The idea that if we could rewrite the plant genome, much better plants could be created.

Plant's energy cycle has built-in inefficiency. There are leaps of design that evolution can never take. But, if someone rewrote their chemical cycles in a lab, you could make plants that used their energy more efficiently, to grow twice as fast as any natural plant. The first variety like this would take over the world first, and then evolve to dominate each environment.