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

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.

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 460 ◽  
Author(s):  
Vesna Krnjaja ◽  
Slavica Stanković ◽  
Ana Obradović ◽  
Tanja Petrović ◽  
Violeta Mandić ◽  
...  

Fusarium graminearum as the main causal agent of Fusarium head blight (FHB) and its ability to produce trichothecenes was investigated by molecular techniques. A total of 37 strains isolated from the wheat, harvested in Serbia in 2005, 2008 and 2015, and previously designated by morphological observation as F. graminearum, were used for trichothecene genotypes characterization. The strains were identified using the species-specific primer set FG16R/FG16F while genotypic characterization was done using specific TRI13 and TRI3 sequences of the trichothecene gene clusters. The PCR assays identified all strains as species of F. graminearum sensu stricto with the DON/15-ADON genotype. The quantification of the mycotoxin (DON) was performed using the biochemical assay. The high levels of DON (>20,000 µg kg−1) were recorded in all of the strains from 2005, four strains from 2008 and two strains from 2015. Weather data of the investigated seasons, showed that the optimal temperature, frequent rains and high relative humidity (RH) was very favourable for the development of F. graminearum, affecting the DON biosynthesis.


2017 ◽  
Author(s):  
C.P. Nicolli ◽  
F.J. Machado ◽  
P. Spolti ◽  
E.M. Del Ponte

AbstractFusarium graminearum of the 15-acetyl(A)deoxynivalenol(D0N) chemotype is the main cause of Fusarium head blight (FHB) of wheat in south of Brazil. However, 3-ADON and nivalenol(NIV) chemotypes have been found in other members of the species complex causing FHB in wheat. To improve our understanding of the pathogen ecology, we assessed a range of fitness-related traits in a sample of 30 strains representatives of 15-ADON (F. graminearum), 3-ADON (F. cortaderiae and F. austroamericanum) and NIV (F. meridionale and F. cortaderiae). These included: perithecia formation on three cereal-based substrates, mycelial growth at two suboptimal temperatures, sporulation and germination, pathogenicity towards a susceptible and a moderately resistant cultivar and sensitivity to tebuconazole. The most important trait favoring F. graminearum was its 2x higher sexual fertility (> 40% PPI = perithecia production index) than the other species (< 30% PPI); PPI varied among substrates (maize > rice > wheat). In addition, sensitivity to tebuconazole appeared lower in F. graminearum which had the only strain with EC50 > 1 ppm. In the pathogenicity assays, the DON-producers were generally more aggressive (1.5 to 2x higher final severity) towards the two cultivars, with 3-ADON or 15-ADON leading to higher area under the severity curve than the NIV strains in the susceptible and moderately resistant cv., respectively. There was significant variation among strains of a same species with regards asexual fertility (mycelial growth, macroconidia production and germination), which suggest a strain-rather than a species-specific differences. These results contribute new knowledge to improve our understanding of the pathogen-related traits that may explain the dominance of certain members of the species complex in specific wheat agroecosystems.


Plant Disease ◽  
2014 ◽  
Vol 98 (9) ◽  
pp. 1274-1274 ◽  
Author(s):  
G. A. Díaz ◽  
B. A. Latorre ◽  
S. Jara ◽  
E. Ferrada ◽  
P. Naranjo ◽  
...  

