scholarly journals First report of Head blight of wheat caused by Fusarium vorosii in Serbia

Plant Disease ◽  
2021 ◽  
Author(s):  
Ana Obradović ◽  
Jelena Stepanovic ◽  
Vesna Krnjaja ◽  
Aleksandra Bulajic ◽  
Goran Stanković ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Species Recognition ◽  
Histone H3 ◽  
Elongation Factor ◽  
Phylogenetic Species ◽  
Head Blight ◽  
Single Spore ◽  
First Report ◽  
Genealogical Concordance ◽  
Β Tubulin

The cosmopolitan species Fusarium graminearum Schwabe directly reduces yield, as well as grain quality of cereals, due to its ability to synthesize mycotoxins. Previously it was considered to be one species occurring on all continents. However, phylogenetic analysis employing the GCPSR method (Genealogical Concordance Phylogenetic Species Recognition) revealed the existence of 15 phylogenetic species within what is now recognised as the Fusarium graminearum Species Complex (FGSC) (Sarver et al. 2011). During 1996-2008, a MRIZP collection of FGSC isolates was established and isolates originating from wheat (5), maize (3) and barely (2) were selected for further study. Morphological features including the appearance of colonies and macroconidia (average size 38.5-53.1 × 4.6-5.4 µm, No 50) of all 10 isolates on PDA were consistent with descriptions of F. graminearum (O’Donnell et al. 2004, Leslie and Summerell 2006). Total DNA was isolated from mycelium removed from 7-day old colonies of single-spore isolates grown on PDA using the DNeasy Plant Mini Kit (Qiagen, Hilden). Further identification was based on amplification and sequencing of elongation factor TEF−1α, histone H3 and β−tubulin in both directions, with primers ef1/ef2, H3-1a/H3-1b and T1/T22, respectively (Jacobs et al. 2010). The sequences were deposited in NCBI under accession numbers MF974399 - MF974408 (TEF−1α), MG063783 - MG063792 (β−tubulin) and MF999139 - MF999148 (histone H3). Sequence analysis was performed using BLAST while genetic similarity was calculated using MEGA 6.0 software. Isolate 1339 originating from wheat (collected at the locality of Kikinda in 2006), shared 100% nucleotide identity with TEF−1α (DQ459745), histone H3 (DQ459728) and β−tubulin (DQ459643) of F. vorosii isolate NRRL37605 (Starkey et al. 2007). The remaining nine isolates were identified as F. graminearum as they shared 99% to 100% nucleotide similarity with F. graminearum NRRL 28439 (O’Donnell et al. 2004). Pathogenicity was tested using artificial inoculations of spikes during wheat flowering (Mesterhazy et al. 1999). Thirty classes were inoculated with each isolate, in three replicates. Inoculum was prepared from 7-day colonies on PDA, and 30 ml of a conidia suspension (1x105 conidia/ml) was used. Control plants were inoculated with sterile water. Three weeks after inoculation, typical Fusarium head blight symptoms were visible on inoculated plants, from which all 10 isolates were successfully reisolated. Control spikes remained symptomless. Disease severity was estimated on the 1-7 scale (Blandino et al. 2012). Average pathogenicity of the F. vorosii isolate 1339 was 1.9, and 2.4 -5.1 of F. graminearum isolates. Toxin production was determined using gas chromatography-tandem mass spectrometry. Kernels inoculated with the 10 isolates were ground and tested for the presence of deoxynivalenol (DON) and its acetyl derivatives 3ADON, 15ADON and NIV. F. vorosii isolate 1339 possessed the 15ADON chemotype, as well as eight F. graminearum isolates, while only one F. graminearum isolate was 3ADON chemotype. To date, F. vorosii has only been detected in Hungary on wheat (Toth et al. 2005) and Korea on barley, corn and rice (Lee et al. 2016). This is the first report of F. vorosii in Serbia, which is of great importance, because it indicates the spread of this toxigenic species. Further studies should be focused on determining the distribution, aggressiveness and toxicological profile of F. vorosii.

