Phenolic compounds and antifungal activity of ethyl acetate extract and methanolic extract from Capsicum chinense Jacq. ripe fruit / Compostos fenólicos e atividade antifúngica dos extratos acetato de etila e metanólico dos frutos maduros de Capsicum chinense Jacq

Food loss due to contamination caused by fungi has much impact on agriculture and leads to significant economic losses. Synthetic and natural fungicides have been used for avoiding losses of several food products due to fungal contamination. As a result, species of the genus Capsicum have been used for preserving food because of their chemical compounds with antifungal activity. Therefore, this study aimed at identifying some phenolic compounds found in both ethyl acetate extract (EAE) and methanolic extract (ME) from habanero pepper (C. chinense) ripe fruit by liquid chromatography tandem mass spectrometry with electrospray ionization (LC-ESI-MS/MS) and at evaluating their antifungal activities against fungi Sclerotinia sclerotiorum, Rhizopus stolonifer and Colletotrichum gloeosporioides. Extracts resulted from a sequential process of maceration. Antifungal activity was evaluated by the disk diffusion method (DDM) at the following doses of both diluted extracts: 25 µL, 50 µL, 100 µL and 200 µL. The chemical analysis showed that there were protocatechuic acid, gentisic acid, vanillic acid, kaempferol-3-O-robinobiosideo and naringenin in both extracts. EAE showed high inhibition of mycelial growth at both doses 100µL and 200µL against the three fungi while methanolic exhibited weak activity even at the highest dose under investigation. However, further in-depth studies are needed to reinforce their uses and practical applications to the agricultural field.

As perdas de alimentos por contaminação causada por fungos são de grande impacto negativo para a agricultura, gerando altos prejuízos econômicos. Para evitar as perdas de diversos produtos alimentícios pela contaminação fúngica são utilizados fungicidas sintéticos e naturais. As espécies do gênero Capsicum são usadas há muitos anos para auxiliar na conservação de alimentos por possuírem substâncias químicas com ação antifúngica entre outras. Neste contexto, o objetivo deste estudo foi identificar alguns compostos fenólicos por cromatografia líquida de alta eficiência acoplada à espectrometria de massas sequencial (LC-ESI-MS/MS) presentes nos extratos acetato de etila (EAE) e metanólico (ME) dos frutos maduros da pimenta biquinho (C. chinense) e avaliar atividade antifúngica de EAE e ME contra os fungos Sclerotinia sclerotiorum, Rhizopus stolonifer e Colletotrichum gloeosporioides. Os extratos foram obtidos de forma sequencial, utilizando o procedimento de maceração. A atividade antifúngica foi avaliada seguindo a metodologia de difusão em disco, nas doses de 25 µL, 50 µL, 100 µL e 200 µL de cada extrato diluído. A análise química evidenciou a presença de ácido protocatequico, ácido gentisico, ácido vanílico, kaempferol-3-O-robinobiosídeo e naringenina em ambos os extratos. EAE revelou maior poder de inibição do crescimento micelial nas doses de 100µL e 200µL contra os três fungos testados, enquanto ME exibiu fraca atividade inclusive na maior dose investigada. Entretanto, estudos mais aprofundados ainda são necessários para consolidar seu uso e aplicação prática na área agronômica.

Phenolic compounds and antifungal activity of ethyl acetate extract and methanolic extract from Capsicum chinense Jacq. ripe fruit

Abstract Food loss due to contamination caused by fungi has much impact on agriculture and leads to significant economic losses. Synthetic and natural fungicides have been used for avoiding losses of several food products due to fungal contamination. As a result, species of the genus Capsicum have been used for preserving food because of their chemical compounds with antifungal activity. Therefore, this study aimed at identifying some phenolic compounds found in both ethyl acetate extract (EAE) and methanolic extract (ME) from habanero pepper (C. chinense) ripe fruit by liquid chromatography tandem mass spectrometry with electrospray ionization (LC-ESI-MS/MS) and at evaluating their antifungal activities against fungi Sclerotinia sclerotiorum, Rhizopus stolonifer and Colletotrichum gloeosporioides. Extracts resulted from a sequential process of maceration. Antifungal activity was evaluated by the disk diffusion method (DDM) at the following doses of both diluted extracts: 25 µL, 50 µL, 100 µL and 200 µL. The chemical analysis showed that there were protocatechuic acid, gentisic acid, vanillic acid, kaempferol-3-O-robinobiosideo and naringenin in both extracts. EAE showed high inhibition of mycelial growth at both doses 100µL and 200µL against the three fungi while methanolic exhibited weak activity even at the highest dose under investigation. However, further in-depth studies are needed to reinforce their uses and practical applications to the agricultural field.

Resumo As perdas de alimentos por contaminação causada por fungos são de grande impacto negativo para a agricultura, gerando altos prejuízos econômicos. Para evitar as perdas de diversos produtos alimentícios pela contaminação fúngica são utilizados fungicidas sintéticos e naturais. As espécies do gênero Capsicum são usadas há muitos anos para auxiliar na conservação de alimentos por possuírem substâncias químicas com ação antifúngica entre outras. Neste contexto, o objetivo deste estudo foi identificar alguns compostos fenólicos por cromatografia líquida de alta eficiência acoplada à espectrometria de massas sequencial (LC-ESI-MS/MS) presentes nos extratos acetato de etila (EAE) e metanólico (ME) dos frutos maduros da pimenta biquinho (C. chinense) e avaliar atividade antifúngica de EAE e ME contra os fungos Sclerotinia sclerotiorum, Rhizopus stolonifer e Colletotrichum gloeosporioides. Os extratos foram obtidos de forma sequencial, utilizando o procedimento de maceração. A atividade antifúngica foi avaliada seguindo a metodologia de difusão em disco, nas doses de 25 µL, 50 µL, 100 µL e 200 µL de cada extrato diluído. A análise química evidenciou a presença de ácido protocatequico, ácido gentisico, ácido vanílico, kaempferol-3-O-robinobiosídeo e naringenina em ambos os extratos. EAE revelou maior poder de inibição do crescimento micelial nas doses de 100µL e 200µL contra os três fungos testados, enquanto ME exibiu fraca atividade inclusive na maior dose investigada. Entretanto, estudos mais aprofundados ainda são necessários para consolidar seu uso e aplicação prática na área agronômica.

