Mumbai, Dec. 12 -- The Indian rupee is extending its sharp slide beyond Rs 90 per dollar mark in opening trades on Friday. INR opened at Rs 90.43 per dollar and fell further to hit a new low of 90.56 so far during the day. Yesterday rupee plunged 39 paise to close at an all-time low of 90.33 against the US dollar amid persistent uncertainty over the India-US trade deal. Moreover, prevailing risk-averse market sentiment and sustained foreign fund outflows weighed on the local unit. Weakness in dollar and positive local equities is seen supporting the local unit at lower levels. Indian shares are seen opening higher on Friday, extending gains from the previous session on expectations of a trade deal with the United States. The BSE benchmark...