Recubrimiento biodegradable antifúngico a base de quitosano y aceite esencial de cítricos para la conservación de papaya (Carica papaya L.) en poscosecha / Biodegradable antifungal coating based on chitosan and citrus essential oil for the conservation of papaya (Carica papaya L.) in postharvest

RESUMEN La papaya es una fruta climatérica altamente perecedera. La antracnosis, enfermedad provocada por hongos, es una de las principales causas de pérdida poscosecha. La actividad de extractos vegetales ha permitido la inhibición del desarrollo de microorganismos, en particular se ha reportado la actividad antifúngica de aceites esenciales. El objetivo de la presente investigación fue evaluar el efecto de un recubrimiento biodegradable a base de quitosano con aceite esencial de cítricos, aplicado en etapa poscosecha, en las propiedades físicoquímicas, fisiológicas e inhibición del crecimiento del hongo Colletotrichum gloeosporioides en frutos de papaya (Carica papaya L.). El recubrimiento se preparó con quitosano, glicerol, ácido acético, aceite esencial de Citrus reticulata (0.5 %, 1.0 % y 1.5 %) y Tween® 80. La solución se aplicó con una brocha en la epidermis de los frutos de papaya y se almacenaron a temperatura ambiente (24 °C ± 2 °C) por 10 d, junto con los frutos testigo. Las variables evaluadas en los frutos fueron color, pH, sólidos solubles totales (SST), firmeza, pérdida de peso, producción de CO2, de etileno y daño por antracnosis. Se utilizó un modelo estadístico completamente al azar. Los datos se sometieron al análisis de varianza (ANOVA) y comparación de medias por la prueba de Tukey (P < 0.05). El recubrimiento aplicado retrasó el cambio de color de la epidermis de los frutos de papaya, la pérdida de peso, firmeza y SST respecto a los frutos testigo. Los cambios estuvieron asociados a la modificación de la tasa de respiración y de producción de etileno de los frutos con recubrimiento. La matriz del quitosano conteniendo aceites escenciales, usada como recubrimiento, mejoró significativamente la vida de anaquel de la papaya y disminuyó más del 80 % el daño por antracnosis.

ABSTRACT Papaya is a highly perishable climacteric fruit. Anthracnose, a disease provoked by fungus, is one of the main causes of postharvest losses. The activity of plant extracts has allowed the inhibition of the development of microorganisms; in particular, the antifungal activity of essential oils has been reported. The aim of this research was to evaluate the effect of a biodegradable antifungal coating based on chitosan with citrus essential oil in the physicochemical and physiological properties and the antifungal activity of postharvest papaya (Carica papaya L.). The coating was prepared with chitosan, glycerol, acetic acid, essential oil of Citrus reticulata (0.5 %, 1.0 % and 1.5 %) and Tween® 80. The solution was applied with a brush to the epidermis of the postharvest papaya fruits and stored at room temperature (24 °C ± 2 °C) for 10 d. The variables evaluated in the fruits were color, pH, °Brix, firmness, weight loss, production of CO2 and ethylene and anthracnose damage. An analysis of variance (ANOVA) was performed under a completely randomized design and a comparison of Tukey means (P < 0.05). The coating applied delayed the color change of the epidermis of the papaya fruits, these maintained the high firmness values with respect to the control fruits. The changes were associated with the modification of the respiration rate and ethylene production of the coated fruits. The chitosan matrix containing essential oils used as a coating significantly improved shelf life of papaya and decreased anthracnose damage by 80 %.

