ABSTRACT Cotton (Gossypium hirsutum L.) is economically important in Xinjiang, China, for many years; Verticillium wilt, arid climate, and soil salinization reduce cotton production, which has inhibited development of the cotton economy. Thus, creating a microbial agent specifically for cotton to resisting environmental stress is crucial. In this study, water dispersible granules strains (Bacillus tequilensis C-9 and B. sphingosporium A1) were screened for antagonistic bacteria of Verticillium dahliae from the rhizosphere soil of Ferula sinkiangensis K.M. Shen, and screened for carrier and auxiliary that could enhance the survival of strains A1+C-9. To test the efficacy and practicality of the water dispersible granules, their growth-promoting effect was examined. Meanwhile, bursts of reactive oxygen species and changes in the physiological indicators related to cotton growth were detected after the application of these granules to cotton that had been subjected to biotic and abiotic stresses to study the ability of the water dispersible granules to induce immunity in cotton. It was found that the treated group could increase the above-ground and below-ground fresh weight of cotton by 20.06% and 22.71% relative to the control group, and the biocontrol effect on cotton was increased by 46.55%. In salt and drought stress, catalase activity could be increased by 14.61% and 15.52%, respectively, relative to the control group. Comprehensive analyses showed that the application of water dispersible granules that contained A1+C-9 helped the cotton to grow and develop, inhibited V. dahliae from infecting cotton plants, reduced the damage from drought and salt stress, and increased the resilience of cotton to stress.

Resumo As bactérias endofíticas desempenham papel fundamental na manutenção da saúde e do crescimento das plantas. Poucos estudos até o momento, no entanto, exploraram as propriedades antagônicas e promotoras de crescimento de plantas (PGP) de endófitos de Prunus cerasifera. Para esse fim, isolamos bactérias endofíticas de amostras de tecido de P. cerasifera e usamos um ensaio de placa de cultura dupla para rastrear esses micróbios quanto à atividade antagonista contra Verticillium dahliae, Botryosphaeria dothidea, Fusarium oxysporum, F. graminearum e F. moniliforme. Das 36 cepas de bactérias isoladas, quatro (cepas P1, P10, P16 e P20) exibiram efeitos antagônicos contra todos os cinco patógenos modelo, e a cepa P10 exibiu o antagonista mais forte para cinco patógenos. Essa cepa P10 foi então caracterizada em profundidade por meio de avaliações fenotípicas, análises fisiológicas e sequenciamento de rDNA 16s, revelando ser uma cepa de Bacillus subtilis. A aplicação de uma suspensão de células P10 (1 × 108 UFC / mL) aumentou significativamente a germinação das sementes e o crescimento das mudas de tomate em casa de vegetação. Essa cepa P10 suprimiu ainda mais a murcha de Verticillium do tomate com incidência de doença muito menor e pontuações de índice de doença sendo observadas após o tratamento com P10 em relação a plantas não tratadas em experimentos baseados em vasos. As plantas de tomate que foram tratadas com a cepa P10 também aumentaram as enzimas relacionadas à defesa, peroxidase, superóxido dismutase e atividade da catalase após o desafio de V. dahliae em relação às plantas que não foram tratadas com essa bactéria endofítica. Os resultados revelaram que a cepa bacteriana P10 tem valor potencial como agente de biocontrole para uso na prevenção da murcha de Verticillium em tomate.

Abstract Endophytic bacteria serve key roles in the maintenance of plant health and growth. Few studies to date, however, have explored the antagonistic and plant growth-promoting (PGP) properties of Prunus cerasifera endophytes. To that end, we isolated endophytic bacteria from P. cerasifera tissue samples and used a dual culture plate assay to screen these microbes for antagonistic activity against Verticillium dahliae, Botryosphaeria dothidea, Fusarium oxysporum, F. graminearum, and F. moniliforme. Of the 36 strains of isolated bacteria, four (strains P1, P10, P16, and P20) exhibited antagonistic effects against all five model pathogens, and the P10 strain exhibited the strongest antagonistic to five pathogens. This P10 strain was then characterized in-depth via phenotypic assessments, physiological analyses, and 16s rDNA sequencing, revealing it to be a strain of Bacillus subtilis. Application of a P10 cell suspension (1×108 CFU/mL) significantly enhanced the seed germination and seedling growth of tomato in a greenhouse setting. This P10 strain further significantly suppressed tomato Verticillium wilt with much lower disease incidence and disease index scores being observed following P10 treatment relative to untreated plants in pot-based experiments. Tomato plants that had been treated with strain P10 also enhanced defense-related enzymes, peroxidase, superoxide dismutase, and catalase activity upon V. dahliae challenge relative to plants that had not been treated with this endophytic bacterium. The results revealed that the P10 bacterial strain has potential value as a biocontrol agent for use in the prevention of tomato Verticillium wilt.