Biosíntesis inducida de fengicina y surfactina en una cepa de Bacillus amyloliquefaciens con actividad oomiceticida sobre zoosporas de Phytophthora capsica / Induced biosynthesis of fengycin and surfactin in a strain of Bacillus amyloliquefaciens with oomyceticidal activity on zoospores of Phytophthora capsici

Resumen La aplicación de metabolitos antimicrobianos biosintetizados por especies de Bacillus es una alternativa potencial para controlar Phytophthora capsici (P. capsici) en hortalizas y podría evitar el uso de productos químicos con acción oomiceticida. El objetivo de este estudio fue evaluar el impacto de la adición al medio de cultivo de distintos agentes (ácido glutámico, hierro, celulosa, quitina y células inactivas de Colletotrichum spp.) sobre la biosíntesis de lipopéptidos en Bacillus amyloliquefaciens KX953161.1 y examinar la capacidad oomiceticida de dichos compuestos in vitro sobre las zoosporas de P. capsici. Los lipopéptidos identificados y cuantificados por cromatografía en capa fina de alta resolución (HPTLC) en los extractos crudos fueron fengicina y surfactina. El cultivo bacteriano adicionado con células inactivas de Colletotrichum spp. demostró la mayor biosíntesis de lipopéptidos: 1.847,02 ±11,8 pg/mL de fengicina y 2.563,45 ± 18,4 pg/mL de surfactina. Los tratamientos con menor producción de estos lipopéptidos fueron aquellos a los que se añadió hierro (608,05 ± 22,6 pg/mL de fengicina y 903,74 ±22,1 pg/mL de surfactina) o celulosa (563,31 ±11,9 y 936,96 ±41,1 pg/mL, igual orden). El extracto con los lipopéptidos presentó una inhibición del 100% en la germinación de zoosporas de P. capsici, se observó enquistamiento, malformaciones en el tubo germinal y degradación celular. Se concluye que los lipopéptidos producidos por B. amyloliquefaciens KX953161.1 podrían contribuir al control de P. capsici, sin embargo, se requieren más estudios a fin de elucidar el modo de acción biológica de estos compuestos y optimizar el perfil de producción y el rendimiento.

Abstract A potential alternative to the use of chemical products with oomyceticidal action for the control of Phytophthora capsici in vegetables is the use of antimicrobial metabolites, biosynthesized in Bacillus species. The objective of this study was to induce the biosynthesis of lipopeptides in Bacillus amyloliquefaciens KX953161.1 by using glutamic acid, iron, cellulose, chitin, or inactive Colletotrichum spp. cells. The in vitro oomyceticidal effect of the bacterial lipopeptides on zoospores of Phytophthora capsici was evaluated. The lipopeptides identified and quantified in the crude extracts by high performance thin layer chromatography (HPTLC) were fengycin and surfactin. The bacterial culture with inactive fungal cells yielded the greatest biosynthesis of lipopeptides, at 1847.02± 11.8 and 2563.45± 18.4 pg/ml of fengycin and surfactin, respectively and the treatments that obtained lower production of these lipopepti-des, were those to which iron and cellulose were added with 608.05 ± 22.6 and 903.74± 22.1; 563.31± 11.9 and 936.96± 41.1 pg/ml for fengicin and surfactin, respectively. The lipopeptide extracted showed 100% germination inhibition on zoospores of P. capsici, revealing encystment, malformations in the germ tube and cellular degradation. Lipopeptides have the potential to control P. capsici; however, the biosynthesis of these lipopeptides requires further study to determine their biological mode of action and optimize lipopeptide performance and profile.

In vitro bioprospecting of rhizospheric fungi associated to cactus (Opuntia cochenillifera) to plant growth promotion / Bioprospección in vitro de hongos rizosféricos asociados al cactus (Opuntia cochenillifera) para la promoción del crecimiento vegetal

Abstract This study aimed to evaluate in vitro the plant growth promotion capacity of rhizospheric fungi from Opuntia cochenillifera. The isolates were submitted to phosphate solubilization, acetic acid-3-indole (AIA) production, antagonism against phytopathogens, and growth under water activity. All test results were subjected to statistical analysis. The studied isolates were able to solubilize phosphate, being F04 (Aspergillus sp.) and F05 (Coprinellus radians) the ones that presented the highest solubilization indices. As to produce AIA, F02 (Penicillium sp.) and F07 (Aspergillus sp.) were the most promising. All isolates could inhibit the growth of Colletotrichum sp. and Fusarium sp. Water restriction provided mycelial growth for all isolates. Therefore, these characteristics confer characteristics as growth promoters in plants.

Resumen El objetivo de este estudio fue evaluar in vitro la capacidad de los hongos rizosféricos aislados del cactus Opuntia cochenillifera para promover el crecimiento de las plantas. Los aislados fueron sometidos a pruebas de solubilización de fosfato, producción de ácido 3-indol acético (AIA), antagonismo contra fitopatógenos y crecimiento bajo actividad de agua. Todos los resultados de las pruebas se sometieron a análisis estadístico. Los aislados estudiados fueron capaces de solubilizar fosfato, siendo F04 (Aspergillus sp.) y F05 (Coprinellus radians) los que presentaron los mayores índices de solubilización. Sobre la producción de AIA, los que más produjeron fueron F02 (Penicillium sp.) y F07 (Aspergillus sp.). Todos los aislados pudieron inhibir el crecimiento de Colletotrichum sp. e Fusarium sp.. La restricción de agua proporcionó el crecimiento del micelio para todos los aislados. Por lo tanto, estes aspectos les confieren características como promotores del crecimiento en las plantas.

