scholarly journals First Report of Fusarium Maize Ear Rot Caused by Fusarium kyushuense in China

Plant Disease ◽  
2014 ◽  
Vol 98 (2) ◽  
pp. 279-279 ◽  
Author(s):  
J.-H. Wang ◽  
H.-P. Li ◽  
J.-B. Zhang ◽  
B.-T. Wang ◽  
Y.-C. Liao
Keyword(s):  
Fusarium Species ◽  
Morphological Characteristics ◽  
Distilled Water ◽  
Ear Rot ◽  
Tubulin Gene ◽  
Average Growth ◽  
First Report ◽  
Maize Ear Rot ◽  
Maize Ear ◽  
Β Tubulin

From September 2009 to October 2012, surveys to determine population structure of Fusarium species on maize were conducted in 22 provinces in China, where the disease incidence ranged from 5 to 20% in individual fields. Maize ears with clear symptoms of Fusarium ear rot (with a white to pink- or salmon-colored mold at the ear tip) were collected from fields. Symptomatic kernels were surface-sterilized (1 min in 0.1% HgCl2, and 30 s in 70% ethanol, followed by three rinses with sterile distilled water), dried, and placed on PDA. After incubation for 3 to 5 days at 28°C in the dark, fungal colonies displaying morphological characteristics of Fusarium spp. (2) were purified by transferring single spores and identified to species level by morphological characteristics (2), and DNA sequence analysis of translation elongation factor-1α (TEF) and β-tubulin genes. A large number of Fusarium species (mainly F. graminearum species complex, F. verticillioides, and F. proliferatum) were identified. These Fusarium species are the main causal agents of maize ear rot (2). Morphological characteristics of six strains from Anhui, Hubei, and Yunnan provinces were found to be identical to those of F. kyushuense (1), which was mixed with other Fusarium species in the natural infection in the field. Colonies grew fast on PDA with reddish-white and floccose mycelia. The average growth rate was 7 to 9 mm per day at 25°C in the dark. Reverse pigmentation was deep red. Microconidia were obovate, ellipsoidal to clavate, and 5.4 to 13.6 (average 8.8) μm in length. Macroconidia were straight or slightly curved, 3- to 5-septate, with a curved and acute apical cell, and 26.0 to 50.3 (average 38.7) μm in length. No chlamydospores were observed. Identity of the fungus was further investigated by sequence comparison of the partial TEF gene (primers EF1/2) and β-tubulin gene (primers T1/22) of one isolate (3). BLASTn analysis of the TEF amplicon (KC964133) and β-tubulin gene (KC964152) obtained with cognate sequences available in GenBank database revealed 99.3 and 99.8% sequence identity, respectively, to F. kyushuense. Pathogenicity tests were conducted twice by injecting 2 ml of a prepared spore suspension (5 × 105 spores/ml) into maize ears (10 per isolate of cv. Zhengdan958) through silk channel 4 days post-silk emergence under field conditions in Wuhan, China. Control plants were inoculated with sterile distilled water. The ears were harvested and evaluated 30 days post-inoculation. Reddish-white mold was observed on inoculated ears and the infected kernels were brown. No symptoms were observed on water controls. Koch's postulates were fulfilled by re-isolating the pathogen from infected kernels. F. kyushuense, first described on wheat in Japan (1), has also been isolated from rice seeds in China (4). It was reported to produce both Type A and Type B trichothecene mycotoxins (1), which cause toxicosis in animals. To our knowledge, this is the first report of F. kyushuense causing maize ear rot in China and this disease could represent a serious risk of yield losses and mycotoxin contamination in maize and other crops. The disease must be considered in existing disease management practices. References: (1) T. Aoki and K. O'Donnell. Mycoscience 39:1, 1998. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (3) F. Van Hove et al. Mycologia 103:570, 2011. (4) Z. H. Zhao and G. Z. Lu. Mycotaxon 102:119, 2007.

scholarly journals First Report of Fusarium miscanthi Causing Ear Rot on Maize in China

Plant Disease ◽  
2020 ◽  
Author(s):  
Guofu Shang ◽  
Huan Yu ◽  
Jie Yang ◽  
Zhu Zeng ◽  
Zuquan Hu
Keyword(s):  
Miscanthus Sinensis ◽  
Sodium Hypochlorite Solution ◽  
Pathogenicity Test ◽  
Sterile Water ◽  
Ear Rot ◽  
Average Growth ◽  
First Report ◽  
Maize Ear Rot ◽  
Maize Ear ◽  
Β Tubulin

