UPDATE 1 — India's Tata Sons gets listing backing from second — largest shareholder

(Adds details; paragraphs 3-8) Sept 18 (Reuters) — Shapoorji Pallonji Group, the second-largest shareholder in India's Tata Sons, backed on Friday a potential listing of the holding company of the sprawling Tata conglomerate, a move that could reshape ownership of the famed business group. The support comes a day after Tata Sons' board said it would move towards complying with Reserve Bank of India rules that could require the holding company to list. "We look forward to working closely and constructively with Tata Sons," group chairman Shapoorji Pallonji Mistry said in a statement. Tata Sons is the promoter of Tata Group, with businesses spanning technology, autos, steel, consumer products, aviation and financial services. The proposed listing has become a key point of contention in a boardroom dispute between Tata Sons and the Tata Trusts, the philanthropic trust that owns 66% of the holding company and employs dividends from its stake to fund charitable activities. The Shapoorji Pallonji Group, a 160-year-old Indian construction, infrastructure and real estate conglomerate, owns 18.4% of Tata Sons, making it the second-largest shareholder after the Tata Trusts. The group has sou