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The genetic architecture of quantitative characters in plants can be influenced by stress due to environmental changes, in combination with the decrease in the organism’s average performance, resulting in genetic and environmental variances. The main objective of this study was to determine how the high-temperature stress affects the sensitivity of three populations of the soybean foliar blight pathogen Rhizoctonia solani AG-1 IA from Mato Grosso, Maranhão, and Tocantins to a broad-spectrum fungicide. The specific objective was to determine the effect of environmental stress on evolvability components (i.e., the selection response measures such as genotypic, environmental, and phenotypic variances) associated with sensitivity to the broad spectrum dithiocarbamate fungicide mancozeb. The fungal isolates from the three pathogen populations were grown under two temperatures (25 °C and 33.5 ºC, optimum and stress, respectively) and three fungicide concentrations (0.0, 0.32, and 0.64 g·L-1 of active ingredient). The mycelial growth was measured, and evolvability components, such as the genotypic variance coefficient (IG), the environmental variance (IE), and the broad-sense heritability (h2), were determined. The results showed that high-temperature stress decreased (≈ 0.1 units, in a scale from 0 to 1.0) the genotypic variance and the heritability for mancozeb sensitivity in three populations of the soybean foliar blight pathogen R. solani AG-1 IA.

Summary Environmental adaptation and cell differentiation processes are factors that influence the anatomical elements of wood. The objective of this study was to investigate the effect of water deficit on lignin composition in anatomical elements and on the characteristics of vessel-neighboring cells. Six-year-old clones of Eucalyptus urophylla and Eucalyptus grandis × Eucalyptus camaldulensis from wet and dry regions were used. All regions received a rainfall exclusion treatment. Cell wall width, cell wall thickness, and form factor of fibers close to and far from vessels were measured. In the same cells, lignin was measured in the middle lamella and vessels by a fluorescence technique. The vessel differentiation process affected cell wall thickness and lignin composition in neighboring cells. Lignin composition was increased in vessels compared to fibers or vasicentric tracheids. Middle lamella lignin was not affected by vessel differentiation or water deficit in either eucalyptus clone. E. grandis × E. camaldulensis is originally from a dry climate region and, therefore, did not suffer alterations in lignin when subjected to water stress conditions; however, this clone exhibited a higher number of vasicentric tracheids. E. urophylla is originally from a humid climate region and, when subjected to water deficit, showed increased wood lignin composition, which seems to be a strategy for better use of water resources. Alterations in lignin composition of vessel, vasicentric tracheid, and fiber cell walls resulting from exposure to water deficit conditions vary according to eucalyptus species.

Quinone outside inhibitor (QoI) fungicides have not been effective in controlling the wheat blast disease [Pyricularia oryzae Triticum lineage (PoTl)] in Brazil. The first report of resistance of PoTl to QoIs in this country occurred in 2015. This study aimed to test hypotheses about the changes in fitness parameters and competitive advantage of the QoI-resistant (R) PoTl isolate group compared to the sensitive (S) isolate group. Mycelial growth on PDA medium and in vivo conidial production, incubation period and disease severity were analyzed as fitness parameters. The competitive ability was measured on wheat leaves and heads inoculated with mixtures of R:S isolates at the following proportions: 0S:100R, 20S:80R, 50S:50R, 80S:20R, 100S:0R, and 0S:0R.The QoI-R isolate group had significantly higher fitness than the sensitive isolate group, considering both in vitro and in vivo parameters. The highest in vivo conidial production on wheat leaves and the highest leaf and head disease severity were detected when resistant strains were predominant in the isolate's mixtures (20S:80R or 0S:100R proportions), in the absence of fungicide pressure. Conidia harvested from wheat blast lesions on leaves inoculated with 20S:80R and 0S:100R mixtures were resistant to QoIs in vitro assays based on discriminatory doses of the fungicide.Therefore, QoI resistance facilitated a higher fitness and a competitive advantage in PoTl, which contrasts with the evolutionary theory that associates a fitness cost to fungicide resistance. We discuss the evolutionary and ecological implications of the higher fitness as found in the fungicide-resistant adapted populations of the wheat blast pathogen. © 2022 Society of Chemical Industry.

Made available in DSpace on 2021-06-25T10:24:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Cercospora leaf spot, an important disease in coffee caused by the fungus Cercospora coffeicola, can appear as two distinct symptoms on leaves, which are ‘brown eye spot’ (BES) and the ‘black spot’ (BS) in field conditions. However, it was unknown whether these two distinct symptoms could be obtained when plants are inoculated under greenhouse conditions and whether the C. coffeicola strains causing the distinct symptoms would induce defense-related genes in a similar pattern. Thus, this work was performed to address these questions. C. coffeicola strains were isolated from diseased leaves collected from coffee fields. The coffee leaves were inoculated with each of the two strains under greenhouse conditions. Leaf samples were collected from a time-course experiment and the disease progression was analyzed using scanning electron microscopy. The plant defense response was analyzed using qRT-PCR of defense-related genes. Both strains showed very similar germination, colonization, and sporulation patterns in the coffee leaves. The expression analysis showed that both strains were able to induce defense-related genes. Both strains produced symptoms of the typical BES for the conditions used, there might be other factors leading to the development of black spot symptom under field conditions and further investigation is needed. Departamento de Fitopatologia Universidade Federal de Lavras –UFLA Universidade Estadual Paulista “Julio de Mesquita Filho” -UNESP Campus Ilha Solteira Universidade Estadual Paulista “Julio de Mesquita Filho” -UNESP Campus Ilha Solteira

