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Jose Renato Stangarlin - One of the best experts on this subject based on the ideXlab platform.

  • damages caused by Bipolaris maydis in panicum maximum cv tanzânia
    Semina-ciencias Agrarias, 2010
    Co-Authors: Alexandra Da Silva Martinez, Gilmar Franzener, Jose Renato Stangarlin
    Abstract:

    The aim of this research was to evaluate the damage caused by Bipolaris maydis in the quantity and quality of the Tanzania grass production. Tanzania grass plants were cultivated in pots of PVC tubes (50 cm of height x 15 cm of diameter) containing a mixture of soil and sand (3:1). The plants were inoculated with spore pathogen suspension containing 10 2 , 10 4 and 10 6 conidia/mL to obtain different levels of disease. Severity and number of tillers were evaluated weekly. After four weeks, it were evaluated the weight of the fresh matter of leaves (FM), percentage of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF). The disease reduced significantly the plant tillering and FM after the second evaluation (P

  • dano causado por Bipolaris maydis em panicum maximum cv tanzânia damages caused by Bipolaris maydis in panicum maximum cv tanzânia
    2010
    Co-Authors: Alexandra Da Silva Martinez, Gilmar Franzener, Jose Renato Stangarlin
    Abstract:

    The aim of this research was to evaluate the damage caused by Bipolaris maydis in the quantity and quality of the Tanzania grass production. Tanzania grass plants were cultivated in pots of PVC tubes (50 cm of height x 15 cm of diameter) containing a mixture of soil and sand (3:1). The plants were inoculated with spore pathogen suspension containing 10 2 , 10 4 and 10 6 conidia/mL to obtain different levels of disease. Severity and number of tillers were evaluated weekly. After four weeks, it were evaluated the weight of the fresh matter of leaves (FM), percentage of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF). The disease reduced significantly the plant tillering and FM after the second evaluation (P < 0.05). There was no significant correlation among the variables DM, ADF, and the area under disease progress curve (AUDPC). However, there were positive (P < 0.01) and negative (P < 0.05) correlations among CP and NDF, respectively, with AUDPC, as possible result of the activity of the pathogen. These results showed that B. maydis inhibits the development of the Tanzania grass and promotes alteration in the quality of the forage.

Chihiro Tanaka - One of the best experts on this subject based on the ideXlab platform.

  • an arabinose induced enhancement of asexual reproduction and concomitant changes in metabolic state in the filamentous fungus Bipolaris maydis
    Microbiology, 2021
    Co-Authors: Hiroshi Yoshida, Chihiro Tanaka
    Abstract:

    l-Arabinose, a major constituent pentose of plant cell-wall polysaccharides, has been suggested to be a less preferred carbon source for fungi but to be a potential signalling molecule that can cause distinct genome-wide transcriptional changes in fungal cells. Here, we explore the possibility that this unique pentose influences the morphological characteristics of the phytopathogenic fungus Bipolaris maydis strain HITO7711. When grown on plate media under different sugar conditions, the mycelial dry weight of cultures on l-arabinose was as low as that with no sugar, suggesting that l-arabinose does not substantially contribute to vegetative growth. However, the intensity of conidiation on l-arabinose was comparable to or even higher than that on d-glucose and on d-xylose, in contrast to the poor conidiation under the no-sugar condition. To explore the physiological basis of the passive growth and active conidiation on l-arabinose, we next investigated cellular responses of the fungus to these sugar conditions. Transcriptional analysis of genes related to carbohydrate metabolism showed that l-arabinose stimulates carbohydrate utilization through the hexose monophosphate shunt (HMP shunt), a catabolic pathway parallel to glycolysis and which participates in the generation of the reducing agent NADPH (the reduced form of nicotinamide adenine dinucleotide phosphate). Then, the HMP shunt was impaired by disrupting the related gene BmZwf1, which encodes glucose-6-phosphate dehydrogenase in this fungus. The resulting mutants on l-arabinose showed remarkably decreased conidiation, but a conversely increased mycelial dry weight compared with the wild-type. Our study demonstrates that l-arabinose acts to enhance resource allocation to asexual reproduction in B. maydis HITO7711 at the cost of vegetative growth, and suggests that this is mediated by the concomitant stimulation of the HMP shunt.

