Are my suppliers required to be registered in SAM.GOV?

I am a higher education institution who recieves federal grants.  It was my understanding that my service providers or goods providers don't need to be registered in SAM.GOV but I do need to verify they are not debarred. Recently I have recieved other information which has me confused.  As I am not a federal agency per se, I am a grantee, do my service and good providers need to register in SAM.GOV in order to be able to offer services under my grants?