Sarocladium species are common endophytes of tropical forage grasses and may offer benefits to host plants against biotic and abiotic stresses. We investigated a collection of 88 Sarocladium isolates previously obtained as endophytes from Panicum maximum, Pennisetum purpureum, Cynodon nlemfuensis, and Brachiaria spp. in Brazil. Multilocus phylogenetic analyses and morphological characterization were used for species delimitation. Sixty-eight isolates were identified as S. spinificis, and five as S. terricola; S. bactrocephalum, S. kiliense, S. spirale, and S. strictum were represented by one to three isolates. A well-supported clade containing eight endophytic isolates occupied a sister position to the clade containing S. bactrocephalum, S. mali, and S. strictum, and is described as a new taxon, Sarocladium graminicola. This work provides new insights on the distribution and diversity of endophytic Sarocladium species in the tropics.

Made available in DSpace on 2022-04-28T19:44:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-02-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Newton Fund Fundação Araucária Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Wheat blast is one of the most important and devastating fungal diseases of wheat in South America, South-east Asia, and now in southern Africa. The disease can reduce grain yield by up to 70% and is best controlled using integrated disease management strategies. The difficulty in disease management is compounded by the lack of durable host resistance and the ineffectiveness of fungicide sprays. New succinate dehydrogenase inhibitor (SDHI) fungicides were recently introduced for the management of wheat diseases. Brazilian field populations of the wheat blast pathogen Pyricularia oryzae Triticum lineage (PoTl) sampled from different geographical regions in 2012 and 2018 were shown to be resistant to both QoI (strobilurin) and DMI (azole) fungicides. The main objective of the current study was to determine the SDHI baseline sensitivity in these populations. Moderate levels of SDHI resistance were detected in five out of the six field populations sampled in 2012 and in most of the strains isolated in 2018. No association was found between target site mutations in the sdhB, sdhC, and sdhD genes and the levels of SDHI resistance, indicating that a pre-existing resistance mechanism not associated with target site mutations is probably present in Brazilian wheat blast populations. Department of Crop Protection Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos) UNESP - São Paulo State University, São Paulo Vale do Paraná S.A. Álcool e Açúcar, São Paulo Biomass Innovation Institute SENAI, Mato Grosso do Sul Department of Plant Pathology UFLA - Federal University of Lavras, Minas Gerais Paraná Rural Development Institute IDR - Paraná/IAPAR, Paraná Brazilian Agriculture Research Corporation - EMBRAPA Wheat, Rio Grande do Sul Biointeractions and Crop Protection Rothamsted Research National Institute of Agricultural Botany Plant Pathology Group Institute of Integrative Biology ETH Zürich Department of Crop Protection Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos) UNESP - São Paulo State University, São Paulo FAPESP: 2013/10655-4 FAPESP: 2015/10453-8 FAPESP: 2020/07611-9 CAPES: 775202/2012 Newton Fund: BB/S018867/2 Fundação Araucária: FPS2020011000057 CNPq: Pq-1D 313825/2018-1 CNPq: Pq-2 307295/2015-0 CNPq: Pq-2 307361/2012-8

Cinnamon essential oil (CEO) has proven activity against several plant-pathogenic fungi and can reduce fungal diseases to an extent comparable to that achieved using commercial fungicides. Thus, the goal of the present work was to identify the active constituents of this essential oil and determine the direct fungicidal mode of action as well as putative indirect action by activation of citrus plant resistance against Alternaria brown spot (ABS). Gas chromatography–mass spectrometry (GC-MS) of essential oil extracted from Cinnamomum zeylanicum leaves resulted in the identification of the active constituents eugenol and trans-cinnamaldehyde, which had, respectively, minimal inhibitory concentrations (MICs) of 250 and 62.5 μg mL−1 against Alternaria alternata, while, under the same conditions, the MICs for a commercial fungicide and CEO were 1250 and 500 μg mL−1 respectively. Fungal growth inhibition assays showed that eugenol and trans-cinnamaldehyde (CNE) prevent fungal growth by direct fungicidal action and proved that CNE is mainly responsible for the anti-fungal activity of C. zeylanicum essential oil (CEO). CEO decreased the incidence of ABS disease to a greater extent than a commercial copper fungicide and was comparable to a commercial plant activator. Both CEO and its active constituent showed the ability to activate plant defense enzymes, demonstrating a high capacity to induce the citrus plant defense response. Therefore, both the essential oil and its active constituent have potential use in the development of new organic structures and analogues to control ABS disease caused by A. alternata.

Sugarcane pineapple rot is an important sugarcane stem disease that also affects germination and sprouting. In Brazil, the disease is caused by Thielaviopsis paradoxa sensu lato which has been split into at least five distinctive phylogenetic and biological species in the reinstated genus Thielaviopsis. In this study, three purported strains of T. paradoxa s. lat. isolated from sugarcane stems were characterized and compared with a strain from pineapple fruit, using morphology, DNA sequence analyses and sexual compatibility tests. Inoculations were also performed on asymptomatic stems of plants to assess the pathogenicity of the four fungal strains on sugarcane. Based on results of the phylogenetic analyses of combined ITS and TEF-1a gene sequences, the strains were identified as T. ethacetica. This was also supported by sexual compatibility tests, as crossings between the pineapple strain and some sugarcane strains resulted in the formation of perithecia exuding ascospore masses at their apices. The inoculation test on sugarcane resulted in stem rot and in reduced germination of buds. Thielaviopsis ethacetica is thus the species causing pineapple sett rot disease in Brazil.

