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Fungi ( Neolentinus lepideus , Nl , and Trametes versicolor , Tv ) impart wood rot, leading to economic and environmental issues. To overcome this issue, toxic chemicals are commonly employed for wood preservation, impacting the environment and human health. Surface coatings based on antimicrobial chitosan (CS) of high molar mass (145 × 10 5 Da) were tested as wood preservation agents using an innovative strategy involving ultra-pressurizing CS solutions to deposit organic coatings on wood samples. Before coating deposition, the antifungal activity of CS in diluted acetic acid (AcOOH) solutions was evaluated against the rot fungi models Neolentinus lepideus ( Nl ) and Trametes versicolor ( Tv ). CS effectively inhibited fungal growth, particularly in solutions with concentrations equal to or higher than 0.125 mg/mL. Wood samples ( Eucalyptus sp. and Pinus sp.) were then coated with CS under ultra-pressurization at 70 bar. The polymeric coating deposition on wood was confirmed through X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) images, and water contact angle measurements. Infrared spectroscopy (FTIR) spectra of the uncoated and coated samples suggested that CS does not penetrate the bulk of the wood samples due to its high molar mass but penetrates in the surface pores, leading to its impregnation in wood samples. Coated and uncoated wood samples were exposed to fungi ( Tv and Nl ) for 12 weeks. In vivo testing revealed that Tv and Nl fungi did not grow on wood samples coated with CS, whereas the fungi proliferated on uncoated samples. CS of high molar mass has film-forming properties, leading to a thin hydrophobic film on the wood surface (water contact angle of 118°). This effect is mainly attributed to the high molar mass of CS and the hydrogen bonding interactions established between CS chains and cellulose. This hydrophobic film prevents water interaction, resulting in a stable coating with insignificant leaching of CS after the stability test. The CS coating can offer a sustainable strategy to prevent wood degradation, overcoming the disadvantages of toxic chemicals often used as wood preservative agents.

Fusarium graminearum is ranked among the five most destructive fungal pathogens that affect agroecosystems. It causes floral diseases in small grain cereals including wheat, barley, and oats, as well as maize and rice. We conducted a systematic review of peer-reviewed studies reporting species within the F. graminearum species complex (FGSC) and created two main data tables. The first contained summarized data from the articles including bibliographic, geographic, methodological (ID methods), host of origin and species, while the second data table contains information about the described strains such as publication, isolate code(s), host/substrate, year of isolation, geographical coordinates, species and trichothecene genotype. Analyses of the bibliographic data obtained from 123 publications from 2000 to 2021 by 498 unique authors and published in 40 journals are summarized. We describe the frequency of species and chemotypes for 16,274 strains for which geographical information was available, either provided as raw data or extracted from the publications, and sampled across six continents and 32 countries. The database and interactive interface are publicly available, allowing for searches, summarization, and mapping of strains according to several criteria including article, country, host, species and trichothecene genotype. The database will be updated as new articles are published and should be useful for guiding future surveys and exploring factors associated with species distribution such as climate and land use. Authors are encouraged to submit data at the strain level to the database, which is accessible at https://fgsc.netlify.app.

Food security goes beyond food being available; the food needs to be free of contaminants. Trichothecenes mycotoxins, produced by Fusarium fungus, are. among the most frequently found contaminants of wheat. In this study, we evaluated the production of trichothecenes Deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), and nivalenol (NIV) by Fusarium meridionale, F. austroamericanum, and F. graminearum grown in wheat plants and rice medium. Fusarim meridionale was efficient only in the production of NIV (production range (pr) from 1340 to 2864 µg kg -1 in wheat plant), and F. austroamericanum in the production of 3-AcDON (pr from 50 to 192 µg kg -1 in wheat plant, and from 986 to 7045 µg kg -1 in rice medium) and DON (pr from 4076 to 13,701 µg kg -1 in wheat plant, and from 184 to 43,395 µg kg -1 in rice medium). Already, F. graminearum was efficient in the production of 3-AcDON only in rice medium (pr from 81 to 2342 µg kg -1 ), 15-AcDON in wheat plant (pr from 80 to 295 µg kg -1 ) and in rice medium (pr from 436 to 8597 µg kg -1 ), and DON also in wheat plant (pr from 7746 to 12,046 µg kg -1 ) and in rice medium (pr from 695 to 49,624 µg kg -1 ). The specificity of F. meridionale in the production of NIV but not the production of DON could generate a food security problem in regions where this species occurs and the amounts of NIV in grains and derivatives are not regulated in the food chain, as in Brazil., (© 2021. The Author(s) under exclusive licence to Society for Mycotoxin (Research Gesellschaft für Mykotoxinforschung e.V.) and Springer-Verlag GmbH Germany, part of Springer Nature.)