Resumen Se evaluó la capacidad antagónica de cepas nativas, de Trichoderma spp. frente a Verticillium dahliae, en diferentes condiciones de cultivo e incubación. Se realizó el aislamiento e identificación molecular de cepas nativas antagónicas y del fitopatógeno. Los mismos, fueron evaluadas en dos ensayos in vitro, empleando medio de cultivo ADP en dos condiciones de pH e incubados bajo dos condiciones de iluminación. Mediante técnicas de cultivo dual se efectuó un ensayo con diseño completamente aleatorizado con arreglo factorial 2 x 2 x 2, y de microcultivos. Se evaluó la capacidad antagonista de dos cepas nativas de Trichoderma, TT (T. hamatum) y M5A (T. hamatum) sobre la cepa del fitopatógeno nativo (Verticillium dahliae). Los resultados obtenidos demostraron que la cepa TT a pH 6.5 con 16 h luz/8 h oscuridad tuvo el menor Tiempo de Contacto y mayor Porcentaje de Inhibición de Crecimiento con 8 h de luz/16 h. de oscuridad. En ambos ensayos y tratamientos se obtuvo Clase 1, siendo ambas eficientes en la competencia por sustrato y espacio. Se observó que la cepa nativa M5A y la cepa patrón TT parasitan al fitopatógeno. Por lo que se concluye que la cepa TT presenta mayores atributos de antagonismo frente al fitopatógeno V. dahliae, en condiciones de 8 h luz/ 16 h oscuridad.

Summary The antagonistic capacity of native strains of Trichoderma spp. against Verticillium dahliae, under different culture and incubation conditions. The isolation and molecular identification of antagonistic native strains and the phytopathogen were carried out. They were evaluated in two in vitro tests, using ADP culture medium in two pH conditions and incubated under two lighting conditions. By means of dual culture techniques, a trial was carried out with a completely randomized design with a 2 x 2 x 2 factorial arrangement, and microcultures. The antagonistic capacity of two native strains of Trichoderma, TT (T. hamatum) and M5A (T. hamatum) on the native phytopathogen strain (Verticillium dahliae) was evaluated. The results obtained showed that the TT strain at pH 6.5 with 16 h light / 8 h Darkness had the shortest Contact Time and the highest Growth Inhibition Percentage with 8 h of light /16 h. of darkness. Class 1 was obtained in both tests and treatments, both being efficient in the competition for substrate and space. It was observed that the native strain M5A and the standard strain TT, parasitize the phytopathogen. Therefore, it is concluded that the TT strain has greater antagonistic attributes against the phytopathogen V. dahliae, under conditions of 8 h light / 16 h dark.

SUMMARY Olive growing is affected by a syndrome that causes wilt in the tree top. One of the main microorganisms accountable for this disease is the fungus Verticillium dahliae, which causes verticillium wilt (VW). Two pathotypes are distinguished within V dahliae, defoliating (D) and non-defoliating (ND), depending on symptom severity. The pathogen is generally diagnosed by polymerase chain reaction (PCR). Our objective was to compare the efficiency of two sets of primers in detecting the ND pathotype in olive plants, the only pathotype found in Argentina, by nested PCR. For this purpose, the commonly used primer combination NDf/NDr - INTND2f/INTND2r (PCR-I) and a new combination, INTNDf/INTNDr - INTND2f/INTND2r (PCR-II), were evaluated. Samples of symptomatic olive trees from 39 commercial fields from La Rioja province were analyzed. PCR-II had higher detection efficiency than PCR-I (57.8 % and 16.7 %, respectively). PCR-II amplified in almost all the olive cultivars, plant ages and VW disease severity levels, whereas PCR-I detected the fungus only in very susceptible cultivars and in trees with low VW severity levels. The use of PCR-II for the detection of V dahliae in olive plants will provide more accurate incidence results and will contribute to a proper management of VW.

