The New York State United Teachers union on Monday formally endorsed Democrat John Mannion in his second bid for a central New York Senate district.

“John’s intimate knowledge of public education and the issues facing our students and staff would be a huge boon to the Senate,” NYSUT President Andy Pallotta said.

“NYSUT supports candidates who share our values and strong belief in the power of organized labor, and in John, we know we have a true friend and advocate who will put Central New York’s students and working families first.”

Mannion, a biology teacher and president of the West Genesee District Teachers Association, is running again for the seat that’s being vacated by Republican Bob Antonacci at the end of the year. Antonacci defeated Mannion last year for the district, formerly held by Sen. John DeFrancisco, a Republican.

It’s not year clear when or if a special election would be called to fill the seat, though Gov. Andrew Cuomo last month indicated he would consider doing so.