Pyrenophora teres f. teres is well known for causing net form net blotch on barley, but its pathogenicity on wheat has also been reported in Hungary (Tóth et al. 2008) and east Russia (Mikhailova et al. 2010). The report from Hungary mentioned symptoms of dark brown necrotic lesions with or without chlorotic margins, while the report from Russia described symptoms similar to tan spot. A survey of fungal pathogens causing leaf spot diseases on wheat in the humid subtropical areas of Paraná State, southern Brazil, was conducted in 2016. Twenty four isolates, representing different wheat fields in the municipalities of Guarapuava and Pinhão, in the state of Paraná, were collected from wheat plants at the soft dough stage. The isolates analyzed in our study were obtained from leaf fragments of wheat cv. Toruk and were removed from the edge of lesions resembling tan spot, a major fungal disease of wheat in that region, caused by Pyrenophora tritici-repentis . The leaves presented oval, diamond, or elongate-shape lesions with tan necrotic spots. Still, they did not always show the brown center, which seemed not very characteristics of tan spot caused by P. tritici-repentis . Yellow halos surrounded the necrotic lesions. The fragments were superficially disinfected for 30 sec in 0.5% sodium hypochlorite, washed in sterile water, dried with a sterile paper towel, and transferred to petri plates containing potato dextrose agar (PDA) medium. After four days of incubation at 24±2ºC and a photoperiod of 12 h, hyphal tips were removed from the PDA medium and transferred to petri plates containing V-8 medium. Plates were incubated for 14 days in alternate cycles of 12 h at 23±2ºC under light and 12 h at 19±2ºC in darkness for sporulation. Pure cultures were obtained from single conidia produced on V-8 medium. Single spore isolates, representing different fields, were obtained from individual leaves. Conidia measuring 38-82 µm × 16-20 µm were smoothly cylindrical and straight, with rounded ends, subhyaline or yellowish brown, with four to seven pseudosepta. Genomic DNA extracted from cultures grown in yeast extract broth medium was used for PCR amplification of the ribosomal internal transcribed spacers and the 5.8S ribosomal DNA gene (ITS-5.8S rDNA) using the primers ITS4 and ITS5 described by White et al. (1990). A BLAST search of the GenBank database revealed that the ITS-5.8S rDNA sequence fragments (505 bp) from 12 out of 67 isolates were 99-100% similar to P. teres accession number EF452452 (Andrie et al. 2008). The DNA sequences of three P. teres isolates (20C3, 20A3, and 20A1) were deposited in GenBank (accession nos. MH594043.1, MH594042.1, and MH594041.1, respectively). These isolates were obtained from different fields in the municipality of Pinhão (25° 42 '26 "S; 51° 38' 0" W), in Paraná State. To test the pathogenicity of the isolates 20C3, 20A3, and 20A1, a conidial suspension for each isolate with 2-3 × 103 conidia per mL was sprayed at the boot stage (BBCH-scale 45) on leaves of wheat cv. Toruk and on susceptible barley cv. Ana 01 plants growing in pots. Each pot containing 5-7 plants was considered as replicate. Wheat plants were also inoculated with a P. tritici-repentis isolate with a conidial suspension at the same concentration described above to serve as reference of symptoms for tan spot. Wheat and barley plants were also inoculated with sterile water to serve as a control. Six replications were inoculated for each treatment. After inoculation, the plants were maintained in a dew chamber for 24 h and then moved to a growth room at 20±2ºC and 16 h photoperiod. Initially, the leaves of wheat plants inoculated with P. teres exhibited small, irregular, dark lesions surrounded by yellow halos, and later exhibited oval to elongate, pale brown, necrotic lesions, and yellow halos. Differently from tan spot caused by P. tritici-repentis , the wheat leaves inoculated with P. teres f. teres presented a more diffuse yellowing, and the center of necrotic lesions was pale brown. The symptoms observed in the barley leaves were the net form net blotch, which allowed us to infer that the disease was caused by P. teres f. teres isolates. All inoculated plants presented symptoms, with some variation among them. Pyrenophora teres f. teres was reisolated from the inoculated wheat and barley plants. This is the first report of P. teres f. teres causing leaf disease on wheat in Brazil. The finding contributes to a better understanding of the etiology of wheat leaf spots in humid subtropical areas of southern Brazil.

