Sealer primer or not?

Hello,
I will be laying down my gray 2K primer before wet sanding for the final white BC/CC. My question is, do I need a sealer over the 2K for white paint?
I don't want yellow spots. All the prework was bringing the entire car down to bare steel, doing bodywork with Evercoat (light blueish/white color) and then hitting the bare steel with green etch primer.
Will the 2K be sufficient to seal all of this in?

Clark
Author: ClarkDart70