analysis of the sequences of the isolates of ZMHG12 showed 100% to A. alternata (KP739875 and LC132712). In pathogenicity tests, a conidial suspension (2.5 × 105 conidia per ml) was prepared from 7 days-old cultures of isolate ZMHG12 grown on PDA at 25°C. Fruit of 10 two-month-old potted sesame plants (Variety “Liaozhi 8”) were sprayed with the conidia suspension until runoff. Another 10 plants sprayed with distilled water to served as non-inoculated controls. All plants were maintained for 48 h in a humid chamber with a temperature of 25°C to 26°C, and then moved to a greenhouse. Ten days after inoculation, all fruit of inoculated plants exhibited symptoms similar to those observed in the field and non-inoculated control plants remained symptomless. The experiment was repeated twice with similar results. A. alternata has been reported as a pathogen caused leaf blight disease of sesame in Pakistan (Nayyar et al. 2017). To our knowledge, this is the first report of A.alternata causing fruit blight of sesame in China. To date, we have observed the disease on sesames in fields of Fuxin, Chaoyang and Tieling city in Liaoning Province, and Tongliao city in Inner Mongolia of China, and it has become an important disease in sesame production of China. References : Simmons E. G. 2007. Alternaria: An identification manual. CBS Fungal Biodiversity Center, Utrecht, Netherlands. White T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego. Carbone I., et al. 1999. Mycologia, 91: 553-556. Nayyar, B. G., et al. 2017. Plant Pathology Journal, 33 (6): 543-553.

scholarly journals First Report of Paraphoma chrysanthemicola Causing Crown and Leaf Rot of Atractylodes lancea in China

Plant Disease ◽  
2022 ◽  
Author(s):  
Hongyang Wang ◽  
Chuanzhi Kang ◽  
Wang Yue-Feng ◽  
Sheng Wang ◽  
Zhang Yan ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Morphological Characteristics ◽  
Crown Rot ◽  
Post Inoculation ◽  
Conidial Suspension ◽  
Sterile Water ◽  
First Report ◽  
Atractylodes Lancea ◽  
Detached Leaves ◽  
Leaf Rot

Atractylodes lancea is an important traditional Chinese medicinal plant whose rhizome is used for treating complaints such as rheumatic diseases, digestive disorders, night blindness and influenza. Jiangsu Province is the optimal cultivation location for high-quality A. lancea rhizome. Since June 2019, symptoms of crown rot and leaf rot were observed in about 10-20% of the A. lancea in a plantation (31° 36' 1" N, 119° 6' 40" W) in Lishui, Jiangsu, China. Lesions occurred on the stem near the soil line and on the leaves (Fig. 1A). Disease incidence reached approximately 80-90% by September, 2021 (Fig. 1B) and resulted in severe loss of rhizome and seed yields. For pathogen isolation, ten samples of symptomatic stem segments and ten diseased leaves were collected, surface-sterilized using 5% NaClO solution, rinsed with sterile water, cut into 0.5-2 cm segments, and plated to potato dextrose agar (PDA), and then incubated at 30°C in darkness. Pure cultures of four isolates showing morphological characteristics of Paraphoma spp. were obtained, identified as a single P. chrysanthemicola strain, and named LSL3f2. Newly formed colonies initially consisted of white mycelia; the five-day-old colonies developed a layer of whitish grey mycelia with a grey underside. 20-day-old colonies had white mycelium along the margin and with a faint yellow inner circular part with irregular radial furrows, and the reverse side looking caramel and russet (Fig. 1C). Pycnidia were subglobose (diameter: 5 to 15 μm; Fig. 1D). Unicellular, bicellular or strings of globose or subglobose chlamydospores developed from hyphal cells (Fig. 1E and 1F). The internal transcribed spacer (ITS) region and large subulin-28S of LSL3f2 were cloned using primers ITS1/ITS4 and LR0R/LR7 (Aveskamp et al. 2010, Li et al. 2013), and deposited in GenBank (OK559658 and OK598973, respectively). BLASTn search and phylogenetic analysis showed the highest identity between LSL3f2 and P. chrysanthemicola sequences (Fig. 1G) and confirmed LSL3f2 as P. chrysanthemicola. Koch’s postulates were completed using one-month-old vegetatively propagated A. lancea plantlets growing on autoclaved vermiculite/peat mixture at 26°C with a light/dark cycle of 12/12 hours. Each plantlet was inoculated with 5 ml of conidial suspension in water (1 × 108 cfu/ml) by applying to soil close to the plantlet, with sterile water used as a mock control (n = 10). By 20 days post-inoculation, inoculated plantlets showed a range of disease symptoms consistent to those observed in infested fields (Fig. 1H). Pathogenicity was additionally confirmed using detached leaves inoculated with a colonized agar plug of LSL3f2 or an uninoculated control comparison (diameter = 5 mm) and incubated at 26℃ in the dark. Five to seven days post-inoculation, detached leaves showed leaf rot symptoms including lesions, yellowing and withering consistent with those in infested fields, while control leaves remained healthy (n = 10, Fig. 1I). The pathogen was reisolated from the diseased plantlets and detached leaves, in both cases demonstrating the micromorphological characteristics of LSL3f2. P. chrysanthemicola has been reported to cause leaf and crown rot on other plants such as Tanacetum cinerariifolium (Moslemi et al. 2018), and leaf spot on A. japonicain (Ge et al. 2016). However, this is the first report of P. chrysanthemicola causing crown and leaf rot on A. lancea in China.

