  We briefly review the various proposed scenarios that may lead to nonthermal
radio emissions from exoplanetary systems (planetary magnetospheres,
magnetosphere-ionosphere and magnetosphere-satellite coupling, and star-planet
interactions), and the physical information that can be drawn from their
detection. The latter scenario is especially favorable to the production of
radio emission above 70\,MHz. We summarize the results of past and recent radio
searches, and then discuss FAST characteristics and observation strategy,
including synergies. We emphasize the importance of polarization measurements
and a high duty-cycle for the very weak targets that radio-exoplanets prove to
be.