scholarly journals Genealogical concordance of phylogenetic species recognition-based delimitation of Neopestalotiopsis species associated with leaf spots and fruit canker disease affected guava plants

2021 ◽  
Vol 58 (04) ◽  
pp. 1301-1313
Author(s):  
Imran Ul Haq
Keyword(s):  
Species Recognition ◽  
Elongation Factor ◽  
Plant Diseases ◽  
Morphological Data ◽  
Phylogenetic Species ◽  
Translation Elongation ◽  
Canker Disease ◽  
Leaf Spots ◽  
Genealogical Concordance ◽  
Elongation Factor 1

Neopestalotiopsis species are known to be involved in plant diseases as associated pathogens. The taxonomic identification of the fungal group Neopestalotiopsisis little bit difficult due to its complex evolutionary history. In the present study, seven fungal isolates were investigated from canker-affected guava plants. The phylogeny for generic placement of these isolates was analyzed to validate them as Neopestalotiopsis genus by phylogenetic signals from the 28S nrRNA region (LSU). Generated morphological data was segregated as new morpho-species of the Neopestalotiopsis genus. Hence, the internal transcribed spacer (ITS), Translation elongation factor 1-α (TEF1-α) and Tubulin (TUB) genic region of these isolates were studied in juxtaposition with morphological data to resolve species limits. Both phylogenetic and morphological data revealed four novel species of the Neopestalotiopsis genus out of seven isolates studied. These Neopestalotiopsis species could be of great significance for further investigation as putative pathogens associated with canker or scabby canker disease in guava.

scholarly journals Three-Locus Sequence Identification and Differential Tebuconazole Sensitivity Suggest Novel Fusarium equiseti Haplotype from Trinidad

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 175 ◽  
Author(s):  
Ria T. Villafana ◽  
Sephra N. Rampersad
Keyword(s):  
Rna Polymerase ◽  
Species Recognition ◽  
Elongation Factor ◽  
Phylogenetic Species ◽  
Translation Elongation Factor ◽  
Translation Elongation ◽  
Fusarium Equiseti ◽  
Homogeneous Groups ◽  
Sequence Identification ◽  
Genealogical Concordance

The Fusarium incarnatum-equiseti species complex (FIESC) consists of 33 phylogenetic species according to multi-locus sequence typing (MLST) and Genealogical Concordance Phylogenetic Species Recognition (GCPSR). A multi-locus dataset consisting of nucleotide sequences of the translation elongation factor (EF-1α), calmodulin (CAM), partial RNA polymerase largest subunit (RPB1), and partial RNA polymerase second largest subunit (RPB2), was generated to distinguish among phylogenetic species within the FIESC isolates infecting bell pepper in Trinidad. Three phylogenetic species belonged to the Incarnatum clade (FIESC-15, FIESC-16, and FIESC-26), and one species belonged to the Equiseti clade (FIESC-14). Specific MLST types were sensitive to 10 µg/mL of tebuconazole fungicide as a discriminatory dose. The EC50 values were significantly different among the four MLST groups, which were separated into two homogeneous groups: FIESC-26a and FIESC-14a, demonstrating the “sensitive” azole phenotype and FIESC-15a and FIESC-16a as the “less sensitive” azole phenotype. CYP51C sequences of the Trinidad isolates, although under positive selection, were without any signatures of recombination, were highly conserved, and were not correlated with these azole phenotypes. CYP51C sequences were unable to resolve the FIESC isolates as phylogenetic inference indicated polytomic branching for these sequences. This data is important to different research communities, including those studying Fusarium phytopathology, mycotoxins, and public health impacts.

scholarly journals First Report on Identification of Fusarium graminearum Species Complex Members from Turkey and Iran