Quiescence as a strategic stage for the infective process of Colletotrichum species

Colletotrichum, a genus of Ascomycota fungi with a diversity of species grouped into several species complexes, or clades, is associated with diseases known as "Anthracnose". It affects significantly different tropical and subtropical fruit species. Infections occur in the field and postharvest; quiescent stages are mainly responsible for postharvest losses. An analysis of this pre-infective stage is made based on consulted papers. The infective process is modulated by the length of the quiescent period of the fungus during the vegetative or pre-productive stages of trees. Quiescent stage is determined by the host's biochemical responses and the pathogen's activity. Once the pathogen is activated, it develops an infectious necrotrophic process. Colletotrichum quiescence has been studied mainly in subtropical fruits and horticultural species, and the studies highlight the role of volatile compounds, metabolites and enzymes involved in the length and breaking of quiescence, as well as the differential responses according to the phenological stage and the genotype of the plant. Transcriptomic and proteomic analysis of the host-fungus interaction have revealed the role of genes in the occurrence and breaking of quiescence. Knowledge about the quiescence of Colletotrichum in tropical fruits is necessary to improve management efficiency. Detection and induction of quiescent infections has been studied and genomics has allowed to understand the occurrence of quiescence in the infective process; however, in crops in the tropics, such as mango, an important crop in Colombia, questions about associated species and biology of their quiescence are still unanswered.

Colletotrichum es un hongo ascomicete, con diversidad de especies agrupadas en complejos o clados y se asocia a enfermedades conocidas, como "Antracnosis" y afecta significativamente especies de frutas tropicales y subtropicales. Las infecciones ocurren en el campo y postcosecha; los estados quiescentes son los principales responsables de pérdidas en postcosecha. Se realizó un análisis de esta etapa pre-infectiva, a partir de publicaciones consultadas. La infección está modulada por la duración del período de quiescencia del hongo durante las etapas vegetativa o pre-productivas de los árboles y está determinado por las respuestas bioquímicas del hospedante y la actividad del patógeno. Una vez se activa el patógeno, se desarrolla un proceso infeccioso necrotrófico. La quiescencia de Colletotrichum se ha estudiado, principalmente, en frutas subtropicales y especies hortícolas y destacan el papel de compuestos volátiles, metabolitos y enzimas en la duración y en la pérdida de la quiescencia, así como las respuestas diferenciales, según la fenología y el genotipo. Análisis transcriptómicos y proteómicos de la interacción hospedante-hongo han revelado el papel de genes en la ocurrencia y pérdida de quiescencia. Conocer la quiescencia de Colletotrichum en frutas tropicales es necesario para hacer más eficiente el manejo de la enfermedad. Se ha estudiado la detección e inducción de infecciones quiescentes y estudios genómicos han permitido entender su ocurrencia durante la infección; sin embargo, en cultivos en el trópico, como el mango, un cultivo importante en Colombia, las preguntas sobre las especies asociadas y la biología de la quiescencia de estas, aún están sin respuesta.

Caracterización química y evaluación de la actividad antifúngica del aceite esencial foliar de Lippia alba contra Colletotrichum gloeosporioides

El objetivo de este estudio fue caracterizar y evaluar in vitro la eficiencia del aceite esencial foliar de Lippia alba contra Colletotrichum gloeosporioides. Se extrajo el aceite esencial a partir de las hojas mediante el método de hidrodestilación asistida por microondas (MWHD) y se identificaron sus metabolitos mediante una cromatografía de gases acoplada a espectrometría de masas (GC/MS). La evaluación in vitro se realizó empleando 4 concentraciones del aceite esencial (500, 1000, 3000 y 10000 ppm) diluidas en acetona; se utilizó un control positivo con Benomil 1 g/L, un control negativo con acetona y un testigo absoluto; la eficiencia del aceite se midió mediante el porcentaje de índice antifúngico (%I.A). El componente mayoritario en el aceite esencial fue el citral (34.62 a 40.03%) y que el mayor %I.A se encontró a la concentración de 10000 ppm (97.8%), muy similar a la del Benomil (100%). Lo anterior demostraría la eficacia del aceite esencial de L. alba para controlar a C. gloeosporioides, y su posible uso como fungicida biológico.

