The state covenants with the purchasers and all subsequent holders and transferees of notes and bonds issued by the authority, in consideration of the acceptance of and payment for the notes and bonds, that the notes and bonds of the authority, issued pursuant to this part, and the income from the notes and bonds, and all its fees, charges, gifts, grants, revenues, receipts and other moneys received or to be received, pledged to pay or secure the payment of the notes or bonds, shall at all times be free from taxation by the state or any county, municipality or political subdivision of the state, except for estate and gift taxes and taxes on transfers.