  • an adaptor protein bmste50 interacts with bmste11 mapkkk and is involved in host infection conidiation melanization and sexual development in Bipolaris maydis
    Mycoscience, 2020
    Co-Authors: Takuya Sumita, Yuki Kitade, Kosuke Izumitsu, Hiroshi Yoshida, Sae Shigeyoshi, Shunsuke Gotoh, Hiroki Yoshida, Kenya Tsuji, Chihiro Tanaka
    Abstract:

    Abstract A mitogen-activated protein kinase (MAPK) signaling pathway regulates specialized cellular responses to external stimuli. In Bipolaris maydis, a Chk1 MAPK orthologous to Fus3/Kss1 MAPKs of Saccharomyces cerevisiae is known to regulate various developmental processes, including the formation of appressoria. However, upstream factors that regulate the Chk1 cascade have not been well clarified. In this study, we identified and characterized the BmSte50 gene, an ortholog of the yeast Ste50 in B. maydis. Our yeast two-hybrid assay indicated that BmSte50 interacts with a MAPK kinase kinase BmSte11, a component of the Chk1 cascade. ΔBmSte50 strains exhibited a loss of pathogenicity due to a lack of appressorial formation. The mutants also showed a reduction in melanization, conidial production, and aerial-mycelial and sexual development. Such phenotypes of the mutants were consistent with those of the Chk1 cascade gene mutants previously reported. In addition, ΔBmSte50 strains indicated lower conidial germination efficiency than the wild type. Notably, a significant number of ΔBmSte50 conidia could be germinated, while the Chk1 cascade gene mutants were reported to lack conidial germination ability. Our results suggested that BmSte50 may act as an adaptor protein for the Chk1 cascade and is involved in the regulation of various cellular processes.

  • cla4 pak like kinase is required for pathogenesis asexual sexual development and polarized growth in Bipolaris maydis
    Current Genetics, 2019
    Co-Authors: Yuki Kitade, Kosuke Izumitsu, Takuya Sumita, Chihiro Tanaka
    Abstract:

    PAK (p21-activated protein kinases)-like kinases are master regulators of development and morphogenesis, which were conserved among eukaryotes, including fungi. In budding yeast, two types of PAK-like kinases, Ste20 and Cla4 have distinct but shared roles in the regulation of pseudohyphal development, budding and mating. In this study, to examine the broad functions of PAK-like kinases in growth, pathogenicity and asexual/sexual reproduction in filamentous fungi, we identified and characterized two PAK-like kinases, Ste20 and Cla4 in Bipolaris maydis. A single mutant of both Ste20 and Cla4 gene was viable, while the double mutant was not available, possibly because of lethality. In growth, conidiation, and pathogenicity, Δste20 strains showed phenotypes similar to those of the wild-type, while Δcla4 strains showed severely defected phenotypes. In this study, we also clarified that Ste20 is partially involved in pseudothecium development but is dispensable for maternity, while Cla4 is essential for maternal pseudothecium development and also involve in ascospore development in paternal pseudothecium. Fluorescent microscopy visualized the disorder in cell polarity at the hyphal tip in Δcla4. These results suggested that not Ste20 but Cla4 is a master regulator of growth, pathogenicity and asexual/sexual development in B. maydis. In addition, we successfully visualized alternation of branching pattern and distribution of Spitzenkorper at the hyphal tip in Δcla4 strains.

  • monitoring of in planta gene expression for xylan degradation and assimilation in the maize pathogen Bipolaris maydis
    Mycoscience, 2019
    Co-Authors: Hiroshi Yoshida, Chihiro Tanaka
    Abstract:

    Abstract Swift and efficient onset of feeding on host tissue by phytopathogenic fungi is a requisite event for their successful infection and propagation. Necrotrophic fungi colonizing host cell walls appear to obtain carbon and energy sources from plant wall degradants, but what they actually utilize for nutrition after host invasion remains unclear. Here we focus on plant wall xylan, the major hemicellulosic polysaccharide in cereal plants, and study its participation in post-invasion nutrition of the maize necrotrophic pathogen Bipolaris maydis (syn: Cochliobolus heterostrophus). Using a fluorescence reporter assay, we demonstrated that a B. maydis β-xylosidase gene, BmXyp1, is strongly upregulated at the beginning of infection, specifically within invading hyphae. Additionally, our time-course measurements of mRNA expression during maize infection revealed that xylan degradation and assimilation are concomitantly induced during an early infection stage. These findings suggest that this fungus can access xylan degradants as an early in planta nutrient source after host penetration; however, mutant strains deficient in xylan-assimilation ability still retained virulence, although the lesion size was decreased as compared with the wild-type strain. Overall, we conclude that xylan degradation and assimilation by B. maydis are initial post-invasion events but do not play an essential role in fungal nutrient acquisition.

