I do not think so . Mildew is brought on by moisture. Do not think it does affect the plant on a cellular level. Seeds should be ok.I have read that clones from a plant that had mildew is a bad idea as it infects on a cellular level and will infect the clone some time later.
but what about the seeds? if you germinated seeds that came from a previously infected plant, would the new plants get mildew?