New York Gov. Andrew Cuomo on Tuesday signed a bill he supported that could potentially lead to seven more casinos in the state provided voters approve a constitutional amendment in a referendum in November.Cuomo’s signature sets the stage for what is expected to be a massive campaign for and against the proposal leading up to the November vote. The legislation signed by Cuomo would allow for casinos in three upstate areas, including the Saratoga Springs region, the home of Saratoga Racecourse and a casino at a harness track. The bill also bars the state from awarding any casino license in the New York City metropolitan area for the next seven years, protecting the market area now served by a massive casino at Aqueduct racetrack in Queens. The casino, operated by the Malaysian conglomerate Genting, is the most lucrative casino property in the country, based on win per machine figures, and it is currently generating tens of millions of dollars annually for Aqueduct’s operator, the New York Racing Association, and its horsemen.The bill will also allow two county-owned off-track betting operators on Long Island, Suffolk and Nassau to operate one slot-machine parlor each if the referendum passes. Suffolk has filed for bankruptcy protection, and Nassau officials have said the company is struggling financially. If the OTBs open slot-machine casinos, 2.75 percent of the gross gambling revenues will be diverted to purses at NYRA’s three tracks. Another 0.5 percent would be directed to breeders’ awards.