It's a classic story: María Elena Orantes López is a senator, and was until recently a prominent member of the PRI - until that party denied her the nomination to be its gubernatorial candidate in Chiapas.
The left stepped in, negotiated, and Manuel Camacho Solís, coordinator of the PRD-PT-MC-MORENA electoral alliance, just announced her candidacy for the left coalition to be 2012-18 governor of Chiapas..
The mayor of Tuxtla Gutiérrez, Yassir Vázquez (PRD) is not happy. He was also the delfín of current governor Juan Sabines (also an ex-PRI member recruited by the left when, you got it, he, too, was denied its nomination in 2006), and need to be awarded some kind of consolation price.
Given that the PRI is also in turmoil in Chiapas for much of the same reasons, Orantes stands a good chance of winning, and was also strongly backed by AMLO, who noted her alleged progressive record as Senator.