  • Genetic analyses of reddish-brown polyoxin-resistant mutants of Bipolaris maydis
    Mycoscience, 2018
    Co-Authors: Daidi Chen, Hiroshi Masumoto, Yuki Kitade, Kosuke Izumitsu, Chihiro Tanaka
    Abstract:

    Abstract In the southern corn blight fungus, Bipolaris maydis, five polyoxin-resistance genes (Pol1 to Pol5) have been reported. Pol2 and Pol5 are pleiotropic for not only polyoxin resistance but also reddish brown colonies. Here, we used a comparative genomics approach to identify Pol2 and Pol5 at a molecular genetics level. Our analysis revealed that nucleotide sequence variations in the genes for hydroxymethylbilane synthase (HMBS) and ferrochelatase (FECH) were linked to the phenotypes of Pol2 and Pol5, respectively. Further variations in the nucleotide sequences of these genes were also found in other strains of Pol2 and Pol5. Complementation tests with the wild type genes confirmed that these mutations at Hmbs and Fech were responsible for the polyoxin resistance in the Pol2 and Pol5 mutants. The deletion mutants of these genes (ΔHMBS and ΔFECH) were conditionally lethal without exogenous heme. The heme contents of Pol2 and Pol5 mutants were lower than that in the wild type, suggesting that the mutations in hmbs and fech reduced the functions of HMBS and FECH, although neither was completely inactivated. These results suggested Pol2 and Pol5 encode HMBS and FECH, members of enzymes in the heme-biosynthetic pathway of this fungus.

Alexandra Da Silva Martinezfranzener - One of the best experts on this subject based on the ideXlab platform.

  • avaliacao do dano provocado por Bipolaris maydis em panicum maximum cv tanzânia 1
    2006
    Co-Authors: Alexandra Da Silva Martinezfranzener
    Abstract:

    A mancha foliar causada por Bipolaris maydis representa uma das principais doencas da graminea forrageira Panicum maximum cv. Tanzânia-1 (capim Tanzânia), no entanto, nao ha informacoes sobre o dano gerado por esta doenca. O objetivo deste trabalho foi avaliar o dano causado por B. maydis na quantidade e qualidade da producao do capim Tanzânia-1. Inicialmente elaborou-se uma escala diagramatica para a avaliacao da doenca e em seguida realizou-se ensaio em casa de vegetacao. Plantas de capim Tanzânia-1 foram cultivadas em tubos de PVC (50cm de altura x 15 cm de diâmetro) contendo mistura solo/areia (3:1). Foram realizados quatro tratamentos (agua e 102, 104 e 106 conidios/ml) para obtencao de diferentes niveis de doenca, com sete repeticoes. Foram realizadas avaliacoes semanais da severidade e do numero de perfilhos. Apos quatro semanas avaliou-se o peso da materia fresca de folhas (MF), porcentagem de materia seca (PMS), proteina bruta (PB), fibra em detergente neutro (FDN) e fibra em detergente acido (FDA). A escala diagramatica apresentou os seguintes niveis de severidade: 0,4; 1; 3; 6; 13 e 26%. A severidade nas plantas inoculadas variou de 0 a 20%. A doenca reduziu significativamente o perfilhamento e MF a partir da segunda avaliacao (P<0,05). Nao houve correlacao significativa entre as variaveis PMS, FDA e a area abaixo da curva de progresso da doenca (AACPD). No entanto, houve correlacao positiva (P<0,01) e negativa (P<0,05) entre PB e FDN, respectivamente, com a AACPD, como possivel resultado da atividade do patogeno. Estes resultados indicam que B. maydis inibe o desenvolvimento do capim Tanzânia-1 e promove alteracao na qualidade da forragem, mas maiores estudos sao necessarios para compreender os mecanismos envolvidos

Marcelo Vivas - One of the best experts on this subject based on the ideXlab platform.