Alternaria brown spot (ABS) is one of the main diseases of tangerine worldwide. It is necessary to use a practical and reliable method to quantify the disease severity of ABS and thus suggest management strategies. Thus, a diagrammatic scale (DS) constructed with color photographs was developed and validated to quantify the disease severity. Leaves were collected from crops and a nursery with different levels of ABS symptoms to determine the real severity digitally. The scale levels were determined according to the minimum and maximum severity values found and based on the frequency distribution of severity values. The DS validation was carried out by eleven assessors who estimated the severity of 50 leaves with different symptom levels. One assessment was performed without the DS and two using the DS at seven day intervals. The precision, accuracy, repeatability and reproducibility of the estimates were measured. The developed DS has nine score levels: 0 (0%), 1 (0.1–0.49%), 2 (0.5–1.0%), 3 (1.1–2.0%), 4 (2.1–4.0%), 5 (4.1–8%), 6 (8.1–18%), 7 (18.1–30%) and 8 (30.1–50%). The linear regression and Lin’s concordance correlation coefficient (LCCC) demonstrated an improved accuracy, precision repeatability and reproducibility of the estimates using the DS. The scale is appropriate, useful and reliable to visually estimate with the ABS severity in tangerine leaves.

Background The demand for industrialized foods that contribute to health and well‐being has characterized the new generation of consumers. Yam (Dioscorea sp.) is a nutritious food; however, it is not used very much in industrial food processes. The objective of this study was to develop and to characterize a truly dairy‐free low‐fat ice cream prepared from unfermented and fermented with yam dough. Results The fermentation was conducted by Leuconostoc lactic CCMA 0415 remained viable (107 CFU/g) during 90 days of storage. The fermentation process reduced the starch concentration from 26.82% to 22.35% and the protein concentration from 4.68% to 3.99% and increased the concentration of some minerals (K, S, Cu, Mn, Zn, and Fe). The total phenolic contents for fermented and unfermented ice creams were 51 and 54 mg, respectively. The radical scavenging activity were 18% and 10% with the 1,1‐diphenyl‐2‐picrylhydrazyl method and 44% and 26% with the 2,2’‐azino‐bis (3 ethylbenzo‐thiazoline‐6‐sulfonic acid) method for the unfermented and fermented samples, respectively. The fermented and unfermented ice creams were both characterized as non‐Newtonian fluids exhibiting pseudoplastic behaviors. Conclusions These results indicated that yam is a suitable substitute for milk, thus making it an option to produce edible lactose‐free ice cream with low fat.

Made available in DSpace on 2021-06-25T10:14:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fungicides have not been effective in controlling the wheat blast disease in Brazil. An earlier analysis of 179 isolates of Pyricularia oryzae Triticum lineage (PoTl) sampled from wheat fields across six populations in central-southern Brazil during 2012 discovered a high level of resistance to strobilurin fungicides. Here we analysed azole resistance in the same strains based on EC50 measurements for tebuconazole and epoxiconazole. All six Brazilian populations of PoTl exhibited high resistance to both azoles, with in vitro EC50 values that were at least 35 to 50 times higher than the recommended field doses. We sequenced the CYP51A and CYP51B genes to determine if they were likely to play a role in the observed azole resistance. Although we found five distinct haplotypes in PoTl carrying four nonsynonymous substitutions in CYP51A, none of these substitutions were correlated with elevated EC50. CYP51B was sequenced for nine PoTl isolates, three each representing low, medium, and high tebuconazole EC50. Both PoTl CYP51A and CYP51B could complement yeast CYP51 function. All PoTl CYP51A-expressing yeast transformants were less sensitive to triazoles than the PoTl CYP51B ones. Transformants expressing PoTl CYP51A haplotype H1 carrying the R158K substitution were not more resistant than those expressing PoTl CYP51A haplotype H5, which is synonymous to haplotype H6, found in triazole-sensitive P. oryzae Oryza isolates from rice blast. Therefore, the reduced triazole sensitivity of wheat blast isolates compared to rice blast isolates appears to be associated with a non-target-site related resistance mechanism acquired after higher exposure to triazoles. Department of Crop Protection Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos) São Paulo State University UNESP Brazilian Agriculture Research Corporation EMBRAPA Wheat Plant Pathology Group Institute of Integrative Biology ETH Zürich Biointeractions and Crop Protection Rothamsted Research National Institute of Agricultural Botany (NIAB) Centre for Cytochrome P450 Biodiversity Institute of Life Science School of Medicine Swansea University Department of Crop Protection Agricultural Engineering and Soil (Departamento de Fitossanidade Engenharia Rural e Solos) São Paulo State University UNESP FAPESP: 2013/10655-4 FAPESP: 2015/10453-8 CAPES: 775202/2012 CNPq: Pq1D 313825/2018-1