A new Phytophthora species was found associated with gummosis in black wattle plantations in the subtropical, humid, south of Brazil. The new species Phytophthora acaciae is formally named herein based on phylogenetic and morphological analyses. This is the fourth Phytophthora species found from this pathogen complex in black wattle plantations causing gummosis in Brazil. The other three species are P. nicotianae, P. boehmeriae , and P. frigida. Phytophthora acaciae is heterothallic with amphigynous antheridia, noncaducous, papillate sporangia and is placed in the Phytophthora clade 2 based on nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) sequences. Maximum parsimony and maximum likelihood phylogenetic analyses of P. acaciae isolates based on multigene sequences, including partial DNA sequences of three nuclear protein-coding genes (β-tubulin, translation elongation factor-1α, and ras-related protein), two mitochondrial protein-coding genes (cytochrome c oxidase subunits I and II), in addition to ITS sequence data, support the delimitation of this new species on Acacia mearnsii from the other previously described clade 2 Phytophthora species. Pathogenicity trial confirmed that the new species causes necrotic lesions on the plant stem, with either the presence or absence of gum.

Surveys were conducted in commercial wheat and barley fields in the south central production regions of state of Paraná, Brazil, from 2011 to 2015. Spikes displaying visible Fusarium head blight symptoms were collected and the pathogen isolated from the tissues. The 754 Fusarium isolates recovered were identified by a high-throughput multilocus genotyping assay (MLGT) designed to identify trichothecene toxin-producing fusaria (i.e., formerly B-clade, but referred to here as F. sambucinum species complex lineage 1 [FSAMSC-1]) together with sequencing a portion of the translation elongation factor 1-α (TEF1) gene. One strain was discovered that appeared to be closely related to but phylogenetically distinct from F. praegraminearum based on the relatively low 97.7% TEF1 identity and positive genotype obtained with one of the two F. praegraminearum species-specific MLGT probes. Molecular phylogenetic analyses of a 10-gene data set resolved this novel FSAMSC-1 species and F. praegraminearum as sisters. Formally described herein as F. subtropicale, it is phenotypically distinct from the 22 other FSAMSC-1 species in that it produces mostly 1-3-septate macroconidia. Whole-genome sequence data were used to predict its potential to produce mycotoxins. Chemical analyses confirmed that F. subtropicale could produce the mycotoxins 4,15-diacetylnivalenol, butenolide, culmorin, and fusarin C in vitro, and the pathogenicity experiment revealed that F. subtropicale could infect but not spread in susceptible hard red spring wheat cultivar "Norm."

Isolates of Fusarium obtained from soybean plants showing symptoms of root rot collected in subtropical southern and tropical central Brazil were characterized based on phylogenetic analyses, sexual crossing, morphology, and pathogenicity tests. A novel species within the Fusarium solani species complex (FSSC) causing soybean root rot is formally described herein as Fusarium paranaense. This species can be distinguished from the other soybean root rot pathogens in the FSSC, which are commonly associated with soybean sudden death syndrome (SDS) based on analyses of the combined DNA sequences of translation elongation factor 1-α and the second largest subunit of RNA polymerase II and on interspecies mating compatibility. Bayesian and maximum parsimony phylogenetic analyses showed that isolates of F. paranaense formed a distinct group in clade 3 of the FSSC in contrast to the pathogens currently known to cause SDS, which are in clade 2. Female fertile tester strains were developed that can be used for the identification of this new species in the FSSC based on sexual crosses. All isolates were heterothallic and belonged to a distinct mating population. Fusarium tucumaniae, a known SDS pathogen, was found in the subtropical southern region of the country., (Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

