RAP2.3 is required for MYB51 and SIGMA3 expression during the response of Arabidopsis thaliana to multifactorial stress combination

Recent studies revealed that when three or more stress factors impact a plant simultaneously (termed ‘multifactorial stress combination’; MFSC), plant survival declines, even if the intensity of each individual stress involved in the MFSC is low. We previously identified RAP2.3 as a key transcription factor (TF) required for Arabidopsis thaliana survival, specifically under a MFSC of salt+excess light+heat stress (i.e., S+EL+HS).

Here we report that RAP2.3 is required for the expression of SIGMA3, a nuclear-encoded factor that directs plastid RNA polymerase to specific plastid promoters, and MYB51, a key stress response TF involved in glucosinolate metabolism and oxidative stress responses, specifically during a MFSC of S +EL+HS. Like rap2.3 mutants, myb51 and sig3 mutants display significantly low survival rate specifically under the MFSC of S+EL+HS.