Chile is considered the third major exporter of kiwifruits (Actinidia deliciosa (A. Chev.) C. F. Liang & A. R. Ferguson) worldwide after Italy and New Zealand (1). The genus Diaporthe Nitschke (anamorph: genus Phomopsis) has been reported as causing postharvest rot in kiwifruit (4). During the current study, 1,400 fruits arbitrarily collected from seven controlled atmosphere (CA) rooms after 90 days of storage conditions (2% O2, 5% CO2) determined that 21.5% of the fruit were affected by decay and 0.86% developed symptoms different than those caused by Botrytis cinerea, the main postharvest pathogen associated to kiwifruit. Symptoms were soft rot with brown skin that started at the stem-end and in severe cases affected the entire fruit. Internally, affected fruit showed browning and watery tissues. Twelve affected fruits were surface disinfested (75% ethanol) and small pieces of internal rotten tissues were placed on acidified potato dextrose agar (APDA) for 7 days at 20°C. Twelve isolates were obtained, and four of them were identified morphologically and molecularly as Diaporthe ambigua, a species that has been previously described causing rot in stored kiwifruits in Chile (2). However, eight other flat, white to grayish colonies with sparse dirty-white aerial mycelium at the edge of the dish were obtained (3). Black pycnidia contained unicellular, hyaline, biguttulate, oval to cylindrical alpha conidia, with obtuse ends of (7.9) 6.7 (5.3) × (2.9) 2.5 (2.1) μm (n = 30). These isolates were tentatively identified as a Diaporthe sp. The species identification was determined by sequencing comparison of the internal transcribed spacer (ITS1-5.8S-ITS2) region of the rDNA (GenBank Accession Nos. KJ210020 to 24, KJ210027, and KJ210033) and a portion of beta-tubulin (BT) (KJ210034 to 38, KJ210041, and KJ210047) using primers ITS4-ITS5 and Bt2a-Bt2b, respectively. BLAST analyses showed 99 to 100% identity with D. novem J.M. Santos, Vrandecic & A.J.L Phillips reference ex-type (KC343156 and KC344124 for ITS and BT, respectively) (3). Eighteen mature kiwifruits cv. Hayward were inoculated using a sterile cork borer on the surface of the fruit and placing 5-mm agar plugs with mycelial of D. novem (DN-1-KF). An equal number of fruits treated with sterile agar plugs were used as negative controls. After 30 days at 0°C under CA, all inoculated fruit showed rot symptoms with lesions 7.8 to 16.4 mm in diameter. The same D. novem isolate was inoculated with 30 μl of a conidial suspension (106 conidia/ml) on the surface of 18 ripe kiwifruits that were previously wounded and non-wounded as described above. An equal number of wounded and non-wounded fruits, treated with 30 μl sterile water, were used as negative controls. All inoculated wounded fruits developed rot symptoms with necrotic lesions of 14.1 to 20.2 mm of diameter after 14 days at 25°C. Inoculated non-wounded and negative control fruits remained symptomless. Koch's postulates were fulfilled by re-isolating D. novem only from the symptomatic fruits. To our knowledge, this is the first report of rot caused by D. novem on kiwifruit during cold storage in Chile and worldwide. Therefore, both Diaporthe species appears to be associated to Diaporthe rot of kiwifruit in Chile. References: (1) Belrose, Inc. World Kiwifruit Review. Belrose, Inc. Publishers, Pullman, WA, 2012. (2) J. Auger et al. Plant Dis. 97:843, 2013. (3) R. Gomes et al. Persoonia 31:1, 2013. (4) L. Luongo et al. J. Plant Pathol. 93:205, 2011.


2010 ◽  
Vol 90 (6) ◽  
pp. 905-917 ◽  
Author(s):  
M.R. Fernandez ◽  
W.E. May ◽  
G.P. Lafond

It is of importance to reduce the spread of Fusarium graminearum to western regions of the Canadian prairies where Fusarium head blight has so far occurred to a limited extent. Determining the effectiveness of fungicides against F. graminearum in infected seed under various growing conditions will help design a comprehensive strategy for preventing the spread of this pathogen. Field trials at various locations in eastern Saskatchewan were conducted (2003-2005) to examine the performance of registered and experimental fungicides on Fusarium colonization of subcrown internodes (SIs) of plants derived from Fusarium-infected barley (Hordeum vulgare L.), common (Triticum aestivum L.) and durum [T. turgidum L. ssp. durum (Desf.) Husn.] wheat seed, and on SI discoloration. Among the fungi isolated from discolored SIs were Fusarium spp., including F. graminearum, and Cochliobolus sativus. Fusarium graminearum infections were mostly seed-borne whereas infection by other fungi appeared to be mostly soil-borne. Compared with the untreated infected control, the combined seed treatments reduced discoloration of SIs, but no single fungicide reduced discoloration consistently across site-years or crops. Similarly, no product consistently reduced the isolation of F. graminearum or other Fusarium pathogens, although some fungicides appeared to be more effective than others in reducing isolation of F. graminearum or C. sativus. Our observations agree with results from a controlled-environment study of effects of seed treatments on F. graminearum colonization of plants derived from infected common and durum wheat seed, thus confirming that treatment of F. graminearum-infected seed with fungicides will not likely prevent the spread of this pathogen.


