UPDATE 1-Vulcan seeks to reject Martin Marietta's board nominees

April 30 (Reuters) - Vulcan Materials Co sent a letter to its shareholders asking them to reject rival Martin Marietta Materials Inc's bid to acquire it by voting against Martin Marietta's board nominations in the upcoming annual meeting.

Martin Marietta is trying to nominate four members to Vulcan's board during a shareholder meeting on June 1.

Martin Marietta launched a hostile bid, valued at roughly $5 billion, for Vulcan in December, with the hope of building the world's largest producer of sand, gravel and other construction materials. Vulcan rejected the offer calling it inadequate.

Shares of Vulcan Materials closed at $42.36 on Friday on the New York Stock Exchange. Martin Marietta shares closed at $83.40.