Variabilidade morfocultural e genética de fungos associados a podridão peduncular do mamão

Abstract

RESUMO -Objetivou-se, com este trabalho, verificar a variabilidade morfocultural e genética de fungos associados à podridão peduncular do mamão (Carica papaya L. MORPHOCULTURAL AND GENETIC VARIABILITY OF FUNGI ASSOCIATED WITH STEM-END ROT OF PAPAYAABSTRACT -The objective of this work was to look at the variability between isolates of the three fungal species, Colletotrichum gloeosporioides, Fusarium solani and Phoma caricae-papayae associated with stem-end rot in papaya fruits (Carica papaya L.) which were produced in different regions of Brazil. In one trial, comparisons were made considering morphological and cultural characteristics exhibited by the fungi grown in different media: Potato dextrose agar (PDA), Papaya extract agar (PEA) and Czapek. In general, mycelial growth of all fungi was higher in PDA and PEA and no correlation was seen between growth rates and other morphocultural characteristics such as color, colony type and others for all isolates compared. The analysis of AFLP markers revealed that there is a huge genetic variation between isolates as demonstrated by the production of 339 bands in eletrophoretic gel. With basis on genetic diversity it was possible to characterize four groups of C. gloeosporioides, F.solani and P. caricae-papayae. No correlation was seen between morphocultural characteristics and AFLP analysis.

In vitro effect of UV-C irradiation on Guignardia citricarpa and on postharvest control of citrus black spot

“…In the following evaluations the colonies in UV-C treatments had already recovered and were developing normally and had an appearance equivalent to that of control. In addition, regression analysis between the mycelial growth index calculated according to Peres et al (2003) and UV-C doses did not show a correlation (data not shown), indicating that UV-C do not significantly influence G. citricarpa mycelial growth.…”

Ethanol on the postharvest control of anthracnose in ‘Kumagai’ guava

“…The collected data was used to calculate the MGR (mycelial growth rate), as demonstrated by Peres et al (2003), according to the mathematical equation: determination of peel and pulp color, a colorimeter Hunter Lab -MiniScan XE Plus, L C °H system [L represents luminance, C represents chroma, and °H (Hue), the color angle (0° to 360° -0°: Red; 90°: yellow; 180°: green; and 270°: blue)], with readings in two opposite points in the equatorial region of the fruit; Soluble solids content was determined with the fruit juice, obtained by the centrifugation of two fruit per repetition, directly read in a digital refractometer Pal -1 (Atago®), and the results were expressed in °Brix; Titratable acidity was determined by titration, with sodium hydroxide solution (NaOH) 0.1 N until pH 8.10 (pH meter Digimed®), using 10 g of juice, diluted in 90 mL of distilled water. The results were expressed as percentage citric acid.…”

Atividade celulolítica in vitro de Cylindrocladium clavatum e o efeito de filtrados de cultivo do fitopatógeno sobre plântulas de eucalipto

“…A baixa atividade apresentada pode indicar que a celobiose, na concentração utilizada, teria reprimido a ação enzimática extracelular, sendo esse substrato hidrolizado pela enzima celobiase intracelular, levando ao acúmulo de glicose que age como repressor enzimático (Mandels e Reese, 1960). A produção de ß-glucosidase in vitro também já foi relatada por Peres et al (2000) para Fusarium, Ascochyta e Colletotrichum e por Kader e Omar (1998), que observaram a produção da enzima por três espécies de Aspergillus e duas de Trichoderma, quando cultivadas em meios de cultivo suplementados com carboximetilcelulose.…”