Development of a transient expression system for functional characterization of sugarcane promoters

Abstract

Sugarcane is a C4 grass used for food and bioenergy production. Despite its importance, biotechnology for sugarcane is less advanced compared to other important crops, mainly due to the complexity of its genome. The production of transgenic plants is a promising option to improve tolerance to stresses, higher yield, or to generate varieties better suited for bioenergy purposes. However, sugarcane transformation is a very laborious and time consuming task. Here, we propose the establishment of an in vivo transient expression system using protoplasts to characterize sugarcane promoters. Previous gene expression studies showed an up-regulation of several genes in plants submitted to drought stress. The promoters of four drought-induced genes will be cloned into expression vectors harboring the luciferase reporter gene. These plasmids will be transfected into sugarcane protoplasts and these cells will be submitted to osmotic stress to identify active and stress-induced promoters by detection of the reporter gene. These results will be important to narrow down the number of targets to produce transgenic sugarcane plants, and the establishment of this protocol will be useful for future work on the functional characterization of promoters and genes by our group. (AU)