Cercosporin has excellent properties of photosensitization that have been widely used in organophotocatalyst and photodynamic therapy as well as an antimicrobial agent. Therefore, there is a need to quantify it accurately with accessible methods. A comparative analysis of cercosporin quantification obtained by spectrophotometry (SPEC) and high-performance liquid chromatography (HPLC) was performed for nineteen Cercospora coffeicola isolates from different coffee-producing municipalities in Brazil. Image analysis of cercosporin crystals was performed in isolates with either high or low production of the toxin. Our results show that SPEC and HPLC are equally valid for the cercosporin evaluation of C. coffeicola cultures grown in vitro. The isolates with high cercosporin production had a higher crystal number and size when compared to the one with low cercosporin production info:eu-repo/semantics/publishedVersion

Endophytic fungi are capable of infecting plants without inducing the development of any observable symptoms. Certain fungal species can also coexist as latent pathogens in their specific hosts. Several species of Fusarium have been reported to form an association with grasses as endophytes or latent pathogens, some of which are also mycotoxin producers. In this study, we aimed to address whether forage grasses could act as potential reservoirs of species that are pathogenic to maize (Zea mays). To this end, we performed morphological and phylogenetic analyses of the elongation factor 1-α (EF-1α) and the second largest subunit of RNA polymerase II (RPB2) genes and characterized three fungal strains isolated from Panicum maximum (cv. Mombaça) as a new phylogenetic species, Fusarium gigantea, within the Fusarium fujikuroi species complex. Moreover, the results of the pathogenicity test such as the toothpick inoculation assay, revealed that these species caused the stalk rot disease in maize when maintained under greenhouse conditions. This finding highlights P. maximum as a potential reservoir of this pathogen and its role as a threat to maize cultivation. Made available in DSpace on 2021-09-26T02:02:26Z (GMT). No. of bitstreams: 1 Panicum-maximum.pdf: 996965 bytes, checksum: 8c1720f8ade5e2b087f525210423a4db (MD5) Previous issue date: 2021

Wheat blast was first reported in Brazil in 1985. It spread rapidly across the wheat cropping areas of Brazil to become the most important biotic constraint on wheat production in the region. The alarming appearance of wheat blast in Bangladesh in 2016 greatly increased the urgency to understand this disease, including its causes and consequences. Here, we summarize the current state of knowledge of wheat blast and aim to identify the most important gaps in our understanding of the disease. We also propose a research agenda that aims to improve the management of wheat blast and limit its threat to global wheat production.

White thread blight is one of the most common diseases affecting several tree species that grow in warm and humid regions. The typical symptoms of this disease include blighted leaves hanging by a white thread of fungal hyphae. Leaf samples exhibiting white thread blight symptoms were collected from neem (Azadirachta indica A. Juss) and Brazilian cherry pitanga (Eugenia uniflora L.) plants in Northeastern Brazil, and from Indian green-tea (Camellia sinensis (L.) O. Kuntze), coffee (Coffea arabica L.), and persimmon (Diospyros kaki L.) in agricultural areas neighboring the Atlantic forest in Southeastern Brazil. Fungal isolates were obtained indirectly from leaf fragments or directly by transferring mycelia and sclerotia to culture medium. Bright field and scanning electron microscopy images revealed the association of Rhizoctonia-like hyphae and basidiospores with the infected leaves. In pathogenicity tests, Rhizoctonia-like fungal isolates induced leaf necrosis on their hosts, and the pathogens were re-isolated from inoculated plants. Phylogenetic analyses based on sequences of the ITS rRNA region indicated the occurrence of Ceratobasidium lineages distinct from previously reported Ceratobasidium species. Our study leads to the description of two new species of Ceratobasidium: the fungal isolates from A. indica, C. sinensis, and E. uniflora were classified as Ceratobasidium niltonsouzanum sp. nov., and those obtained from C. arabica and D. kaki as Ceratobasidium chavesanum sp. nov.

Candies are foods made from sugar mixture with other ingredients with multiple shape, aroma, color, and consistency. Their consumption is prevalent in children, but spread through all age groups. The packaging ink of some candies may adhere to the surface of the product. These wastes are difficult to remove, and may be ingested. Scanning Electron Microscopy with dispersive energy spectroscopy (SEM/EDS) is used to analyze chewable candies. The results revealed mainly calcium, silicon, potassium, chlorine and sodium. The transfer of iron, titanium and aluminium from the packaging to the candies was observed in 3 lots. Lead residues were found in one batch. From the total samples (n = 40), 15 % were contaminated with packing ink. From those, 66.7 % presented traces of metal and 16.7 % are contaminated with lead. Finally, the results evinced SEM/EDS as an interesting tool for metal analysis in food being easy to operate, portable and non-destructive.

Yellow Sigatoka that is caused by Pseudocercospora musae is an important banana disease. The aim of this study was to elucidate the infection process of P. musae in banana leaves by scanning electron microscopy. Leaf samples were inoculated on the abaxial surface with P. musae and then analysed at 12, 24, 36, 48, 72, 96, 120, 144, and 168 h post inoculation (hpi) and at 36 and 50 days post inoculation (dpi). The conidia were found to be germinated between 24 and 36 hpi and penetrated through the stomata between 96 and 120 hpi, or more generally from 144 hpi. P. musae colonized the spongy parenchyma at 36 dpi and the palisade parenchyma at 50 dpi. Sporulation occurred at 50 dpi on the adaxial surface of leaves through the emergence of conidia on conidiophores through the stomata. Considering the importance of yellow Sigatoka in banana production, our results provide a better understanding of the life cycle of the fungus for treatment processes.

