Download Hydrolytic enzymes of membrane and cell wall assay secreted by

Hydrolytic enzymes of membrane and cell wall assay secreted by endophytic bacteria as an
antifungal factor against Mycosphaerella fijiensis Morelet.
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Gloria Margarita-Macedo Raygoza, 2Miguel Juan-Beltrán García.
Universidad Autónoma de Baja California, Mexicali B.C; 2Universidad Autónoma de Guadalajara,
Departamento de Química, Zapopan, Jalisco.
E-mail: [email protected]
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Mycosphaerella fijiensis is a fungus that produces Black sigatoka in banana plants making economic
losses in a 100% of commercial banana (Musa acuminata Cavendish) production around the world.
Black sigatoka is a strictly foliar disease, which inhibits the photosynthetic capacity of the plant
producing a premature ripening and a loss of weight of the fruit. Nowadays, chemical control
(fungicides) is the alternative to combat this plague, but it is not the most effective treatment, causing
an annual cost of over 500 millions of pesos, besides this method increases the resistant strains and
causes an ecologic damage. New control alternatives are emerging, and biological control seems to be
the best option. In this research we analyzed antifungal factors (membrane and cell wall hydrolityc
enzymes) produced by Pseudomas aeruginosa, Enterobacter cloacae, Enteorcoccus faecalis and
Bacillus cereus (banana endophytic bacteria) they were selected by its highly antifungal effects in
previous works, using an inactive mycelium of M. fijiensis as a culture medium. The results showed an
80% of fungal inhibition when the supernatant from bacteria grown in a fungal cell wall medium was
used, also we observed enzyme activity of 119.7 U/min of glucanase, 8.7 U/min chitinase, 37.87 U/min
protease and 61.85 U/min lipase in the supernatant of these bacterias. A microscopic hyphae assay was
performed, the results showed mechanical damage in the hyphae when used 1U of commercial
chitinase after 24 hours incubation. Also when Pseudomas was cultured with active mycelium of M.
fijiensis, we observed a biofilm formation after 24 hours of incubation.This research may contribute in
the development of a possible biofungicide formulation in the combat of Black sigatoka.