Filamentous fungi produce a great variety of enzymes, and research on their biotechnological potential has recently intensified. The objective of this work was to identify, at the species level, using DNA barcoding, 46 fungal isolates obtained from maize grains with rot symptoms. We also analyzed the production of extracellular amylases, cellulases, proteases and lipases of 33 of those fungal isolates. The enzymatic activities were evaluated by the formation of a clear halo or a white precipitate around the colonies in defined substrate media. The found fungi belong to the genera Talaromyces, Stenocarpella, Penicillium, Phlebiopsis, Cladosporium, Hyphopichia, Epicoccum, Trichoderma, Aspergillus, Irpex, Fusarium, Microdochium, Mucor and Sarocladium. In the genus Fusarium, the species Fusarium verticillioides was predominant and this genus presented the highest diversity, followed by the genera Aspergillus. The best genera for lipase production were Cladosporium and Penicillium; while Cladosporium, Aspergillus and Penicillium were best for cellulase activity; Hyphopichia, Aspergillus and Irpex for amylase activity; and Cladosporium and Sarocladium for proteases activity. In conclusion, a collection of fungi from maize seeds presenting rotten symptoms were obtained, among which exist important producers of hydrolases.

A multiyear survey of >200 wheat fields in Paraná (PR) and Rio Grande do Sul (RS) states was conducted to assess the extent and distribution of Fusarium graminearum species complex (FGSC) diversity in the southern Brazilian wheat agroecosystem. Five species and three trichothecene genotypes were found among 671 FGSC isolates from Fusarium head blight (FHB)-infected wheat heads: F. graminearum (83%) of the 15-acetyldeoxynivalenol (15-ADON) genotype, F. meridionale (12.8%) and F. asiaticum (0.4%) of the nivalenol (NIV) genotype, and F. cortaderiae (2.5%) and F. austroamericanum (0.9%) with either the NIV or the 3-ADON genotype. Regional differences in FGSC composition were observed, with F. meridionale and the NIV type being significantly (P<0.001) more prevalent in PR (>28%) than in RS (≤9%). Within RS, F. graminearum was overrepresented in fields below 600 m in elevation and in fields with higher levels of FHB incidence (P<0.05). Species composition was not significantly influenced by previous crop or the stage of grain development at sampling. Habitat-specific differences in FGSC composition were evaluated in three fields by characterizing a total of 189 isolates collected from corn stubble, air above the wheat canopy, and symptomatic wheat kernels. Significant differences in FGSC composition were observed among these habitats (P<0.001). Most strikingly, F. meridionale and F. cortaderiae of the NIV genotype accounted for the vast majority (>96%) of isolates from corn stubble, whereas F. graminearum with the 15-ADON genotype was dominant (>84%) among isolates from diseased wheat kernels. Potential differences in pathogenic fitness on wheat were also suggested by a greenhouse competitiveness assay in which F. graminearum was recovered at much higher frequency (>90%) than F. meridionale from four wheat varieties inoculated with an equal mixture of F. graminearum and F. meridionale isolates. Taken together, the data presented here suggest that FGSC composition and, consequently, the trichothecene contamination in wheat grown in southern Brazil is influenced by host adaptation and pathogenic fitness. Evidence that F. meridionale and F. cortaderiae with the NIV genotype are regionally significant contributors to FHB may have significant implications for food safety and the economics of cereal production.

