Figure: By manipulating the activity of the gene ScGAI in transgenic sugarcane lines, Brazilian researchers substantially increased culm volume (photo: left to right, ScGAI-silenced, unmodified, ScGAI-overexpressing sugarcane / Rafael Garcia Tavares)

A team led by Professor Marcelo Menossi at the University of Campinas's Biology Institute (IB-UNICAMP) in Brazil has found that the key to overcoming a major constraint on sugarcane yield could lie in a gene called ScGAI.

Sugarcane yields have been static for decades due to the constraints on culm development. The culm's sugar storage capacity is physically limited, restricting the volume of sucrose and biomass that can be obtained from the crop for sugar and ethanol production.

Menossi said that breaking through this developmental threshold by conventional breeding has been difficult. His team discovered that ScGAI is an important regulator of culm development, and manipulating its activity increases culm volume and changes the allocation of carbon to structural and storage molecules.

ScGAI was also found to mediate the regulation of sugarcane developmental hormones, such as ethylene and gibberellins. Gibberellins are widely used to improve yields and accelerate sugarcane ripening by triggering the rapid degradation of DELLA proteins, which are thereby prevented from interacting with and degrading other proteins that stimulate culm development.

For more details, read the news article from Agencia FAPESP.