Trinamool Congress MP Sushmita Dev on Wednesday resigned from the Rajya Sabha, becoming the second member of the party's parliamentary wing to quit within a week and deepening the crisis confronting the Mamata Banerjee-led outfit.Dev's resignation comes days after veteran TMC leader and Rajya Sabha MP Sukhendu Shekhar Ray stepped down from both the party and the Upper House, citing concerns over corruption, governance and the handling of the RG Kar hospital rape-murder case.The back-to-back exits have added to the challenges facing the TMC leadership after an unprecedented revolt in its legislative wing in West Bengal. As many as 61 TMC MLAs backed rebel leader Ritabrata Banerjee for the post of Leader of the Opposition, rejecting the party's official nominee and exposing deep divisions within the organisation following its defeat in the state assembly elections.Dev's resignation marks a setback, as she was among its prominent national faces. A former Congress MP from Assam's Silchar constituency, Dev joined the Trinamool Congress in 2021 after leaving the Congress following her defeat in the 2019 Lok Sabha elections. She subsequently emerged as one of the party's national spokespersons and was later elected to the Rajya Sabha.Ray's departure had already sparked concerns that the unrest witnessed in the TMC's legislative wing could spread to its representation in Parliament. In announcing his resignation earlier this week, Ray alleged that corruption had become pervasive within the party and claimed that dissenting voices were being marginalised.The latest resignation is expected to further deepen concerns within the TMC leadership about maintaining unity at a time when the party is grappling with both organisational and electoral setbacks.