RESUMEN La olivicultura está afectada por un síndrome que genera marchitez en la copa del árbol. Uno de los microorganismos responsables es el hongo Verticillium dahliae, que provoca la enfermedad denominada verticilosis del olivo (VO). Según la severidad de los síntomas, se distinguen dos patotipos, defoliante (D) y no defoliante (ND). Su diagnóstico emplea la reacción en cadena de la polimerasa (PCR). Nuestro objetivo fue comparar la eficiencia de dos juegos de cebadores para detectar en planta el patotipo ND, el único presente en Argentina, mediante PCR anidada. Para ello se utilizaron los juegos de cebadores NDf/NDr - INTND2f/INTND2r (PCR-I), empleados comúnmente, y una nueva combinación, INTNDf/INTNDr - INTND2f/INTND2r (PCR-II). Se analizaron muestras de olivos sintomáticos de 39 fincas de la provincia de La Rioja. PCR-II tuvo mayor eficiencia en la detección, 57,8 % frente a 16,7 % de PCR-I. PCR-II amplificó en casi todas las variedades, edades de plantas y niveles de severidad de la enfermedad, mientras que PCR-I detectó el hongo sólo en variedades muy susceptibles y con niveles de severidad leve. El uso de PCR-II para detectar a V. dahliae en olivo permitirá estudios más precisos sobre su incidencia que contribuirán al manejo adecuado de la verticilosis.

SUMMARY Verticillium wilt caused by the soil-borne fungus Verticillium dahliae Kleb. is a disease that affects olive (Olea europaea L.) and cotton crops, among others. According to their pathogenicity, V. dahliae isolates can be classified as defoliating (D) and non-defoliating (ND). The objectives of this study were: i) to determine the pathotypes of a collection of 42 V dahliae isolates from olive plants in the provinces of Catamarca, Córdoba, La Rioja and Mendoza kept at IPAVE-INTA Córdoba, and (ii) to evaluate the virulence of eight recently isolated isolates belonging to this collection. Nested PCR was used for molecular analysis of the 42 fungal isolates and virulence evaluation was performed by artificial inoculations on cotton seedlings with a completely randomized design. The total of the isolates was characterized as ND. Two strains from La Rioja, two from Catamarca and one from Mendoza, were significantly more virulent (p< 0.05) for the relative area under disease progress curve, final mean severity, average severity percentage and severity index.

RESUMEN La verticilosis causada por el hongo habitante de suelo Verticillium dahliae Kleb. es una enfermedad que afecta el cultivo del olivo (Olea europaea L.) y algodón (Gossypium hirsutum L.), entre otros. De acuerdo a su patogenicidad, los aislados del patógeno pueden clasificarse como patotipos defoliantes (D) y no defoliantes (ND). Los objetivos de este estudio fueron: i) determinar los patotipos de una colección de 42 aislados de V. dahliae provenientes de plantas de olivo de las provincias de Catamarca, Córdoba, La Rioja y Mendoza existente en el IPAVE-INTA Córdoba, y ii) evaluar la virulencia de ocho cepas recientemente aisladas pertenecientes a dicha colección. Se utilizó la técnica de PCR anidado para el análisis molecular de los aislados del hongo y la evaluación de la virulencia se realizó mediante inoculaciones artificiales en plantines de algodón con un diseño completamente aleatorizado. El 100 % de los aislados fueron caracterizados como ND. Dos cepas provenientes de La Rioja, dos de Catamarca y una de Mendoza, fueron significativamente más virulentas (p< 0,05) para el área bajo la curva de progreso de la enfermedad relativa, severidad media final, porcentaje de severidad media e índice de severidad.

