WASHINGTON, Sept 22 (Reuters) - U.S. Treasury Secretary Janet Yellen urged Irish Finance Minister Paschal Donohoe on Wednesday to take a “once in a generation opportunity” for a global tax deal that stops a race to the bottom on corporate tax rates, the Treasury said in a statement. Treasury said during their call, Yellen “expressed appreciation for Ireland’s constructive participation” in the OECD tax reform talks and the two ministers agreed to keep in close communication on the issue. (Reporting by David Lawder Editing by Chris Reese)