The aim of this study was to characterize and evaluate the in vitro efficiency of leaf essential oil of Lippia alba against Colletotrichum gloeosporioides. Essential oil from the leaves was extracted by the method of assisted microwave hydrodistillation (MWHD) and metabolites were identified by gas chromatography coupled to mass spectrometry (GC/ MS). The in vitro evaluation was performed using 4 concentrations of essential oil (500, 1000, 3000 and 10000 ppm) diluted in acetone; positive control with Benomyl 1 g /L, a negative control with acetone and absolute control was used; oil efficiency was measured by the percentage of antifungal index (% IA). It was found that the major component was in the essential oil citral (34.62 to 40.03%) and the highest %I.A was found to 10000 ppm concentration (97.8%) very similar to Benomyl (100%). This would demonstrate the efficacy of the L. alba essential oil to control C. gloeosporioides, and its possible use as a biological fungicide.

Caracterización molecular de Colletotrichum gloeosporioides aislado de plantas de ñame de la Costa Atlántica Colombiana utilizando la técnica "DNA Amplification Fingerprinting (DAF)" / Molecular characterization of Colletotrichum gloeosporioides isolated from yam plants of Colombia Atlantic Coast using DNA Amplification Fingerprinting technique (DAF)

La antracnosis en ñame, causada por el hongo Colletotrichum gloeosporioides, es una enfermedad relevante que posee el potencial de destruir el 100% de la cosecha, convirtiéndose en la principal limitante fitosanitaria para el rendimiento del cultivo en el país. Esta es una situación preocupante considerando que aproximadamente 35.000 familias de pequeños y medianos agricultores de la Costa Atlántica Colombiana subsisten de este cultivo; es por esto que el objetivo de este trabajo fue caracterizar molecularmente 42 aislamientos del hongo procedentes de plantas de ñame con síntomas de la enfermedad, utilizando la técnica molecular "DNA Amplification Fingerprinting (DAF)", caracterizada por su resolución en la determinación de la variabilidad genética de diferentes organismos. Para la determinación de polimorfismos, se amplificaron 16 marcadores DAF implementando iniciadores tipo decámero, los cuales fueron visualizados por electroforesis en microchip con el equipo MCE-202 MultiNA. Se evaluó la reproducibilidad de la técnica DAF. La amplificación arrojó 391 bandas inequívocamente polimórficas en todas las muestras, el coeficiente de Dice identificó cinco grupos con 0.30% de similaridad y el índice de diversidad genética fue de 0.28; datos que reflejan un alto grado de variabilidad en la colección estudiada de C. gloeosporioides. Ésta puede deberse, al intercambio de germoplasma, a su condición heterotálica, a las mutaciones y al alto potencial de dispersión de las conidias que le permiten mantener la viabilidad bajo condiciones adversas. Por último, se encontró que DAF es una técnica reproducible, confirmando que es una metodología fiable para la caracterización molecular de hongos.

Yam anthracnose, caused by the fungus Colletotrichum gloeosporioides, is a significant disease that has the potential to destroy harvests in 100%, causing the decrease in crop yields nationally. Consequently, its situation affects approximately 35.000 families of small farmers the Atlantic Coast for whom it is the livelihoods. Due to above, the objective of this work was to perform the molecular characterize of 42 C. gloeosporioides isolates from yam plants with symptoms of the disease, using the molecular technique "DNA Amplification Fingerprinting (DAF)" useful for its resolution in determining the genetic variability of different organisms. For polymorphisms determination, were amplified 16 DAF markers by using primers decamers type, the banding patron was visualized by electrophoresis in microchip 202 MCE-MultiNA equipment also, we assessed of DAF technique reproducibility. The amplification process yielded 391 unequivocally polymorphic bands in all samples, Through Dice coefficient we identified five groups with 0.30% of similarity and a genetic diversity index of 0.28. Our data show a high degree of variability in the collection of C. gloeosporioides studied. The high variability could be due to several reasons like germplasm exchanges, the heterothallic condition of fungal isolates, a presence of mutations and the high potential for conidia dispersal that allow it to maintain its viability under adverse conditions. Finally, we found that DAF technique is reproducible, confirming that it is a reliable methodology for the fungi molecular characterization.