Resistance to diseases of sour, sweet and wild passion fruit genotypes

The cultivation of passion fruit is important for Brazil, since the country is currently the largest producer and consumer of fruit in the world. However, the fields of passion fruit still face important problems due to the incidence and severity of diseases in the field. Thus, the present study aimed to assess resistance to bacterial and fungal diseases in 13 genotypes of sour, sweet and wild passion fruit, in field conditions in the Distrito Federal, Brazil. For this, a field experiment was installed in a randomized block design, with four replications and 13 treatments (genotypes). The characteristics of incidence, severity and degree of resistance for bacteriosis, septoriosis, scab and anthracnose diseases were evaluated in 5 fruits per plot of each genotype. Genetic parameters of the evaluated traits were also estimated. High heritability values and CVg/Cve ratio were observed for most of the evaluated characteristics. The genotypes presented mean values of incidence and severity of bacteriosis, septoriosis, scab and anthracnose different among them, and the one that presented the best results in the degree of resistance for all diseases was F1 (MAR20 # 24 x ECL7 P1 R4).

Antagonismo de rizobacterias sobre hongos fitopatógenos, y su actividad microbiana con potencial biofertilizante, bioestimulante y biocontrolador / Antagonism of rhizobacteria on phytopathogenic fungi, and their microbial activity with biofertilizer, biostimulant and biocontroller potential

RESUMEN Las rizobacterias forman parte de la gran cantidad de microorganismos que actúan como agentes de biocontrol, produciendo metabolitos que inducen resistencia sistémica en las plantas que inhiben el crecimiento de patógenos. El objetivo de esta investigación fue evaluar la capacidad de diez rizobacterias de los géneros Rhizobium, Bradyrhizobium, Sinorhizobium, Ochrobactrum y Pseudomonas para producir ácido cianhídrico (HCN), sideróforos y ácido indol-acético (AIA), disolver fosfato, fijar nitrógeno e inhibir el crecimiento de fitopatógenos. Se realizaron todas las pruebas fisiológicas y bioquímicas correspondientes, así como la prueba de antagonismo in vitro contra los fitopatógenos Fusarium oxysporum, Colletotrichum gloeosporioides y Rhizoctonia solani. Cinco cepas produjeron una mayor cantidad de AIA en relación a las otras en presencia de triptófano, la cepa ES1 (Ochrobactrum sp.) produjo HCN, el 50 % de las cepas evaluadas liberaron sideróforos, el 60 % disolvió fósforo, y todas resultaron positivas para la fijación de nitrógeno. Nueve cepas inhibieron el crecimiento de F. oxysporum entre 40 % y 65 %, la cepa Alf (Pseudomonas fluorescens) inhibió además el crecimiento de C. gloeosporioides en un 22 %, y ninguna inhibió el crecimiento de R. solani. Los rizobios evaluados y la cepa de Pseudomonas fluorescens podrían ejercer efectos beneficiosos sobre las plantas a través de mecanismos directos e indirectos, o una combinación de ambos, lo que las convierte en una opción sostenible para la producción de cultivos.

ABSTRACT Rhizobacteria are part of the large number of microorganisms that act as biocontrol agents, producing metabolites that induce systemic resistance in plants and inhibit the growth of pathogens. The objective of this research was to evaluate the capacity of ten rhizobacteria of the genera Rhizobium, Bradyrhizobium, Sinorhizobium, Ochrobactrum and Pseudomonas to produce hydrogen cyanide (HCN), siderophores and indole acetic acid (IAA), dissolve phosphate, fix nitrogen and inhibit the growth of phytopathogens. All the corresponding physiological and biochemical tests were carried out, in addition to an in vitro antagonism test against the phytopathogens Fusarium oxysporum, Colletotrichum gloeosporioides and Rhizoctonia solani. Five strains produced a greater amount of IAA with respect to the others in the presence of tryptophan, the strain ES1 (Ochrobactrum sp.) produced HCN, 50% of the evaluated strains released siderophores, 60% solubilized phosphorus and all were positive for nitrogen fixation. Nine strains inhibited the growth of F. oxysporum by 40% to 65%. The Alf strain (Pseudomonas fluorescens) inhibited the growth of C. gloeosporioides by 22% while none inhibited the growth of R. solani. The rhizobia tested and the Pseudomonas fluorescens strain may have favorable effects on plants through direct and indirect mechanisms, or a combination of both, making them a sustainable option for crop production.

Antagonistic activity of bacteria from wild honey against Colletotrichum musae, and testing of wild honey as biopesticide spray to control banana anthracnose

Anthracnose is a foliar and fruit disease caused by Colletotrichum spp. affecting a wide range of crops. Infection occurs early followed by quiescence in fruits, such as in banana, where chemical-based pesticides are used as a dependable fungal control for many years. There is an increasing need for a safe control and as implicated in the Organic Agriculture Act of 2010 (RA 10068) in the Philippines. This scenario drove the use of alternative pest control such as the use of biologicals and natural products. In this study, seven bacteria were isolated from wild honey, produced by Apis mellifera, wherein four (BC2, BC3, BC6 and BC7) were found to be an effective antagonist against Colletotrichum musae in in vitro conditions. These bacteria were identified to belong to the genus Lactobacillus spp. (BC2, BC3, BC7) and Bacillus spp. (BC6) based on sugar utilization tests, morphological and cultural growth in PDPA. For the in vivo test, different dilutions of wild honey were used and it was found out that lower concentrations were effective as biopesticide spray to prevent anthracnose infection. Lastly, we report herewith the first isolation of bacteria with biological control potential from wild honey, and to apply the raw or natural product as biopesticide in postharvest fruits.

