TORONTO, March 7 (Reuters) - Canada's main stock index fell on Wednesday, led by materials and auto parts shares, as the resignation of Gary Cohn, top economic adviser to U.S. PresidentDonald Trump, intensified investor worries over a global trade war and its repercussions for the world economy.
* The resignation of Cohn could give free trade skeptics the upper hand in the White House. At 9:54 a.m. EST (14:54 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE fell 17.65 points, or 0.11 percent, to 15,527.54.
* The shares of trade-sensitive auto parts companies lost ground. Magna International Inc MG.TO fell 0.8 percent toC$67.39.
* The materials group, which includes precious and basemetals miners and fertilizer companies, lost 0.4 percent.
* Gold futures GCc1 fell 0.2 percent to $1,330.6 an ounce,while U.S. crude CLc1 prices were down 0.7 percent at $62.16 abarrel. GOL/ O/R
* The energy group dipped 0.1 percent, while industrialsdeclined 0.4 percent as railroad shares fell.
* The TSX posted 1 new 52-week highs and 2 new lows. Six ofthe index's 10 main groups fell.