By Alain Iloniaina

ANTANANARIVO (Reuters) - The wife of Madagascar's ousted President Marc Ravalomanana has put herself forward to run in July's presidential election, a move that could be aimed at preparing a comeback by the fallen leader.

The impoverished island nation has been in crisis since Marc Rajoelina, now president, led an uprising that ousted Ravalomanana from office in 2009, triggering turmoil that scared off investors and devastated the vital tourism industry.

Rajoelina, a former disc jockey, said in January he would not run in the vote scheduled for July 24, after he came under pressure from regional powers which had pressed him to stand aside to prevent fresh unrest in this year's vote.

Ravalomanana, a wealthy businessman now in exile in South Africa, has also agreed not to run again. He was sentenced in absentia to life in prison after he was accused of ordering elite troops to kill Rajoelina's supporters.

Speaking outside the election court that is accepting nominations, the former president's wife, Lalao Ravalomanana Rakotonirainy, told reporters: "We give thanks to God. The application is indeed filed."

She was surrounded by a few hundred cheering supporters outside the court, where 15 other candidates have already submitted their names. The authorities are due to draw up an official list of candidates by May 3.

"As President Ravalomanana cannot stand in the presidential election, his wife is our natural candidate," Mamy Rakotoarivelo, member of parliament and former close associate of Ravalomanana, told Reuters ahead of the submission.

"It should allow us to regain the power that was seized in an illegal manner."

Critics say the presidential bid could be an attempt by Ravalomanana to make a return to politics by the backdoor.

"It is a trick of Marc Ravalomanana," said political commentator and author Toavina Ralambomahay, saying his wife had no political experience but could still win with the backing of Ravalomanana's supporters.

"It could prepare the return of her husband," he said.

Rajoelina led demonstrations against Ravalomanana in early 2009, accusing him of political repression and criticizing his plans to lease tracts of land to the Korean company Daewoo.

A general strike in the capital turned into deadly protests before the army stepped in and backed Rajoelina.

Countries from the Southern African Development Community (SADC) brokered a deal in September 2011 that confirmed Rajoelina as president and allowed for the unconditional return of Ravalomanana from self-imposed exile in South Africa.

But the plan has been beset by disagreements, including over whether Ravalomanana should be imprisoned if he returns home. SADC leaders urged both men not to stand in the election.

The first round of the presidential election is scheduled for July 24 and the second round, coupled with a legislative vote, is set for September 25.

(Editing by Edmund Blair and Alison Williams)