By Nat Worden Of DOW JONES NEWSWIRES NEW YORK (Dow Jones)--Mazda Motor Corp. (7261.TO) said Monday it will make WPP Group PLC (WPPGY, WPP.LN) its full-service advertising agency in North America, severing its longtime relationship with Doner Co., the agency that developed the auto maker's "Zoom Zoom Zoom" song that has been played on television and radio advertisements throughout the world. The move came as a tough blow for Doner, one of the world's largest independent ad agencies. Mazda, the Japan-based auto maker, was its largest account, bringing in about one fifth of the firm's revenue. The agency's owners--David DeMuth, Rob Strasberg and Tim Blett--broke the news to its staff in a memo circulated through its office Monday. The firm gave no specific reason for Mazda's departure, only saying that the auto maker "has decided to go in a new direction." Don Romano, Mazda's chief marketing officer in North America, said the company has no plans to change its "Zoom-Zoom" tagline, which was developed a decade ago by Doner, but after an internal review that began in early March, the company concluded a new marketing communications partner could help it reach its sales goals in North America. Mazda spent $152 million on measured media in the U.S. last year, according to Kantar Media, down from $245.5 million in 2008. WPP was a logical replacement, since the firm has managed Mazda's advertising in much of the world outside of North America for over a decade. Hill & Knowlton, a WPP-owned public relations agency, has handled Mazda's public relations in North America for more than 30 years. "While each one of the agencies we interviewed had unique qualifications, WPP has the broadest set of assets that best fit Mazda's global needs," said Jim O'Sullivan, Mazda's North America chief executive. "I'm extremely confident that WPP can take Mazda to the next level." As part of its marketing campaign developed with Doner, Mazda used the phrase "Zoom-Zoom" to describe what it calls the "emotion of motion" that it claims is inherent in its cars. The tag line has endured far longer than those used by other major auto makers, and it has spread from North America to markets around the world. Doner said in its internal memo that "it's important to know that Doner was a vital agency before Mazda and we will remain a vital agency after Mazda." The agency's clients include Coca-Cola Co.'s (KO) Minute Maid brand and Wilson Tennis. DeMuth, Strasberg and Blett acquired the firm from its former chief executive, Alan Kalter, late last year, and it has been trying to pivot from its reputation as a TV-oriented agency to one focused more on digital media campaigns. -By Nat Worden, Dow Jones Newswires; 212-416-2472; [email protected] (END) Dow Jones Newswires June 21, 2010 15:16 ET (19:16 GMT)