Cry genes from Bacillus thuringiensis applied to crop genetic engineer, for insect resistance improvement

Abstract

This study presents a bibliographic synthesis about the entomopathogen Bacillus thuringiensis and the cry genes application on the genetic engineering of cultivated crops which codify insecticide proteins. Over the last decade, the importance of the transgenic crops – named Bt crops – has increased commercially, leading them to take the second place among genetically modified (GM) crops most used and distributed. In the last harvest (2006), total Bt crops reached 19 million hectares worldwide, and the Bt-corn already presented 16 commercial approvals, given that the first commercial Bt-rice plantation was made in Iran, 2005. The clean technology development, such as GM cultivars, presents several advantages in comparison to formulated insecticides, which depends on appropriated application methods according to the crop culture or the insect behavior, and the impacts over the nontarget organisms and the environment. In this sense, the Btrice has the potential to increase productivity, decrease the pesticide application and thus improve the environmental quality on the agricultural systems, which are highly related to environment conservation areas such as flooded regions of Rio Grande do Sul. The potential benefits that Bt-rice can offer, based on already obtained results with Bt-cotton and Bt-corn, should motivate new researches and the development of different varieties of Bt-rice. As a result, it could accelerate the approval and release of this technology to the rice farmers.

Key words: Bacillus thuringiensis, insects, cry genes, transgenic plants.