scholarly journals First Report of Pod and Stem Blight of Lima Bean Caused by Diaporthe phaseolorum var. sojae in Malaysia

Plant Disease ◽  
2013 ◽  
Vol 97 (2) ◽  
pp. 287-287 ◽  
Author(s):  
F. Mahmodi ◽  
J. B. Kadir ◽  
A. Puteh ◽  
M. Y. Wong ◽  
A. Nasehi
Keyword(s):  
Disease Incidence ◽  
Morphological Characteristics ◽  
Lima Bean ◽  
Phaseolus Lunatus ◽  
Conidial Suspension ◽  
First Report ◽  
Stem Blight ◽  
Cameron Highlands ◽  
Pure Cultures ◽  
Plant Pathol

In July 2011, a severe outbreak of pod and stem blight was observed on lima bean (Phaseolus lunatus L.) plants grown in the Cameron Highlands, located in Pahang State, Malaysia. Disease incidence varied from 33 to 75% in different fields. Pods and stems exhibited withered, light brown to reddish brown necrotic areas. Sub-circular and brown lesions were produced on the leaves. These lesions varied in size, often reaching a diameter of 1 to 2 cm. After tissue death, numerous pycnidia were observed on the surface of the pod or stem. The pycnidia diameter varied from 155 to 495 μm, averaging 265.45 μm, and on the surface of the pod or stem, pycnidia were often arranged concentrically or linearly, respectively. Pycnidiospores were hyaline, 1-celled, usually straight, and rarely, slightly curved. The α-spores varied from 5.5 to 9.0 × 2.5 to 4.0 μm; averaging 7.3 × 3.5 μm. The β-spores found either alone or with pycnidiospores in pycnidia were slender, hyaline, nonseptate, and straight or curved. Size varied from 15.8 to 38.0 × 1.3 to 2.1 μm; averaging 25.86 × 1.8 μm. The colony characteristics were recorded from pure cultures grown on potato dextrose agar plates, and incubated in darkness for 7 days at 25 °C, then exposed to 16/8 h light and dark periods at 25°C for a further 14 to 21 days. Morphological characteristics of the colonies and spores on PDA matched those described for P. phaseolorum var. sojae (2). Colonies were white, compact, with wavy mycelium and stromata with pycnidia that contained abundant β-spores. Sequence analysis of the ribosomal DNA internal transcribed spacer obtained from the Malaysian isolate FM1 (GenBank Accession No. JQ514150) using primers ITS5 and ITS4 (1) aligned with deposited sequences from GenBank confirmed identity and revealed 99% to 100% DNA similarity with P. phaseolorum strains (AY577815, AF001020, HM012819, JQ936148). The isolate FM1 was used for pathogenicity testing. Five non-infected detached leaves and pods of 4-week-old lima bean were surface sterilized and inoculated by placing 10 μl of conidial suspension (106 conidia ml–1) on the surface of leaves and pods using either the wound/drop or non-wound/drop method and distilled water used as control (3). The inoculated leaves and pods were incubated at 25 °C and 98% RH, and the experiment was performed twice. Disease reactions and symptoms were evaluated after inoculation. After one week, typical symptoms of pod and stem blight appeared with formation of pycnidia on the surface of the tissues, but not on non-inoculated controls. P. phaseolorum var. sojae was consistently reisolated from symptoms. To our knowledge, this is the first report of P. phaseolorum var. sojae causing pod and stem blight of lima bean in Malaysia. References: (1) R. Ford et al. Aust. Plant Pathol. 33:559, 2004. (2) G. L. Hartman et al. Compendium of Soybean Diseases. 4th ed. American Phytopathological Society, St. Paul, MN, 1999. (3) P. P. Than et al. Plant Pathol. 57:562, 2008.

