Tatooine is "far beyond the reach of the Trade
Federation," unlike Naboo. In the Senate, people are introduced
as being "of the Tund system,"
or "of the Naboo System,"
etc. In the novelization, mention is made of the Jedi helping the "hundred
thousand" systems of the Republic, which Tatooine is not a part
of. Qui-Gon, interestingly, tells Anakin that most stars have planets
orbiting them.