As far as I know there is only one program you can transfer points into Marriott Rewards from & that is Diners Club. Details can be found here: https://www.marriott.com/rewards/earn-points.mi (bottom Left, under "Convert Other Points"

& Here: https://www.citibank.com/dinersus/js...egory=e350b05d

(On a side note, I guess I never knew that Diners Club was associated with CitiBank...)