The consumption of probiotics has increased due to the reported health benefits, mainly in preventing or treating gastrointestinal pathology. This study investigated the antimicrobial capacity of yeasts, Saccharomyces cerevisiae and Pichia kluyveri, previously isolated from fermented foods (indigenous beverage, kefir and cocoa) against the adhesion of foodborne pathogens to Caco-2 cells. Co-aggregation of yeasts with pathogens and were evaluated by quantitative analysis and using scanning electron and laser confocal microscopies. All yeasts strains were able to co-aggregate with the tested pathogens, however, this activity was strain-dependent. The inhibition tests showed that the adhesion of Escherichia coli EPEC, Listeria monocytogenes and Salmonella Enteritidis to Caco-2 was reduced by all the yeasts studied. Most of the evaluated yeasts showed inhibition rates equal to or greater than the commercial probiotic Saccharomyces boulardii. The yeasts were able to reduce up to 50% of the bacterial infection, as observed for CCMA0615 towards EPEC in exclusion assay; CCMA0731, CCMA0732 and CCMA0615 towards L. monocytogenes in exclusion and competition assays; and CCMA0731 in exclusion and CCMA0731, CCMA0732, CCMA0615 in competition assay towards S. Enteritidis. No antimicrobial compounds were produced by the yeasts, showing that competition for nutrients and/or receptors in the intestinal mucosa was the mechanism to bacterial inhibition.

This study aimed to isolate and identify endophytic fungi from the forage grass P. maximum and evaluate their ability to inhibit the growth of plant pathogenic fungi. One sample from P. purpureum grass was also included. Surface disinfected stem fragments were used for endophytic fungal isolation. One hundred and twenty-six endophytic fungi were isolated, of which 118 were from P. maximum and eight from P. purpureum. Morphological characteristics and internal transcribed spacer (ITS) and 18S (NS) sequence comparisons identified most isolated endophytic fungi as belonging to the phylum Ascomycota, with Sarocladium being the dominant genus. The isolates were subjected to in vitro antagonism tests against pathogenic fungi, and 31 endophytic fungi inhibited the growth of Bipolaris maydis, Penicillium expansum, and Sclerotinia minor. The results expand our knowledge of the diversity of endophytes associated with tropical grasses and suggest that they may represent new sources of antifungal metabolites for biocontrol and biotechnological purposes.

A brusone é causada pelo fungo Ascomyceto Pyricularia oryzae, sendo a doença mundialmente mais importante do arroz. Além do arroz, P. oryzae causa a brusone em trigo no Brasil, no Paraguai e na Bolívia. A alta variabilidade genético-patotípica observada em populações locais de P. oryzae, é possivelmente responsável pela baixa durabilidade da resistência de cultivares de arroz e trigo a referida doença, e talvez também seja determinante em eventos de 'mudança de hospedeiro' pelo patógeno. Esta revisão tem por objetivo apresentar aspectos relevantes da reprodução sexuada de P. oryzae, bem como informações sobre mecanismos de regulação do ciclo reprodutivo sexual do patógeno por meio dos genes mating type e feromônios, num sistema de reconhecimento específico. O conhecimento da biologia reprodutiva e da importância da reprodução sexuada em P. oryzae é essencial para o manejo da brusone baseado em resistência durável.

The wheat blast disease has been a serious constraint for wheat production in Latin America since the late 1980s. We used a population genomics analysis including 95 genome sequences of the wheat blast pathogenPyricularia graminis-tritici(Pygt) and otherPyriculariaspecies to show thatPygtis a distinct, highly diverse pathogen species with a broad host range. We assayed 11 neutral SSR loci in 526Pygtisolates sampled from wheat and other grasses distributed across the wheat-growing region of Brazil to estimate gene flow, assess the importance of sexual reproduction, and compare the genetic structures ofPygtpopulations infecting wheat and nearby grasses. Our results suggest a mixed reproductive system that includes sexual recombination as well as high levels of gene flow among regions, including evidence for higher gene flow from grass-infecting populations and into wheat-infecting populations than vice versa. The most common virulence groups were shared between the grass- and wheat-infectingPygtpopulations, providing additional evidence for movement ofPygtbetween wheat fields and nearby grasses. Analyses of fruiting body formation found that proto-perithecia and perithecia developed on senescing stems of wheat and other grass hosts, suggesting that sexual reproduction occurs mainly during the saprotrophic phase of the disease cycle on dead residues.Phalaris canariensis(canarygrass) supported the fullest development of perithecia, suggesting it is a promising candidate for identifying the teleomorph in the field. Based on these findings, we formulated a more detailed disease cycle for wheat blast that includes an important role for grasses growing near wheat fields. Our findings strongly suggest that widely grown pasture grasses function as a major reservoir of wheat blast inoculum and provide a temporal and spatial bridge that connects wheat fields across Brazil.Author summaryAfter the first wheat blast epidemic occurred in 1985 in Paraná, Brazil, the disease spread to Bolivia, Argentina, and Paraguay, and was introduced into Bangladesh in 2016 followed by India in 2017. Wheat blast is caused byPyricularia graminis-tritici(Pygt), a highly diverse pathogen species related to the rice blast fungusP. oryzae, but with an independent origin and a broader host range. We conducted a large scale contemporary sampling ofPygtfrom symptomatic wheat and other grass species across Brazil and analyzed the genetic structure ofPygtpopulations.Pygtpopulations on both wheat and other grasses had high genotypic and virulence diversity, a genetic structure consistent with a mixed reproductive system that includes regular cycles of recombination. The pathogen formed sexual fruiting structures (perithecia) on senescing stems of wheat and other grasses. Historical migration analyses indicated that the majority of gene flow has been fromPygtpopulations on other grasses and into thePygtpopulation infecting wheat, consistent with the hypothesis thatPygtoriginated on other grasses before becoming a wheat pathogen. We found that thePygtpopulations infecting wheat were indistinguishable from thePygtpopulations infecting other grass species, including signal grass (Urochloa brizantha). BecauseU. brizanthais a widely grown grass pasture often found next to wheat fields, we propose that it functions as reservoir ofPygtinoculum that provides a temporal and spatial bridge that connects wheat fields in Brazil.