RESUMEN El complejo marchitez del aguacate (CMA) es la enfermedad más importante de este cultivo. El CMA puede ser causado por distintos agentes causales que inducen síntomas similares. Las escalas de desarrollo de la enfermedad (EDE) y los cambios fisiológicos pueden ser de gran importancia para el diagnóstico y manejo del CMA. El objetivo de este trabajo fue diseñar y calibrar EDE específicas para los agentes causales más comunes asociados al CMA en Colombia, Phytophthora cinnamomi Rands y Verticillium dahliae Klebahn, y el desorden hipoxia-anoxia en plántulas de invernadero y plantas adultas en condiciones de campo. Además, se determinó la respuesta fisiológica durante la infección. La enfermedad se monitoreó en condiciones de campo e invernadero. Los síntomas de la parte aérea de la planta fueron registrados y se cuantificó el inóculo en el suelo y tejido afectado. Se describieron las escalas visuales basadas en síntomas externos las cuales fueron calibradas con la cantidad de inóculo mediante análisis de regresión. En invernadero, se midieron la fotosíntesis neta, la conductancia estomática y la transpiración durante diferentes etapas del desarrollo de la enfermedad. Los tres agentes causales de enfermedad indujeron una reducción progresiva de la fotosíntesis neta, la conductancia estomática y la transpiración. Las escalas diseñadas pueden ser una herramienta valiosa para su uso epidemiológico y de apoyo en el diagnóstico y manejo del AWC.

ABSTRACT Avocado wilt complex (AWC) is the most important disease in this crop. AWC may be caused by different causal agents that induce similar symptoms. Accurate scales of disease development (SDD) and physiological changes may be of special importance for the diagnosis and management of AWC. The objective of this work was to design and calibrate a specific SDD for the most common causal agents associated with AWC in Colombia, Phytophthora cinnamomi Rands and Verticillium dahliae Klebahn, and the hypoxia-anoxia disorder in both seedlings in net house and adult plants under field conditions. Furthermore, physiological responses to infection were determined. The disease was monitored under field and net house conditions. Shoot symptoms were recorded and quantification of inoculum in infected soil and tissue was performed. The visual scale was described based on external symptoms and calibrated with the inocula values by regression analysis. In the net house, net photosynthesis, stomatal conductance, and transpiration were measured during the different stages of disease development. The three causal agents induced a progressive reduction of net photosynthesis, stomatal conductance, and transpiration. The designed scales can be a valuable tool for epidemiological use and support in the diagnosis and management of AWC.

RESUMO Murcha de Verticillium em berinjela é uma doença de raiz de difícil controle. Este trabalho relata a relação entre a disponibilidade de água no solo e a intensidade da doença, visando identificar estratégias de manejo que são desfavoráveis ao patógeno e capazes de reduzir o progresso e o dano causados pela doença. Quatro estratégias de manejo de água foram comparadas em solo infestado ou não infestado com Verticillium dahliae, a saber: irrigação mantendo a umidade do solo em 90% (WA90%), 55% (WA55%) e 20% (WA20%) durante todo o ciclo da cultura, e 20% no estágio vegetativo, seguido por irrigação mantendo 90% no estágio reprodutivo (WA20-90%). O desenho experimental foi em blocos ao acaso com oito tratamentos em esquema fatorial (4 x 2) e três repetições. A estratégia WA20-90% levou a uma redução significativa da severidade da doença e na extensão da colonização do xilema pelo patógeno. A massa seca das plantas em solo infestado foi 12% inferior a das plantas nos tratamentos controle, e foi maior com a estratégia de irrigação WA90% do que em WA55% ou WA20%. A estratégia WA20-90% foi eficiente em reduzir a doença, sem causar perdas de massa seca.

ABSTRACT Verticillium wilt in eggplants is a root disease of difficult control. In this study, we report the relationship between soil water availability and the disease intensity in order to identify management strategies that are unfavourable to the pathogen and capable of reducing the disease progression and the damage caused by it. Four irrigation management strategies were compared in soil infested or not infested with Verticillium dahliae, which consisted of: irrigating when the available soil moisture was maintained at 90% (WA90%), 55% (WA55%) and 20% (WA20%) during the entire growing cycle, and kept at 20% in the vegetative stage, and at 90% in the production stage (WA20-90%). Experimental design was in randomized blocks, including eight treatments in factorial arrangement (4x2) and three replicates. The management strategy WA20-90% led to a significant reduction in the disease severity and in the extent of xylem colonization by the pathogen. The dry mass of plants in infested soil was 12% lower than that of control treatments and was higher with the irrigation strategy WA90% than with WA55% or WA20%. The strategy WA20-90% was efficient in reducing the disease with no significant reduction in dry mass.