INDUCCIÓN DE FENILALANINA AMONIO LIASA Y VARIACIÓN EN EL CONTENIDO DE COMPUESTOS FENÓLICOS EN FRUTOS DE LULO (Solanum quitoense Lam) INFECTADOS CON Colletotrichum acutatum. / Induction of phenylalanine ammonia lyase and variation in phenolic compounds content in Lulo fruits (Solanum quitoense Lam) infected by Colletotrichum acutatum)

Se evaluó la dinámica de la actividad fenilalanina amonio liasa (PAL) en corteza de frutos de lulo (Solanum quitoense Lam) con el fin de determinar su participación en respuestas bioquímicas hacia Colletotrichum acutatum. Se establecieron como mejores condiciones para la extracción de la enzima, buffer ácido bórico-borato de sodio 0.1M pH 8.8, 1% SDS, 3% PVPP y para medir la actividad, sustrato L-fenilalanina 5 mM , pH 8,0, 20°C , 30 ΜL de extracto y 45 min. Se realizó un ensayo in vivo usando frutos en tres estados de madurez, los cuales fueron inoculados con el patógeno o tratados con agua estéril. A cinco tiempos (hpi = horas post-infección) se determinó la actividad PAL y el contenido total de fenoles, encontrándose que hay una respuesta diferencial de la enzima por efecto del patógeno y por el estado de madurez. Para frutos en el estado pintón se obtuvo el mayor aumento de PAL, el que perduró hasta 48 hpi, al compararlo con los controles y con los otros dos estados de madurez. Este aumento mostró relación con un marcado incremento en el contenido total de fenoles y con el desarrollo más tardío de síntomas característicos de antracnosis, observado para los frutos pintones. Estos resultados permiten postular, una posible relación positiva entre inducción de PAL, aumento de fenólicos y respuesta de tolerancia a C. acutatum. Para lulos en estado verde y maduro se observó aumento de PAL a 12 y 24 hpi que coincidió también con incremento en el contenido de fenoles totales, aunque para estos dos últimos estados dicho contenido disminuyó significativamente a tiempos mayores.

Phenylalanine ammonia lyase (PAL) activity induction was evaluated in lulo fruits to determine the role of this enzyme in biochemical responses towards the pathogen Colletotrichum acutatum. We studied the experimental conditions to obtain the enzyme, using lulo peel, and found that the best conditions for extraction were buffer of boric acid-sodium borate 0.1M pH 8.8, 1% SDS, 3% PVPP and, for measuring the enzymatic activity: L- phenylalanine 5mM, pH 8.0, 20°C , 30 ΜL of extract and incubation during 45 min. Then, we performed an in vivo assay using lulo fruits in three maturity stages, which were inoculated either with the fungus or sterile water. Enzymatic induction was studied at five post-inoculation times, and it was found that there is a differential response as a consequence of the presence of the pathogen and the maturity stage. In semi-mature lulos, a bigger increase in PAL was obtained among 12-48 hpi which is related to a higher content of phenolic compounds and to the latest development in the characteristic symptoms of anthracnose. These results allow postulating, in a preliminary way, a possible positive relationship between inductions of PAL, phenolics and responses of tolerance to C. acutatum. For green and mature lulos we observed as well, an increase of PAL activity but only at 12 and 24 hpi which showed relation with an increase in the total phenolic content. However, for these stages the phenolics were significantly lower at higher times.

Resistência parcial à necrose dos frutos em genótipos de café arábica / Partial resistance to fruit necrosis in arabic coffee genotypes

Neste trabalho, objetivou-se identificar em genótipos de café arábica (Coffea arabica L.) fontes de resistência à necrose de frutos em condições de campo. As variáveis resistência à necrose de frutos ("NF"), quantidade média de frutos por nó produtivo ("FN") e índice de luminosidade dentro da copa da planta ("LUM") foram avaliadas em ensaio de campo no IAPAR (Londrina), em dezembro de 2004, em cafeeiros com três anos de idade. Foi avaliada a variável "NF", atribuindo notas de 1 a 5 sendo 1 para plantas com 0 por cento a 5 por cento de frutos necrosados. "FN" foi avaliada seguindo uma escala de notas de 1 a 5, onde 1 representa plantas com 0 a 3 frutos/ nó e nota 5 com mais do que 15 frutos/ nó. A avaliação da variável "LUM" foi visual e seguiu as notas de 1 a 5, onde 1 representa plantas com pouca luminosidade dentro da copa da planta. Dos 19 genótipos avaliados, 2 apresentaram moderada resistência, 7 moderada suscetibilidade, 5 suscetíveis e 5 altamente suscetíveis. As cultivares Obatã IAC 1669-20 e Catucaí Vermelho 4-79 apresentaram o melhor nível de resistência parcial de campo, ou seja, com moderada resistência à necrose de frutos associada ao Colletotrichum spp.