scholarly journals First report of banana (Musa acuminate L. AAA Cavendish, cv. Formosana) leaf spot disease caused by Curvularia geniculata in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Yanxiang Qi ◽  
Yanping Fu ◽  
Jun Peng ◽  
Fanyun Zeng ◽  
Yanwei Wang ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Universal Primers ◽  
Leaf Spot Disease ◽  
Leaf Margin ◽  
Conidial Suspension ◽  
Tropical Fruit ◽  
First Report ◽  
Spot Disease

Banana (Musa acuminate L.) is an important tropical fruit in China. During 2019-2020, a new leaf spot disease was observed on banana (M. acuminate L. AAA Cavendish, cv. Formosana) at two orchards of Chengmai county (19°48ʹ41.79″ N, 109°58ʹ44.95″ E), Hainan province, China. In total, the disease incidence was about 5% of banana trees (6 000 trees). The leaf spots occurred sporadically and were mostly confined to the leaf margin, and the percentage of the leaf area covered by lesions was less than 1%. Symptoms on the leaves were initially reddish brown spots that gradually expanded to ovoid-shaped lesions and eventually become necrotic, dry, and gray with a yellow halo. The conidia obtained from leaf lesions were brown, erect or curved, fusiform or elliptical, 3 to 4 septa with dimensions of 13.75 to 31.39 µm × 5.91 to 13.35 µm (avg. 22.39 × 8.83 µm). The cells of both ends were small and hyaline while the middle cells were larger and darker (Zhang et al. 2010). Morphological characteristics of the conidia matched the description of Curvularia geniculata (Tracy & Earle) Boedijn. To acquire the pathogen, tissue pieces (15 mm2) of symptomatic leaves were surface disinfected in 70% ethanol (10 s) and 0.8% NaClO (2 min), rinsed in sterile water three times, and transferred to potato dextrose agar (PDA) for three days at 28°C. Grayish green fungal colonies appeared, and then turned fluffy with grey and white aerial mycelium with age. Two representative isolates (CATAS-CG01 and CATAS-CG92) of single-spore cultures were selected for molecular identification. Genomic DNA was extracted from the two isolates, the internal transcribed spacer (ITS), large subunit ribosomal DNA (LSU rDNA), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), translation elongation factor 1-alpha (TEF1-α) and RNA polymerase II second largest subunit (RPB2) were amplified and sequenced with universal primers ITS1/ITS4, LROR/LR5, GPD1/GPD2, EF1-983F/EF1-2218R and 5F2/7cR, respectively (Huang et al. 2017; Raza et al. 2019). The sequences were deposited in GenBank (MW186196, MW186197, OK091651, OK721009 and OK491081 for CATAS-CG01; MZ734453, MZ734465, OK091652, OK721100 and OK642748 for CATAS-CG92, respectively). For phylogenetic analysis, MEGA7.0 (Kumar et al. 2016) was used to construct a Maximum Likelihood (ML) tree with 1 000 bootstrap replicates, based on a concatenation alignment of five gene sequences of the two isolates in this study as well as sequences of other Curvularia species obtained from GenBank. The cluster analysis revealed that isolates CATAS-CG01 and CATAS-CG92 were C. geniculata. Pathogenicity assays were conducted on 7-leaf-old banana seedlings. Two leaves from potted plants were stab inoculated by puncturing into 1-mm using a sterilized needle and placing 10 μl conidial suspension (2×106 conidia/ml) on the surface of wounded leaves and equal number of leaves were inoculated with sterile distilled water serving as control (three replicates). Inoculated plants were grown in the greenhouse (12 h/12 h light/dark, 28°C, 90% relative humidity). Necrotic lesions on inoculated leaves appeared seven days after inoculation, whereas control leaves remained healthy. The fungus was recovered from inoculated leaves, and its taxonomy was confirmed morphologically and molecularly, fulfilling Koch’s postulates. C. geniculata has been reported to cause leaf spot on banana in Jamaica (Meredith, 1963). To our knowledge, this is the first report of C. geniculata on banana in China.

