UPDATE 1-Allentown, Pennsylvania, mayor's corruption trial gets under way

(Changes dateline from HARRISBURG; adds quotes from opening statements)

ALLENTOWN, Pa., Jan 22 (Reuters) - The mayor of Allentown, Pennsylvania's third most-populous city, solicited bribes to fund an expected run for the U.S. Senate, prosecutors told a court on Monday, but the defense said the Federal Bureau of Investigation had falsely accused him.

Edwin Pawlowski, a Democrat who was elected in November to his fourth term as mayor despite a sweeping "pay-to-play" indictment, went on trial in U.S. District Court in Allentown on 54 criminal counts, including bribery, conspiracy and fraud.

Pawlowski and former Reading, Pennsylvania, Mayor Vaughn Spencer were charged in July in a long-running federal corruption investigation. The trial of Spencer, who is also a Democrat, is scheduled to begin on March 5.

In his opening argument to the seven-man, five-woman jury, Assistant U.S. Attorney Anthony Wzorek described a quid pro quo scheme for city contracts.

"It is a case about a man who sold his office, soliciting bribes from the highest bidder," Wzorek said.

Wzorek said Pawlowski solicited bribes to fund his expected 2016 Senate campaign against incumbent Pat Toomey, a Republican. The mayor had attempted a run for the Democratic nomination for governor of Pennsylvania in 2014 but gave it up for lack of funds.

He realized he needed lots of money to run for Senate, Wzorek said. "He vowed to raise $1 million in three months after he announced his candidacy (in 2015)."

Pawlowski suspended his campaign before the primary because of the FBI investigation. Toomey was re-elected in November 2016.

Pawlowski is accused of accepting more than $150,000 in contributions to his various campaigns from vendors with the understanding that they would receive city contracts in exchange.

The mayor sought to cover up the scheme by deleting emails, instructing his campaign aides to do the same and sweeping his office for listening devices installed by law enforcement, the indictment said.

In opening defense arguments, lawyer Jack McMahon said Pawlowski sought perfectly legal campaign contributions, with no explicit promise to the donors. Instead, he was the unwitting victim of an overzealous FBI and a scheme concocted by two mayoral consultants, Mike Fleck and his assistant Sam Ruchlewicz.

Several defendants have pleaded guilty in the Allentown and Reading schemes, including Fleck, a former campaign manager for both mayors.

Early last year, the former managing director of Allentown, which has about 120,000 residents, pleaded guilty as part of the investigation and implicated Pawlowski in a $3 million bid-rigging scheme to benefit a campaign donor. (Editing by Barbara Goldberg, Frances Kerry and Lisa Von Ahn)