A microstrip to circular waveguide transition having an elongated circular waveguide portion and a stripline circuit portion disposed within the waveguide portion. The desired extension and the intermediate worm thread section are both selectable based on the desired application, the desired gearing ratio, and other features. Also provided are methods of using a plant stress-regulated gene to confer upon a plant a selective advantage to a stress condition, methods of identifying an agent that modulates the activity of a plant stress-regulated regulatory element, and methods of determining whether a plant has been exposed to a stress.