Cyclic hexadepsipeptides in wheat field samples and esyn1 gene divergence among enniatin producing Fusarium avenaceum strains

2013 ◽  
Vol 6 (4) ◽  
pp. 399-409 ◽  
Author(s):  
Ł. Stȩpień ◽  
M. Jestoi ◽  
J. Chełkowski

Fusarium avenaceum is one of the most important pathogenic species in agricultural and forest environments of moderate climate, particularly in cereals and legume pulse crops. Numerous mycotoxins can be synthesized by the species, with moniliformin and enniatins (ENN) being the prevailing metabolites. The aims of this work were to examine the amounts of ENN and beauvericin present in naturally contaminated field samples of wheat kernels and chaffs collected in Poland in 2005 and 2009 from heads infected with F. avenaceum, and to reveal the divergence of the esyn1 gene among F. avenaceum strains of different origin. ENN-B and ENN-B1 were the major metabolites identified in wheat field samples. Chaff fractions contained significantly more mycotoxins than grain. Samples originating from 2005 were in general less contaminated with ENN than those from the 2009 season. The highest amount of ENN-B found in grain was 28,520 μg/kg. Beauvericin was only found in trace amounts in all the samples tested. F. avenaceum strains isolated from the analysed wheat samples were identified using species-specific DNA marker and translation elongation factor 1α (tef-1α) sequence analysis. A higher level of sequence polymorphism was revealed for the enniatin synthetase (esyn1) gene than ecorded by tef-1α analysis. Moreover, species known to be typical beauvericin producers, e.g. Fusarium oxysporum and Fusarium proliferatum, were clustered into a separate branch on the dendrogram, apart from the strains of ENN-producing species, i.e. F. avenaceum and Fusarium scirpi.

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 472 ◽  
Author(s):  
Francesca Ramires ◽  
Mario Masiello ◽  
Stefania Somma ◽  
Alessandra Villani ◽  
Antonia Susca ◽  
...  

Wheat, the main source of carbohydrates worldwide, can be attacked by a wide number of phytopathogenic fungi, included Alternaria species. Alternaria species commonly occur on wheat worldwide and produce several mycotoxins such as tenuazonic acid (TA), alternariol (AOH), alternariol-monomethyl ether (AME), and altenuene (ALT), provided of haemato-toxic, genotoxic, and mutagenic activities. The contamination by Alternaria species of wheat kernels, collected in Tuscany, Italy, from 2013 to 2016, was evaluated. Alternaria contamination was detected in 93 out of 100 field samples, with values ranging between 1 and 73% (mean of 18%). Selected strains were genetically characterized by multi-locus gene sequencing approach through combined sequences of allergen alt1a, glyceraldeyde-3-phosphate dehydrogenase, and translation elongation factor 1α genes. Two well defined groups were generated; namely sections Alternaria and Infectoriae. Representative strains were analyzed for mycotoxin production. A different mycotoxin profile between the sections was shown. Of the 54 strains analyzed for mycotoxins, all strains included in Section Alternaria produced AOH and AME, 40 strains (99%) produced TA, and 26 strains (63%) produced ALT. On the other hand, only a very low capability to produce both AOH and AME was recorded among the Section Infectoriae strains. These data show that a potential mycotoxin risk related to the consumption of Alternaria contaminated wheat is high.


2012 ◽  
Vol 25 (6) ◽  
pp. 418 ◽  
Author(s):  
Roy E. Halling ◽  
Mitchell Nuhn ◽  
Todd Osmundson ◽  
Nigel Fechner ◽  
James M. Trappe ◽  
...  

