RESUMO
Opuntia ficus-indica Mill. (forage cactus) is farmed with relative success in the semi-arid region of the Brazilian northeast for commercial purposes, particularly as forage and food. Endophytic microorganisms are those that can be isolated inside plant tissues and can be a new source to production of enzymes with different potentialities. The objective of this study was to describe the richness of endophytic fungi from O. ficus-indica and to detect the capacity of these species to produce extracellular hydrolytic enzymes. Forty-four endophytic fungi species were isolated. Among them, the most commonly found were Cladosporium cladosporioides (20.43%) and C. sphaerospermum (15.99%). Acremonium terricola, Monodictys castaneae, Penicillium glandicola, Phoma tropica and Tetraploa aristata are being reported for the first time as endophytic fungi for Brazil. The majority of isolated fungi exhibited enzymatic potential. Aspergillus japonicus and P. glandicola presented pectinolytic activity. Xylaria sp. was the most important among the other 14 species with positive cellulase activity. All 24 isolates analysed were xylanase-positive. Protease was best produced by isolate PF103. The results indicate that there is a significant richness of endophytic fungi in O. ficus-indica, and that these isolates indicate promising potential for deployment in biotechnological processes involving production of pectinases, cellulases, xylanases and proteases.
Assuntos
Biodiversidade , Endófitos/enzimologia , Endófitos/isolamento & purificação , Fungos/enzimologia , Fungos/isolamento & purificação , Opuntia/microbiologia , Brasil , Celulase/análise , Endófitos/classificação , Fungos/classificação , Programas de Rastreamento/métodos , Peptídeo Hidrolases/análise , Poligalacturonase/análise , Xilosidases/análiseRESUMO
O cupim asiático Coptotermes gestroi é considerado praga em áreas urbanas, causando danos expressivos em casas, edifícios e árvores. Esta pesquisa avaliou a eficiência de Isaria javanica URM4993 e I. javanica URM4995 sobre operários de C. gestroi. Os insetos foram pulverizados nas concentrações de 104 a 108 conídios/mL e mantidos em incubadora a 25 ± 1º C e 80 ± 10% de umidade relativa. Determinou-se a Concentração Letal (CL50) e o Tempo Letal (TL50), bem como foi quantificada a produção de conídios sobre os insetos mortos. Os aspectos biológicos referentes à germinação e esporulação, antes e após a infecção em C. gestroi, foram avaliados. O fungo foi virulento ao cupim, causando infecção em todas as concentrações utilizadas, sendo que I. javanica URM4993 foi mais eficiente, por causar mortalidade de 100%, após o 6º dia de inoculação (CL50 de 4,86 conídios/mL e TL50 de 2,26 dias). A esporulação nos insetos mortos não diferiu entre as linhagens. Foi observado que o percentual de germinação foi maior nas linhagens reisoladas do que nas linhagens padrão. Contudo, I. javanica URM4993 apresentou maior potencial de esporulação. Esses resultados mostram o fungo como um candidato ao controle biológico desse cupim.
The Asiatic termite Coptotermes gestroi is considered a pest in urban areas causing extensive damage to houses, buildings and trees. The present study evaluated the effectiveness of Isaria javanica URM4993 and URM4995 on workers of C. gestroi. Insects were sprayed with concentrations of 104 at 108 conidia/mL and kept in an incubator at 25 ± 1º C and 80 ± 10% relative humidity. Results were used to determine the lethal concentration (LC50) and lethal time (LT50). Conidia production on dead insects was assessed. Biological aspects related to germination and sporulation, before and after infection with C. gestroi were also assessed. The fungus was virulent to termites, causing infection at all tested concentrations, with I. javanica URM4993 being the most virulent, causing 100% mortality after six days of inoculation (LC50 of 4.86 x 10 conidia/mL and LT50 of 2.26 days). Sporulation on dead insects did not differ between strains. The percentage of germination was greater for reisolated strains than for standard strains. However, I. javanica URM4993 showed greater sporulation. These results show that the fungus is a candidate for the biological control of termites.
Assuntos
Controle de Pragas , Controle Biológico de Vetores , IsópterosRESUMO
ABSTRACT The Asiatic termite Coptotermes gestroi is considered a pest in urban areas causing extensive damage to houses, buildings and trees. The present study evaluated the effectiveness of Isaria javanica URM4993 and URM4995 on workers of C. gestroi. Insects were sprayed with concentrations of 104 at 108 conidia/mL and kept in an incubator at 25 ± 1º C and 80 ± 10% relative humidity. Results were used to determine the lethal concentration (LC50) and lethal time (LT50). Conidia production on dead insects was assessed. Biological aspects related to germination and sporulation, before and after infection with C. gestroi were also assessed. The fungus was virulent to termites, causing infection at all tested concentrations, with I. javanica URM4993 being the most virulent, causing 100% mortality after six days of inoculation (LC50 of 4.86 x 10 conidia/mL and LT50 of 2.26 days). Sporulation on dead insects did not differ between strains. The percentage of germination was greater for reisolated strains than for standard strains. However, I. javanica URM4993 showed greater sporulation. These results show that the fungus is a candidate for the biological control of termites.
RESUMO O cupim asiático Coptotermes gestroi é considerado praga em áreas urbanas, causando danos expressivos em casas, edifícios e árvores. Esta pesquisa avaliou a eficiência de Isaria javanica URM4993 e I. javanica URM4995 sobre operários de C. gestroi. Os insetos foram pulverizados nas concentrações de 104 a 108 conídios/mL e mantidos em incubadora a 25 ± 1º C e 80 ± 10% de umidade relativa. Determinou-se a Concentração Letal (CL50) e o Tempo Letal (TL50), bem como foi quantificada a produção de conídios sobre os insetos mortos. Os aspectos biológicos referentes à germinação e esporulação, antes e após a infecção em C. gestroi, foram avaliados. O fungo foi virulento ao cupim, causando infecção em todas as concentrações utilizadas, sendo que I. javanica URM4993 foi mais eficiente, por causar mortalidade de 100%, após o 6º dia de inoculação (CL50 de 4,86 conídios/mL e TL50 de 2,26 dias). A esporulação nos insetos mortos não diferiu entre as linhagens. Foi observado que o percentual de germinação foi maior nas linhagens reisoladas do que nas linhagens padrão. Contudo, I. javanica URM4993 apresentou maior potencial de esporulação. Esses resultados mostram o fungo como um candidato ao controle biológico desse cupim.
RESUMO
Members of the Fusarium solani species complex are agents of human mycoses, also affecting plants and other animals. Nevertheless, this fungus has not been reported on scorpions. Ten specimens of Tityus stigmurus collected in the field and showing their surface covered by white mycelia were used to assess fungus presence in the animal after its death. Identification of the fungi was based upon the cultural and morphological characteristics. The fungus was isolated from chelicerae and intersegmental regions. Infected individuals had their behaviour modified by reducing feeding and locomotion. None of the infected individuals survived. It is likely that this fungus may have a role in the regulation of field scorpion populations.