MEXICO CITY (Reuters) - The first man in modern Mexican history to win a gubernatorial election as an independent said on Wednesday he aimed to run in the 2018 presidential election, putting pressure on the leading anti-establishment contender, Andres Manuel Lopez Obrador.

Jaime Rodriguez ruptured the political status quo by capturing the wealthy northern state of Nuevo Leon by a landslide in 2015 after he broke with President Enrique Pena Nieto's Institutional Revolutionary Party, or PRI.

Rodriguez adds to a fragmented landscape of contenders led by twice presidential runner-up Lopez Obrador, a former Mexico City mayor who has spent years pitching himself as the only solution to ongoing political corruption and chronic inequality.

"I want to give it a try, and I want to show that the people are tired of political parties and the politicians themselves," Rodriguez, 59, told Mexican broadcaster Radio Formula.

ADVERTISEMENT

Known as "El Bronco" due to his blunt style, Rodriguez has trailed far behind Lopez Obrador in early opinion polls.

However, his entry into the race could eat away at anti-establishment support for Lopez Obrador, a leftist with nationalist leanings. That, in turn, could help the PRI.

The avid horseman said he planned to register on Saturday and will have four months to gather 866,593 signatures - or one percent of the electorate - in at least 17 regions of Mexico to qualify as an independent ahead of the July 2018 vote.

Voter surveys show all presidential hopefuls struggling to win the backing of as much as one third of the electorate.

In June, the PRI was able to exploit those divisions, winning a tight gubernatorial race in the State of Mexico, the country's most populous region, with barely a third of the vote.

Leading PRI officials say privately the party hopes to take advantage of that fragmentation again to eke out victory in 2018. However, it is still unclear who will be the party's candidate. Pena Nieto is barred by law from seeking re-election.

Further crowding the pool of anti-systemic candidates, Senator Armando Rios Piter, an independent former member of the center-left Party of the Democratic Revolution (PRD), also registered a run for the presidency on Wednesday.

The PRD was once led by Lopez Obrador, but he turned his back on it to found a new leftist movement in 2014, frequently accusing his former allies as being lackeys of the PRI.

The PRD meanwhile, has decided to forge a "broad front" with the main center-right opposition party, the National Action Party (PAN), to defeat the PRI. Officials from both parties say they could back an independent candidate to lead their bid.

ADVERTISEMENT

All told, ten independents have so far registered, according to the National Electoral Institute (INE). Three of those contenders failed to meet initial requirements, the INE said.

Lopez Obrador has attacked Rodriguez's independent credentials, describing him as a tool of the PRI, and helping to fuel an increasingly bitter rivalry between the two.

"According to him (Lopez Obrador), he's the only good guy in the country," Rodriguez told Radio Formula. "We're all devils in the rest of the country, he's the only saint."

(Reporting by Dave Graham; editing by Diane Craft)