A novel pathogenic Colletotrichum species for rhizome rot disease of Polygonatum kingianum / 中国中药杂志

Rhizome rot disease is one of the main disease of planted Polygonatum kingianum. In this study, six strains of pathogenic fungus was isolated from P. kingianum samples with rhizome rot disease collected from six counties in Yunnan province. Its pathogenicity was confirmed by inoculation to healthy P. kingianum rhizome according to Koch's postulates. The colonies of the isolated fungi on potato dextrose agar(PDA) were orange with abundant crescentic conidia which were eseptate with a mean size of 19. 3-24. 9 μm×5. 2-5. 9 μm and a L/W ratio of 3. 4-4. 5. There was an oil ball in the center of the conidium. It's easy to see setae on PDA colony.The phylogenetic tree based on ITS, GAPDH, CHS-1, HIS3, ACT, and TUB2 sequences by maximum likelihood(ML) method indicated that the pathogenic fungus for P. kingianum rhizome rot disease was clustered into the clade of Colletotrichum spaethianum species complex, and was close to C. spaethianum. However, there were some differences in morphological and genetic characteristics between the pathogenic fungus and C. spaethianum. Therefore, the pathogenic fungus for rhizome rot disease of P. kingianum was identified as a new Colletotrichum species named C. kingianum. The disease spreads primarily due to the plantation of infected seedlings of P. kingianum. It is necessary to choose healthy seedlings and take rigorous disinfection measures for the disease prevention.

A new phenolic acid ester from solid culture of Colletotrichum capsici, an endophytic fungus from Paeonia lactiflora / 中国中药杂志

A new phenolic acid ester, 4'-hydroxyphenylethyl 4,8(R)-dihydroxyphenylpropionate(1), was isolated from an endophytic fungus Colletotrichum capsici of Paeonia lactiflora roots, along with eight known phenolic derivatives, tyrosol(2), 2-(4-hydroxyphenyl) ethyl acetate(3), methyl p-hydroxyphenylacetate(4), methyl m-hydroxyphenylacetate(5), 4-(4-hydroxyphene-thoxy)-4-oxobutanoic acid(6), 4-hydroxyphenethyl methyl succinate(7), trichodenol B(8) and 4-hydroxyphenethyl 2-(4-hydroxyphenyl) acetate(9). Their structures were identified by a combination of high-resolution electrospray ionization mass spectrometry(HR-ESI-MS), nuclear magnetic resonance(NMR) spectroscopy, ultraviolet(UV) spectroscopy and electronic circular dichroism(ECD) spectroscopy. Compounds 2-9 were isolated from this fungus for the first time.

Morphological and molecular identification of Fusarium spp. and Colletotrichum spp. isolated from infected vanilla orchid

Aims@#This study aimed to isolate and identify fungi involved in causing diseases to Vanilla planifolia as well as to study their pathogenicity level in causing disease.@*Methodology and results@#The diseased parts of vanilla plants were collected from vanilla farms located in Pahang and Sabah, Malaysia from May 2015 to May 2016. Diseases tissue transplantation was adopted to isolate the fungi for morphology identification prior to the polymerase chain reaction (PCR) amplification of internal transcribed spacer (ITS) regions using universal primers for fungi, ITS1 and ITS4. After being isolated, the fungi pathogenicity was tested on detached fresh and mature vanilla leaves. A total of 22 fungal isolates were identified, Fusarium fujikuroi and F. oxysporum were the two most recovered species, followed by Colletotrichum gloeosporioides, Fusarium sp., F. proliferatum and F. solani. Pathogenicity test revealed a significantly high pathogenicity of F. oxysporum and C. gloeosporiodes (p<0.01) on detached vanilla leaf, with high level of damage. @*Conclusion, significance and impact of study@#This study provides valuable information on fungi-associated diseases on vanilla plants grown in Malaysia and can be used for future development in disease management.

Diagrammatic scale for assessment of anthracnose severity in feijoa fruit / Escala diagramática para avaliação da severidade de Antracnose em frutos de feijoa

ABSTRACT: A diagrammatic scale of anthracnose in feijoa fruit was elaborated and validated in order to standardize disease severity assessments. The proposed scale showed six disease severity levels: 2, 10, 20, 40, 70 and 100% of the injured fruit surface. The scale took into account the minimum and maximum limits of disease severity observed in the field and the intermediate values followed logarithmic increments according to the Weber-Fechner stimulus-response law. Eight inexperienced raters validated the scale by quantifying the disease severity (using/not using the scale) of 50 feijoas with anthracnose symptoms. In conclusion, the scale improved the assessment of anthracnose in feijoa. Eight genotypes from different crosses were tolerant to anthracnose.

RESUMO: Com o objetivo de padronizar avaliações da severidade da antracnose em frutos de feijoa elaborou-se e validou-se uma escala diagramática com os seguintes níveis de severidade: 2, 10, 20, 40, 70 e 100% de área superficial do fruto com lesão. A escala considerou os limites de severidade mínima e máxima da doença observados em campo e os níveis intermediários seguiram incrementos logarítmicos, obedecendo-se a "Lei do estímulo de Weber-Fechner". A severidade foi estimada, por oito avaliadores sem experiência, em 50 frutos sem e com o auxílio da escala proposta. Em conclusão, a escala melhorou a avaliação da antracnose na feijoa. Oito genótipos de diferentes cruzamentos foram tolerantes à antracnose.