Made available in DSpace on 2021-07-14T10:20:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2017. Added 1 bitstream(s) on 2021-07-14T11:27:41Z : No. of bitstreams: 1 S0100-54052017000100041.pdf: 664040 bytes, checksum: 2086c652e4efeeef2f61937f2a8e64a8 (MD5) A elevada susceptibilidade da soja ao mofo-branco tem impactado negativamente a sua produtividade. Atualmente métodos de controle biológico como o uso de Trichoderma spp. têm proporcionado alternativas ao controle químico, com menor impacto ambiental e favorecimento do desenvolvimento vegetal. Objetivou-se avaliar os efeitos de T. harzianum sobre a emergência de sementes de soja inoculadas com Sclerotinia sclerotiorum; além de verificar a interação entre os fungos e com a soja, por meio da microscopia eletrônica de varredura (MEV). Sementes de soja foram submetidas aos tratamentos: 1. Sem S. sclerotiorum, em BDA+Manitol; 2. Com S. sclerotiorum, em BDA+Manitol; 3. Com Ecotrich®WP e sem S. sclerotiorum, em BDA+Manitol; 4. Com S. sclerotiorum e Ecotrich® WP, em BDA+Manitol. O teste de emergência foi conduzido em bandejas com areia esterilizada a 25 ºC por 8 dias. Após isto foram seccionados órgãos vegetativos das plântulas emergidas para avaliar, por meio da Microscopia Eletrônica de Varredura (MEV), o potencial de T. harzianum em parasitar e inibir S. sclerotiorum. De fato, o mofo-branco é capaz de colonizar e deteriorar todas as sementes de soja. T. harzianum mostra-se efetivo em colonizar o sistema radicular da soja, porém não contribui para a emergência quando comparada com a testemunha. A análise ultraestrutural permitiu evidenciar o micoparasitismo de T. harzianum a S. sclerotiorum, porém o controle do agente causal do mofo-branco não foi efetivo quanto se mostrou em outros estudos. The high susceptibility of soybean to white mold has negatively impacted its productivity. Currently, biological control methods, such as the use of Trichoderma spp., have provided alternatives to chemical control, as they promote less environmental impact and favor the plant growth. The aim of this study was to evaluate the effects of T. harzianum on the emergence of soybean seeds inoculated with Sclerotinia sclerotiorum, besides identifying the interaction between fungi and soybeans by means of scanning electron microscopy (SEM). Soybean seeds were subjected to the following treatments: 1. Without S. sclerotiorum, in PDA+Mannitol; 2. With S. sclerotiorum, in PDA+Mannitol; 3. With Ecotrich®WP and without S. sclerotiorum, in PDA+Mannitol; 4. With S. sclerotiorum and Ecotrich® WP, in PDA+Mannitol. The emergence test was conducted on trays with sterile sand at 25 °C for 8 days. Then, the vegetative organs of emerged seedlings were sectioned to evaluate, by scanning electron microscopy (SEM), T. harzianum potential to parasitize and inhibit S. sclerotiorum. In fact, the white mold is capable of colonizing and deteriorating all soybean seeds. T. harzianum is effective in colonizing the root system of soybeans but does not contribute to emergence, compared to control. Based on the ultrastructural analysis, mycoparasitism of T. harzianum and S. Sclerotiorum was evidenced, but the control of the causal agent of white mold was not as effective as shown in other studies. Universidade Federal de Lavras, Departamento de Fitopatologia Universidade Estadual Paulista “ Júlio de Mesquita”, Faculdade de Ciências Agrárias Universidade Estadual Paulista “ Júlio de Mesquita”, Faculdade de Ciências Agrárias