scholarly journals First Report of Fruit Rot of Melon Caused by Fusarium asiaticum in China

Plant Disease ◽  
2020 ◽  
Author(s):  
Fangmin Hao ◽  
Quanyu Zang ◽  
Weihong Ding ◽  
Erlei Ma ◽  
Yunping Huang ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Its Region ◽  
Fruit Rot ◽  
Post Inoculation ◽  
Basal Cells ◽  
First Report ◽  
Fusarium Asiaticum ◽  
Sterile Needle

Melon (Cucumis melo L.) is a member of the Cucurbitaceae family, an important economical and horticultural crop, which is widely grown in China. In May 2020, fruit rot disease with water-soaked lesions and pink molds on cantaloupe melons was observed in several greenhouses with 50% disease incidence in Ningbo, Zhejiang Province in China. In order to know the causal agent, diseased fruits were cut into pieces, surface sterilized for 1 min with 1% sodium hypochlorite (NaClO), 2 min with 75% ethyl alcohol, rinsed in sterile distilled water three times (Zhou et al. 2018), and then placed on potato dextrose agar (PDA) medium amended with streptomycin sulfate (100 μg/ml) plates at 25°C for 4 days. The growing hyphae were transferred to new PDA plates using the hyphal tip method, putative Fusarium colonies were purified by single-sporing. Twenty-five fungal isolates were obtained and formed red colonies with white aerial mycelia at 25°C for 7 days, which were identified as Fusarium isolates based on the morphological characteristics and microscopic examination. The average radial mycelial growth rate of Fusarium isolate Fa-25 was 11.44 mm/day at 25°C in the dark on PDA. Macroconidia were stout with curved apical and basal cells, usually with 4 to 6 septa, and 29.5 to 44.2 × 3.7 to 5.2 μm on Spezieller Nährstoffarmer agar (SNA) medium at 25°C for 10 days (Leslie and Summerell 2006). To identify the species, the internal transcribed spacer (ITS) region and translational elongation factor 1-alpha (TEF1-α) gene of the isolates were amplified and cloned. ITS and TEF1-α was amplified using primers ITS1/ITS4 and EF1/EF2 (O’Donnell et al. 1998), respectively. Sequences of ITS (545 bp, GenBank Accession No. MT811812) and TEF1-α (707 bp, GenBank Acc. No. MT856659) for isolate Fa-25 were 100% and 99.72% identical to those of F. asiaticum strains MSBL-4 (ITS, GenBank Acc. MT322117.1) and Daya350-3 (TEF1-α, GenBank Acc. KT380124.1) in GenBank, respectively. A phylogenetic tree was established based on the TEF1-α sequences of Fa-25 and other Fusarium spp., and Fa-25 was clustered with F. asiaticum. Thus, both morphological and molecular characterizations supported the isolate as F. asiaticum. To confirm the pathogenicity, mycelium agar plugs (6 mm in diameter) removed from the colony margin of a 2-day-old culture of strain Fa-25 were used to inoculate melon fruits. Before inoculation, healthy melon fruits were selected, soaked in 2% NaClO solution for 2 min, and washed in sterile water. After wounding the melon fruits with a sterile needle, the fruits were inoculated by placing mycelium agar plugs on the wounds, and mock inoculation with mycelium-free PDA plugs was used as control. Five fruits were used in each treatment. The inoculated and mock-inoculated fruits were incubated at 25°C with high relative humidity. Symptoms were observed on all inoculated melon fruits 10 days post inoculation, which were similar to those naturally infected fruits, whereas the mock-inoculated fruits remained symptomless. The fungus re-isolated from the diseased fruits resembled colony morphology of the original isolate. The experiment was conducted three times and produced the same results. To our knowledge, this is the first report of fruit rot of melon caused by F. asiaticum in China.

