Optimus Prime is the new leader of the heroic Autobots since the death of Zeta Prime. Optimus is the first Prime to recieve the Matrix of Leadership, which was given to him by the core of Cybertron itself. After saving the planet's core, the core told him that in order to truly recover, the planet needed to shut down, and because of that, Cybertron would become a barren wasteland. It was then that Prime ordered the evacuation of their world, while some of them stayed behind. These Autobots that stayed behind that we know of right now are Optimus Prime, Bumblebee, Jazz, Cliffjumper, and Grimlock. In Exodus, the official history of the War for Cybertron, it is revealed that Optimus, back then Optronix, and Megatron were once very good friends. That all changed when Optronix was named the next Prime.
Optimus Prime's vehicle mode has changed to a futuristic truck.