Harrya is described as a new genus of Boletaceae to accommodate Boletus chromapes, a pink-capped bolete with a finely scabrous stipe adorned with pink scabers, a chrome yellow base and a reddish-brown spore deposit. Phylogenetic analyses of large-subunit rDNA and translation elongation factor 1α confirmed Harrya as a unique generic lineage with two species, one of which is newly described (H. atriceps). Some Chinese taxa were recently placed in a separate genus, Zangia, supported by both morphology and molecular data. Multiple accessions from Queensland, Australia, support the synonymy of at least three species in a separate Australian clade in the new genus, Australopilus. The truffle-like Royoungia is also supported as a separate lineage in this clade of boletes. Even though it lacks stipe characters, it possesses the deep, bright yellow to orange pigments in the peridium. Additional collections from Zambia and Thailand represent independent lineages of uncertain phylogenetic placement in the Chromapes complex, but sampling is insufficient for formal description of new species. Specimens from Java referable to Tylopilus pernanus appear to be a sister group of the Harrya lineage.


Plant Disease ◽  
2022 ◽  
Author(s):  
Liu Yang ◽  
Tian Yuan ◽  
Xia Zhao ◽  
Yue Liang ◽  
UWAREMWE CONSTANTINE ◽  
...  

Root rot is a serious disease in plantations of A. sinensis, severely affecting yield and quality and threatening sustainable production. Fusarium isolates (n=32) were obtained from field samples of root rot tissue, leaves and infected soil. Isolates were identified by comparing the sequences of their internal transcribed spacer (ITS) region and translation elongation factor 1-ɑ (TEF-1ɑ) to sequences of known species in the NCBI-database. These Fusarium isolates include F. tricinctum (43.75%), F. equiseti (31.25%), F. solani (9.37%), F. oxysporum (6.25%), F. acuminatum (6.25%), and F. incarnatum (3.12%). For pathogenicity testing under greenhouse conditions, seven isolates were selected based on a phylogenetic analysis, including four strains of F. tricinctum and one strain each of F. solani, F. oxysporum, and F. acuminatum. The seven isolates were all pathogenic but differed in their ability to infect: the four F. tricinctum strains were capable pathogens causing root rot in A. sinensis at 100% incidence and the highly aggressive. Furthermore, the symptoms of root rot induced by those seven isolates were consistent with typical root rot cases in the field, but their disease severity varied. Observed histopathological preparations of F. tricinctum-infected seedlings and tissue-slides results showed this fungal species can penetrate epidermal cells and colonize the cortical cells where it induces necrosis and severe plasmolysis. Plate confrontation experiments showed that isolated rhizosphere bacteria inhibited the Fusarium pathogens that cause root rot in A. sinensis. Our results provide timely information for informing the use of biocontrol agents for suppression of root rot disease.


Plant Disease ◽  
2014 ◽  
Vol 98 (3) ◽  
pp. 344-350 ◽  
Author(s):  
Vladimiro Guarnaccia ◽  
Dalia Aiello ◽  
Giancarlo Polizzi ◽  
Giancarlo Perrone ◽  
Gaetano Stea ◽  
...  

Management of Calonectria spp. infections in nurseries requires scheduled fungicide applications, particularly with methyl benzimidazole carbamates (MBCs) and sterol demethylation inhibitors (DMIs). Due to rising concerns about the occurrence of MBC resistance in different Calonectria populations and variability in prochloraz efficacy in controlling these pathogens, a detailed study on prochloraz sensitivity distributions of Calonectria isolates belonging to the Calonectria scoparia complex was carried out. In total, 105 isolates collected in two distinct periods (1993 to 1996 and 2005 to 2009) were analyzed for prochloraz sensitivity. Based on DNA sequencing and phylogenetic analyses of β-tubulin, histone H3, and translation elongation factor-1α gene sequences, 69 and 36 isolates were identified as C. pauciramosa and C. polizzii, respectively. The isolates collected more recently (group B) had a reduced prochloraz sensitivity, as indicated by greater values for the effective dose to reduce growth by 50% than those collected earlier (group A). The reduced sensitivity detected in vitro corresponded to partial loss of fungicide efficacy in controlling infections in red clover and feijoa under controlled and semi-field conditions, respectively. Frequent prochloraz application in nurseries for controlling Calonectria spp. infections is discouraged.