2019 ◽  
Vol 7 (7) ◽  
pp. 1040
Author(s):  
Berna Tunalı ◽  
Emre Yörük ◽  
Özlem Sefer ◽  
Bayram Kansu ◽  
Bahram Sharifnabi
Keyword(s):  
Fusarium Head Blight ◽  
Fusarium Graminearum ◽  
Species Complex ◽  
Histone H3 ◽  
28S Rdna ◽  
Head Blight ◽  
Identification Methods ◽  
Fusarium Graminearum Species Complex ◽  
Blight Disease ◽  
Β Tubulin

Fusarium graminearum species complex is the major Fusarium head blight disease pathogen in worldwide. Fusarium head blight disease lead to damages on small grain cereals. The identification of the F. graminearum species complex is important for improving disease control and management. Traditional identification methods such as macroscopy and microscopy analysis need to be supported by biochemical and genetics assays. Thus, DNA sequencing-based methods is one of the most preferred, reliable, low priced in the identification methods. In the study, 54 F. graminearum isolates obtained from diseased wheat, barley and corn fields in Turkey and Iran were identified by morphological characteristics and then characterized by species-specific SCAR marker. β-tubulin, Tef1-α, 28s rDNA and Histone H3 genes amplified, purified and then sequenced. The merged multiloci length was obtained as last of all 2215 bp. These sequencing results was used to multiloci genotyping assays. Last of all, 20 isolates were determined as F. graminearum sensu stricto by multiloci genotyping analysis. Remaining isolates were identified as F. asiaticum or Fusarium sp. . The findings are important in terms of revealing the first-time identification in Turkish and Iranian isolates as F. graminearum species complex members by amplification four (β-tubulin, Tef1-α, 28s rDNA and Histone H3) highly conserved DNA regions.

scholarly journals Phylogeny and species delimitation of Strobilomyces (Boletaceae), with an emphasis on the Asian species

2020 ◽  
Vol 44 (1) ◽  
pp. 113-139
Author(s):  
L.H. Han ◽  
G. Wu ◽  
E. Horak ◽  
R.E. Halling ◽  
J. Xu ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Molecular Phylogenetics ◽  
Species Recognition ◽  
Elongation Factor ◽  
Distribution Patterns ◽  
Distinct Species ◽  
Morphological Characters ◽  
Phylogenetic Species ◽  
Type Specimens ◽  
Genealogical Concordance

Strobilomyces is broadly distributed geographically and serves an important ecological function. However, it has been difficult to delimit species within the genus, primarily due to developmental variations and phenotypic plasticity. To elucidate phylogenetic relationships among species within the genus and to understand its species diversity, especially in Asia, materials of the genus collected from five continents (Africa, Asia, Australia, Europe, and North/Central America) were investigated. The phylogeny of Strobilomyces was reconstructed based on nucleotide sequences of four genes coding for: the largest and the second largest subunits of the RNA polymerase II (RPB1 and RPB2); the translation elongation factor subunit 1-α (TEF1); and the mitochondrial cytochrome oxidase subunit 3 (COX3). The combined results based on molecular phylogenetics, morphological characters, host tree associations, and geographical distribution patterns support a new classification consisting of two sections, sect. Strobilomyces and sect. Echinati. Using the genealogical concordance phylogenetic species recognition (GCPSR) approach, at least 33 phylogenetic species in Asia can be delimited, all of which are supported by morphological features, and five phylogenetic species remain to be described. The mountainous region of Southwest China is especially special, containing at least 21 species and likely represents a centre of diversification. We further compared our specimens with the type specimens of 25 species of Strobilomyces. Our comparisons suggest that, there are a total of 31 distinct species, while S. sanmingensis, S. verruculosus, S. subnigricans, and S. zangii/S. areolatus, are synonyms of S. mirandus, S. giganteus, S. alpinus and S. seminudus, respectively. Eight new species, namely, S. albidus, S. anthracinus, S. calidus, S. cingulatus, S. densisquamosus, S. douformis, S. microreticulatus and S. pinophilus, are described. A dichotomous key to the Asian Strobilomyces species is provided.