The aim of this research was to identify in Coffea arabica L. coffee genotypes resistance sources to fruit necrosis in field conditions. The variables fruit necrosis ("NF"), fruits per productive nodes average ("FN") and luminosity index inside of the plant canopy ("LUM") were evaluated in field assay at IAPAR (Londrina), in December 2004 on three years old coffee trees. The "NF" variable were evaluated attributing scores from 1 to 5, where score 1 represented plants with 0 to 5 percent of necrosed fruits. "FN" were evaluated following a score scale from 1 to 5, where score 1 represented plants with 0 to 3 fruits/ node and score 5 with more than 15 fruits/ node. The evaluation of the variable "LUM" was visual and followed the scores from 1 to 5, where score 1 represented plants with low luminosity inside the canopy. Out of the 19 evaluated coffee genotypes, 2 presented moderate resistance, 7 moderate susceptibility, 5 susceptibility and 5 high susceptibility. The cultivars Obatã IAC 1669-20 and Catucaí Vermelho 4-79 presented the best level of partial field resistance, or either, with moderate resistance to fruit necrosis associated to Colletotrichum spp.

Sensibilidade de Colletotrichum gloeosporioides (mancha manteigosa do cafeeiro) a diferentes concentrações de fungicidas / Sensibility of Colletotrichum gloeosporioides (coffee blister spot) to different fungicide concentrations

Com o objetivo de avaliar a eficiência de alguns fungicidas sobre Colletotrichum gloeosporioides, agente etiológico da mancha manteigosa do cafeeiro (Coffea arabica L.), testes in vitro foram conduzidos no Laboratório de Diagnose e Controle/UFLA. Utilizou-se o método de incorporação de fungicidas ao meio de cultura MEA 2 por cento para a avaliação da inibição do crescimento micelial e em lâmina escavada contendo água com fungicida para a germinação de conídios. Os fungicidas, tetraconazol, triadimenol, chlorotalonil e mancozeb foram testados quanto à inibição do crescimento do micelial (nas concentrações de 1, 5, 10, 25, 50, 100, 500 e 1.000 mg L-1) e quanto à inibição da germinação de conídios (nas concentrações de 1, 5, 10, 25, 50 e 100 mg L-1). Os fungicidas tetraconazol e triadimenol apresentaram alta eficiência na inibição do crescimento micelial. Os fungicidas chlorotalonil e mancozeb mostraram baixa eficiência e ineficiência, respectivamente. Quanto à germinação dos conídios, os fungicidas que demonstraram maior eficiência em baixas concentrações foram o chlorotalonil e o tetraconazol.

With the aim of assessing the effect of selected fungicides on Colletotrichum gloeosporioides, the cause of coffee blister spot, in vitro tests were carried out in the Laboratory of Diagnosis and Control/UFLA, Federal University of Lavras, Brazil. In the in vitro experiments the fungicides were incorporated into malt extract medium (MEA 2 percent) to evaluate the effect on the fungus growth rate, and concavity slides containing water plus fungicide to assess the conidia germination. The fungicides tetraconazol, triadimenol, chlorothalonil and mancozeb were tested on the mycelial growth inhibition (in the concentrations of 1, 5, 10, 25, 50, 100, 500 and 1.000 mg L-1) and on the inhibition conidia germination (in the concentrations of 1, 5, 10, 25, 50 e 100 mg L-1). The fungicides tetraconazol and triadimenol showed high efficiency on the mycelial growth inhibition. Chlorotalonil and mancozeb showed low efficiency and inefficiency, respectively. As to the germination of conidia, chlorothalonil and tetraconazol demonstrated to be more efficient in low concentrations.

