* Mexican president defiant amid U.S. energy dispute worries
* Peru's Castillo marks first turbulent year in power
* Argentina reshuffles ministers with economy in shambles
* London court rules against Venezuela's Maduro in gold case
July 29 (Reuters) - The latest in Latin American politics today:
President's tough talk masks Mexican concern over energy dispute with U.S.
A potentially costly U.S.-led complaint against Mexico's energy policy has stirred considerable concern inside the Mexican government in spite of President Andres Manuel Lopez Obrador's defiant attitude, officials and people close to the matter say.
Last week, the U.S. Trade Representative demanded dispute settlement talks with Mexico, arguing Lopez Obrador's drive to tighten state control of the energy market is unfair to U.S. companies and likely in breach of a regional trade deal.
With rousing appeals to national sovereignty, Lopez Obrador said he would set out Mexico's position on the issue alongside an independence day military parade on Sept. 16, even as he sought to downplay any possible fallout with the United States.
Argentina's Fernandez bets on 'superministry' to stop economic bleeding
Argentine President Alberto Fernandez launched his latest effort to tackle an economy in crisis on Thursday, tapping one of the ruling coalition's most powerful figures to lead a new "superministry" on the same day the central bank hiked its key interest rate to 60%.
Fernandez picked politician Sergio Massa for the new role of overseeing economic, manufacturing and agricultural policy. Massa currently heads the lower house of Congress for the ruling Peronist coalition.
Fernandez spoke by phone with International Monetary Fund Managing Director Kristalina Georgieva on Friday to discuss the South American nation's path following the appointment of Massa to the new post.
The ministerial shake-up, which moves current Economy Minister Silvina Batakis to lead state-run lender Banco Nacion, comes less than a month after her predecessor abruptly resigned.
Peru's Castillo marks one year in power amid corruption investigation
Peru's President Pedro Castillo marked one year since his inauguration earlier this week, a milestone in a term tainted by a corruption investigation against him, high turnover among ministers and an impeachment attempt.
Both pro-Castillo and anti-government protesters took to the streets to mark the occasion, although overall his popularity has dwindled since he took office.
London court rules against Venezuela's Maduro in $1 billion gold battle
London's High Court has rejected President Nicolas Maduro's latest efforts to gain control of more than $1 billion of Venezuela's gold reserves stored in the Bank of England's underground vaults in London.
The court ruled on Friday that previous decisions by the Maduro-backed Venezuelan Supreme Court, aimed at reducing opposition leader Juan Guaido's say over the gold, should be disregarded.
It marked the latest victory for Guaido, who has won a series of legal clashes over the bullion after the British government recognized him rather than Maduro as the South American country's president. (Compiled by Isabel Woodford and Anthony Esposito; Editing by Paul Simao)