Virginia Governor Robert F. McDonnell faces scrutiny over his relationship with dietary supplement manufacturer. (Tracy A. Woodward/The Washington Post)

RICHMOND — A Democratic state senator Wednesday called on Gov. Robert F. McDonnell (R) to step down over a growing gifts scandal, becoming the first elected official to directly demand his resignation.

“I don’t see the purpose of the governor continuing in office when the trust between his office and Virginians has been so eroded,” Sen. Barbara Favola (Arlington) said Wednesday morning, shortly after making similar comments in a TV interview with Bruce DePuyt. “When you’ve broken that ethical bond, I don’t know to what purpose he can really execute the activities of his office effectively at this point.”

Favola made her comments in response to a story in Wednesday’s Washington Post that Virginia businessman Jonnie R. Williams Sr. had given $70,000 to a corporation owned by McDonnell and his sister, a $50,000 check to first lady Maureen McDonnell and $10,000 to their daughter, Jeanine, to help defray the costs of her May wedding. Those gifts or loans came on top of $15,000 that, as The Post reported in March, Williams provided to cover the catering at the wedding of another McDonnell daughter, Cailin, in June 2011.

McDonnell spokesman Tucker Martin declined to comment. McDonnell has previously said that he has done nothing wrong and provided no favors to Williams in exchange for any gifts.

McDonnell and his wife have helped Williams promote Star Scientific’s nutritional supplement, Anatabloc, with personal appearances by the first lady and a launch party at the governor’s mansion. But McDonnell has said their efforts have been in line with what they would do to boost any Virginia business.

Timeline: Star Scientific and Gov. McDonnell

House Speaker William J. Howell (R-Stafford) dismissed any talk of resignation as “partisan political potshots.”

“What has he done other than perhaps not report some things on time?” Howell said, referring to financial disclosure forms that did not include some of the gifts.

Favola went further than Sen. Chap Petersen (D-Fairfax), who on his blog last week called on McDonnell to return the gifts and fully explain them to the public or resign. Petersen repeated that call on his blog Tuesday night when the Post story went online.

“I’ll repeat what I stated in writing one week ago: it’s time for the Governor to come clean on all these gifts, return the retail items, and make this right,” Petersen said. “Otherwise, it’s time to step down.”

Favola also went further than House Democratic leaders did in a telephone news conference organized Wednesday morning in response to the Post report. House Democratic Leader David Toscano (Charlottesville) and chairman Mark Sickles (Fairfax) called on McDonnell to explain the gifts and loans, but did not call for his resignation. Sen. Mark R. Herring (Loudoun), the Democratic nominee for attorney general, struck a similar note in a conference call of his own.

“Just tell everybody what’s been going on,” Sickles said. “Why loans were made, why careful procedures were made to have technical compliance with the letter of the law, apparently in a lawyer’s view, but certainly not in the spirit of the law.”

Asked directly about whether he would demand McDonnell’s resignation, Toscano said federal and state investigations into the matter need to first run their course.

“Until we have more information, we’re not ready to make that request,” Toscano said. “Every day more revelations emerge and give us more cause for concern, but we want to see where this investigation goes.”

While expressing confidence that the governor can and should weather the controversy, Howell said the matter had exposed weaknesses in state law governing gifts to elected officials.

Virginia has one of the most lax ethics laws in the nation, allowing office-holders to accept gifts of unlimited value so long as they annually report any worth more than $50. It does not require disclosure of gifts to immediate family members.

When news of the $15,000 wedding payment first broke in March, McDonnell said there had been no need to disclose it because it was a gift to his daughter, not him. Since that time, The Post has reported that Williams treated Maureen McDonnell to a designer clothing shopping spree in New York City and gave the first lady a $6,500 men’s Rolex watch that she, in turn, gave to the governor.

In response, some Democrats have called for dollar limits on gifts. In his first public comments on the matter, Howell said Wednesday that he doesn’t think that is the answer.

“Money and influence, unfortunately, is part of politics, and it’s not going away,” he said. “And efforts to limit it often have the unintended consequence of driving it underground. . . . I really like what we do in Virginia, and have done successfully for some time. We believe disclosure and transparency is more effective than more heavy-handed regulations.”

That said, Howell contended that the law should be changed to address gifts to relatives if they are provided by someone with a political or business relationship with state government. Office-holders do not have to disclose gifts provided directly to them if the giver is a personal friend. Howell said that policy probably should be changed if the friend has political or business interests with the state.

Howell said he has asked members of the House Republican caucus to come up with ideas for amending ethics law for the purpose of proposing legislation in the 2014 session.

Ben Pershing contributed to this report.