Correlação entre a necrose de frutos associada ao Colletotrichum spp. com as características frutos por nó e produtividade entre genótipos de café arábica / Correlation between fruit necrosis associated to Colletotrichum spp. with the fruits per node and yield traits of arabic coffee

O fungo Colletotrichum spp. vem sendo associado à graves perdas para a cafeicultura brasileira. Objetivou-se neste trabalho verificar a existência de relação entre a variável necrose de frutos associada ao Colletotrichum spp. ("COL") com a quantidade média de frutos por nó produtivo ("FN") e com a produção ("PRD") em genótipos de café arábica. O ensaio de campo foi realizado no IAPAR (Londrina, PR, Brasil) em dezembro de 2004 e em cafeeiros com três anos de idade. A variável "COL" foi avaliada atribuindo-se notas de 1 a 5, onde 1 representam plantas com 0 por cento a 5 por cento de frutos necrosados. "FN" foi avaliada seguindo uma escala de notas de 1 a 5, onde 1 representa plantas com 0 a 3 frutos/ nó e nota 5 com mais do que 15 frutos/ nó. A avaliação visual subjetiva da produção foi estimada em litros de frutos em estádio cereja, por planta. A correlação de Pearson foi estimada para avaliar a existência de associações entre as variáveis. Foram observadas correlações positivas e significativas a 1 por cento entre "COL" e "FN" e entre "COL" e "PRD". A necrose de frutos foi mais intensa em cafeeiros com mais produção e com mais frutos por nó produtivo. Sugere-se que a avaliação da resistência de campo à necrose dos frutos associada à presença de Colletotrichum spp. seja realizada em cafeeiros com alta produção e com alta quantidade de frutos por nó produtivo.

Different fungi species of genus Colletotrichum has been associated with losses to the Brazilian coffee crop. The aim of this research was to evaluate the association between the variable fruit necrosis associated to Colletotrichum spp. ("COL") with the fruits per productive node average ("FN") and between "COL" and the yield ("PRD") in Coffea arabica L. genotypes. The field assay was evaluated at IAPAR (Londrina, PR, Brazil), in December 2004 and on coffee trees with three years old. The "COL" variable was evaluated attributing scores from 1 to 5, where score 1 represents plants with 0 percent to 5 percent of necrosed fruits. "FN" was evaluated following a score scale from 1 to 5, where score 1 represents plants with 0 to 3 fruits/ node and score 5 with more than 15 fruits/ node. The yield per plant was estimated by visual evaluation in liters of cherry fruits per plant. The Pearson's coefficient of correlation was estimated to evaluate the associations between variables. Positive and significant correlations were observed at 1 percent between "COL" x "FN" and between "COL" x "PRD". The fruit necrosis was higher on coffees with higher yield and higher number of fruits per productive node. It is suggested that the field evaluation for resistance to fruit necrosis would be better if accomplished on coffee trees with high yield and high number of fruits per productive node.

INDUCCIÓN DE POLIFENOLOXIDASA EN FRUTOS DE LULO (Solanum quitoense) COMO RESPUESTA A LA INFECCIÓN CON Colletotrichum acutatum / Polyphenol Oxidase Induction in Lulo Fruits (Solanum quitoense) Infected by Colletotrichum acutatum