Maize (Zea mays L.), an important food and feed crop worldwide, can be infected by Fusarium pathogens that can contaminate grain with mycotoxins. From August to October in 2018 and 2019, a field survey for maize ear rot was conducted in 76 counties of Guizhou province. The incidence ranged from 3% to 15% at individual fields in different areas. A total of 175 diseased maize ears with similar symptoms, including kernels covered with white, pink or salmon-colored mold or exhibiting a white streaking (“starburst”) symptom, were collected from fields. Symptomatic kernels were surface-sterilized by soaking for 30 s in 70% alcohol and for another 2 min in 2% sodium hypochlorite solution, followed by five rinses with sterile water. Each kernel was cut into half and placed on potato dextrose agar (PDA). After incubation at 28 °C in the dark for 5 days, colonies displaying morphological characteristics of Fusarium were transferred to fresh PDA (Leslie and Summerell 2006). Single-sporing was conducted to purify the putative Fusarium colonies. A total of 120 isolates belonged to 16 Fusarium species were determined and F. meridionale was the dominant species. Five isolates from Huaxi district of Guiyang City were identified as F. miscanthi (Gams et al. 1999). Colonies on PDA were white and floccose, and pigmentation as viewed from the underside of the Petri dish was violet. The average growth rate was 7.5-8.0 mm/day at 28 °C in the dark. In cultures grown on PDA, 0-1-septate microconidia were produced in slimy heads. Microconidia were clavate to fusiform with a truncate base and a broadly rounded tip, 4.8-13.3 μm × 1.8-3.3 μm (n=110). In cultures grown on half-strength CMC broth (Xu et al. 2010), macroconidia were mostly 3-septate, almost straight for most of the length, with a slightly foot-shaped basal cell and curved apical cell that gradually tapered, 17.8-71.3 μm × 2.0-4.3 μm (n=78). The identity of the fungus was confirmed by sequence comparison of the partial translation elongation factor-1α (TEF-1α), RNA polymerase II subunit (RPB2), mitochondrial small subunit rDNA (mtSSU) and β-tubulin genes (Mirete et al. 2004; O’Donnell et al. 2010; O’Donnell and Cigelnik 1997). BLASTn searches of GenBank, using the partial TEF-1α (MN750829), RPB2 (MN750834), mtSSU (MT594104) and β-tubulin (MT584781) sequences of representative isolate GYHXB03 as the queries, revealed 99.84%, 99%, 100% and 100% sequence identity, respectively, to F. miscanthi NRRL 26231 accessions AF324331, JX171634, AF060371 and AF060384. Inoculum of isolate GYHXB03 was prepared (Xu et al. 2010), and a pathogenicity test was conducted on maize hybrid “Shundan7” and repeated twice. A 106/mL spore suspension (2 mL) or sterile water was injected into each of 8 maize ears through the silk channel at the blister stage of reproductive development in field (Duan et al. 2019). After three weeks, typical Fusarium kernel rot symptoms the same as those previously shown in the field was observed on all pathogen-inoculated plants, while the controls were asymptomatic. The pathogens re-isolated from two diseased kernels were identified as F. miscanthi based on morphology and TEF-1α and mtSSU analyses. F. miscanthi was first isolated from Miscanthus sinensis in Denmark (Gams et al. 1999), and also identified from M. × giganteus rhizomes in Belgium (Scauflaire et al. 2013). To our knowledge, this is the first report of F. miscanthi causing maize ear rot in China. This disease should be monitored in Guizhou due to its threat to maize production.

scholarly journals First Report of Fusarium Head Blight of Wheat Caused by Fusarium sacchari in China

Plant Disease ◽  
2015 ◽  
Vol 99 (1) ◽  
pp. 160-160 ◽  
Author(s):  
J.-H. Wang ◽  
X.-D. Peng ◽  
S.-H. Lin ◽  
A.-B. Wu ◽  
S.-L. Huang
Keyword(s):  
Fusarium Head Blight ◽  
Yangtze River ◽  
Fusarium Species ◽  
Gene Sequencing ◽  
Morphological Characteristics ◽  
Distilled Water ◽  
The Yangtze River ◽  
Head Blight ◽  
Average Growth ◽  
First Report