scholarly journals First Report of Fusarium graminearum Causing Flower Blight On Hemp (Cannabis sativa) in Kentucky

Plant Disease ◽  
2021 ◽  
Author(s):  
Gabdiel Yulfo-Soto ◽  
Henry S Smith ◽  
Desiree Szarka ◽  
Ed Dixon ◽  
Lisa Vaillancourt ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Cannabis Sativa ◽  
Elongation Factor ◽  
Fungal Growth ◽  
Tween 20 ◽  
Conidial Suspension ◽  
Ear Rot ◽  
Head Blight ◽  
Dark Cycle ◽  
First Report

In October of 2020, a grower in Boyle County, KY, reported mold and blight symptoms on flowers of field-grown hemp. Plants were approaching harvest, and the mold was affecting 100% of the cultivar ‘White CBG’ being grown for cannabinoid (CBD) extraction. Mycelium colonized the flower heads and any seeds within bracts. Affected flower bracts were necrotic, and mycelium and necrosis in the most severe cases also encompassed adjacent (sugar) leaves. Necrotic symptomatic tissue was collected, disinfested in 10% bleach for one minute, and cultured on acidified potato dextrose agar (APDA). Each isolate was single-spored, transferred to PDA, stored in 15% glycerol at -80°C and maintained at room temperature under blacklight blue and fluorescent bulbs on a 12-hour light-dark cycle. Colonies produced white-pink mycelia with a dark red pigment on the undersides. Conidia collected after 7-9 days were falcate and septate (5 to 6). No microconidia were produced. Macroconidia measured 35.4-49.7 µm x 3.4-5.8 µm (n=50). The strains produced blue-black fertile perithecia on carrot agar when induced according to the method of (Bowden and Leslie, 1999). To confirm pathogenicity, flowers of hemp cultivars ‘Lifter’, ‘Trump Towers’, ‘Wife’ and ‘White CBG’ were inoculated in the greenhouse with a representative fungal strain (20Hemp010). Plants were inoculated at two different stages: when the styles were still green or after they had become senescent. Macroconidia were collected from 7- to 9-day-old cultures grown under a 12-hour light-dark cycle. Plants were spray-inoculated with a 5 x 105 per ml conidial suspension in 0.05% Tween 20 until runoff. Flower heads were individually covered with clear plastic bags and incubated for 72 h at 95-100% humidity under greenhouse benches to avoid direct light. Bags were removed after 72 h and returned to the bench. Greenhouse conditions were 23-25°C with a 14-hour photoperiod and 50% RH. Symptoms developed 7 dai in 1% of the flowers inoculated when styles were green, and 36% of the flowers that had senescent styles. Symptoms were similar to those initially noticed in Boyle County, including necrotic flower bracts and sugar leaves, and visible fungal growth. Symptoms were more severe on plants inoculated when styles were necrotic. Recovered fungi were morphologically similar to 20Hemp010. Genomic DNA was extracted from the mycelium with the Zymo Research Quick-DNA Fungal/Bacterial Miniprep Kit. A fragment of the translation elongation factor 1-alpha 1 gene was amplified with primers EF1 and EF2 as described by (O’Donnell et al. 1998). Amplicons were sequenced and the consensus (MZ407909) was compared with the NCBI GenBank Refseq database by BLASTn. The top hit was Fusarium graminearum with 100% identity (JF270185.1). Pairwise alignments via MycoBank Fusarium MLST and Fusarium-ID also revealed a top hit of F. graminearum with 100% identity (AY452957.1). Conidial and colony morphology were also consistent with F. graminearum (Leslie and Summerell, 2006), thus we conclude that this species was the causal agent of the flower blight and mold. The same disease was subsequently confirmed on hemp in Breathitt and Franklin Counties in KY in 2020. This is the first report of this disease in KY, although F. graminearum has been reported previously causing a similar flower blight on hemp in NY and NC (Bergstrom et al., 2019, Thiessen et al. 2020). Fusarium graminearum is common in KY as a cause of Fusarium head blight on wheat and Gibberella ear rot on corn. In cereals, fungal infection is facilitated by the production of the mycotoxin deoxynivalenol (DON), which is harmful to humans and livestock (Desjardins and Hohn, 1997). As hemp production in Kentucky continues to rise for production of CBD products and edible grains, accumulation and concentration of DON in these products could become a concern.

