The Quebec government professionals' union is taking legal action to defend Louis Robert.
The agronomist in the agriculture ministry was fired in January after 32 years in the department for leaking documents to the media claiming private-sector interference in a public study on pesticide use.
Agriculture minister André Lamontagne initially said it was a departmental decision, but in February admitted he had made the decision to fire Robert.
The union says it will build a defamation case against the CAQ government based on comments Lamontagne made after Robert's dismissal.
The provincial ombudsman is investigating the dismissal.