Fusarium head blight (FHB), or scab, caused by Fusarium species, is an economically devastating disease of wheat and other cereal crops worldwide. FHB epidemics in wheat occur frequently in China, especially along the middle and lower reaches of the Yangtze River, including Jiangsu and Shanghai. In 2013, wheat spikes showing clear FHB symptoms were collected from fields in Jiangsu and Shanghai. Symptomatic seeds were surface-sterilized for 1 min with a 5% sodium hypochlorite solution and dipping in 70% ethanol for 30 s, then rinsed three times in sterile distilled water and dried. They were placed onto potato dextrose agar (PDA) and incubated for 3 to 5 days at 28°C in the dark. Fungal colonies displaying morphological characteristics of Fusarium spp. (1,2) were purified by the single-spore technique and characterized at the species level by morphological observations (1,2) and translation elongation factor 1-α (TEF) gene sequencing. The results indicated that members of the Fusarium graminearum clade were predominant on wheat, while the morphological characteristics of 16 isolates were found to be identical to those of F. sacchari (1,2). Colonies on PDA were densely cottony, initially pale but becoming violet with age. The average growth rate was 6 to 8 mm per day at 25°C in the dark. Reverse pigmentation was brownish red to violet-brown. Microconidia, abundant in the aerial mycelium and formed in false heads, were oval to ellipsoidal in shape, primarily zero-septate, measuring 5.7 to 18.8 (average 10.6) μm in length. Macroconidia were slender, three- to five-septate, with a curved apical cell and a poorly developed basal cell, 26.3 to 68.9 (average 44.0) μm in length. No chlamydospores were observed. Two F. sacchari strains (Y37 and S43), isolated from Jiangsu and Shanghai, respectively, were investigated by sequence comparison of their partial TEF gene sequences (Accession Nos. KM233195 and KM233196). BLASTn analysis of the TEF sequences obtained with sequences available in the GenBank database revealed 99.8 and 99.5% sequence identity to F. sacchari (GenBank Accession Nos. JF740708 and JF740709). Pathogenicity tests were conducted by injecting 10 μl of a spore suspension (5 × 105 spores/ml) into wheat florets (20 per isolate of cv. Yangmai16), which were then grown under field conditions in Shanghai. Control plants were inoculated with sterile distilled water. Spikes were harvested and evaluated 14 days post-inoculation. Reddish white mold was observed on inoculated wheat spikes; in addition, spikelets adjacent to the inoculation point and the infected florets were brown. No symptoms were observed on water controls. Koch's postulates were fulfilled by reisolating the pathogen from infected florets and identifying them by TEF gene sequencing. F. sacchari is the cause of an important disease of sugar cane, pokkah boeng (1), and has been reported to produce the mycotoxin beauvericin, which causes toxicosis in human and other animals (3). To our knowledge, this is the first report of F. sacchari causing wheat head blight in China. The report contributes to an improved understanding of the composition of Fusarium species on wheat in the lower reaches of the Yangtze River in China, which will be useful for exploring appropriate disease management strategies in this region. References: (1) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (2) J. F. Leslie et al. Mycologia 97:718, 2005. (3) A. Moretti et al. Int. J. Food Microbiol. 118:158, 2007.

scholarly journals First Report of Maize Ear Rot Caused by Exserohilum rostratum in Hainan Province in Southern China

Plant Disease ◽  
2021 ◽  
Author(s):  
Hua Sun ◽  
Ning Guo ◽  
HongXia Ma ◽  
Shusen Liu ◽  
Jie Shi
Keyword(s):  
Zea Mays ◽  
Molecular Identification ◽  
Hebei Province ◽  
Hainan Province ◽  
Distilled Water ◽  
Ear Rot ◽  
First Report ◽  
Exserohilum Rostratum ◽  
Maize Ear Rot ◽  
Maize Ear