A comparative study of the antifungal activity of essential oils of Varronia curassavica Jacq. obtained by different distillation methods / Estudo comparativo da atividade antifúngica dos óleos essenciais de Varronia curassavica Jacq. obtidos por diferentes métodos de destilação

This work aimed to compare the antifungal activity of the essential oil of Varronia curassavica obtained by hydrodistillation and microwave against the fungus Colletotrichum musae and verify the alterations caused by these extraction methods on the leaf surface. This study used four essential oil samples obtained by different methods, two by hydrodistillation [HD1 (1.0 L of water and 100 min.) and HD2 (2.0 L of water and 140 min.)] and two by microwave [MI1 (500W, 20 min, without water) and MI2 (700W, 40 min, with 50 mL of water added to fresh leaves)]. Essential oils concentrations of 0.05, 0.1, 0.5, 1.0, and 3.0% (v / v) were tested in PDA medium. The mycelial growth of C. musae was evaluated by measuring the diameter, every 24 hours up to 144 hours after the beginning of the incubation. Untreated leaves and leaves treated with HD1 and MI1 were prepared for observation in a scanning electron microscope (SEM) LEO EVO 40. The most abundant compounds detected in the essential oil samples analyzed by gas chromatography were: shyobunol, germacrene D-4-ol, E-caryophyllene, bicyclogermacrene, and α-cadinol. Up to 72 hours after the beginning of the incubation, C. musae presented no mycelial growth, even at the lowest essential oil concentration. Conversely, mycelial growth was detected in the control (PDA + DMSO) from 24 hours after incubation. At 144 hours after incubation, regardless of the concentration, the essential oil samples obtained by HD provided lower mycelial growth of C. musae (1.49 cm) when compared with samples obtained by MI (1.80 cm). This difference possibly occurred due to the reduction to less than half of the germacrene D-4-ol content in the samples obtained by MI. The four essential oil samples tested inhibited the mycelial growth and thus presented a inhibitory effect on C. musae. The SEM revealed more drastic changes on the surface of the leaf treated with MI than on those treated with HD. The essential oil of V. curassavica, mainly when obtained by hydrodistillation, has the potential for use in the control of C. musae.

O objetivo do trabalho foi comparar a atividade antifúngica do óleo essencial de Varronia curassavica obtido por hidrodestilação e micro-ondas frente ao fungo Colletotrichum musae e verificar as alterações que esses métodos de extração causam na superfície da folha. Quatro amostras de óleo essencial obtidas em diferentes condições foram utilizadas. Sendo duas por hidrodestilação, HD1 (1,0 L de água e 100 min.) e HD2 (2,0 L de água e 140 min.); e duas por micro-ondas, MI1 (500W, 20 min. sem adição de água) e MI2 (700W, 40 min. com adição de 50 mL de água às folhas frescas). Foram testadas as concentrações 0,05; 0,1; 0,5; 1,0 e 3,0 % (v/v) de óleo essencial em meio BDA. O crescimento micelial do C. musae foi avaliado por medições do diâmetro, a cada 24 horas até 144 horas após o início da incubação. Folhas sem qualquer tratamento e após os tratamentos HD1 e MI1 foram preparadas para observação em microscópio eletrônico de varredura (MEV) LEO EVO 40. Os compostos mais abundantes nas amostras de óleo essencial analisadas por cromatografia gasosa foram: shyobunol, germacreno D-4-ol, E-cariofileno, biciclogermacreno e α-cadinol. Até 72 horas após o início da incubação, não foi observado nenhum crescimento micelial do C. musae, mesmo nas concentrações mais baixas de óleo essencial, enquanto, para o controle (BDA + DMSO), foi observado crescimento do fungo a partir de 24 horas. Após 144 horas, independentemente da concentração, as amostras de óleo essencial obtidas por HD proporcionaram menor crescimento micelial do C. musae (1,49 cm) quando comparadas às amostras obtidas por MI (1,80 cm). Possivelmente essa diferença ocorreu devido à redução para menos da metade, do teor de germacreno D-4-ol, nas amostras obtidas por MI. As quatro amostras de óleo essencial testadas foram capazes de inibir o crescimento micelial, apresentando portanto, um efeito inibitório sobre o C. musae. Alterações mais drásticas observadas através da MEV foram visualizadas na superfície da folha submetida ao processo de extração por MI em comparação à HD. O óleo essencial de V. curassavica, sobretudo o obtido por hidrodestilação, apresenta potencial para o controle de C. musae.

Variability in Colletotrichum infecting chilli plants of Andaman and Nicobar Islands, India

Aim: The aim of the present study was to understand the basic pathogen dynamics of Colletotrichum species infecting chilli crop in the Andaman and Nicobar Islands for disease management practices. Methodology: Twenty fungal isolates associated with chilli (Capsicum annuum) anthracnose disease from diverse locations of tropical Andaman, India were characterized using polyphasic approaches. Results: Upon morphological studies, out of twenty isolates, fourteen isolates were found chromogenic and eleven showed concentric ring pattern of mycelial growth. Based on conidial morphology, the isolates were grouped into two species (C. capsici and C. gloesporioides). The pathogenicity tests on three chilli varieties revealed difference in the pathogenic potential among the collected isolates. The sequence analysis using internal transcriber spacer (ITS) region revealed the presence of two other species C. siamense and C. plurivorum, in addition to C. gloesporioides and C. capsici. Interpretation: The present study revealed the presence of high level of genetic and pathogenic variability among the Colletotrichum isolates infecting chilli in Andaman Islands.

Antifungal activity of essential oils of Myrcia ovata chemotypes and their major compounds on phytopathogenic fungi / Atividade antifúngica de óleos essenciais de quimiotipos de Myrcia ovata e seus principais compostos em fungos fitopatogênicos

This work evaluated the antifungal activity of essential oils of Myrcia ovata chemotypes (MYRO-175, MYRO-156, MYRO-154, MYRO-165, and MYRO-015) and their major compounds (linalool, geraniol, citral, and (E)-nerolidol) on the phytopathogenic fungi Fusarium pallidoroseum (which causes melon postharvest rot) and Colletotrichum musae (which causes anthracnose in banana). The essential oils were obtained by hydrodistillation and analyzed by GCMS/FID. To evaluate the antifungal activity, the essential oils and their major compounds were tested at different concentrations (0.1; 0.3; 0.4; 0.5; 0.7; 1.0; 3.0, and 5.0 mL/L). The major compounds found in the essential oils were nerolic acid, linalool, geraniol, citral, and (E)-nerolidol. The essential oils of the plants MYRO-154, MYRO-165, and MYRO-015 had the minimum inhibitory concentration (MIC) (0.3 mL/L) for F. pallidoroseum and the lowest minimum fungicidal concentration (MFC) (0.7 mL/L), for C. musae. Geraniol and citral had the lowest MFC (0.5 mL / L) for the two fungi tested. For F. pallidoroseum, the essential oils of the chemotypes were more effective than their major compounds. Conversely, the major compounds geraniol of the chemotype MYRO-156 (74.37%) and citral were more effective than their respective essential oils for C. musae. (E)-nerolidol and geraniol of the chemotype MYRO-015 (33.15%) were responsible for the antifungal activity of the essential oils of their respective chemotypes.

