Chennai,May 25 (PTI) Thirty one candidates have filed their nominations for the June 12 bye-election to the Pudukottai Assembly constituency which will witness a direct face-off between former allies AIAMDK and DMDK for the second consecutive time in an electoral battle this year. Nominations closed today with AIADMK's Karthik Thondaiman and DMDK's Jahir Hussain, among others, filing their papers for the bypoll which was necessitated following the death of CPI MLA P Muthukumaran in a road accident on April 1,2012. Special Chief Electoral Officier D Raajendiran said in a release that 31 persons had filed nominations. The ruling AIADMK and its former ally DMDK had earlier locked horns for the March 18 Sankarankoil bypoll which the former won. Another key opposition party, the M Karunanidhi-led DMK, is not contesting the Pudukottai bypoll.