Pyricularia oryzae is a species complex that causes blast disease on more than 50 species of poaceous plants. Pyricularia oryzae has a worldwide distribution as a rice pathogen and in the last 30 years emerged as an important wheat pathogen in southern Brazil. We conducted phylogenetic analyses using 10 housekeeping loci for 128 isolates of P. oryzae sampled from sympatric populations of wheat, rice, and grasses growing in or near wheat fields. Phylogenetic analyses grouped the isolates into three major clades. Clade 1 comprised isolates associated only with rice and corresponds to the previously described rice blast pathogen P. oryzae pathotype Oryza (PoO). Clade 2 comprised isolates associated almost exclusively with wheat and corresponds to the previously described wheat blast pathogen P. oryzae pathotype Triticum (PoT). Clade 3 contained isolates obtained from wheat as well as other Poaceae hosts. We found that Clade 3 is distinct from P. oryzae and represents a new species, Pyricularia graminis-tritici (Pgt). No morphological differences were observed among these species, but a distinctive pathogenicity spectrum was observed. Pgt and PoT were pathogenic and highly aggressive on Triticum aestivum (wheat), Hordeum vulgare (barley), Urochloa brizantha (signal grass), and Avena sativa (oats). PoO was highly virulent on the original rice host (Oryza sativa), and also on wheat, barley, and oats, but not on signal grass. We conclude that blast disease on wheat and its associated Poaceae hosts in Brazil is caused by multiple Pyricularia species. Pyricularia graminis-tritici was recently found causing wheat blast in Bangladesh. This indicates that P. graminis-tritici represents a serious threat to wheat cultivation globally., Persoonia - Molecular Phylogeny and Evolution of Fungi, 37

Pyricularia oryzae is a species complex that causes blast disease on more than 50 species of poaceous plants. Pyricularia oryzae has a worldwide distribution as a rice (Oryza) pathogen and in the last century emerged as an important wheat (Triticum) pathogen in southern Brazil. Presently, P. oryzae pathotype Oryza is considered the rice blast pathogen, whereas P. oryzae pathotype Triticum is the wheat blast pathogen. In this study we investigated whether the Oryza and Triticum pathotypes of P. oryzae were distinct at the species level. We also describe a new Pyricularia species causing blast on several other poaceous hosts in Brazil, including wheat. We conducted phylogenetic analyses using 10 housekeeping loci from an extensive sample (N = 128) of sympatric populations of P. oryzae adapted to rice, wheat and other poaceous hosts found in or near wheat fields. The Bayesian phylogenetic analysis grouped the isolates into two major monophyletic clusters (I and II) with high Bayesian probabilities (P = 0.99). Cluster I contained isolates obtained from wheat as well as other Poaceae hosts (P = 0.98). Cluster II was divided into three host-associated clades (Clades 1, 2 and 3; P > 0.75). Clade 1 contained isolates obtained from wheat and other poaceous hosts, Clade 2 contained exclusively wheat-derived isolates, and Clade 3 comprised isolates associated only with rice. Our interpretation was that cluster I and cluster II correspond to two distinct species: Pyricularia graminis-tritici sp. nov. (Pgt), newly described in this study, and Pyricularia oryzae (Po). The host-associated clades found in P. oryzae Cluster II correspond to P. oryzae pathotype Triticum (PoT; Clades 1 and 2), and P. oryzae pathotype Oryza (PoO; Clade 3). No morphological or cultural differences were observed among these species, but a distinctive pathogenicity spectrum was observed. Pgt and PoT were pathogenic and highly aggressive on Triticum aestivum (wheat), Hordeum vulgare (barley), Urochloa brizantha (signal grass) and Avena sativa (oats). PoO was highly virulent on the original rice host (Oryza sativa), and also on wheat, barley, and oats, but not on signal grass. We concluded that blast disease on wheat and its associated Poaceae hosts in Brazil is caused by multiple Pyricularia species: the newly described Pyricularia graminis-tritici sp. nov., and the known P. oryzae pathotypes Triticum and Oryza. To our knowledge, P. graminis-tritici sp. nov. is still restricted to Brazil, but obviously represents a serious threat to wheat cultivation globally.

The quality of baby carrots may be associated to the standard of the raw material that in turn, may be influenced by agronomic practices. Thus, the effect of planting density and harvest age were assessed on physical and morphological characteristics, yield and end quality of intact and minimally processed carrots in the form of baby carrots. A randomized block experimental design was used with the density in the plots (4 x 20 cm and 4 x 7.5 cm) and the harvest age in the subplots (50, 57, 64, 71, 78, 85, 92, 99 and 106 days), with five replications. The experimental unit consisted of 25 plants. The assessments of diameter, length, yield, secondary phloem translocation with the cambio and total carotenoids were decisive in selecting the carrot harvest age for baby carrot manufacture. Under the 4 x 20 cm and 4 x 7.5 cm adensed conditions, harvested between 85 and 92 days, carrot roots became thinner and more orange in color (with maximum carotenoid accumulation), larger and with satisfactory yields and therefore more acceptable for minimal processing in the form of baby carrots. Thus the decision of populational density associated to harvest age will depend on the market demand, on price, quality and other variables. The use of adensed cropping with early harvests may lead to obtain carrots and respective baby carrots that are more acceptable for commercialization. A qualidade final de minicenoura pode estar associada ao padrão da matéria prima, que, por sua vez, pode ser influenciada por práticas agronômicas. Por isso, objetivou-se avaliar o efeito da densidade de plantio e da idade de colheita em características físicas, morfológicas, no rendimento e na qualidade final de cenoura inteira e minimamente processada na forma de minicenoura. O delineamento experimental utilizado foi em blocos casualizado, tendo nas parcelas as densidades (4 x 20 cm e 4 x 7,5 cm) e nas subparcelas a idade de colheita (50, 57, 64, 71, 78, 85, 92, 99 e 106 dias), com 5 repetições onde a unidade experimental foi composta por 25 plantas. As características de diâmetro, comprimento, rendimento, descolamento do floema secundário com o câmbio e carotenóides totais foram decisivos para selecionar a idade de colheita de cenoura destinada à fabricação de minicenoura. Nos dois adensamentos estudados, as raízes colhidas entre 85 e 92 dias, tornaram-se mais finas, de cor mais laranja (com máximo acúmulo de carotenóides), maiores, com rendimentos satisfatórios e, portanto, mais aceitáveis ao processamento mínimo na forma de minicenoura. Logo, a decisão de uso de densidade populacional associado à idade para se realizar a colheita, dependerá da exigência do mercado, do preço, qualidade e de outras variáveis. O uso de adensamentos de cultivo associados com colheitas antecipadas pode proporcionar a obtenção de cenoura e respectivas minicenouras mais aceitáveis para comercialização.