Greater plantain or common plantain (Plantago major L.) is an herbaceous plant native to most of Europe, northern and central Asia, and it has adapted well to tropical regions where it is used as a medicinal plant. Between November 2011 and April 2012, greater plantains cultivated in the Medicinal Plant Garden at the Umuarama Advanced Campus of the State University of Maringa (UEM-CAU) suddenly died off. A visual examination revealed the presence of white mycelium and sclerotia on the lower third of the plant. These sclerotia were collected and deinfested by immersion in 70% alcohol and 0.5% sodium hypochlorite for 45 s, and in sterilized water for 1 min. Next, the sclerotia were placed on 10 petri dishes containing potato dextrose agar (PDA) culture medium and incubated at 29°C. After 7 days, the culture medium was entirely coated with a cottony white mycelial growth and, 15 days after isolation, sclerotia began to form. Healthy seedlings were transplanted individually into pots containing autoclaved soil (120°C/2 h). After 10 days, eight seedlings were inoculated with 8-mm mycelia disks deposited on the base of the plant, and eight seedlings inoculated with fungus-free PDA disks (control). The plants were irrigated and the pots placed in with plastic bags and kept at an average temperature of 28°C. Three days after inoculation, we observed a cottony white mycelial growth and symptoms of rot on the plants. The plastic bags were then removed and the plants kept under the same temperature, relative humidity of 80% and 12 h of light. Seven days after inoculation, the plants treated with the fungus died, whereas the plants treated with PDA developed normally. The fungus was re-isolated from the symptomatic plants and slides evaluated under a light microscope, revealing that the mycelium was thick, septate, and hyaline. The sclerotia formed were spherical, initially white or light brown, becoming dark brown or black, with diameters ranging from 0.5 to 1.5 mm. The fungus was subjected to DNA analysis using ribosomal region oligonucleotides ITS4 (5'-TCCTCCGCTTATTGATAT-3') and ITS5 (5'-GGAAGTAAAAGTCGTAACAAGG-3') (1) to amplify the target region. The segment including the 5.8S gene and rDNa regions ITS1 and ITS2 was 630 bp long. DNA analysis revealed that it was 99% identical to Athelia rolfsii (Curzi) Tu and Kimbr (anamorph: S. rolfsii) (GenBank Accession No. HM222638.1). The isolate was deposited in the fungus collection at the UEM-CAU Phytopathology Laboratory under code F-Sr-01-UMU. Reference: (1) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications, M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990.

Syagrus oleracea (Mart.) Becc. (bitter coconut), a palm tree species that is native to central Brazil, has been increasingly cultivated in this country for heart-of-palm production. Epidemics of a necrotic leaf spot of unknown etiology have been recorded on bitter coconut plants in transplant nurseries and plantation since 2008. The first symptoms appear as small, yellow, hydrotic flecks on young or mature leaves that evolve to necrotic brown streaks that run parallel to the leaf veins. Usually, yellow halos occur around the lesions and hydrosis is common during lesion expansion. Necrotic lesions can reach up to 40 mm in length and 10 mm in width, and the lesions often coalesce, causing extensive tissue damage. During a survey in a 3-year-old bitter coconut plantation in Maringá County (coordinates: 23°23'51.25″ S, 51°57'02.09″ W; elevation: 507 m) in the state of Parana, a dozen symptomatic leaves were collected with the aim of elucidating the etiology of this disease. Conidia and conidiophores typical of Cladosporium were frequently observed on the diseased leaf tissue under natural field conditions as well on the surfaces of disinfected leaf tissues kept in a humid chamber for 48 h at 25 ± 2°C with a 12-h photoperiod. Five monoconidial cultures growing on potato dextrose agar (PDA) medium were obtained from different leaves showing leaf spot symptoms. The cultures were grown on PDA to induce sporulation. At 7 days after incubation at 25 ± 2°C and a 12-h photoperiod, gray to gray-olive colonies were observed. The conidiophores were macronematous, erect, oblong, branched, 1 to 5 septate, and 75.0 to 120.0 × 1.90 to 3.20 μm. The ramoconidia were cylindrical or oblong, 0 to 2 septate, and 28.0 to 40.0 × 2.8 to 3.6 μm, with a truncate base of 1.9 to 2.2 μm; secondary ramoconidia were cylindrical or oblong, 0 to 2 septate, 8.0 to 31.0 × 2.2 to 3.1 μm, with 3 to 5 distal conidial hila; intercalary 1-septate conidia were 5.5 to 17.0 × 2.1 to 3.4 μm, with 1 to 3 distal conidial hila; terminal 1-septate conidia were catenulate and 2.2 to 4.2 × 1.8 to 3.1 μm. Species identification was performed based on morphology and DNA sequence data (1). Portions of the elongation factor 1α (551 bp; TEF) and actin (213 bp; ACT) genes were amplified by PCR. A BLAST search of the GenBank database revealed that the TEF (KC484658 to KC484662) and ACT (KC484663 to KC484667) sequence fragments from isolates Gua1, Gua2, Gua3, Gua4, and Gua5 had 100% identity with the accessions HM148616 and HM148371 of Cladosporium perangustum (1). Isolates were tested for pathogenicity against bitter coconut. Ten potted plants with 4 to 6 fully expanded leaves were inoculated with each isolate by spraying a suspension of conidia (10 5 spores per ml) onto leaves until runoff using a handheld spray bottle. Non-inoculated controls (10 plants) were sprayed with distilled water. The plants were kept in a humid plastic chamber at 20 to 26°C. All examined isolates were pathogenic to bitter coconut, causing symptoms identical to those described above 12 days after inoculation. All inoculated tissues were plated onto PDA to confirm the presence of the pathogen. Live cultures are being maintained at the Micoteca/URM/UFPE ( www.ufpe.br/micoteca ), Brazil. To our knowledge, this is the first report of a disease caused by C. perangustum on S. oleracea worldwide, and the study provides valuable plant disease diagnostic information for the palm hearth industry in Latin America. Reference: (1) K. Bensch et al. Stud Mycol. 67:1, 2010.

