Efeitos de inibidores de proteinases de soja em organismos não-alvo associados à cultura da cana-de-açúcar / Effects of soybean proteases inhibitors on non-target organisms associated to sugarcane

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Genes of plants expressing insect proteinase inhibitors have been introduced into plants for pest control. Proteases inhibitors are present in plant tissues, mainly in seeds, and act in response to predators and pathogens. The Bowman-Birk type and Kunitz type of serine proteases inhibitors (PI) from soybean seeds are been used to increase resistance of sugarcane to Diatraea saccharalis (Fabr.), the most important pest of this crop. The sustainability and environmental safety of PI crops is still unknown. For these reasons, it is necessary to understand the stability and the non-target effects of this new trait. The objective of this study was to evaluate the direct and indirect effects of soybean PI on the following non-target organisms associated to sugarcane: the larval parasitoid, Cotesia flavipes (Cam.) (Hymenoptera: Braconidae); the entomopathogen, Metarhizium anisopliae (Mestch.) Sorokin (Deuteromycotina: Hyphomycetes); the pollinator Apis mellifera L. (Hymenoptera: Apidae) and the soil mite involved in the process of recycling organic matter, Scheloribates praeincisus (Berlese) (Acari: Oribatida: Scheloribatidae). Kunitz and BBI did not affect S. praeincisus survival. On the other hand, Kunitz semi-purified and purified inhibitor ingestion reduced duration of the immature stages of S. praeincisus. Ingestion of GM senescent leaves did not have an effect on mite immatures development time and survival compared to ingestion of its isolines leaves. The semi-purified and purified proteinases inhibitors did not alter either the duration of larval and pupal stages of C. flavipes on D. saccharalis, or weight and number of pupae and parasitoid emergence. In other hand, the parasitism and proportion of female was higher on the treatment where caterpillars were fed with diet containing 0.5% of semi-purified inhibitors, comparing to control. The ratio female:male was significantly higher also when parasitoids were fed to the Kunitz type inhibitor compared to the control and BBI. The addition of 0.5 % (w/v) of semi- purified proteinase inhibitors and 0.05% (w/v) of Kunitz type purified inhibitors on two culture media (CM and PDA), resulted in increase of vegetative growth and production of conidia. BBI type purified inhibitors did not change the fungus sporulation. The results from the studies with A. mellifera were not conclusive and investigations are needed to clarify the potential impact of proteinase inhibitors on A. mellifera. Overall, proteinase inhibitors (Kunitz and BBI) did not negatively affect the non-target organisms tested. Conversely, ingestion of the Kunitz type of proteinase inhibitors altered positively some biological parameters of C. flavipes, M. anisopliae and S. praeincisus.

ASSUNTO(S)

proteases inhibitors scheloribates praeincisus. cana-de-açúcar non-target organisms braconidae metarhizium anisopliae proteinase - inibidores. hymenoptera fungo entomopatogênico apidae apis mellifera sugarcane acari lepidoptera diatraea saccharalis cotesia flavipes

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