Combined multi-gene backbone tree for the genus Coniochaeta with two new species from Uzbekistan

Phytotaxa ◽  
2018 ◽  
Vol 336 (1) ◽  
pp. 43 ◽  
Author(s):  
MILAN C. SAMARAKOON ◽  
YUSUFJON GAFFOROV ◽  
NINGGUO LIU ◽  
SAJEEWA S. N. MAHARACHCHIKUMBURA ◽  
JAYARAMA D. BHAT ◽  
...  
Keyword(s):  
New Species ◽  
Sequence Data ◽  
Species Recognition ◽  
Phylogenetic Species ◽  
Phylogenetic Studies ◽  
Genealogical Concordance ◽  
Two New Species ◽  
Backbone Tree

The genus Coniochaeta is an important ascomycete because its members live in diversified habitats and nutritional modes. In this study, two new species, C. acaciae and C. coluteae, are introduced from dead branches of Acacia sp. and Colutea paulsenii Freyn (both Fabaceae) respectively from Uzbekistan, based on morphological and phylogenetic studies. Analyses of combined ITS and LSU sequence data with Genealogical Concordance Phylogenetic Species Recognition (GCPSR) and comparison of similar taxa, provide evidences for placement of these new species in Coniochaeta, as distinct lineages.

Species and trichothecene genotype of pathogens causing Fusarium head blight of wheat in Nebraska, USA

2021 ◽  
Author(s):  
Esteban Valverde-Bogantes ◽  
Andreia Bianchini ◽  
Stephen Wegulo ◽  
Heather Hallen-Adams
Keyword(s):  
Fusarium Head Blight ◽  
Fusarium Species ◽  
Management Strategies ◽  
Elongation Factor ◽  
Head Blight ◽  
Single Spore ◽  
Additional Species ◽  
Growing Seasons ◽  
Worldwide Distribution ◽  
Pathogen Populations

Fusarium head blight (FHB) is an economically important disease caused by several Fusarium species affecting wheat and other small grain cereals. In recent years, reports of shifts in populations of FHB pathogens around the world have shown that these populations are dynamic and change continuously, often resulting in increased yield losses or changes in the mycotoxins produced in the grain, which highlights the need for increased vigilance. The objective of this research was to identify the species and trichothecene genotypes of FHB pathogens in Nebraska in order to monitor their populations and the major toxigenic risks in the state. A total of 74 single-spore Fusarium isolates were obtained from 42 FHB symptomatic wheat spikes collected from Nebraska fields during the growing seasons in 2015-2018. Most of the isolates were identified as F. graminearum (n=67) based on translation elongation factor 1α (TEF1), trichothecene 3-O-acetyltransferase (TRI101), and reductase (RED) sequences. Additional species included F. boothii (n=3), F. poae (n=2), F. acuminatum (n=1), and one isolate was an F. graminearum × F. boothii interspecific hybrid. All F. graminearum and F. boothii isolates had the 15-ADON trichothecene genotype. This study shows that F. graminearum is not the only pathogen causing FHB in Nebraska and helps expand knowledge on the worldwide distribution of F. boothii. The information obtained from this survey will be useful in developing effective FHB management strategies in Nebraska, since different pathogen populations can cause varying levels of disease intensity and can be selectively sensitive to management tactics.

