Maryland Lt. Governor Anthony G. Brown. (AP Photo/Jose Luis Magana)

The campaign of Maryland gubernatorial hopeful Anthony G. Brown on Wednesday attacked rival Democrat Douglas F. Gansler for backing a cut in the state’s corporate income tax rate, highlighting one of only a few major policy disputes that have emerged so far in the primary.

The Brown campaign chose to act on a day in which Republican senators pushed a similar plan to reduce the corporate tax rate from 8.25 percent to 6 percent — the same as in Virginia — during a legislative hearing in Annapolis.

Justin Schall, the campaign manager for Brown, the state’s current lieutenant governor, accused Gansler of being “in lockstep with Republicans” in his support for a “corporate tax handout.” Schall said that Gansler, the state’s attorney general, “should come clean and explain which programs he’ll slash or which schools he’ll close to balance the budget.”

The Brown campaign also released a video that showed footage of Gansler promoting his plan at seven different stops along the campaign trail in recent months.

Gansler spokesman Bob Wheelock called the Brown video a “campaign gimmick” and said Gansler is pushing an idea that would improve the state’s economy.

“He believes it’s the right thing to do,” Wheelock said, arguing that a lower rate would allow Maryland to attract and retain more businesses and increase the state’s tax base. Gansler is expected to release a broader economic plan as early as next week.

Wheelock said Gansler is “proud to stand with President Obama, Congressman Chris Van Hollen and other well-respected Democrats in calling for a re-evaluation of the corporate tax.”

On Wednesday, a committee in Annapolis heard testimony on a bill sponsored by Sen. David R. Brinkley (R-Frederick) that mirrors Gansler’s plan to reduce the corporate tax rate to 6 percent. According to legislative analysts, the state would lose about $300 million a year in revenue as a result of the tax cut.

Gansler did not take part in the hearing.

A third Democrat in race, Del. Heather R. Mizeur (D-Montgomery), has said Gansler’s plan goes too far and that the state should focus instead on targeted tax cuts for small businesses.

Brown’s attack on Gansler was a role reversal of sorts. For months, Gansler has been on the offensive, seeking to highlight Brown’s role in the botched debut of Maryland’s online health insurance exchange. Brown was tasked with leading the implementation of federal health care reforms in Maryland. The exchange site crashed on its first day in October and has experienced serious glitches since then.