Resumen En el sector Atusparia, Tocache, de la Región de San Martin, Perú, plantas de Theobroma cacao L. (Malvaceae) clon CCN-51 de dos años de edad presentaron, por primera vez en enero de 2010, síntomas de amarillamiento en hojas, marchitez y muerte, e internamente obstrucción del sistema vascular. Para el aislamiento del agente causal, tejidos enfermos fueron sembrados en placas Petri que contenían medio papa dextrosa agar oxitetraciclina, cuya identificación fue con base en un análisis morfológico, microscópico y secuenciación de Sanger. Las pruebas de patogenicidad se hicieron en T. cacao clon ICS-1 con edad de tres meses, inoculadas con una suspensión de conidias de 1x107 ufc/mL por dos métodos de inoculación (Drench al suelo y punción en el tallo). La capacidad antagónica (micoparasitismo y antibiosis) se determinó in vitro con aislamientos de Trichoderma endofito sobre el patógeno. En ambos métodos de inoculación, se observaron síntomas de marchitez de diferentes grados de severidad y se confirmó que el agente causal de la muerte súbita del T. cacao fue el hongo Verticillium dahliae Kleb. El análisis de la secuencia blast revelo que el aislamiento tuvo un 100 % de homología con las secuencias de V. dahliae en GenBank. El Trichoderma TE-91 fue identificado como el micoparasito más agresivo, debido a que sus metabolitos inhibieron completamente el crecimiento micelial del patógeno.

Abstract In the Atusparia sector, Tocache, of the San Martin region in Peru, two-year-old plants of Theobroma cacao L. (Malvaceae) of the CCN-51 clone showed for the first time in January 2010, symptoms of leaf yellowing, wilt and dieback, with an internal obstruction of the vascular system of the plant. To isolate the fungus, diseased tissues were cultured in Petri dishes containing potato dextrose agar oxytetracycline, and the identification was based on morphological and microscopic analyses and by the Sanger sequencing. Pathogenicity tests were carried out on three-months-old T. cacao ICS-1 clone plants and were inoculated with a conidia suspension of 1x107 cfu/mL employing two inoculation methods (Drench to the soil and stem puncture). Likewise, the antagonistic capacity (mycoparasitism and antibiosis) was established in vitro with endophytic Trichoderma isolates on the pathogen. With both inoculation methods symptoms of wilt of different degrees of severity were observed and the causal agent of sudden death in T. cacao was confirmed to be the fungus Verticillium dahliae Kleb. blast sequence analysis revealed that the isolate showed 100 % homology with V. dahliae sequences in GenBank. Trichoderma TE-91 was identified as the most aggressive mycoparasite because its metabolites inhibited completely the mycelial growth of the pathogen.

Abstract Agricultural crops suffer many diseases, including fungal and bacterial infections, causing significant yield losses. The identification and characterisation of pathogenesis-related protein genes, such as chitinases, can lead to reduction in pathogen growth, thereby increasing tolerance against fungal pathogens. In the present study, the chitinase I gene was isolated from the genomic DNA of Barley (Hordeum vulgare L.) cultivar, Haider-93. The isolated DNA was used as template for the amplification of the ∼935 bp full-length chitinase I gene. Based on the sequence of the amplified gene fragment, class I barley chitinase shares 93% amino acid sequence homology with class II wheat chitinase. Interestingly, barley class I chitinase and class II chitinase do not share sequence homology. Furthermore, the amplified fragment was expressed in Escherichia coli Rosetta strain under the control of T7 promoter in pET 30a vector. Recombinant chitinase protein of 35 kDa exhibited highest expression at 0.5 mM concentration of IPTG. Expressed recombinant protein of 35 kDa was purified to homogeneity with affinity chromatography. Following purification, a Western blot assay for recombinant chitinase protein measuring 35 kDa was developed with His-tag specific antibodies. The purified recombinant chitinase protein was demonstrated to inhibit significantly the important phytopathogenic fungi Alternaria solani, Fusarium spp, Rhizoctonia solani and Verticillium dahliae compared to the control at concentrations of 80 µg and 200 µg.

