Biologists at University of California San Diego have discovered a new
genetic pathway in plants made up of four genes from three gene families
that control the density of breathing pores, or stomata, in plant leaves in
response to elevated carbon dioxide (CO2) levels. Led by Julian Schroeder,
the team sought to understand the fundamental mechanisms and genes by which
CO2 represses stomatal pore development. Using Arabidopsis, Schroeder and
his team found that the proteins encoded by the four genes they discovered
repress the development of stomata at elevated CO2 levels.

The biologists isolated proteins which took away the plant's ability to
respond to stress when mutated. They found that when plants sense
atmospheric levels rising, they increase their expression of a key hormone
called Epidermal Patterning Factor-2 (EPF2). The team also identified a new
protein that they called CRSP (CO2 Response Secreted Protease) which, they
determined, is crucial for activating the EPF2 peptide.

[ucsdnews.ucsd.edu]