Ear rots caused by Fusarium spp. are among the main fungal diseases that contribute to poor quality and the contamination of maize grains with mycotoxins. This study aimed to determine the visual incidence of fungal-damaged kernels (FDKs), the incidence of two main Gibberella (a teleomorph of Fusarium) complexes (G. fujikuroi and G. zeae) associated with maize using a seed health blotter test, and the fumonisin levels, using high performance liquid chromatography, in samples of maize grains grown across 23 municipalities during the 2008/09 and 2009/10 growing seasons. Additionally, 104 strains that were representative of all of the analysed samples were identified to species using PCR assays. The mean FDK was seven per cent, and only six of the samples had levels greater than six per cent. Fusarium spp. of the G. fujikuroi complex were present in 96% of the samples, and G. zeae was present in 18% of the samples (5/27). The mean incidence of G. fujikuroi was 58%, and the incidence of G. zeae varied from 2 to 6%. FB1 was found in 58.6%, FB2 in 37.9%, and both toxins in 37.9% of the samples. The FB1 and FB2 levels were below the quantification limits for 41.3% of the samples, and the mean FB1 levels (0.66 μg/g) were higher than the mean FB2 levels (0.42 μg/g). The PCR identification separated the 104 isolates into three of the G. fujikuroi complex: F. verticillioides (76%), F. subglutinans (4%) and F. proliferatum (2%); and G. zeae (anamorph = F. graminearum) (18%). Our results confirmed the dominance of F. verticillioides, similar to other regions of Brazil, but they differed due to the relatively higher incidence of F. graminearum. Total fumonisin levels were below the maximum limit determined by current Brazilian regulations.

Fusarium verticillioides and Fusarium subglutinans are important fungal pathogens of maize and other cereals worldwide. In this study, we developed PCR-based protocols for the identification of these pathogens targeting the gaoB gene, which codes for galactose oxidase. The designed primers recognized isolates of F. verticillioides and F. subglutinans that were obtained from maize seeds from several producing regions of Brazil but did not recognize other Fusarium spp. or other fungal genera that were either obtained from fungal collections or isolated from maize seeds. A multiplex PCR protocol was established to simultaneously detect the genomic DNA from F. verticillioides and F. subglutinans. This protocol could detect the DNA from these fungi growing in artificially or naturally infected maize seeds. Another multiplex reaction with a pair of primers developed in this work combined with a pre-existing pair of primers has allowed identifying F. subglutinans, F. konzum, and F. thapsinum. In addition, the identification of F. nygamai was also possible using a combination of two PCR reactions described in this work, and another described in the literature.

