RAP2.6 negatively regulates Arabidopsis submergence tolerance through GSNOR1-dependent redox and hormonal signaling

RAP2.6 acts as a negative regulator of submergence tolerance in Arabidopsis thaliana, with RAP2.6 overexpression reducing survival after dark submergence.

• Why it matters: The roles of AP2/ERF transcription factors beyond ERFVIIs in flooding and hypoxia responses are unclear, limiting understanding of how plants coordinate oxygen, redox, and hormonal signaling.
• What they did: RAP2.6 expression was tested under hypoxia, and survival, membrane injury, pigments, sugars, NO/SNO, ethylene, and ABA-responsive gene expression were measured in RAP2.6 gain- and loss-of-function lines, including GSNOR1 gain- and loss-of-function backgrounds.
• The result: GSNOR1-dependent GSNO homeostasis strongly modified RAP2.6-dependent submergence responses: higher GSNOR1 activity suppressed RAP2.6 overexpression sensitivity and reduced nitro-oxidative stress, while loss of GSNOR1 activity abolished rap2.6-1 enhanced tolerance.