Maize (Zea mays L.) is one of three major grain crops in China, with production reaching 261 million tons in 2019(NBS, 2020). Some fungi cause maize ear rot which lead to significant yield and quality losses. In 2016, about 5% of maize ears were dark brown and covered with a white mould in seed production fields in Lingshui, Hainan Province, China. These ears were brought back to the laboratory for analysis. Molded kernels were surface sterilized in 75% ethanol for 3 min and in 10% sodium hypochlorite for 3 min, subsequently rinsed three times in sterile-distilled water, placed onto potato dextrose agar (PDA), and incubated at 28°C in the dark for 3 days. mycelia tips grown from kernels were transferred into fresh PDA plates. Seven fungal isolates with similar morphology characteristics were obtained, and three of them were identified by morphology and molecular identification. The colonies grew rapidly. The aerial mycelia turned white to black with age. Conidia were straight to slightly curved, oval, pyriform or geniculate, brown to dark brown, and had 2 to 7 septa, with both basal and caudal septa thicker and darker than others, 39.47 to 78.66 ×13.96 to 22.78 μm, with a distinctly protruding hilum swelled from the basal cell. Conidiophores were dark brown, with geniculate tip and many septa. For molecular identification, genomic DNA of isolate was extracted from mycelia. The internal transcribed spacer (ITS), 1,3,8-trihydroxynaphthalene reductase (Brn) and glyceraldehyde-3-phosphate dehydrogenase-like (Gpd) genes were amplified with primers ITS1/ITS4 (White et al. 1990), Brn01/Brn02 (Shimizu et al. 1998) and gpd1/gpd 2 (Berbee et al. 1999) , respectively. BLASTn analysis showed that high identities with Exserohilum rostratum (ITS, LT837845.1, 100%; Brn, AY621165.1, 99.87%; Gpd, LT882543.1, 99.75%). Sequences of ITS, Brn and Gpd were deposited in GenBank with accession numbers MW362495, MW363953 and MW363954, respectively. Based on morphological characteristics and molecular analysis, the isolate was identified as E. rostratum (Hernández-Restrepo et al. 2018). Koch’s postulates were completed by using ears of maize inbred line Huangzaosi and Chang7-2 growing in the experimental field of Baoding, Hebei Province. Three days post-silk emergence, each of the four maize ears was injected with 2 ml conidial suspension (1×106 conidia/ml) of isolate ZBSF005 through the silk channel. In the control groups, three ears were inoculated with an equal amount of sterile-distilled water. The inoculated ears grew under natural conditions for 30 days, the diseased kernels and ear tips were black brown and the surface covered with white or gray black mildew layer. The kernels with severe infection were wizened. But the bract could not be infected by the pathogen. Meanwhile, the control remained asymptomatic. The same fungus was successfully re-isolated from the inoculated kernels, and its identity was confirmed by morphological and molecular biology approaches, thus fulfilling Koch’s postulates. E. rostratum has been reported to cause leaf spots in a wide range of hosts, such as Calathea picturata, Lagenaria siceraria, Saccharum officinarum, Ananas comosus, Hevea brasiliensis, Zea mays and so on (Chern et al. 2011; Ahmadpour et al. 2013; Choudhary et al. 2018), and it was also reported to cause root rot in Lactuca saliva (Saad et al. 2019). To our knowledge, this is the first report of E. rostratum causing maize ear rot in China. The pathogen was simultaneously inoculated to 8 maize inbred lines in Hebei province, but the disease only occurred in some varieties and the incidence area was large. Therefore, attention should be paid to the prevention and treatment of ear rot caused by this pathogen in the breeding process.

scholarly journals First Report of Pepper Fruit Rot Caused by Fusarium concentricum in China

Plant Disease ◽  
2013 ◽  
Vol 97 (12) ◽  
pp. 1657-1657 ◽  
Author(s):  
J. H. Wang ◽  
Z. H. Feng ◽  
Z. Han ◽  
S. Q. Song ◽  
S. H. Lin ◽  
...  
Keyword(s):  
Fusarium Species ◽  
Fruit Rot ◽  
Post Inoculation ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Average Growth ◽  
First Report ◽  
Control Fruit ◽  
Pepper Fruit ◽  
Fruit Samples