Author(s):  
Patricia Rivas-Valencia ◽  
Alejandra Almaraz-Sánchez ◽  
Adriana Cano-Salgado ◽  
Lervin Hernández-Ramos ◽  
Iobana Alanís-Martínez ◽  
...  

<p>El área productora de durazno (<em>Prunus persica</em>) y ciruelo (<em>Prunus domestica</em>) en Michoacán, se localiza en el municipio de Zinapécuaro. Recientemente se han presentado síntomas de un deterioro progresivo de los árboles que les ocasiona la muerte, poniendo en riesgo la producción de fruta. El objetivo de este estudio fue identificar y caracterizar molecularmente el patógeno responsable. En las localidades de Ucareo, Jeráhuaro, Huajúmbaro, San Joaquín y La Galera con antecedentes del problema, se colectaron muestras de raíz, tronco y suelo. Se identificaron signos característicos del hongo <em>Armillaria</em> spp., confirmado por secuenciación molecular del gen Tef-1α (translation elongation factor 1α). El análisis filogenético agrupó las secuencias como dos especies nuevas, filogenéticamente emparentada en el mismo clado que <em>A. mellea</em>, que es una especie patógena agresiva. En México no se cuenta actualmente con portainjertos tolerantes, y por tanto, se recomienda continuar con estudios de búsqueda de resistencia genética y manejo de la enfermedad en las huertas.</p>


Plant Disease ◽  
2020 ◽  
Vol 104 (10) ◽  
pp. 2551-2555
Author(s):  
Luoye Li ◽  
Mengying Lei ◽  
Honghong Wang ◽  
Xiaozhu Yang ◽  
Mebeaselassie Andargie ◽  
...  

Ormosia pinnata (Lour.) Merr. is an important tree used for landscape and plant recovery of barren slopes in China. During an investigation of plant disease on landscape trees in 2018, a dieback was observed on O. pinnata trees in Guangzhou, Guangdong Province, China. Symptoms were characterized by initial dryness of the twigs and eventual death of the whole branch of the tree. Isolations from symptomatic branches yielded 13 isolates including two main morphotypes. Pathogenicity tests showed that isolate GDOP1 from Type I caused dieback of O. pinnata. Based on morphological characteristics and molecular analysis of the internal transcribed spacer rDNA (ITS1-5.8S-ITS2) and partial sequence of the translation elongation factor 1α (EF1-α), the fungus causing dieback on O. pinnata was identified as Lasiodiplodia pseudotheobromae. This is the first report of L. pseudotheobromae infecting O. pinnata in the world.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nimali I. de Silva ◽  
Alan J. L. Phillips ◽  
Jian-Kui Liu ◽  
Saisamorn Lumyong ◽  
Kevin D. Hyde

Abstract Two new species of Lasiodiplodia (Lasiodiplodia endophytica and Lasiodiplodia magnoliae) are described and illustrated from Magnolia forests in Yunnan, China. Endophytic and saprobic Lasiodiplodia pseudotheobromae and endophytic L. thailandica are new records from this host. The internal transcribed spacers (ITS), part of the translation elongation factor-1α (tef1) and partial β-tubulin (tub2) sequence data were analyzed to investigate the phylogenetic relationships of the new species with other Lasiodiplodia species. Lasiodiplodia magnoliae is phylogenetically sister to L. mahajangana and L. pandanicola but morphologically distinct from L. mahajangana in having larger conidia. Lasiodiplodia endophytica is most closely related to L. iraniensis and L. thailandica and the three species can be distinguished from one another by 2 base pair differences in ITS and three or four base pair differences in tef1. The new collections suggest that Magnolia forest plants are good hosts for Lasiodiplodia species with endophytic and saprobic life-styles.


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