Fusarium head blight is a disease of primary concern to small-grain cereals of Brazil, including barley. Its main causal agent, Fusarium graminearum species complex (Fg complex)¸ is able to produce mycotoxins, especially deoxynivalenol (DON) and nivalenol (NIV), that usually contaminate grain. Strains that produce DON may also produce its acetylated derivatives: 3-acetyl-DON (3-ADON) and 15-acetyl-DON (15-ADON). Ninety two isolates were obtained from samplings of barley grain during three years (2007, 2008 and 2009) from several fields in both southern and northern production regions of Rio Grande do Sul state, Brazil. These isolates were examined for polymerase chain-reaction-based (PCR) trichothecene genotype based on the amplification of portions of Tri3 and Tri12. There was no effect of year or region on the proportion of trichothecene genotypes. Overall, 66% of the strains (61/92) were 15-ADON, 4.4% (4/92) were 3-ADON and 29.3% (27/92) were NIV. The overall NIV/DON ratio estimated (0.41) was five times higher than that found in previous studies with strains from wheat grown in the same region. Species identification of nine strains representing the trichothecene genotypes, based on comparisons of DNA sequences of portions of the PHO, RED and URA genes with sequences from curated reference isolates of Fusarium from GenBank, revealed that they belong to F. graminearum sensu stricto (four 15-ADON and one 3-ADON strain), F. meridionale (three NIV strains) and F. austroamericanum (one 3-ADON strain). These results add to the current regional knowledge of trichothecene genotypes and species within the Fg complex affecting barley in the region., (Copyright © 2011 Elsevier B.V. All rights reserved.)

We estimated general and specific combining abilities and examined resistance to northern leaf blight (Exserohilum turcicum) and to gray leaf spot (Cercospora zeae-maydis) in a set of nine inbred popcorn lines. These inbreds were crossed in a complete diallel scheme without reciprocals, which produced 36 F(1) hybrids. Two experiments with a square lattice design and three replications were conducted during the 2008/2009 crop season, in Maringá, PR, Brazil. The severity of northern leaf blight and gray leaf spot was assessed under natural infestation conditions. Data were examined by individual and joint analysis of variance. Individual and joint Griffing's diallel analyses were carried out for adjusted means. General combining ability and specific combining ability were significant (P < 0.10) by the F-test for northern leaf blight and gray leaf spot infestation levels. This denotes that additive and non-additive gene effects both contributed to resistance to these diseases, but that the additive gene effects were more important. Among the inbred lines, P(8) and P(9) gave the highest resistance to northern leaf blight, and P(3) and P(4.3) gave the highest resistance to gray leaf spot. The hybrids P(7.4) x P(8) and P(4.3) x P(9) could be exploited by reciprocal recurrent selection to provide genotypes with both northern leaf blight and gray leaf spot resistance. Significant interaction between general combining ability and crop season (P < 0.10) denotes the importance of environment, even though the disease levels in the hybrids were quite consistent.

The main objective of this work was to develop a PCR protocol for the identification of Fusarium graminearum, based on a pair of primers targeted to a segment of the 3´coding region of the gaoA gene that codes for the enzyme galactose oxidase (GO). This region has low homology with the same region of GO genes from other fungi. Genomic DNA from 17 strains of Fusarium spp. isolated from diseased cereals, from several other Fusarium species, and from other fungi genera was analyzed in a PCR assay using this primer set. The 17 strains of Fusarium spp. were also analyzed for the GO enzyme production in submerse fermentation in a new formulated liquid medium. All strains that were morphologically and molecularly identified as F. graminearum were able to secrete the enzyme and had a positive result in the used PCR protocol. No DNA fragment was amplified using genomic DNA from other Fusarium species and species of other fungi genera. The results suggest that the proposed PCR protocol is specific and can be considered as a new molecular tool for the identification of F. graminearum. In addition, the new formulated medium is a cheap alternative for screening for GO screening production by F. graminearum.