  • gene effects from Bipolaris maydis incidence and severity on popcorn
    Revista Brasileira de Ciências Agrárias - Brazilian Journal of Agricultural Sciences, 2019
    Co-Authors: Juliana Saltires Santos, Antonio Teixeira Do Amaral, Marcelo Vivas, Rodrigo Moreira Ribeiro, Gabrielle Sousa Mafra, G F Pena
    Abstract:

    Popcorn suffers severe economic losses resulting from harmful effects caused by several diseases such as southern corn leaf blight (SCLB), which is one of the main leaf diseases able to cause considerable damages to corn crops. The realization conducting genetic studies in order to identify genotypes presenting genetic resistance to this disease it is essential. Accordingly, the aim of the current study is to estimate gene effects and combining abilities in popcorn, with emphasis on the resistance to Bipolaris maydis. Full diallel crosses were performed, including reciprocal crosses between eight lines (L76, L88, L70, L77, L55, L61, P1 and P8), in order to produce 56 hybrids (F1’s and reciprocal hybrids). The experiment followed a randomized block design, with four replicates; in two different cultivation periods (first and second periods), in Campos dos Goytacazes, RJ. Southern corn leaf blight incidence and severity, caused by B. maydis, were assessed in each cultivation period. No reciprocal effect was observed for the evaluated characteristics, since the diallel analysis did not find significant effect from this variation source. With respect to SCLB incidence and severity in the two cultivation periods, the mean square of the effects showed that the dominance components were superior to the additivity ones. Hybrids that stood out in the two cultivation periods to the assessed features were: L88 x L61, L88 x L70, L88 x L76, L61 x L77, L61 x P1, L70 x P1, P1 x L76, L77 x L76, and P8 x L77.

  • efeitos genicos da incidencia e severidade de Bipolaris maydis em milho pipoca doi 10 5039 agraria v14i4a5677
    Revista Brasileira de Ciências Agrárias (Agrária), 2019
    Co-Authors: Juliana Saltires Santos, Antonio Teixeira Do Amaral, Marcelo Vivas, Rodrigo Moreira Ribeiro, Gabrielle Sousa Mafra, Guilherme Ferreira Pena
    Abstract:

    Popcorn suffers severe economic losses resulting from harmful effects caused by several diseases such as southern corn leaf blight (SCLB), which is one of the main leaf diseases able to cause considerable damages to corn crops. The realization conducting genetic studies in order to identify genotypes presenting genetic resistance to this disease it is essential. Accordingly, the aim of the current study is to estimate gene effects and combining abilities in popcorn, with emphasis on the resistance to Bipolaris maydis . Full diallel crosses were performed, including reciprocal crosses between eight lines (L76, L88, L70, L77, L55, L61, P1 and P8), in order to produce 56 hybrids (F1 ’s and reciprocal hybrids). The experiment followed a randomized block design, with four replicates; in two different cultivation periods (first and second periods), in Campos dos Goytacazes, RJ. Southern corn leaf blight incidence and severity, caused by B. maydis , were assessed in each cultivation period. No reciprocal effect was observed for the evaluated characteristics, since the diallel analysis did not find significant effect from this variation source. With respect to SCLB incidence and severity in the two cultivation periods, the mean square of the effects showed that the dominance components were superior to the additivity ones. Hybrids that stood out in the two cultivation periods to the assessed features were: L88 x L61, L88 x L70, L88 x L76, L61 x L77, L61 x P1, L70 x P1, P1 x L76, L77 x L76, and P8 x L77.