Pepper (Capsicum annuum L.) is an important vegetable crop worldwide. Some Fusarium species can cause pepper fruit rot, leading to significant yield losses of pepper production and, for some Fusarium species, potential risk of mycotoxin contamination. A total of 106 diseased pepper fruit samples were collected from various pepper cultivars from seven provinces (Gansu, Hainan, Heilongjiang, Hunan, Shandong, Shanghai, and Zhejiang) in China during the 2012 growing season, where pepper production occurs on approximately 25,000 ha. Pepper fruit rot symptom incidence ranged from 5 to 20% in individual fields. Symptomatic fruit tissue was surface-sterilized in 0.1% HgCl2 for 1 min, dipped in 70% ethanol for 30 s, then rinsed in sterilized distilled water three times, dried, and plated in 90 mm diameter petri dishes containing potato dextrose agar (PDA). After incubation for 5 days at 28°C in the dark, putative Fusarium colonies were purified by single-sporing. Forty-three Fusarium strains were isolated and identified to species as described previously (1,2). Morphological characteristics of one strain were identical to those of F. concentricum. Aerial mycelium was reddish-white with an average growth rate of 4.2 to 4.3 mm/day at 25°C in the dark on PDA. Pigments in the agar were formed in alternating red and orange concentric rings. Microconidia were 0- to 1-septate, mostly 0-septate, and oval, obovoid to allantoid. Macroconidia were relatively slender with no significant curvature, 3- to 5-septate, with a beaked apical cell and a foot-shaped basal cell. To confirm the species identity, the partial TEF gene sequence (646 bp) was amplified and sequenced (GenBank Accession No. KC816735). A BLASTn search with TEF gene sequences in NCBI and the Fusarium ID databases revealed 99.7 and 100% sequence identity, respectively, to known TEF sequences of F. concentricum. Thus, both morphological and molecular criteria supported identification of the strain as F. concentricum. This strain was deposited as Accession MUCL 54697 (http://bccm.belspo.be/about/mucl.php). Pathogenicity of the strain was confirmed by inoculating 10 wounded, mature pepper fruits that had been harvested 70 days after planting the cultivar Zhongjiao-5 with a conidial suspension (1 × 106 spores/ml), as described previously (3). A control treatment consisted of inoculating 10 pepper fruits of the same cultivar with sterilized distilled water. The fruit were incubated at 25°C in a moist chamber, and the experiment was repeated independently in triplicate. Initially, green to dark brown lesions were observed on the outer surface of inoculated fruit. Typical soft-rot symptoms and lesions were observed on the inner wall when the fruit were cut open 10 days post-inoculation. Some infected seeds in the fruits were grayish-black and covered by mycelium, similar to the original fruit symptoms observed at the sampling sites. The control fruit remained healthy after 10 days of incubation. The same fungus was isolated from the inoculated infected fruit using the method described above, but no fungal growth was observed from the control fruit. To our knowledge, this is the first report of F. concentricum causing a pepper fruit rot. References: (1) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (2) K. O'Donnell et al. Proc. Nat. Acad. Sci. USA 95:2044, 1998. (3) Y. Yang et al. 2011. Int. J. Food Microbiol. 151:150, 2011.

scholarly journals Fumonisins and related Fusarium species in pre-harvest maize ear rot in Poland

2017 ◽  
Vol 45 (1) ◽  
pp. 35-46 ◽  
Author(s):  
K. Gromadzka ◽  
M. Wit ◽  
K. Górna ◽  
J. Chełkowski ◽  
A. Waśkiewicz ◽  
...  
Keyword(s):  
Fusarium Species ◽  
Ear Rot ◽  
Maize Ear Rot ◽  
Maize Ear

scholarly journals Mycotoxins and related Fusarium species in preharvest maize ear rot in Poland  

2016 ◽  
Vol 62 (No. 8) ◽  
pp. 348-354 ◽  
Author(s):  
K. Gromadzka ◽  
K. Górna ◽  
J. Chełkowski ◽  
A. Waśkiewicz
Keyword(s):  
Fusarium Species ◽  
Fusarium Ear Rot ◽  
Ear Rot ◽  
Complex Survey ◽  
Maize Kernel ◽  
Fusarium Mycotoxin ◽  
Maize Kernels ◽  
Maize Ear Rot ◽  
Maize Ear

This work presents a survey on mycotoxins (seasons 2013 and 2014) and Fusarium species (seasons from 1985 to 2014) in maize ear rot in Poland. Twelve mycotoxins were identified in maize kernel samples exhibiting symptoms of Fusarium ear rot or rotten kernels at the harvest in two locations in Poland during the seasons 2013 and 2014. This is the first complex survey on the co-occurrence of four Fusarium mycotoxin groups in maize kernels: the group of the mycohormone zearalenone; the group of trichothecenes – deoxynivalenol and nivalenol; the group of fumonisins; and the group of cyclic hexadepsipeptides – beauvericin and enniatins; and in addition, moniliformin. Four Fusarium species were identified in preharvest maize ear rot in the 2013 and 2014 harvests namely:<br /> F. graminearum, F. poae, F. subglutinans and F. verticillioides. Since 1985, eleven Fusarium species have been identified in 13 investigation seasons. Apart from those mentioned above, F. avenaceum, F. cerealis, F. culmorum and<br /> F. sporotrichioides were observed with irregular frequencies, and three species, i.e. F. proliferatum, F. tricinctum and F. equiseti, were identified sporadically. A significant increase of F. verticillioides frequency and a decrease of F. subglutinans frequency and changes of mycotoxin profile have been observed in the two decades since 1995.  