1992 ◽  
Vol 72 (2) ◽  
pp. 469-471
Author(s):  
H. G. Nass ◽  
H. W. Johnston ◽  
C. R. Blatt ◽  
J. S. Bubar ◽  
A. V. Rodd ◽  
...  

AC Baltic is a spring feed wheat (Triticum aestivum L. em. Thell.) with high grain yield, medium maturity and good lodging resistance. It is resistant to powdery mildew (caused by Erysiphe graminis, D.C. ex Merat f. sp. tritici Marchai), moderately susceptible to septoria leaf and glume blotch (caused by Septoria nodorum (Berk.) Berk.) and moderately tolerant to fusarium head blight (caused by Fusarium graminearum Schwabe). AC Baltic is suited for production in eastern Canada.Key words: Wheat (spring), cultivar description


2022 ◽  
Vol 9 ◽  
Author(s):  
Ignacio Crudele ◽  
Juan C. Reboreda ◽  
Vanina D. Fiorini

Avian brood parasites lay their eggs into the nests of other species, which incubate them and raise the chicks until their independence. Despite living their early weeks of life surrounded by heterospecifics, young brood parasites have the ability to recognize and associate to conspecifics after independence. It has been proposed that the initial conspecific recognition develops when a young parasite encounters a unique species-specific signal that triggers the learning of other aspects of the producer of the signal. For cowbirds (Molothrus spp.), this species-specific signal is hypothesized to be the chatter call. Young birds also could express auditory biases, which in some cases lead to discrimination in favor of conspecific songs. Therefore, the perceptual selectivity for chatters might be also present in nestlings. Our aim was to assess if nestlings of the shiny cowbird (M. bonariensis) present a preferential begging response to conspecific chatter calls. We evaluated if they respond more to the parasitic vocalization than host chicks and if they respond more to the chatter than to heterospecific nonhost calls. We tested shiny cowbird chicks reared by chalk-browed mockingbirds (Mimus saturninus) or house wrens (Troglodytes aedon) and host chicks, as control species. We randomly presented to 6-day-old chicks the following playback treatments: (1) conspecific chatter calls, (2) host calls, used as positive controls, and (3) nonhost calls, used as negative control. We measured if chicks begged during the playback treatments and the begging intensity. When responding to the playback of chatter calls, shiny cowbird chicks begged at a higher frequency and more intensively than host chicks. Shiny cowbird chicks reared by mockingbirds begged more intensively to playbacks of conspecific chatter calls than to host calls, while those reared by wrens begged with a similar intensity to playbacks of conspecific chatter and host calls. On the contrary, wren nestlings begged more intensively to playbacks of the wren call than to chatter calls. Mockingbird nestlings did not beg during any treatment. None of the three species begged during the playback of nonhost calls. Our results show that the chatter call produced a preferential begging response in cowbird nestlings, which may be the beginning of a process of conspecific recognition.


Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 496-496 ◽  
Author(s):  
E. Castañares ◽  
S. A. Stenglein ◽  
M. I. Dinolfo ◽  
M. V. Moreno