No presente trabalho avaliou-se a atividade antifúngica de óleos essenciais de quimiotipos de Myrcia lundiana (MYRO-175, MYRO-156, MYRO-154, MYRO-165, and MYRO-015) e seus compostos majoritários (linalol, geraniol, citral e (E)-nerolidol) sobre os fungos fitopatogênicos Fusarium pallidoroseum(causa podridão em frutos de melão) e Colletotrichum musae (causa antracnose em frutos de banana). Os óleos essenciais foram obtidos hidrodestilação e analisados por CGEM/DIC. Para avaliação da atividade antifúngica foram testados os óleos essenciais e os compostos majoritários nas concentrações: 0,1; 0,3; 0,4; 0,5; 0,7; 1,0; 3,0 e 5,0 mL/L. Os principais compostos presentes nos óleos essenciais foram o ácido nerólico, o linalol, o geraniol, o citral e o (E)-nerolidol. Os óleos essenciais das plantas MYRO-154, MYRO-165 e MYRO-015 apresentaram CIM de 0,3 mL/L e a planta MYRO-015 apresentou a menor concentração fungicida mínima (CFM) (1,0 mL/L). O geraniol e o citral foram os compostos que apresentaram o menor valor de CFM, 0,5 mL/L, frente aos dois fungos testados. O óleo essencial dos quimiotipos testados foram mais promissores que seus componentes majoritários puros, frente o F. pallidoroseum. Já para o C. musae, os componentes majoritários geraniol do quimiotipo MYRO-156 (74,37%) e o citral foram mais promissores que seus respectivos óleos essenciais. Já o (E)-nerolidol e o geraniol do quimiotipo MYRO-015 (33,15%) foram os responsáveis pela atividade antifúngica apresentada pelos óleos essenciais dos respectivos quimiotipos.

Control of anthracnose in papaya fruits by acetylsalicylic acid and 1-methylcyclopropene / Controle da antracnose em mamão por ácido acetil salicílico e 1-metilciclopropeno

This study assessed the effect of acetylsalicylic acid (ASA) and 1-methylcyclopropene (1-MCP) to control anthracnose in papaya (cultivar Golden). Disinfested-surface fruits were inoculated with Colletotrichum gloeosporioides and then the compounds were applied. The lesion diameters and the physical-chemical properties were analyzed. Assays were carried out with ASA and 1-MCP targeting the control of anthracnose and maintenance of the fruit's physical-chemical properties. The effect of ASA (20 mM; 20 min) on reducing lesion diameter occurred when applied before inoculation. Fruits treated with 1-MCP (300ppb) for 12 h showed a smaller lesion diameter than control. For the physical-chemical analysis, fruit treated with 1-MCP (200; 300 ppb; 12h) maintained fruit firmness, delayed fruit ripening and fruit fresh weight loss.

Neste trabalho avaliou-se o efeito do ácido acetilsalicílico (ASA) e 1-metilciclopropeno (1-MCP) no controle da antracnose do mamão (cv Golden). Para isso o Colletotrichum gloeosporioides foi inoculado em frutos superfícialmente desinfestados para depois aplicar-se os compostos. O diâmetro das lesões e as características físico-químicas foram determinadas. Os ensaios foram conduzidos com ASA e 1-MCP visando o controle da antracnose e a manutenção das características físico-químicas do fruto. O efeito do AAS (20 mM; 20 min) na redução do diâmetro da lesão ocorreu quando aplicado antes da inoculação. Frutos tratados com 1-MCP (300 ppb) por 12 horas apresentaram menor diâmetro de lesão que controle. Para a análise físico-química, frutos tratados com 1-MCP (200; 300 ppb; 12h) mantiveram a firmeza, o amadurecimento tardio e a perda de massa fresca dos frutos.

Colletotrichum spp. associated with agricultural crops in Malaysia, causal pathogens and potential control methods

ABSTRACT@#Colletotrichum is one of the most significant and common plant pathogens, infecting many economically important crops worldwide. Colletotrichum is also one of the most studied fungal genera in Malaysia because it contains many species that infect various types of agricultural crop including fruit, vegetable and industrial crops. Studies on Colletotrichum spp. are mostly focused on the causal pathogens, the host range and disease management. Among the host crops, most studies on Colletotrichum spp. have been conducted on infection in chilli (Capsicum spp.), which, in Malaysia, first arose in the 1980s and still continues to be a problem to this day. Studies have also been conducted on Colletotrichum spp. associated with anthracnose in fruit crops including dragon fruit, papaya, banana and mango. Disease management of anthracnose pathogens postharvest has also been conducted to prolong the shelf life of these fruit crops. In this review, Colletotrichum spp. associated with chilli and several fruit crops as well as their disease management are highlighted. There have been many changes in Colletotrichum taxonomy and systematics in recent years, affecting the identification of anthracnose pathogens reported in Malaysia. Colletotrichum species identified solely by morphology or solely via the internal transcribed spacer (ITS) region should be referred to as sensu lato (in the broad sense) since many species belong to species complexes. Species within a species complex are closely related, and most are cryptic species particularly species in the C. gloeosporioides and C. acutatum complexes which are commonly associated with agricultural crops in Malaysia. Due to the importance of Colletotrichum spp. as plant pathogens, up-to-date identification methods should be used since accurate species identification of Colletotrichum is crucial for formulating suitable disease management programmes as well as for plant quarantine and biosecurity purposes. This review provides the current knowledge on the status of Colletotrichum spp. associated with agricultural crops in Malaysia and potential control methods on different types of agricultural crops.