scholarly journals Occurrence of Mycotoxigenic Fusarium Species and Competitive Fungi on Preharvest Maize Ear Rot in Poland

Toxins ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 224 ◽  
Author(s):  
Karolina Gromadzka ◽  
Lidia Błaszczyk ◽  
Jerzy Chełkowski ◽  
Agnieszka Waśkiewicz
Keyword(s):  
Fusarium Species ◽  
Fusarium Verticillioides ◽  
Ear Rot ◽  
Fusarium Spp ◽  
Trichoderma Spp ◽  
Lecanicillium Lecanii ◽  
Significant Difference ◽  
Food And Feed ◽  
Maize Ear Rot ◽  
Maize Ear

Maize has become one of the most important crops for food and feed production—both as a silage and crop residue worldwide. The present study aimed to identify the co-occurrence of Fusarium subglutinans, Fusarium verticillioides, Trichoderma atroviride, Sarocladium zeae, and Lecanicillium lecanii on maize ear rot. Further, the accumulation of mycotoxins as secondary metabolites of Fusarium spp. in maize ear samples was also analyzed. Maize ear samples were collected between 2014 and 2017 from two main maize growing areas in Poland (Greater Poland and Silesia region). A significant difference was found in the frequency of two main Fusarium spp. that infect maize ears, namely F. subglutinans and F. verticillioides. In addition to Fusarium spp. T. atroviride, S. zeae, and L. lecanii were also identified. T. atroviride species was found in 14% of maize samples examined between 2014 and 2017, particularly with a high percentage of Trichoderma spp. recorded in 2014, i.e., in 31% of samples. However, mycotoxin content (beauvericin and fumonisins) varied, depending on both the location and year of sampling. The interaction of fungi and insects inhabiting maize ear and kernel is very complex and not yet elucidated. Therefore, further research is required in this area.

scholarly journals First Report of Fusarium Maize Ear Rot Caused by Fusarium meridionale in China

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1156-1156 ◽  
Author(s):  
H. Zhang ◽  
W. Luo ◽  
Y. Pan ◽  
J. Xu ◽  
J. S. Xu ◽  
...  
Keyword(s):  
Fusarium Species ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Fusarium Ear Rot ◽  
Ear Rot ◽  
Translation Elongation Factor ◽  
Translation Elongation ◽  
First Report

Fusarium is an important genus of fungal pathogens that are responsible for devastating diseases, such as Fusarium ear rot on maize, which may result in yield losses and/or mycotoxin contamination. In September 2013, a survey to determine population composition of Fusarium species on maize was conducted at 22 fields in 18 counties in Gansu Province. Maize ears with clear symptoms (with a white to pink- or salmon-colored mold at the ear tip) were collected. Symptomatic seeds were surface-sterilized with 70% ethanol and 10% sodium hypochlorite and rinsed three times with sterile water to eliminate hypochlorite residues. After drying on sterile filter paper, the seeds were placed on potato dextrose agar (PDA) and incubated at 25°C in the dark for 3 days. Mycelium that was characteristic of Fusarium spp. (2) was purified by transferring single spores to fresh PDA. Fusarium species were identified by morphological characteristics (2), multilocus genotyping assay (MLGT) (3), and sequence analysis of the translation elongation factor-1α (TEF) gene. Several Fusarium species were identified and Fusarium verticillioides and F. proliferatum were the predominant species. Based on MLGT, two strains from Chenghong County were identified as F. meridionale with NIV chemotype, a species in F. graminearum species complex (FGSC). Morphological characteristics were also identical to FGSC. Colonies grew rapidly on PDA and produce relatively large amounts of dense mycelia and red pigments. Slender, thick-walled, and moderately curved or straight macroconidia were observed with 5- to 6-septate. Furthermore, conidia on SNA also showed typical characteristics of F. meridionale, as the dorsal and ventral lines were often parallel and gradually curved. Sequences comparison of the partial translation elongation factor (TEF-1α, 644 bp) gene (1) was used to validate these observations. BLASTn analysis with the FUSARIUM-ID database revealed 100% sequence identity to F. meridionale (GenBank Accession No. KJ137017). Thus, both morphological and molecular criteria supported identification of the strains as F. meridionale. A pathogenicity test was performed on Zhengdan958, the maize variety with the largest planted acreage in China. Four days after silk emergence, 2 ml conidial suspension (105 macroconidia/ml) of each isolate were injected into each of 10 maize ears through silk channel. Control plants were inoculated with sterile distilled water. Typical FER symptoms (reddish-white mold) was observed on inoculated ears and no symptoms were observed on water controls. Koch's postulates were fulfilled by re-isolating the same fungus from the infected seeds. F. meridionale was one of the pathogens causing Fusarium head blight on wheat and barley in China and produced nivalenol (4,5) and it also has been isolated from maize in Korea and Nepal. To our knowledge, this is the first report of F. meridionale causing Fusarium ear rot on maize in China. Further studies on biological characteristics such as temperature sensibility and fungicide resistance are needed to gain a better understanding of this new pathogen. References: (1) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (3) T. J. Ward et al. Fungal Genet. Biol. 45:473, 2008. (4) L. Yang et al. Phytopathology 98:719, 2008. (5) H. Zhang et al. Plos one 7:e31722, 2012.

