My colleague Manager's weird behaviour

A little background before I can explain my problem

I have join company few months back and fairly new to organization.

I am responsible for data and digital archive for my department , Now as a business its new structure of our department  and I got appointed.

Until now my another colleague who looks after IT for our business was dealing with it, He has majority input to bring both systems.

Now my MD wants me to take over control of both systems, And my fellow colleague is finding very hard to let it go as he sees both systems as his babies

We decided if I get involve step by step then it would be easy transfer of responsibilities

My colleague has started like a game, Some time he invites me for meetings and sometime I am not even aware about meetings, He is keeping secret about stuff and in last 3 months so many things started coming to me as news

( I can totally understand his condition and wanted to deal with care so he want feel I am just taking away his work but He has turn in to very aggressive and negative attitude with me. )

For e.g, We are having major issue with one system and I email owner of that company and CC my colleague to keep in loop and He call back on my desk and started shouting at me that he is only one person can talk to high level people etc, I am not allowed to talk to them etc.

As a Manager I would like to resolve my issues my self but its not happening as my colleague is making it very difficult

and I have highlighted to my boss this is not right as he should be aware if anything goes wrong but

I am in very awkward situation as currently its creates my impression that I am having conflict with my colleague

One major point about my colleague as he doesn't get on with anyone with in whole department so only that is plus point I have that my VP understands that.

Any suggestion how to deal with this without creating more conflicts and issues.

What would you do If your on my place.

Many Thanks for your reply