scholarly journals First Report on Ovate-leaf Atractylodes Damping-off Caused by Fusarium oxysporum species Complex in South Korea

Plant Disease ◽  
2021 ◽  
Author(s):  
Oliul Hassan ◽  
Taehyun Chang
Keyword(s):  
South Korea ◽  
Fusarium Oxysporum ◽  
Species Complex ◽  
Disease Incidence ◽  
Fusarium Species ◽  
Morphological Characteristics ◽  
Conidial Suspension ◽  
Sterile Water ◽  
Damping Off ◽  
First Report

In South Korea, ovate-leaf atractylodes (OLA) (Atractylodes ovata) is cultivated for herbal medicine. During May to June 2019, a disease with damping off symptoms on OLA seedlings were observed at three farmer fields in Mungyeong, South Korea. Disease incidence was estimated as approximately 20% based on calculating the proportion of symptomatic seedlings in three randomly selected fields. Six randomly selected seedlings (two from each field) showing damping off symptoms were collected. Small pieces (1 cm2) were cut from infected roots, surface-sterilized (1 minute in 0.5% sodium hypochlorite), rinsed twice with sterile water, air-dried and then plated on potato dextrose agar (PDA, Difco, and Becton Dickinson). Hyphal tips were excised and transferred to fresh PDA. Six morphologically similar isolates were obtained from six samples. Seven-day-old colonies, incubated at 25 °C in the dark on PDA, were whitish with light purple mycelia on the upper side and white with light purple at the center on the reverse side. Macroconidia were 3–5 septate, curved, both ends were pointed, and were 19.8–36.62 × 3.3–4.7 µm (n= 30). Microconidia were cylindrical or ellipsoid and 5.5–11.6 × 2.5–3.8 µm (n=30). Chlamydospores were globose and 9.6 –16.3 × 9.4 – 15.0 µm (n=30). The morphological characteristics of present isolates were comparable with that of Fusarium species (Maryani et al. 2019). Genomic DNA was extracted from 4 days old cultures of each isolate of SRRM 4.2, SRRH3, and SRRH5, EF-1α and rpb2 region were amplified using EF792 + EF829, and RPB2-5f2 + RPB2-7cr primer sets, respectively (Carbone and Kohn, 1999; O'Donnell et al. 2010) and sequenced (GenBank accession number: LC569791- LC569793 and LC600806- LC600808). BLAST query against Fusarium loci sampled and multilocus sequence typing database revealed that 99–100% identity to corresponding sequences of the F. oxysporum species complex (strain NRRL 28395 and 26379). Maximum likelihood phylogenetic analysis with MEGA v. 6.0 using the concatenated sequencing data for EF-1α and rpb2 showed that the isolates belonged to F. oxysporum species complex. Each three healthy seedlings with similar sized (big flower sabju) were grown for 20 days in a plastic pot containing autoclaved peat soil was used for pathogenicity tests. Conidial suspensions (106 conidia mL−1) of 20 days old colonies per isolate (two isolates) were prepared in sterile water. Three pots per strain were inoculated either by pouring 50 ml of the conidial suspension or by the same quantity of sterile distilled water as control. After inoculation, all pots were incubated at 25 °C with a 16-hour light/8-hour dark cycle in a growth chamber. This experiment repeated twice. Inoculated seedlings were watered twice a week. Approximately 60% of the inoculated seedlings per strain wilted after 15 days of inoculation and control seedlings remained asymptomatic. Fusarium oxysporum was successfully isolated from infected seedling and identified based on morphology and EF-1α sequences data to confirm Koch’s postulates. Fusarium oxysporum is responsible for damping-off of many plant species, including larch, tomato, melon, bean, banana, cotton, chickpea, and Arabidopsis thaliana (Fourie et al. 2011; Hassan et al.2019). To the best of our knowledge, this is the first report on damping-off of ovate-leaf atractylodes caused by F. oxysporum in South Korea. This finding provides a basis for studying the epidemic and management of the disease.