scholarly journals First Report of Dieback on Euonymus fortunei Caused by Cylindrocladiella parva in Germany

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1120-1120 ◽  
Author(s):  
U. Brielmaier-Liebetanz ◽  
S. Wagner ◽  
S. Werres
Keyword(s):  
Morphological Characteristics ◽  
Day Length ◽  
Morphological Identification ◽  
Malt Extract ◽  
Tubulin Gene ◽  
First Report ◽  
Near Ultraviolet ◽  
Euonymus Fortunei ◽  
Negative Controls ◽  
Β Tubulin

In August 2011, a severe shoot dieback was observed on several hundred plants of 1-year-old Euonymus fortunei cv. Emerald 'n Gold in a nursery in Lower Saxony and on a cemetery in Berlin. Single shoots or the whole plant were affected. Chocolate brown lesions around the shoots spread primarily acropetally to be followed by wilting of the shoot tip, reddish discoloration, dropping of leaves, and finally plant death. Two fungal isolates, JKI 2187 and JKI 1288, forming white mycelium on 2% malt extract agar (MEA) were obtained from symptomatic shoots. Both were identified by their morphology as Cylindrocladiella parva (P.J. Anderson) Boesewinkel (syn. Cylindrocladium parvum). After incubation for one week at 25°C in the dark, the reverse side of the colony became buff to ochreous and this was associated with development of long chains of chlamydospores. Microsclerotia and fruiting bodies were not observed. Morphological characteristics were determined on synthetic nutrient agar (SNA) after 7 days at 25°C under near-ultraviolet light. The conidiophores were penicillately branched. The stipe extensions were thick-walled with clavate to naviculate vesicles. Conidia measured 12.7 to 17.1 (14.9) × 2.2 to 3.3 (2.7) μm. The molecular studies confirmed the morphological identification. Genomic DNA was isolated from the mycelia. The rDNA internal transcribed spacer (ITS) region was amplified with the primers ITS1 and ITS4 and a part of the β-tubulin gene with the primers Bt2a and Bt2b (2). The sequences generated in this study were compared with sequences obtained from GenBank. A BLAST analysis showed that the ITS sequence had a 99% similarity with that of C. parva GenBank Accession No. AY793454 and the β-tubulin gene had a 100% similarity with AY793489. So far, pathogenicity of C. parva has been demonstrated for only a few plant species. Its pathogenicity was confirmed on grapevine (Vitis vinifera) in New Zealand (3), on common oak (Quercus robur) in Italy (4), and on eucalyptus in South Africa (1). To fulfill Koch's postulates for the pathogen on E. fortunei, the isolate JKI 2188 of C. parva was inoculated on 40 two-year-old plants of cv. Emerald 'n Gold. The leaves around one node were removed on five shoots per plant. After wounding the nodes with a needle, colonized agar plugs were placed on them. The plugs were covered with moist cellulose swabs and sealed with Parafilm. To act as negative controls, 20 plants were treated with sterile agar plugs. All the plants were incubated in a growth chamber at 21/16°C (day/night), with a day length of 12 h and a relative humidity of 90 to 100%. Seven weeks after inoculation, all inoculated plants showed symptoms identical to those of the diseased plants from which C. parva was originally isolated. The negative controls remained healthy. The strains reisolated were identical to the original isolates. To our knowledge, this is the first report of C. parva as a pathogen of Euonymus. Since 2011, there were no further reports of this disease. At present, the disease is not of economic importance. References: (1) P. W. Crous et al. Plant Pathol. 42:302, 1993. (2) N. L. Glass and G. C. Donaldson. Appl. Environ. Microbiol. 61:1323, 1995. (3) E. E. Jones et al. Plant Dis 96: 144, 2012. (4) L. Scattolin and L. Monteccio. Plant Dis. 91:771, 2007.

