I have read from somewhere that all the University Wits died mystriously and there is assumption that Shakespeare might have abducted all of them and got them write for him, even as he wrote nothing but used his name for the writings churned by these beautiful (in terms of style and subject matter of their works) wits. How much is the truth behind it?

Yeah, or not!!

What does this mean? Kindly explain. Still I have given you a greenie!

It means it's NOT true.
Sounds like one of those Urban Myths that do the rounds from time to time.

If you actually start doing some back ground research you soon realise just how outlandish this all is.

There's another theory that Shakespeare didn't exist; that his writings were all done by those others as a group, a secret club.