Abstract In this study, we researched the chemical composition and the antifungal and antibacterial activity of volatile oil from Mentha spicata. The Gas chromatography/mass spectrometry (GC/MS) analysis of M. spicata showed that the main component was carvone (56.94%), followed by limonene (11.63%), sabinene hydrate (7.04%) and caryophyllene (4.06%). The antifungal activity of the volatile oil from M. spicata L. was determined with respect to plant pathogenic fungi, such as Fusarium oxysporum f. sp. radicis-lycopersici (Sacc.) W.C. Synder & H.N. Hans (FORL), Rhizoctonia solani J.G. Kühn. (R. solani), Alternaria solani (A. solani), and Verticillium dahliae Kleb (V. dahliae). The volatile oil was shown to have strong antifungal activity against plant pathogenic fungi. The result of the study was that at a dose of 12 μL petri-1, the volatile oil inhibited 100% of mycelium growth in V. dahliae, A. solani FORL and R. solani. Volatile oil exhibited remarkable activity against the selected bacterial strains of Xanthomonas spp. (ZI365, ZI366, ZI368, ZI370, ZI373, ZI375, ZI376, ZI378).

Resumen El objectivo del trabajo fue la investigación de la composición química, de la actividad antifúngica y antibacteriana del aceite volátil Mentha spicata. Desde el análisis Cromatografía de gases / espectrometría de masas (GC-MS), el componte principal M. spicata, resulta constituido por carvona (56.94%), limoneno (11.63%), hidrato de sabineno (7.04%) y cariofileno (4.06%). Se ha ademas detectado la actividad antifúngica del aceite volátil de M. spicata L. Contra hongos patógenos de plantas; Fusarium oxysporum f. sp. radicis-lycopersici (Sacc.) W.C. Synder & H.N. Hans (FORL), Rhizoctonia solani J.G. Kühn. (R. solani), Alternaria solani (A. solani) y Verticillium dahliae Kleb (V. dahliae). Se ha demostrado una fuerte actividad antifúngica del aceite volátil contra los hongos patógenos de plantas. El resultado del estudio, a una dosis de 12 μL petri-1, inhibió el crecimiento del 100% del micelio de V. dahliae, A. solani, FORL y R. solani. El aceite volátil exhibió una actividad notable contra las Xanthomonas spp seleccionadas (ZI365, ZI366, ZI368, ZI370, ZI373, ZI375, ZI376, ZI378) aislados bacterianos.

RESUMO Murchas vasculares em tomateiro constituem importante grupo de doenças causadas por patógenos habitantes do solo, com destaque para Verticillium dahliae, que ocasiona perdas significativas na produção. A dificuldade de controle dessa doença advém de características intrínsecas do patógeno, como alta adaptabilidade ao ambiente subterrâneo, em associação com o hospedeiro, e produção de estruturas de resistência que permanecem viáveis no solo por longo tempo. A introgressão de genes que expressam resistência destaca-se como principal medida de controle, o que requer um programa contínuo de caracterização de acessos resistentes. Objetivou-se avaliar e identificar acessos de tomateiro (Solanum lycopersicum) resistentes a V. dahliae, pelos métodos fenotípico e genotípico. A reação de 33 acessos de tomateiro a diferentes isolados de V. dahliae foi corroborada com análises empregando-se marcadores moleculares ligados aos genes de resistência Ve. A combinação de bioensaios e marcadores moleculares específicos mostrou elevada correlação (94,3 %), com a seleção de 25 acessos resistentes a V. dahliae.

ABSTRACT Vascular wilting in tomato plants is an important disease caused by soil-inhabiting pathogens, especially Verticillium dahliae, which results in significant production losses. Control measures against this disease are difficult to implement due to intrinsic pathogen characteristics, such as high adaptability to the subterranean environment, in association with the host, and development of resistance structures that remain viable in the soil for long periods. The introgression of genes that express resistance is the main control measure and requires a continuous characterization program of resistant accessions. This study aimed at identifying tomato (Solanum lycopersicum) accessions resistant to V. dahlia, by using the phenotypic and genotypic methods. The reaction of 33 tomato accessions to different V. dahliae isolates was reinforced by molecular analysis, through markers linked to Ve resistance genes. The combination of bioassays and specific molecular markers showed a high correlation (94.3 %), with the selection of 25 accessions resistant to V. dahliae.

