May 1 (Reuters) - Canada's main stock index opened lower

on Friday, dragged down by losses in materials and energy

sectors, while investors assessed signs of diplomatic progress

in the Middle East after Iranian state media reported Tehran had

submitted a new negotiation proposal for talks with Washington.

At 9:34 a.m. ET, the Toronto Stock Exchange's S&P/TSX

composite index was down 0.2% at 33,901.72 points.

(Reporting by Tharuniyaa Lakshmi in Bengaluru)