According to Rashtrapati Bhavan spokesperson Venu Rajamony, Joshi was assigned with the additional charge by President Pranab Mukherjee on the advice of Prime Minister Manmohan Singh.
The announcement came on a day the Prime Minister met the President amid speculation of a Cabinet reshuffle.
Joshi already holds the portfolio of Road Transport and Highways ministry.
The President also accepted the resignation of Roy and five other members of Trinamool Congress after the party, which has 19 MPs in the Lok Sabha, withdrew its support to the UPA government.
The others whose resignation was accepted by the President on the advice of the Prime Minister were Ministers of State Sudip Bandyopadhyay (Health and Family welfare), Saugata Roy (Urban Development), Choudhary Mohan Jatua (Information and Broadcasting), Sultan Ahmed (Tourism) and Sisir Adhikari(Rural Development).
