Why is vinegar and spray paint not a good combo?

I am doing a project for Science and for an experiment we saw what things could potentially preserve a pumpkin. On my pumpkin we put on vinegar and some boys put spray paint on theirs and, of course, being just the way we are, we wanted to put some on ours. SO we got carried away and the spray paint ended up on the face of our pumpkin. Our results showed that the side of the pumpkin that had spray paint on it wilted and molded. Why is that? Does this have to do with things that are in vinegar and spray paint that do not agree with one another?