scholarly journals First Report of Nigrospora Leaf Blight on Sesame Caused by Nigrospora sphaerica in China

Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 842-842 ◽  
Author(s):  
H. Zhao ◽  
H. Y. Liu ◽  
X. S. Yang ◽  
Y. X. Liu ◽  
Y. X. Ni ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Leaf Blight ◽  
Morphological Data ◽  
Its2 Region ◽  
Oilseed Crop ◽  
Conidial Suspension ◽  
First Report ◽  
Initial Symptoms ◽  
Central Regions ◽  
Leaf Pathogen

Sesame (Sesamum indicum L.) is an important oilseed crop widely grown in the central regions of China. A new leaf blight has increasingly been observed in sesame fields in Anhui, Hubei, and Henan provinces since 2010. Approximately 30 to 40% of the plants were symptomatic in the affected fields. Initial symptoms were yellow to brown, irregularly shaped lesions. Lesions later expanded and the affected leaves tuned grayish to dark brown and wilted, with a layer of whitish mycelial growth on the underside. Severe blighting caused the center of lesions to fall out, leaving holes in the leaves. Sections of symptomatic leaf tissues were surface-sterilized in 75% ethanol for 30 s, then in 1% HgCl2 for 30 s, rinsed three times in sterile distilled water, and plated onto potato dextrose agar (PDA). The resulting fungal colonies were initially white, and then became grayish-brown with sporulation. Conidia were single-celled, black, smooth, spherical, 14.2 to 19.8 μm (average 17.1 μm) in diameter, and borne on a hyaline vesicle at the tip of each conidiophore. Morphological characteristics of the isolates were similar to those of Nigrospora sphaerica (1). To verify the identification based on morphological features, the ITS1-5.8S-ITS2 region of the ribosomal RNA was amplified using ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′) primers (3), and then sequenced and compared to the GenBank database through a BLAST search. Comparison of the sequence revealed 100% similarity to N. sphaerica (GenBank Accession No. JF817271.1). On the basis of morphological data and the ITS rDNA sequence, the isolate was determined to be N. sphaerica. Pathogenicity tests were conducted using fresh and healthy sesame leaves of 10 plants. A conidial suspension (106 conidia/ml) collected from a 7-day-old culture on PDA was used for inoculation. Leaves of 10 plants were spray-inoculated with the spore suspension at the 6-week-old growth stage, and an additional 10 plants were sprayed with sterile water. Inoculated plants were covered with polyethylene bags to maintain high humidity. Plants were kept at 28°C and observed for symptom every day. Ten to 15 days after inoculation, inoculated leaves developed blight symptoms similar to those observed on naturally infected leaves. No symptoms were observed on the control leaves. N. sphaerica was re-isolated from the inoculated leaves, thus fulfilling Koch's postulates. N. sphaerica has been reported as a leaf pathogen on several hosts worldwide (2). To our knowledge, this is the first report of Nigrospora leaf blight on sesame caused by N. sphaerica in China. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, Surrey, UK, 1971. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ . July 01, 2013. (3) M. A. Innis et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