Antimicrobial activities of endophytic fungi residing in Aloe vera against diabetic wound pathogens

Aims@#Endophytic fungi are organisms that colonize living plant tissues without causing significant symptoms of diseases. They are known as the repository of bioactive compounds. This study was aimed to isolate endophytic fungi associated with Aloe vera and to assess their antimicrobial activity against the diabetic wound pathogens that result to lower limb amputations. @*Methodology and results@#In this study, 84 endophytic fungi were isolated from A. vera by using 5% sodium hypochlorite and 70% ethanol as surface sterilants. On preliminary antimicrobial screening by agar plug assay, 12 (14.3%) isolates showed significant antagonistic activity on the test microorganisms. Two of the endophytes were identified as Aspergillus flavus and Colletotrichum gloeosporioides through morphological and molecular techniques. The fungal cultures fermented in shake flask were extracted subsequently with hexane, dichloromethane, ethyl acetate, and n-butanol. Ethyl acetate and dichloromethane extracts of A. flavus and C. gloeosporioides inhibited all test bacteria. The compounds in the extracts were seemed to be semi-polar in nature. On broth microdilution assay, minimal inhibitory and minimal lethality concentration of ethyl acetate extracts of the fungi were found in the range of 0.63−2.50 and 1.25−5.00 mg/mL, respectively. @*Conclusion, significance and impact of study@#This study reveals that A. vera harbours a wide diversity of endophytic fungi. A. flavus and C. gloeosporioides showing broad spectrum antimicrobial activity on wound pathogens may be potential sources of bioactive compounds. Further investigations should be conducted to isolate and identify the antimicrobial compound produced by these fungal isolates.

In vitro antifungal activity of Myrcia ovata essential oils and their major compounds against pathogens of citrus, sweet potato, and coconut / Atividade antifungica in vitro de óleos essenciais de myrcia ovata e seus compostos majoritários sobre patógenos de citros, batata-doce e coqueiro

Myrcia ovata, an endemic species to the Brazilian Atlantic Forest, presents antifungal properties. The phytopathogens Colletotrichum acutatum, Plenodomus destruens,and Thielaviopsis paradoxa are responsible for the diseases citrus postbloom fruit drop, sweet potato foot rot, and coconut stem bleeding, respectively. The antifungal activity of the essential oils of five M. ovata chemotypes (MYRO-159, nerolic acid chemotype; MYRO-180, nerolic acid + linalool chemotype; MYRO-388, geraniol chemotype; MYRO-157, citral + (E)-nerolidol chemotype; and MYRO-174, isopulegol + linalool chemotype), four major compounds (nerolic acid, nerolic acid + linalool, geraniol, and citral + (E)-nerolidol), and threepure compounds (citral, (E)-nerolidol, and linalool) against the fungi C. acutatum, P. destruens,and T. paradoxawere evaluated. For this, in vitro tests were conducted in a completely randomized design with three replications, testing concentrations (v/v) ranging from 0.01 to 1.0 µL.mL-1. All treatments presented toxicity at different levels to the three fungi. For C. acutatum,the essential oil from the individual MYRO-180 (nerolic acid + linalool chemotype) and its major compound showed the lowest Minimal Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) of 0.03 and 0.1 µL.mL-1, respectively. For P. destruens, the essential oil from the individual MYRO-159 (nerolic acid chemotype) presented the lowest MIC of 0.05 µL.mL-1. The nerolic acid + linalool chemotype and its major compound presented an MFC of 0.07 µL.mL-1. For T. paradoxa, the major compound citral + (E)-nerolidol stood out with the lowest MIC and MFC of 0.03 and 0.2 µL.mL-1, respectively. Linalool presented the lowest toxicity to the three tested fungi.

Myrcia ovata, uma espécie nativa de fitofisionomia de Restinga, possui atividade antifúngica. Os fitopatógenos Colletotrichum acutatum, Plenodomus destruens e Thielaviopsis paradoxa são responsáveis pelas doenças podridão floral de citros, mal-do-pé da batata doce e resinose do coqueiro, respectivamente. A atividade antifúngica de cinco quimiotipos de M. ovata (MYRO-159, quimiotipo ácido nerólico; MYRO-180, ácido nerólico + linalol; MYRO-388, quimiotipo geraniol; MYRO-157, quimiotipo citral + (E)-nerolidol; e, MYRO-174, quimiotipo isopulegol + linalol), quatro compostos majoritários (ácido nerólico, ácido nerólico + linalol, geraniol e citral + (E)-nerolidol) e três compostos isolados (citral, (E)-nerolidol e linalol) foram avaliados sobre os fungos C. acutatum, P. destruens e T. paradoxa. Testes in vitro foram conduzidos em delineamento inteiramente casualizado com três repetições e concentrações (v/v), que variaram de 0,01 a 1,0 µL.mL-1. Todos os tratamentos testados apresentaram atividade antifúngica. Para o fungo C. acutatum, o óleo essencial do indivíduo MYRO-180, de quimiotipo ácido nerólico + linalol, e seu composto majoritário apresentaram menores Concentração Mínima Inibitória (CMI) e Concentração Mínima Fungicida (CMF) de 0,03 e 0,1 µL.mL-1, respectivamente. Para o fungo P. destruens, o óleo essencial do indivíduo MYRO-159, de quimiotipo ácido nerólico, apresentou menor CMI de 0,05 µL.mL-1, e o quimiotipo ácido nerólico + linalol e seu composto majoritário apresentaram a menor CMF de 0,07 µL.mL-1. Para o fungo T. paradoxa,a combinação de citral + (E)-nerolidol destacou-se com CMI e CMF de 0,03 e 0,2 µL.mL-1, respectivamente. Linalol foi o menos tóxico sobre os três fungos testados.