scholarly journals First Report of Blueberry Leaf Spot Caused by Cylindrocladium colhounii in China

Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1553-1553 ◽  
Author(s):  
Y. S. Luan ◽  
L. Feng ◽  
L. J. An
Keyword(s):  
Leaf Spot ◽  
Morphological Traits ◽  
Internal Transcribed Spacers ◽  
Fluorescent Light ◽  
Adaxial Side ◽  
Single Spore ◽  
Tubulin Gene ◽  
First Report ◽  
Plastic Bags ◽  
Β Tubulin

During late July and early August of 2005, leaf spot symptoms were observed in a blueberry nursery at a plantation in Dalian, which to our knowledge, lies within the largest blueberry-production area in China. Symptoms were observed primarily on lowbush species, for example Blomidon, as well as half-highbush cultivars. A slow-growing, white mycelium from the margin of necrotic leaf spots was recovered on potato dextrose agar (PDA). The following morphological traits were observed: erect conidiophores that branch twice and were terminated in a stiped, clavate phialide; hyaline, cylindrical, four-celled conidia; and globose, reddish brown, aggregated chlamydospores. Conidiophores (including stipes and terminal phialides) were 305 to 420 × 5 to 9 μm; primary branches were 9 to 45 × 5 to 6.3 μm; secondary branches were 9 to 17.3 × 3.1 to 4.5 μm; phialides were 7.8 to 17.5 × 2.5 to 6 μm; stipes (from the highest branch area to vesicle) were 150 to 270 μm long; and vesicles were 13 to 30 × 2 to 4.5 μm. Conidia were 50 to 72 × 4 to 5.5 μm. Chlamydospores were 15 to 20 μm in diameter. Koch's postulates were fulfilled by spray inoculating two healthy cultivars with conidiophores homogenized in axenic water. As a control, two healthy plants were sprayed with axenic water. Plants were placed inside plastic bags to maintain humidity and incubated in a growth chamber at 26°C under fluorescent light for 14 h and 20°C in darkness for 10 h. After 2 days, the plastic bags were removed and plants were maintained under the same conditions. After 4 days, small-to-medium brown spots with purplish margins were observed on the adaxial side of leaves from inoculated plants, but not from control plants. Fungi isolated from these lesions had the same morphological traits as the ones isolated previously from field plants. The morphological descriptions and measurements were similar to Cylindorocladium colhounii (2). The 5.8S subunit and flanking internal transcribed spacers (ITS1 and ITS2) of rDNA and the β-tubulin gene were amplified from DNA extracted from single-spore cultures using the ITS1/ITS4 primers and T1/Bt2b primers, respectively, and sequenced (1). The ITS and β-tubulin gene sequences were similar to C. colhounii STE-U 1237 (99%; GenBank Accession No. AF231953) and C. colhounii STE-U 705 (99%; GenBank Accession No. AF231954), respectively. The morphology, secondary conidiation, and sequences of ITS and β-tubulin gene identify the causal fungus as C. colhounii. To our knowledge, this is the first report of C. colhounii on blueberry in China or in the world. References: (1) P. W. Crous et al. Can. J. Bot. 77:1813, 1999. (2) T. Watanabe. Page 222 in: Dictorial Atlas of Soil and Seed Fungi. CRC Press, Inc., Boca Raton, Fl, 1994.

scholarly journals First Report of the Nivalenol Chemotype of Fusarium graminearum Causing Head Blight of Wheat in the Grand Duchy of Luxembourg

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1217-1217 ◽  
Author(s):  
M. Pasquali ◽  
F. Giraud ◽  
C. Brochot ◽  
L. Hoffmann ◽  
T. Bohn
Keyword(s):  
Fusarium Graminearum ◽  
Aerial Mycelium ◽  
Triticum Aestivum L ◽  
Negative Control ◽  
Head Blight ◽  
First Report ◽  
Low Levels ◽  
Species Specific ◽  
Control Water ◽  
Positive Controls