  • reaction of popcorn lines s7 cultivated in distinct phosphorus levels to Bipolaris maydis infection
    Summa Phytopathologica, 2019
    Co-Authors: Antonio Teixeira Do Amaral, Marcelo Vivas, Tathianne Pastana De Sousa Poltronieri, Pedro Henrique Dias Dos Santos, Ismael Fernando Schegoscheski Gerhardt, Beatriz Murizini Carvalho, Camila Da Silva Freitas, Silvaldo Felipe Da Silveira
    Abstract:

    ABSTRACT Popcorn culture is highly susceptible to helminthosporiosis (Bipolaris maydis) (h-Bm). The genetic breeding of this culture should prioritize resistance to h-Bm and develop cultivars that offer greater crop sustainability, especially in soils with phosphorus (P) scarcity. P-mineral is usually supplied to maize culture by the application of phosphate fertilizers, which are produced from mineral sources rich in P, the natural reserves of which will be depleted in the medium term. With the aim of selecting popcorn genotypes resistant to h-Bm and with higher P utilization capacity, the present study evaluated h-Bm incidence and severity for 25 popcorn lines (S7) cultivated under high and low phosphorus conditions. There was a significant interaction between genotype (lines) and P fertilization for h-Bm resistance, expressed as disease severity values in the first ear leaf. There was genetic variability for disease resistance. The incidence analysis identifies the lines L-65 L-69, L-70 and L-76 as potentially resistant genotypes, presenting low mean values of h-Bm. The severity analysis, however, presents L-69, L-76, P-3 and P-7 genotypes as potentially resistant in environments with fertilization and without fertilization. The obtained data show that the lines L-69 and L-76 had the best resistance performance in both environments. The genetic resistance to h-Bm can somehow correlate with the response to P fertilization at planting in soils with low natural fertility.

  • caracteristicas culturais e patologicas de Bipolaris maydis em diferentes meios de cultura
    Revista Brasileira de Milho e Sorgo, 2017
    Co-Authors: Juliana Saltires Santos, Antonio Teixeira Do Amaral, Marcelo Vivas, Janieli Maganha Silva Vivas, Railan Do Nascimento Ferreira Kurosawa, Silvaldo Felipe Da Silveira
    Abstract:

    RESUMO A mancha de Bipolaris, causada por Bipolaris maydis, e uma das principais doencas foliares de Zea mays, apresentando um consideravel potencial de dano, notadamente, na cultura do milho-pipoca, embora trabalhos sobre este patossistema ainda sejam escassos. Neste trabalho, avaliaram-se as influencias de diferentes meios de cultura sobre o crescimento micelial, esporulacao e a infectividade de inoculo conidial de B. maydis em folhas da cultivar suscetivel Beija-flor, de milho-pipoca. Para tal, instalaram-se experimentos em laboratorio e em casa de vegetacao em blocos casualizados com quatro repeticoes. Em laboratorio, avaliaram-se o crescimento micelial e a esporulacao de B. maydis em diferentes meios de culturas (Batata Dextrose Agar, Feijao Agar, Agua de Coco Agar, Arroz Polido Agar, Folha de Milho Agar e Lactose Caseina Agar). Em casa de vegetacao, avaliaram-se o numero de lesoes por folha e a incidencia de doenca na planta suscetivel inoculada com uma suspensao de 104 conidios/mL. O meio de Arroz Polido Agar foi o que mais promoveu o crescimento micelial do fungo, porem nao favoreceu a esporulacao. Para esporulacao, destacaram-se os meios de cultura Batata Dextrose Agar e Feijao Agar. Maior numero de folhas com sintoma da doenca e maior numero de lesoes por folha foram obtidos com o inoculo produzido no meio Feijao Agar. Palavras-Chave: Zea mays L., Crescimento micelial, Mancha de Bipolaris, Esporulacao, Milho-pipoca. CULTURAL AND PATHOLOGICAL FEATURES OF Bipolaris maydis IN DIFFERENT CULTURE MEDIA ABSTRACT. The Southern corn leaf blight, caused by Bipolaris maydis, is a major foliar disease of corn, presenting considerable potential of damage, especially in Zea mays, although studies with this pathosystem are still scarce. In this paper, the effect of different culture media was evaluated on mycelial sporulation and infectivity of conidial inoculum of B. maydis on leaves of the susceptible cultivar Beija-Flor, of corn-popcorn. Experiments in laboratory and greenhouse were installed in a randomized blocks design with four replications. The mycelial growth and sporulation of B. maydis on different culture media (Potato Dextrose Agar, Bean Agar, Coconut Water Agar, Rice Polished Agar, Corn Leaf Agar Lactose Casein Agar) were evaluated in the laboratory. In the greenhouse it was evaluated the number of lesions per leaf and the incidence of disease in susceptible plants inoculated with a suspension of 104 conidia/ml. The culture medium Polished Rice Agar promoted the highest mycelial growth, but did not promote sporulation. Sporulation was higher on culture media Potato dextrose Agar and Agar Bean. A greater number of leaves with symptoms of the disease and a higher number of lesions per leaf were obtained with the inoculum produced in the culture medium Bean Agar. Keywords: Zea mays L, Mycelial growth, Southern corn leaf bligh, Sporulation, Popcorn.