scholarly journals First Report of Nigrospora Leaf Blight on Tea Caused by Nigrospora sphaerica in India

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 417-417 ◽  
Author(s):  
J. Dutta ◽  
S. Gupta ◽  
D. Thakur ◽  
P. J. Handique
Keyword(s):  
Camellia Sinensis ◽  
West Bengal ◽  
Morphological Characteristics ◽  
Its Region ◽  
Causative Organism ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Tea Leaves ◽  
First Report ◽  
Initial Symptoms

Tea [Camellia sinensis (L.) O. Kuntze] is an economically important non-alcoholic caffeine-containing beverage crop widely cultivated for leaves in India, especially in the Darjeeling district of West Bengal. In May 2012, distinct blight symptoms were observed on leaves of popular tea cultivars AV-2, Tukdah 78, Rungli Rungliot 17/144, and Bannockburn 157 in commercial tea estates of the Darjeeling district. This disease reduces yield and quality of the leaves. The initial symptoms were frequently observed on the young leaf margins and apices. Foliar symptoms are characterized by grayish to brown, semicircular or irregular shaped lesions, often surrounded by pale yellow zones up to 9 mm in diameter. The lesions later expand and the affected leaves turn grayish to dark brown and eventually the dried tissue falls, leading to complete defoliation of the plant. The disease causes damage to leaves of all ages and is severe in young leaves. A portion of the symptomatic leaf tissues were surface sterilized in 70% ethanol for 30 s, then in 2% NaClO for 3 min, rinsed three times in sterile distilled water, and plated onto potato dextrose agar (PDA). The fungal colonies were initially white and then became grayish to brown with sporulation. Conidia were spherical to sub spherical, single-celled, black, 19 to 21 μm in diameter, and were borne on a hyaline vesicle at the tip of each conidiophore. Morphological characteristics of the isolates were concurring to those of Nigrospora sphaerica (1). Moreover, the internal transcribed spacer (ITS) region of the ribosomal RNA was amplified by using primers ITS1 and ITS4 and sequenced (GenBank Accession No. KJ767520). The sequence was compared to the GenBank database through nucleotide BLAST search and the isolate showed 100% similarity to N. sphaerica (KC519729.1). On the basis of morphological characteristics and nucleotide homology, the isolate was identified as N. sphaerica. Koch's postulates were fulfilled in the laboratory on tea leaves inoculated with N. sphaerica conidial suspension (106 conidia ml−1) collected from a 7-day-old culture on PDA. Six inoculated 8-month-old seedlings of tea cultivars AV-2 and S.3/3 were incubated in a controlled environment chamber at 25°C and 80 to 85% humidity with a 12-h photoperiod. In addition, three plants of each cultivar were sprayed with sterile distilled water to serve as controls. Twelve to 14 days after inoculation, inoculated leaves developed blight symptoms similar to those observed on naturally infected tea leaves in the field. No symptoms were observed on the control leaves. The pathogen was re-isolated from lesions and its identity was confirmed by morphological characteristics. It was reported that N. sphaerica is frequently encountered as a secondary invader or as a saprophyte on many plant species and also as a causative organism of foliar disease on several hosts worldwide (2,3). To our knowledge, this is first report of N. sphaerica as a foliar pathogen of Camellia sinensis in Darjeeling, West Bengal, India, or worldwide. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, Surrey, UK, 1971. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ July 01, 2013. (3) E. R. Wright et al. Plant Dis. 92:171, 2008.

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.

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