scholarly journals First Report of Lasidiplodia theobromae and Cryptovalsa ampelina Associated with Grapevine Decline from Castilla y León, Spain

Plant Disease ◽  
2009 ◽  
Vol 93 (5) ◽  
pp. 545-545 ◽  
Author(s):  
M. T. Martin ◽  
L. Martin ◽  
M. T. de-Francisco ◽  
R. Cobos
Keyword(s):  
Dna Sequences ◽  
Morphological Characteristics ◽  
Tubulin Gene ◽  
Current Season ◽  
First Report ◽  
Grapevine Decline ◽  
Eutypa Dieback ◽  
Castilla Y Leon ◽  
Pathogenicity Tests ◽  
Β Tubulin

Symptoms of grapevine decline were surveyed. Samples from mature vines exhibiting external symptoms of Eutypa dieback and Esca were collected, as were young plants with and without external symptoms, and fungal isolations were performed. In 2007, 3-year-old grapevines (cv. Tempranillo grafted onto 110R rootstock) with low vigor, reduced foliage, and vascular streaking in the wood were observed. Small pieces of discolored wood were placed onto malt extract agar supplemented with 0.25 g/liter of chloramphenicol, incubated at 25°C, and resulting colonies were transferred to potato dextrose agar (PDA). Isolates were characterized by abundant aerial and fast-growing mycelium covering the plate surface after 3 days, mycelium became dark green. Pycnidia contained thick-walled, aseptate conidia 15 to 35 × 10 to 15 μm. Lasidiplodia theobromae was identified based on morphological characteristics (3) and confirmed by banding patterns obtained after the digestion of the 1,200-bp amplicon generated with ITS1 and NL4 primers (2) using restriction endonucleases (2). Single-spore cultures were generated and DNA sequences of the rDNA internal transcribed spacer region, partial sequence of the 5′ end of the β-tubulin gene, and a fragment of the elongation factor further confirmed the identification and revealed genetic similarity with other isolates of L. theobromae. A sequence of each fragment was deposited in GenBank with Accession Nos. EU600925, EU597297, and EU597298, respectively. Pathogenicity tests were conducted on four replicate rootstocks (110R) and 15 canes of current-season growth (cv. Tempranillo). Plants were inoculated with an agar plug containing L. theobromae; controls were treated with agar only. Grapevines were maintained in a greenhouse at 20 to 25°C. After 3 months, L. theobromae was reisolated from internal vascular lesions in 100 and 66% of inoculated rootstocks and canes, respectively. Control plants were asymptomatic and L. theobromae was not recovered. Using the same methodology, a fungus identified based on morphological characteristics in culture as Cryptovalsa ampelina (1) was isolated from grapevines (cv. Tempranillo) planted in 1987. Cultures in PDA were white to creamy white and cottony with diffuse margins. Colonies covered the 90-mm-diameter petri dish surface in 5 days. Conidia were 20 to 23 × 1 to 1.5 μm, unicellular, hyaline, and filiform. PCR amplifications of the DNA extracts of C. ampelina with Camp-1 and Camp-2R primers gave a characteristic DNA fragment of 300 bp (3) and DNA sequences of the ITS4-ITS5 amplicons (GenBank Accession No. EU597296) confirmed the identification. For the first time, the 5′ end of the β-tubulin gene was sequenced and deposited in GenBank (Accession No. EU600926). Pathogenicity tests were conducted as described above for L. theobromae. Both pathogens were examined in the same experiment. C. ampelina was reisolated from internal brown streaking lesions in 25% of the rootstocks and 33% of the canes. Control plants exhibited no symptoms. L. theobromae appeared to be a more aggressive pathogen than C. ampelina on grapevine with more internal brown streaking and greater recovery of pathogen from inoculated samples. To our knowledge, this is the first report of L. theobromae and C. ampelina causing grapevine decline in Castilla y León. References: (1) J. Luque et al. Phytopathol. Mediterr. 45:S101, 2006. (2) M. T. Martin and R. Cobos. Phytopathol. Mediterr. 46:18, 2007. (3) D. Pavlic et al. Stud. Mycol. 50:313, 2004.

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