How to implement Taxonomy as Role? I am building an application for a university where teachers will submit questions(MCQs) into Topics(Vocabulary) containing many terms infact in hundreds. 

Our business logic is so that teachers will be allowed to submit questions only of their respective academic field, so we need to limit the list of topics to teachers based on their area of field. For example computer science teachers will submit questions in computer science term and its children. 

So basically what I want it, something like one role per taxonomy term, I tried the Taxonomy Access Control module and the user permission module, but to no avail.

Is there a better solution for limiting taxonomy terms per user? Not per role or should I then create a role against every taxonomy term?
The Taxonomy Term Permissions module is what you are looking for.

From the project page description: 


  This module allows taxonomy administrators the ability to restrict
  setting individual terms on nodes by user or role.