S. I. Moreira, Setor de Microbiologia Agricola, Departamento de Biologia, 2 Universidade Federal de Lavras UFLA, 37200-000, Lavras, MG, Brazil; M. P. Melo, 3 C. C. L. Andrade, E. Alves, Departamento de Fitopatologia, Universidade Federal de 4 Lavras UFLA, 37200-000, Lavras, MG, Brazil; O. L. Pereira, Departamento de 5 Fitopatologia, Universidade Federal de Vicosa UFV, 36570-900, Vicosa, MG, Brazil. 6

Estudou-se o efeito da temperatura de armazenamento e do processamento mínimo sobre a atividade da fenilalanina amônia-liase (PAL), peroxidase (POD) e polifenol oxidase (PPO), em folhas de couve (Brassica oleracea var. acephala) por 15 e 9 dias, nas condições de 5 ± 1oC e de 10 ± 1oC, respectivamente. O amarelecimento e a perda de turgescência foram as principais causas para a redução da qualidade visual das folhas inteiras, enquanto nas folhas minimamente processadas apresentaram também, escurecimento, que coincidiu com o aumento na atividade da POD e PPO nas duas temperaturas estudadas. A atividade da PAL em folhas minimamente processadas mantidas a 5oC mais que dobrou até o segundo dia de conservação em relação às conservadas a 10oC. O processamento mínimo influenciou a atividade da PAL, POD e PPO. Todas as enzimas avaliadas, aumentaram a atividade durante a conservação, seja no início, no caso da PAL, ou no final, para a PPO e POD, indicando que as mudanças no metabolismo fenólico desempenha um papel importante no declínio da qualidade de couve. A conservação a 5oC retardou as alterações no metabolismo fenólico, embora nessa temperatura, a atividade da PAL foi maior, em grandeza numérica, em relação às folhas armazenadas à 10oC. We studied the effects of storage temperature on the activities of phenylalanine ammonia- lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO) in minimally processed kale (Brassica oleracea var. acephala) that was stored for 15 and 9 days at 5 ± 1oC and 10 ± 1oC, respectively. The main visual evidence for quality loss in whole leaves was yellowing and loss of turgescence. Minimally processed leaves presented significant browning, indicating increased POD and PPO activities. The PAL activity in minimally processed leaves stored at 5oC was fourfold higher than that of whole leaves after two days of storage. We showed that minimal processing influenced PAL, POD and PPO activities. The activity of all enzymes studied increased during storage, indicating that changes in phenolic metabolism play an important role in the decline of kale quality. PAL activity increased rapidly at the beginning of storage and exhibited a reduced rate of increase over time, while the PPO and POD activities increased continuously over time. The storage at 5 ° C was a great ally in delaying changes in phenolic metabolism; however, the absolute PAL activity was higher at 5 than at 10oC.

The objective of this study was to identify fungi and bacteria associated with the post-harvest rot of ginger rhizomes (Zingiber officinale Roscoe) in the Serrana region of Espírito Santo, Brazil. Rhizomes with symptoms of rot were sampled in the packing-house and in the field soon after harvest. In the packing-house, we report positive pathogenicity tests for Acremonium murorum, Acrostalagmus luteo-albus, Fusarium sp., Fusarium oxysporum, Lasiodiplodia theobromae and Sclerotium rolfsii. For the rhizomes sampled during harvest, the mean incidence of pathogens was as follows: F. oxysporum, 74%; Fusarium sp., 31%; Fusarium solani, 21%; Nigrospora oryzae, 5%; Fusarium semitectum and Nigrospora sphaerica, 6%; Alternaria tenuissima, 4%; Penicillium commune, Verticillium sp.(1) and Verticillium sp.(2), 3%; A. luteo-albus, Aspergillus niger, Chaetomium sp. and Epicoccum sp., 2%; and Curvularia geniculata and Mucor hiemalis, 1%. The mean incidence of bacteria that cause soft rot was as follows: Enterobacter cloacae subsp. cloacae, 4%; and Pseudomonas fluorescens, 1%. The presence of Enterobacter cloacae subsp. cloacae indicated probable fecal contamination. This is the first record of ginger rhizome rot caused by P. fluorescens in the world and the first from A. murorum, A. luteo-albus, L. theobromae and E. cloacae subsp. cloacae causing ginger rhizome rot in Brazil.