Rome, January 12 - Economy Minister Pier Carlo Padoan on Thursday warned against "discrediting" the banking system. He said the "essential factor" for its proper working was trust, which was "easy to destroy but hard to build up again". Padoan said it was "wrong and dangerous" to undermine confidence. Undermining trust could "jeopardise the entire system", Padoan warned. Italy has had to help several banks including its third-biggest, troubled Tuscan lender Monte dei Paschi di Siena, weighed down by bad loans.