  • Popcorn germplasm resistance to fungal diseases caused by Exserohilum turcicum and Bipolaris maydis
    Instituto Agronômico de Campinas, 2017
    Co-Authors: Railan Do Nascimento Ferreira Kurosawa, Antonio Teixeira Do Amaral, Marcelo Vivas, Rodrigo Moreira Ribeiro, Samila Barbosa Miranda, Guilherme Ferreira Pena, Jhean Torres Leite, Freddy Mora
    Abstract:

    ABSTRACT Compared with the common corn, popcorn shows greater susceptibility to pests and diseases occurrence, being the use of resistant cultivars the most efficient strategy. In this regard, Germplasm Banks deserve special attention because they contain accessions that can be used as sources of resistance in breeding programs. The State University of Northern Rio de Janeiro (UENF) maintains a popcorn Germplasm Bank with accessions from tropical and temperate countries, including Diversity Centers for the species. In this study, we investigated the performance of 37 popcorn accessions landraces, hybrids, and inbreed lines ― from the Germplasm Collection of UENF’s Popcorn Breeding Program with respect to the fungal leaf diseases northern leaf blight (NLB) and southern leaf blight (SLB), caused by Exserohilum turcicum and Bipolaris maydis, aiming to select promising accessions for genetic resistance to be used in future crosses to generate new resistant cultivars for farmers. The dendrogram scattering by the UPGMA multivariate technique was efficient in discriminating resistant accessions. Satisfactory results were obtained for resistance to NLB in accessions L71, L75, L76, P7, and PARA-172, which can thus be considered remarkable sources of resistance. For resistance to SLB, the superior accessions that can be indicated as sources of resistance are ARZM-05083, ARZM-07049, and PARA-172

Antonio Teixeira Do Amaral - One of the best experts on this subject based on the ideXlab platform.

  • gene effects from Bipolaris maydis incidence and severity on popcorn
    Revista Brasileira de Ciências Agrárias - Brazilian Journal of Agricultural Sciences, 2019
    Co-Authors: Juliana Saltires Santos, Antonio Teixeira Do Amaral, Marcelo Vivas, Rodrigo Moreira Ribeiro, Gabrielle Sousa Mafra, G F Pena
    Abstract:

    Popcorn suffers severe economic losses resulting from harmful effects caused by several diseases such as southern corn leaf blight (SCLB), which is one of the main leaf diseases able to cause considerable damages to corn crops. The realization conducting genetic studies in order to identify genotypes presenting genetic resistance to this disease it is essential. Accordingly, the aim of the current study is to estimate gene effects and combining abilities in popcorn, with emphasis on the resistance to Bipolaris maydis. Full diallel crosses were performed, including reciprocal crosses between eight lines (L76, L88, L70, L77, L55, L61, P1 and P8), in order to produce 56 hybrids (F1’s and reciprocal hybrids). The experiment followed a randomized block design, with four replicates; in two different cultivation periods (first and second periods), in Campos dos Goytacazes, RJ. Southern corn leaf blight incidence and severity, caused by B. maydis, were assessed in each cultivation period. No reciprocal effect was observed for the evaluated characteristics, since the diallel analysis did not find significant effect from this variation source. With respect to SCLB incidence and severity in the two cultivation periods, the mean square of the effects showed that the dominance components were superior to the additivity ones. Hybrids that stood out in the two cultivation periods to the assessed features were: L88 x L61, L88 x L70, L88 x L76, L61 x L77, L61 x P1, L70 x P1, P1 x L76, L77 x L76, and P8 x L77.