Wheat (Triticum aestivum L.), the most widely grown winter cereal crop in Argentina, is grown on 5 million ha. Fusarium species affect yield and grain quality because of mycotoxins. In December 2009, a screen of fungal species in wheat seeds from a field in Azul, Buenos Aires, Argentina was conducted. Four hundred seeds were surface sterilized by dipping successively into 70% ethanol for 2 min, 5% sodium hypochlorite for 2 min, and finally rinsing twice in fresh sterilized distilled water. The seeds were plated on potato dextrose agar (PDA), pH 6, and incubated at 24 ± 2°C with exposure to 12-h alternate cycles of darkness and light. Eight isolates morphologically similar to Fusarium species were observed after 6 days of incubation. For identification, monosporic isolates were transferred onto PDA and carnation leaf agar (CLA) to grow at the conditions described above (1). One isolate, when grown on PDA, rapidly produced abundant, dense, white, aerial mycelium that became pink with age and formed red pigments in the medium. On CLA, macroconidia were abundant, relatively slender, curved to lunate, and three to five septate. Microconidia were abundant, napiform, oval or pyriform, zero to one septate, and commonly clustered in false heads. Chlamydospores were absent. The fungus was identified as Fusarium tricinctum (Corda) Saccardo on the basis of fungal morphology (1). To complete Koch's postulates, the pathogenicity of the fungus was tested by spraying five healthy inflorescences (on average 16 spikelets per spike) of wheat with a 5-ml suspension (2 × 105 conidia per ml). Another two healthy inflorescences were sprayed with sterile distilled water. Plants were placed in a growth chamber with a 12-h photoperiod at 22 ± 2°C, covered with polyethylene bags that were removed after 3 days, and then moved to a glasshouse. The same procedure was repeated. While control inflorescences were asymptomatic, inoculated inflorescences showed a mean of five bleached spikelets per spike. By using the methodology described above, the fungus was reisolated from all infected grains of inoculated plants but not from the controls. To confirm the morphological diagnosis, the genomic DNA of the isolate was extracted (3) and the internal transcribed spacer (ITS) and the translation elongation factor (TEF) regions were PCR-amplified using primer pairs ITS3/ITS4 (4) and EF-1/EF-2 (2), respectively. The sequences were compared with those in GenBank. The ITS sequence (Accession No. HM635739) showed 100% similarity with several F. tricinctum sequences (e.g., Accession Nos. HM068317, FN598932, and EF589873) but also with other Fusarium species such as F. acuminatum. The TEF sequence (Accession No. HQ214681) showed 99 to 100% similarity with Accession Nos. HM068307, EU744838, and EU744837 of F. tricinctum. To our knowledge, this is the first report of F. tricinctum on wheat in Argentina. This species is known to produce fusarin C, enniatins, and moniliformin toxins. Since F. tricinctum can infect different cereal grains, a large-scale survey of cereals from fields throughout Argentina is in progress. References: (1) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Oxford, UK. 2006. (2) K. O'Donell et al. Proc. Nat. Acad. Sci. USA 95:2044, 1998. (3) S. A. Stenglein and P. A. Balatti. Physiol. Mol. Plant Pathol. 68:158, 2006. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.


Plant Disease ◽  
2021 ◽  
Author(s):  
Ana Obradović ◽  
Jelena Stepanovic ◽  
Vesna Krnjaja ◽  
Aleksandra Bulajic ◽  
Goran Stanković ◽  
...  

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.


2017 ◽  
Vol 2 (3) ◽  
pp. 154-161
Author(s):  
Jiazheng Yuan ◽  
Michelle Zhu ◽  
Khalid Meksem ◽  
Matt Geisler ◽  
Patrick Hart ◽  
...  

Mycotoxin deoxynivalenol (DON), produced by Gibberella zeae (Schwein.) Petch (teleomorph of Fusarium graminearum Schwabe) was known to be both a virulence factor in the pathogenesis of Triticum aestivum L. (wheat) and an inhibitor of Arabidopsis thaliana L. seed germination. Fusarium graminearum causes both Gibberella ear rot in maize (Zea mays L.) and Fusarium head blight (FHB) in wheat and barley. Arabidopsis thaliana was also a host for the related root rot pathogen F. virguliforme Aoki. A. thaliana seedling growth was reduced by the pathogen in a proportional response to increasing spore concentrations. Here, the changes in transcript abundances corresponding to 10,560 A. thaliana expressed sequence tags (ESTs) was compared with changes in 192 known plant defense and biotic/abiotic stress related genes in soybean roots after infestation with F. virguliforme. A parallel comparison with a set of resistance pathways involved in response to the DON toxicity in A. thaliana was performed. A. thaliana data was obtained from the AFGC depository. The variations of transcript abundances in Arabidopsis and soybean treated with pathogen suggest that both plants respond to the pathogen mainly by common, possibly global responses with some specific secondary metabolic pathways involved in defense. In contrast, DON toxin appeared to impact central metabolisms in Arabidopsis plants with significant alterations ranging from the protein metabolism to redox production. Several new putative resistance pathways involved in responding to both pathogen and DON infestation in soybean and A. thaliana were identified.


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