Use of phosphites in postharvest to control anthracnose of yellow passionfruit / Uso de fosfitos em pós-colheita para o controle da antracnose do maracujá-amarelo

Brazil is the largest producer of yellow passionfruit (Passiflora edulis f. flavicarpa) and one of its production problems is the anthracnose (Colletotrichum spp.). The use of fungicides on control of postharvest diseases is a method that protects the fruits during storage. However, precautions must be taken due to fungicide toxicity. The restriction to the use of fungicides in post-harvest led a demand for alternative methods of disease control, and, the phosphite application is one of these methods. Therefore, this work aimed to evaluate the effects of fruit immersion in phosphite on postharvest control of anthracnose. Two tests were developed in vitro to assess the effect on the fungus: phosphite Mg2 (40%P2O5+6%Mg), Zn (40%P2O5+10%Zn), Ca1 (30%P2O5+7%Ca) and K1 (40%P2O5+20%K2O). For the in vivo tests, passionfruit (Gigante Amarelo), were wounded and inoculated (50L; 106conidia mL-1). Two tests were done with: Cu (25%P2O5+5%Cu), 2.5mL L-1; Zn, 2.5mL L-1; K1, 2.5mL L-1; Mg1 (30%P2O5+4%Mg), 3mL L-1; Ca1, 3mL L-1; Ca2 (10%P2O5+6%Ca), 4mL L-1; K2 (40%P2O5+20%K2O), 1.5mL L-1; Mg2 (40%P2O5+6%Mg), 1.5mL L-1; K3 (20%P2O5+20%K2O) 1.75 mL L-1; K4 (30%P2O5+20%K2O), 1.75mL L-1. Other two tests with phosphites Mg2, Ca1, Zn and K1 were with CaCl2 (2%) was developed. In addition, phosphites were tested at 25, 50, 100 and 200% of the dose: K2 (100%; 1.5mL L-1) and Ca1 (100%; 3 mL L-1). The phosphites Mg2, Ca1, K1 and Zn in vitro have reduced mycelial growth and fungus conidia production. The phosphites K1, K2, Ca1 and Zn were the ones that most reduced the size of the anthracnose lesion. There were no differences among treatments, concerning the physico-chemical fruit properties analyzed (% fresh mass loss, total soluble solids, pH and titratable acidity).

O Brasil é o maior produtor mundial de maracujá-amarelo (Passiflora edulis f. flavicarpa) e um dos problemas para sua produção é a antracnose (Colletotrichum spp.). O uso de fungicidas no controle de doenças pós-colheita é um método que protege os frutos durante o armazenamento, mas, precauções adicionais devem ser tomadas quanto à sua toxidade, presença de resíduos e a provável seleção de fungos resistentes. A restrição ao uso de fungicidas na pós-colheita cresceu e levou à procura de alternativas de controle, e, entre tais está à aplicação de fosfitos. Diante disso, este trabalho objetivou avaliar os efeitos da imersão de frutos em soluções de fosfitos no controle da antracnose em pós-colheita. Dois testes in vitro foram feitospara avaliar o efeito de fosfitono fungo: Mg2 (40%P2O5+6%Mg), Zn (40%P2O5+10%Zn), Ca1 (30%P2O5+7%Ca) e K1 (40%P2O5+20%K2O). In vivo, frutos de maracujá (Gigante Amarelo), foram feridos e inoculados (50l; 106conídios mL-1). Dois testes foram feitos com: Cu (25%P2O5+5%Cu), 2,5mL L-1; Zn, 2,5mL L-1; K1, 2,5mL L-1; Mg1 (30%P2O5+4%Mg), 3mL L-1; Ca1, 3mL L-1; Ca2 (10%P2O5+6%Ca), 4mL L-1; K2 (40%P2O5+20%K2O), 1,5mL L-1; Mg2 (40%P2O5+6%Mg), 1,5mL L-1; K3 (20%P2O5+20%K2O), 1,75mL L-1; K4 (30%P2O5+20%K2O), 1,75mL L-1. Outros dois testes com fosfitos foram com CaCl2 (2%) e Mg2, Ca1, Zn e K1. Ainda, dois fosfitos foram testados a 25, 50, 100 e 200% da dose: K2 (100%; 1,5mL L-1) e Ca1 (100%; 3mL L-1). Os fosfitos Mg2, Ca1, K1 e Zn in vitro reduziram o crescimento micelial e a produção de conídios do fungo. Os fosfitos K1, K2, Ca1 e Zn foram que mais reduziram o diâmetro da lesão causada pelo patógeno. Ca1 e K1 com CaCl2 reduziram o tamanho das lesões. Não houve diferenças significativas entre os tratamentos, quanto as características físico-químicas analisadas (% perda de massa fresca, teor de sólidos solúveis totais, pH e acidez titulável) dos frutos.

Identification and characterization of causative agents of brown leaf spot disease of cassava in Kenya

This study was conducted to investigate the causal agent of brown leaf spot (BLS) of cassava in Kenyanfields. Infected cassava leaf samples showing BLS disease symptoms were collected from Kenya Agriculturaland Livestock Research Organization (KALRO) experimental fields in central and western Kenya. Fungalpathogens associated with the disease were isolated from the cassava leaf samples on potato dextrose agaramended with antibiotics. Three fungal isolates, belonging to the genera Colletotrichum, Alternaria, andCladosporium, were identified as the causative agents of BLS with relative prevalence of 41%, 24%, and 18%,respectively. Susceptible cassava variety TME 204 was inoculated with single and combinations of purifiedisolates of the three pathogens in a randomized design in the greenhouse. The combination of the three isolatesresulted in typical BLS symptoms as observed in the field. The findings of this study would help to understandthe disease, contribute to its better management, and eventually alleviate food insecurity, especially in theregions where cassava is a major staple food and a source of income.