Se evaluó la actividad polifenoloxidasa (PFO) en corteza de frutos de lulo con el fin de determinar su participación en respuestas hacia el patógeno Colletotrichum acutatum, causante de la antracnosis. Se estudiaron condiciones para la adecuada extracción de esta enzima, encontrándose que con buffer fosfatos 100 mM pH 7, 1% SDS y 1% PVPP se logran las mayores actividades. Se determinaron como mejores parámetros para medir la actividad de la enzima extraída, sustrato catecol 40 mM, pH 7,0, 23 °C y 30 µL de extracto. Para determinar su posible inducción en la interacción con el patógeno, se realizó un ensayo in vivo usando frutos verdes, pintones y maduros, inoculados con el hongo o con agua estéril. A nueve tiempos postinoculación se determinó la actividad PFO encontrándose que hay una respuesta diferencial con el tiempo y la madurez de los frutos y por efecto del patógeno. Se obtuvo aumento de actividad en lulos verdes a 48, 96 y 144 horas postinoculación (hpi) y en maduros a la mayoría de los tiempos evaluados, siendo éste estado en el que se presentó la respuesta más notable de inducción. En pintones aumentó solo a 72 y 144 hpi. Los mayores valores se registraron en general para frutos en estado verde. Los frutos respondieron al estrés ocasionado por la herida activando también esta enzima. La inducción de actividad se presentó a tiempos más rápidos en los frutos menos afectados por la enfermedad (verdes y maduros), por lo que se puede postular una relación positiva entre inducción de PFO y respuesta de tolerancia a la antracnosis.

Polyphenol oxidase (PFO) activity induction was evaluated in lulo fruits to determine the role of this enzyme in resistance responses towards the pathogen Colletotrichum acutatum which causes anthracnose disease. We studied the experimental conditions to obtain the enzyme, using lulo peel, and found that extraction with phosphates buffer 100 mM pH 7, 1% SDS y 1% PVPP showed higher activities. The adequate parameters for activity measurement was also evaluated and established as cathecol 40 mM, pH 7,0, 23 °C and 30 µL of extract. Then, we performed an in vivo assay using lulo fruits in three maturity stages, green, semimature and mature, which were inoculated with the fungus or with sterile water. Enzymatic induction of this protein was studied at nine postinoculation times, and it was found that the induction was differential according to the time, the maturity stage, and as consequence of pathogen presence. The PFO activity increased in green fruits at 48, 96 y 144 (hours postinoculation (hpi), and in mature lulos for the majority of times studied, with the most significant induction response at this stage. In semimature lulo, the induction was observed only at 72 and 144 hpi. The highest nominal value of activity was found in green fruits. Fruits responded to incision with enzyme activation. The increase in the activity of the enzyme was faster in the fruits with the minor anthracnose symptoms than the ones that were more affected. Therefore, it is possible to postulate a positive relation between PFO induction and tolerance to anthracnose symptoms.

Partial resistance to fruit necrosis associated to Colletotrichum spp. among arabic coffee genotypes

The aim of this study was to evaluate the resistance to fruit necrosis associated to Colletotrichum spp. in Coffea arabica L.. Twenty-two arabic coffee genotypes were performed in a randomized block design, with three replications and ten plants per plot. They were evaluated for the variables fruit necrosis, luminosity index inside of the plant canopy and fruits per productive nodes of the plants. There was genetic variability for the resistance to fruit necrosis. Different partial resistance levels, varying from highly susceptible (score = 3.89) to moderately resistant (score = 1.77) were observed. The genotypes that presented moderate resistance were the cultivars IPR-100, IPR-103, IPR-105 and IPR-108 and the coffee selection IAPAR-00023.

Diferentes espécies de fungo do gênero têm sido associadas a perdas na cafeicultura brasileira. O objetivo deste trabalho foi avaliar a resistência à necrose de frutos associada ao Colletotrichum spp. em Coffea arabica L.. Vinte e dois genótipos de café foram avaliados no delineamento em blocos ao acaso com três repetições e dez plantas por parcela. As avaliações foram realizadas no IAPAR, Londrina, em janeiro de 2004 para as variáveis necrose de frutos, índice de luminosidade dentro da copa da planta e frutos por nó produtivo. Existe variabilidade genética em cafeeiros arábicos para a resistência à necrose de frutos. Foi observado diferentes níveis de resistência parcial, variando de altamente suscetível (nota = 3,89) a moderadamente resistente (nota = 1,77). Os genótipos que apresentaram moderada resistência foram as cultivares IPR-100, IPR-103, IPR-105 e IPR-108 e a seleção de café IAPAR-00023.