Sugarcane cystatins: From discovery to biotechnological applications.

Phytocystatins are tight-binding cysteine protease inhibitors produced by plants. The first phytocystatin described was isolated from Oryza sativa and, since then, cystatins from several plant species were reported, including from sugarcane. Sugarcane cystatins were unraveled in Sugarcane EST project database, after sequencing of cDNA libraries from various sugarcane tissues at different developmental stages and six sugarcane cystatins were cloned, expressed and characterized (CaneCPI-1 to CaneCPI-6).

Construction of a novel synthetic root-specific promoter and its characterization in transgenic tobacco plants.

Synthetic promoter technology offers a framework for designing expression cassettes that could provide precise control of transgene expression. Such artificially designed promoters enable defined transgene regulation, reduce unwanted background expression, and can overcome homology-dependent gene silencing in transgenic plants. In the present study, a synthetic root-specific module was designed using characterized cis-acting elements, fused with minimal promoter (86 bp) from PortUbi882 promoter, and cloned in pCAMBIA1305.

Vacuolar targeting of r-proteins in sugarcane leads to higher levels of purifiable commercially equivalent recombinant proteins in cane juice.

Sugarcane is an ideal candidate for biofarming applications because of its large biomass, rapid growth rate, efficient carbon fixation pathway and a well-developed storage tissue system. Vacuoles occupy a large proportion of the storage parenchyma cells in the sugarcane stem, and the stored products can be harvested as juice by crushing the cane. Hence, for the production of any high-value protein, it could be targeted to the lytic vacuoles so as to extract and purify the protein of interest from the juice.