TOKYO, Jan 22 (Reuters) - Japan's Mitsubishi Motors Corp. will begin selling a flexible fuel vehicle in Brazil sometime in the business year starting in April, followed by a launch in the United States in the 2009/10 business year, the company said on Monday. Flex-fuel vehicles, which can run on any mixture of ethanol and gasoline, make up more than four-fifths of the Brazilian auto market due to an abundance of sugarcane as a source of the biofuel.