O efeito antagônico exercido por fungos do gênero Trichoderma foi avaliado contra os fitopatógenos Sclerotium rolfsii e Verticillium dahliae, isolados de áster ornamental e morangueiro, respectivamente. Utilizaram-se 20 isolados do antagonista, pertencentes às espécies T. asperellum, T. hamatum, T. harzianum, T. koningiopsis, T. spirale e Trichoderma sp. O antagonismo foi verificado por meio de testes de culturas pareadas e produção de metabólitos bioativos pelo método de sobreposição de placas. A maioria dos isolados exibiu efeito inibitório sobre o crescimento micelial de S. rolfsii e V. dahliae quando comparado com as testemunhas. Excetuando-se os testes de produção de metabólitos não-voláteis, verificou-se maior ação inibitória contra V. dahliae. Mesmo os metabólitos não-voláteis termoestáveis apresentaram efeito inibitório contra ambos os patógenos testados, mostrando que os metabólitos secundários do antagonista exercem efeito significativo sobre essas espécies patogênicas.

The antagonistic effect shown by fungi of the genus Trichoderma was assessed against the plant pathogens Sclerotium rolfsii and Verticillium dahlia, isolated from ornamental aster and strawberry, respectively. Twenty isolates of the antagonist were employed; they belonged to the species T. asperellum, T. hamatum, T. harzianum, T. koningiopsis, T. spirale and Trichoderma sp. Antagonism was investigated by means of dual culture tests and bioactive metabolite production based on the overlapping plate method. Most selected isolates had an inhibitory effect on the mycelial growth of S. rolfsii and V. dahlia, compared to controls. Except for non-volatile metabolite production tests, inhibitory action against V. dahliae was highest. Even the thermostable non-volatile metabolites showed inhibitory effect against both tested pathogens, evidencing that the secondary metabolites of the antagonist have a significant effect on these pathogenic species.

The saprophytic fungi Aspergillus niger, Coriolopsis rigida, Fusarium lateritium, F. oxysporum, Mucor racemosus, Paecilomyces farinosus, Penicillium chrysogenum, P. restrictum, Trametes versicolor, Trichoderma harzianum, T. pseudokoningii and T. viride were able to decrease the growth in vitro of Verticillium dahlie in the presence of aqueous extract of olive residue. The conidia number of V. dahliae decreased when grown on aqueous extract of olive residue, autoclaved or filtered through 0.45 micron filters after culture of the fungi. These results suggest not only the predominance of suppressive substances of a biological nature, but also the existence of non-biological inhibitory substances. The olive residue decreased the negative effect of V. dahliae on shoot and root dry weight of tomato (Solanum lycopersicum L.), by the antifungal compounds present in the olive residue and by the antifungal substances produced by the antagonistic saprophytic fungi grown in this residue.

A murcha-de-verticílio (Verticillium dahliae) é uma das doenças mais severas do tomateiro (Solanum lycopersicum L.). Duas raças fisiológicas de V. dahliae foram caracterizadas infectando o tomateiro e ambas estão presentes no Brasil. A estratégia de controle mais efetiva para isolados da raça 1 tem sido a utilização de cultivares resistentes em associação com práticas culturais. Entretanto, não existem cultivares comerciais de tomate resistentes à raça 2 do patógeno. Neste contexto, torna-se importante a identificação de novas fontes de resistência que sejam efetivas contra as duas raças de V. dahliae. Buscou-se fontes de resistência a isolados de V. dahliae (raças 1 e 2). Cem acessos de uma coleção de germoplasma contendo espécies cultivadas e selvagens de Solanum (secção Lycopersicon) foram inicialmente inoculados pelo método de imersão de raízes com um isolado de V. dahliae raça 1 (5 mL de uma suspensão de 10(6) conídios/mL) em condições de casa de vegetação. A avaliação foi feita aos 30 dias após a inoculação, usando uma escala de notas variando de 1 (planta sadia) a 5 (planta morta). Foram considerados resistentes os acessos que apresentaram nota média entre 1 e 2. Um grupo composto por 38 acessos classificados como resistentes neste primeiro ensaio foi reavaliado para resistência a outros quatro isolados de V. dahliae pertencentes às raças 1 e 2. As cultivares Ponderosa e Floradade foram utilizadas como controles. O ensaio foi conduzido em casa de vegetação em delineamento experimental de blocos ao acaso em arranjo fatorial 5 x 40, com três repetições (vasos com quatro plantas). A avaliação foi feita baseada nos parâmetros epidemiológicos: período de incubação e índice de doença. Foram identificados acessos com resistência raça-específica e também com resistência a ambas as raças. Estes acessos podem ser indicados para futuros programas de melhoramento genético visando incorporar resistência ampla à doença.

