There is no check in a sense of rolling a dice, but there is attribute and persuasion requirement.
But my testing shown that only at specific level of persuasion is attribute "check" used (and this varies from encounter and dialogue option chosen). If having higher persuasion it always succeeds and if lower it always fails.
But I have tested with only attributes around 15-16 higher or lower then attribute check needed in my testing. So there is still possibility that +1 persuasion skill adds something like +20 or more to attributes (but highly unlikely, IMHO).