  • efeitos genicos da incidencia e severidade de Bipolaris maydis em milho pipoca doi 10 5039 agraria v14i4a5677
    Revista Brasileira de Ciências Agrárias (Agrária), 2019
    Co-Authors: Juliana Saltires Santos, Antonio Teixeira Do Amaral, Marcelo Vivas, Rodrigo Moreira Ribeiro, Gabrielle Sousa Mafra, Guilherme Ferreira Pena
    Abstract:

    Popcorn suffers severe economic losses resulting from harmful effects caused by several diseases such as southern corn leaf blight (SCLB), which is one of the main leaf diseases able to cause considerable damages to corn crops. The realization conducting genetic studies in order to identify genotypes presenting genetic resistance to this disease it is essential. Accordingly, the aim of the current study is to estimate gene effects and combining abilities in popcorn, with emphasis on the resistance to Bipolaris maydis . Full diallel crosses were performed, including reciprocal crosses between eight lines (L76, L88, L70, L77, L55, L61, P1 and P8), in order to produce 56 hybrids (F1 ’s and reciprocal hybrids). The experiment followed a randomized block design, with four replicates; in two different cultivation periods (first and second periods), in Campos dos Goytacazes, RJ. Southern corn leaf blight incidence and severity, caused by B. maydis , were assessed in each cultivation period. No reciprocal effect was observed for the evaluated characteristics, since the diallel analysis did not find significant effect from this variation source. With respect to SCLB incidence and severity in the two cultivation periods, the mean square of the effects showed that the dominance components were superior to the additivity ones. Hybrids that stood out in the two cultivation periods to the assessed features were: L88 x L61, L88 x L70, L88 x L76, L61 x L77, L61 x P1, L70 x P1, P1 x L76, L77 x L76, and P8 x L77.

  • reaction of popcorn lines s7 cultivated in distinct phosphorus levels to Bipolaris maydis infection
    Summa Phytopathologica, 2019
    Co-Authors: Antonio Teixeira Do Amaral, Marcelo Vivas, Tathianne Pastana De Sousa Poltronieri, Pedro Henrique Dias Dos Santos, Ismael Fernando Schegoscheski Gerhardt, Beatriz Murizini Carvalho, Camila Da Silva Freitas, Silvaldo Felipe Da Silveira
    Abstract:

    ABSTRACT Popcorn culture is highly susceptible to helminthosporiosis (Bipolaris maydis) (h-Bm). The genetic breeding of this culture should prioritize resistance to h-Bm and develop cultivars that offer greater crop sustainability, especially in soils with phosphorus (P) scarcity. P-mineral is usually supplied to maize culture by the application of phosphate fertilizers, which are produced from mineral sources rich in P, the natural reserves of which will be depleted in the medium term. With the aim of selecting popcorn genotypes resistant to h-Bm and with higher P utilization capacity, the present study evaluated h-Bm incidence and severity for 25 popcorn lines (S7) cultivated under high and low phosphorus conditions. There was a significant interaction between genotype (lines) and P fertilization for h-Bm resistance, expressed as disease severity values in the first ear leaf. There was genetic variability for disease resistance. The incidence analysis identifies the lines L-65 L-69, L-70 and L-76 as potentially resistant genotypes, presenting low mean values of h-Bm. The severity analysis, however, presents L-69, L-76, P-3 and P-7 genotypes as potentially resistant in environments with fertilization and without fertilization. The obtained data show that the lines L-69 and L-76 had the best resistance performance in both environments. The genetic resistance to h-Bm can somehow correlate with the response to P fertilization at planting in soils with low natural fertility.

  • caracteristicas culturais e patologicas de Bipolaris maydis em diferentes meios de cultura
    Revista Brasileira de Milho e Sorgo, 2017
    Co-Authors: Juliana Saltires Santos, Antonio Teixeira Do Amaral, Marcelo Vivas, Janieli Maganha Silva Vivas, Railan Do Nascimento Ferreira Kurosawa, Silvaldo Felipe Da Silveira
    Abstract:

    RESUMO A mancha de Bipolaris, causada por Bipolaris maydis, e uma das principais doencas foliares de Zea mays, apresentando um consideravel potencial de dano, notadamente, na cultura do milho-pipoca, embora trabalhos sobre este patossistema ainda sejam escassos. Neste trabalho, avaliaram-se as influencias de diferentes meios de cultura sobre o crescimento micelial, esporulacao e a infectividade de inoculo conidial de B. maydis em folhas da cultivar suscetivel Beija-flor, de milho-pipoca. Para tal, instalaram-se experimentos em laboratorio e em casa de vegetacao em blocos casualizados com quatro repeticoes. Em laboratorio, avaliaram-se o crescimento micelial e a esporulacao de B. maydis em diferentes meios de culturas (Batata Dextrose Agar, Feijao Agar, Agua de Coco Agar, Arroz Polido Agar, Folha de Milho Agar e Lactose Caseina Agar). Em casa de vegetacao, avaliaram-se o numero de lesoes por folha e a incidencia de doenca na planta suscetivel inoculada com uma suspensao de 104 conidios/mL. O meio de Arroz Polido Agar foi o que mais promoveu o crescimento micelial do fungo, porem nao favoreceu a esporulacao. Para esporulacao, destacaram-se os meios de cultura Batata Dextrose Agar e Feijao Agar. Maior numero de folhas com sintoma da doenca e maior numero de lesoes por folha foram obtidos com o inoculo produzido no meio Feijao Agar. Palavras-Chave: Zea mays L., Crescimento micelial, Mancha de Bipolaris, Esporulacao, Milho-pipoca. CULTURAL AND PATHOLOGICAL FEATURES OF Bipolaris maydis IN DIFFERENT CULTURE MEDIA ABSTRACT. The Southern corn leaf blight, caused by Bipolaris maydis, is a major foliar disease of corn, presenting considerable potential of damage, especially in Zea mays, although studies with this pathosystem are still scarce. In this paper, the effect of different culture media was evaluated on mycelial sporulation and infectivity of conidial inoculum of B. maydis on leaves of the susceptible cultivar Beija-Flor, of corn-popcorn. Experiments in laboratory and greenhouse were installed in a randomized blocks design with four replications. The mycelial growth and sporulation of B. maydis on different culture media (Potato Dextrose Agar, Bean Agar, Coconut Water Agar, Rice Polished Agar, Corn Leaf Agar Lactose Casein Agar) were evaluated in the laboratory. In the greenhouse it was evaluated the number of lesions per leaf and the incidence of disease in susceptible plants inoculated with a suspension of 104 conidia/ml. The culture medium Polished Rice Agar promoted the highest mycelial growth, but did not promote sporulation. Sporulation was higher on culture media Potato dextrose Agar and Agar Bean. A greater number of leaves with symptoms of the disease and a higher number of lesions per leaf were obtained with the inoculum produced in the culture medium Bean Agar. Keywords: Zea mays L, Mycelial growth, Southern corn leaf bligh, Sporulation, Popcorn.

  • Popcorn germplasm resistance to fungal diseases caused by Exserohilum turcicum and Bipolaris maydis
    Instituto Agronômico de Campinas, 2017
    Co-Authors: Railan Do Nascimento Ferreira Kurosawa, Antonio Teixeira Do Amaral, Marcelo Vivas, Rodrigo Moreira Ribeiro, Samila Barbosa Miranda, Guilherme Ferreira Pena, Jhean Torres Leite, Freddy Mora
    Abstract:

    ABSTRACT Compared with the common corn, popcorn shows greater susceptibility to pests and diseases occurrence, being the use of resistant cultivars the most efficient strategy. In this regard, Germplasm Banks deserve special attention because they contain accessions that can be used as sources of resistance in breeding programs. The State University of Northern Rio de Janeiro (UENF) maintains a popcorn Germplasm Bank with accessions from tropical and temperate countries, including Diversity Centers for the species. In this study, we investigated the performance of 37 popcorn accessions landraces, hybrids, and inbreed lines ― from the Germplasm Collection of UENF’s Popcorn Breeding Program with respect to the fungal leaf diseases northern leaf blight (NLB) and southern leaf blight (SLB), caused by Exserohilum turcicum and Bipolaris maydis, aiming to select promising accessions for genetic resistance to be used in future crosses to generate new resistant cultivars for farmers. The dendrogram scattering by the UPGMA multivariate technique was efficient in discriminating resistant accessions. Satisfactory results were obtained for resistance to NLB in accessions L71, L75, L76, P7, and PARA-172, which can thus be considered remarkable sources of resistance. For resistance to SLB, the superior accessions that can be indicated as sources of resistance are ARZM-05083, ARZM-07049, and PARA-172