April 22 (Reuters) - Wall Street's main indexes opened higher on Wednesday after U.S. President Donald Trump extended the ceasefire with Iran, even as uncertainty remained over whether Tehran and U.S. ally Israel would honor the truce.

The Dow Jones Industrial Average rose 122.1 points, or 0.25%, at the open to 49,271.5. The S&P 500 rose 38.9 points, or 0.55%, at the open to 7,102.91​, while the Nasdaq Composite rose 202.3 points, or 0.83%, to 24,462.313.

(Reporting by Niket Nishant and Avinash P in Bengaluru; Editing by Devika Syamnath)