Verticillium wilt (Verticillium dahliae) is one of the most destructive diseases of tomato (Solanum lycopersicum). Two V. dahliae races have been described infecting tomatoes and both are present in Brazil. The most effective control strategy of V. dahliae race 1 isolates is based upon the use of resistant cultivars combined with cultural practices. However, there is so far no fresh-market tomato cultivar available with resistance to V. dahliae race 2. Therefore, it is important to identify new sources of effective resistance against both pathogen races. Solanum (section Lycopersicon) accessions were screened to search for resistance sources to both V. dahliae races 1 and 2. A germplasm collection composed by 100 accessions of cultivated and wild tomatoes was first inoculated via root dipping method (5 mL; 10(6) conidia/mL) with one isolate of V. dahliae race 1. Disease assessment was done 30 days after inoculation using a disease severity index ranging from 1 (plant without symptoms) to 5 (dead plant). Accessions with average severity index from 1 to 2 were classified as resistant. A subgroup of 38 race 1 resistant accessions was re-evaluated against four isolates of V. dahliae belonging to races 1 and 2. The cultivars Ponderosa and Floradade were used as controls. The assay was conducted under greenhouse conditions using a completely randomized, factorial (5 x 40) design with three replicates (three pots with four plants each). Evaluation was done based upon two epidemiological parameters: incubation period and disease severity index. Race-specific and multiple-race resistance sources were identified. The most promising accessions could be useful for breeding purposes aiming to develop cultivars with stable resistance to both races.

O objetivo deste trabalho foi determinar as diferenças de composição mineral das folhas entre as cultivares de berinjela (Solanum melongena), 'Faselis' e 'Pala', enxertadas em Solanum torvum ou não enxertadas, e plantadas em solos infestados ou não com Verticillium dahliae e Meloidogyne incognita. A enxertia aumentou as concentrações de P e Mn nas folhas e diminuiu as de nitrogênio, em ambos os solos. A enxertia também aumentou a concentração de Ca foliar em 'Pala', mas não em 'Faselis', conforme o ano agrícola. A concentração de Mg foliar, em plantas enxertadas em solo infestado, foi menor que a de plantas não enxertadas em solo não infestado. Com um mesmo programa de adubação, as plantas enxertadas de 'Faselis' utilizaram os nutrientes de maneira mais eficiente que as de 'Pala'. O uso de S. torvum como porta-enxerto para Faselis, em solo contaminado com os patógenos resultou em proteção efetiva contra a infestação múltipla por patógenos. Fertilizações podem ser necessárias quando plantas enxertadas de 'Faselis' são cultivadas em solos infestados, já que a enxertia e a infestação geralmente reduzem as concentrações foliares de N, Mg, Ca and Fe, seja pela redução direta nos teores dos nutrientes, seja pelo aumento da concentração foliar de Mn. .

The objective of this work was to determine differences in leaf mineral composition between ungrafted and grafted onto (Solanum torvum) eggplant (Solanum melongena), cultivars 'Faselis' and 'Pala', grown in a soil infested with Verticillium dahliae and Meloidogyne incognita, or in a noninfested soil. Grafting increased leaf P and Mn concentrations, and decreased N concentrations, in both soils. Grafting also enhanced leaf Ca concentration of 'Pala', but it did not affect that of 'Faselis' depending on the cropping year. Leaf Mg concentration of grafted plants in infested soil was lower than that of ungrafted ones in noninfested soil. Results showed that, under the same fertilization program, the grafted 'Faselis' plants used the nutrients more efficiently than the 'Pala' ones. Use of S. torvum as a rootstock for 'Faselis' resulted in an effective protection against multiple pathogen infestation. Fertilization may be necessary when grafted 'Faselis' plants are grown in a soil infested with the pathogens, since grafting and infestation generally decrease leaf N, Mg, Ca and Fe concentrations, either by reducing the nutrient concentrations directly or by increasing leaf Mn concentration.