Lisee has repeatedly stated he believes Peladeau should make a stark choice between his political career and his business empire as controlling shareholder of Quebecor Inc. (TSX:QBR.B).
The company's extensive media holdings in the province include the TVA television network, Le Journal de Montreal and the Videotron cable company.
Peladeau has not yet announced whether he will seek the PQ leadership. He said last month he would be willing to put his shares in a trust if he decides to run and is chosen leader next May.
Selling them is out of the question, he said.
Lisee said he will get behind if Peladeau does enter the race and wins.
"If Pierre Karl is elected, it will be because party members will have put their faith in him," he told a news conference Monday.
"He will have come up with the solution he sees fit. People will know my position is different but I will work with him.
"We don't need to agree on everything."
Lisee's comments came a day after he officially announced his candidacy while appearing on "Tout le monde en parle," a very popular show on Radio-Canada.
"The task ahead of us is colossal," he said.
"The defeat we suffered last April is a defeat that marked us."
He was referring to the PQ's crushing setback in the general election when the party won only 30 of the province's 125 ridings.
Lisee is the fifth declared candidate along with former cabinet colleagues Bernard Drainville, Alexandre Cloutier and Martine Ouellet, as well as Pierre Cere, a spokesman for a group that defends the unemployed.
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