Head blight caused by Fusarium graminearum is one of the major diseases of wheat (Triticum aestivum L.) in Luxembourg (2) and there is concern for mycotoxins in diseased grain. Isolates of F. graminearum have been assigned to chemotypes based on the particular toxins produced. Ten wheat fields representing different topoclimatological areas of Luxembourg were surveyed in 2007 and 2008 to determine the frequency and distribution of chemotypes. Partially blighted wheat heads were collected, and diseased grains were plated on Fusarium-selective agar (dichloran-chloramphenicol-peptone) for 12 days at 22 ± 2°C with a 12-h light period. Monoconidial isolates of F. graminearum (79 in 2007 and 85 in 2008) were obtained by conidia dilution on 2% water agar and needle selection under a microscope. F. graminearum isolates showed rapid growth on potato dextrose agar, dense aerial mycelium with red pigment deposits in the plate, macroconidia with five to six defined septa, and a basal cell with the typical foot shape. Microconidia were absent. To confirm species identification, a PCR reaction was carried out using the F. graminearum species-specific primers Fg16F (5′-CTCCGGATATGTTGCGTCAA-3′) and Fg16R (5′-GGTAGGTATCCGACATGGCAA-3′) according to Demeke et al. (1). Chemotype of each isolate was determined according to Ward et al. (4). In particular, PCR primer 12CON (5′ CATGAGCATGGTGATGTC-3′) coupled with primer 12NF (5′-TCTCCTCGTTGTATCTGG-3′) and primer 3CON (5′-TGGCAAAGACTGGTTCAC-3′) coupled with primer 3NA (5′-GTGCACAGAATATACGAGC-3′) identified the nivalenol chemotype, primer 12CON coupled with primer 12-15F (5′-TACAGCGGTCGCAACTTC-3′) and primer 3CON coupled with primer 3D15A (5′-ACTGACCCAAGCTGCCATC-3′) identified the 15-acetylated deoxynivalenol (DON) chemotype, while primer 12CON coupled with primer 12-3F (5′-CTTTGGCAAGCCCGTGCA-3′) and primer 3CON coupled with primer 3D3A (5′-CGCATTGGCTAACACATG-3′) identified 3-acetylated DON chemotype. Reactions were repeated two times and positive controls (provided by Kerry O'Donnell, NRRL collection, Peoria, IL) and a negative control (water) were used in each reaction. Frequency of the nivalenol chemotype was found to be 2.5% in 2007 and 1% in 2008. Interestingly, the nivalenol chemotype was absent in southern Luxembourg. According to this finding, nivalenol was likely to be present at low levels in grain from Reisdorf and Echternach in 2007 (central Luxembourg) and in 2008 from grain of Troisvierges (northern Luxembourg). The remaining isolates in both years belonged to the 15-acetylated DON chemotype and the 3-acetylated DON chemotype was not detected. Compared with a previous report from the Netherlands (3), the nivalenol chemotype in Luxembourg is less frequent and widespread. To our knowledge, this is the first report of the nivalenol chemotype of F. graminearum causing head blight on wheat in Luxembourg. References:(1) T. Demeke et al. Int. J. Food Microbiol. 103:271, 2005. (2) F. Giraud et al. Plant Dis. 92:1587, 2008. (3) C. Waalwijk et al. Eur. J. Plant Pathol. 109:743, 2003. (4) T. J. Ward et al. Fung. Genet. Biol. 45:473, 2008.

scholarly journals First Report of Internal Black Rot Caused byNeoscytalidium dimidiatumonHylocereus undatus(Pitahaya) Fruit in Israel

Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1513-1513 ◽  
Author(s):  
D. Ezra ◽  
O. Liarzi ◽  
T. Gat ◽  
M. Hershcovich ◽  
M. Dudai
Keyword(s):  
Its Region ◽  
Stem Canker ◽  
Brown Spot ◽  
Black Rot ◽  
Post Inoculation ◽  
Single Spore ◽  
Flower Opening ◽  
Disease Symptoms ◽  
First Report ◽  
Β Tubulin

Pitahaya (Hylocereus undatus [Haw.] Britton & Rose) was introduced to Israel in 1994, and is grown throughout the country. In the summer of 2009, fruit with internal black rot was collected from a field in central Israel. Symptomatic tissue from the black rot was placed on potato dextrose agar (PDA) plates amended with 12 μg/ml tetracycline and incubated at 25°C for 3 days. A dark, gray to black, fast-growing fungus was isolated from all samples (10 fruits). For identification, single-spore cultures were grown on PDA at 25°C for 5 days, and colonies with gray to black, wooly mycelium were formed. The mycelia were branched and septate (4 to 8 μm wide). The arthroconidia were dark brown, thick-walled, and one-celled, 6.3 to 14.2 × 2.0 to 4.5 μm (n = 5), and ovate to rectangular. Based on these characteristics, the fungus was identified as Neoscytalidium dimidiatum (Penz.) Crous & Slippers (1). The internal transcribed spacer (ITS) region of rDNA and β-tubulin gene were amplified using ITS1 and ITS4, T121 (2), and Bt1b (3) primers, respectively, and then sequenced (GenBank Accessions KF000372 and KF020895, respectively). Both sequences were identical to sequences previously deposited in GenBank. The ITS (561 bp) and β-tubulin (488 bp) sequences exhibited 99% and 100% identity, and 100% and 84% coverage, respectively, to N. dimidiatum (JX524168 and FM211185, respectively). Thus, the results of the molecular identifications confirmed the morphological characterization. To establish fungal pathogenicity and the mechanism of infection, 60 flowers in a disease-free orchard were marked to form three different treatments (15 flowers per treatment): inoculations of the flower tube by inserting PDA plugs (0.5 × 0.5 cm) from a 5-day-old culture to the base of the flower, inoculations of the flower stigma by placing the fungus plug on intact, or pre-wounded flower stigma. The wounds were made by scratching the stigma with a sterile scalpel. For each treatment, five additional flowers were used as negative controls in which the PDA plugs did not contain any fungus. All flowers were hand-pollinated and left to grow for a month until the fruit had ripened. Only flowers inoculated by insertion of the fungus into the flower tube developed black rot in the fruit (8 of 15 fruit) 3 to 4 weeks post inoculation, suggesting involvement of the flower tube in the mechanism of infection. All other treatments and controls failed to develop any detectable disease symptoms. N. dimidiatum was reisolated from the rot, fulfilling Koch's postulates. Flowers with wounded stigma developed significantly smaller fruit. Interestingly, diseased fruit changed color about a week before ripening from the flower opening downwards, whereas healthy fruit changed color from the attachment point to the stem upwards. These results indicate that N. dimidiatum is the pathogen of pitahaya internal black rot disease. Recently, this pathogen was reported to cause brown spot disease and stem canker disease of pitahaya in China (4) and Taiwan (5), respectively. To date, the disease can be detected in all orchards in Israel, with up to 50% of the fruit being infected. Since the disease symptoms of the Israeli isolate are located in the fruit, the commercial loss due to pathogen attack is significant. To our knowledge, this is the first report of internal black rot caused by N. dimidiatum on pitahaya fruit in Israel.References: (1) P. W. Crous et al. Stud. Mycol. 55:235, 2006. (2) K. O'Donnell and E. Cigelnik. Mol. Phylo, Evol. 7:103, 1997. (3) N. L. Glass and G. C. Donaldson. Appl. Environ. Microiol. 61:1323, 1995. (4) G. B. Lan and Z. F. He. Plant Dis. 96:1702, 2012. (5) M. F. Chuang et al. Plant Dis. 96:906, 2012.

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