FACTBOX-Candidates for Pakistan's Sept. 6 presidential vote

Aug 26 (Reuters) - Pakistan's three main political parties have submitted nominations for a Sept. 6 presidential election for a replacement for Pervez Musharraf, who stepped down last week under threat of impeachment.

Under Pakistan's constitution members of the country's four provincial assemblies and the two-chamber national parliament elect the president.

Here are some facts about the three main presidential candidates:

ASIF ALI ZARDARI

* Former prime minister Benazir Bhutto's widower and political successor, Zardari was thrust into the centre of politics by his wife's assassination on Dec. 27, and then to the centre of power after their Pakistan People's Party won the most seats in a Feb. 18 election.

* Born in the southern province of Sindh to a land-owning family, the telegenic Zardari, 55, has long been controversial.

* He served as a minister in his wife's second government in the 1990s, and was a senator until 1999, but was accused of getting kickbacks on government deals and earned the nickname "Mr Ten Percent".

* Despite spending altogether 11 years in prison on charges of corruption and murder, Zardari, who has denied all accusation and was never convicted, was released on bail in 2004.

* Last year, Musharraf granted an amnesty to Bhutto, Zardari and other party leaders from graft charges under a power-sharing deal with Bhutto.