Abscisic Acid Signaling in the Regulation of Postharvest Physiological Deterioration of Sliced Cassava Tuberous Roots

Phytohormone
abscisic acid (ABA) influences the shelf life of fruit,
vegetables, and tubers after harvest. However, little is known about
the core signaling module involved in ABA’s control of the
postharvest physiological process. Exogenous ABA alleviated postharvest
physiological deterioration (PPD) symptoms of sliced cassava tuberous
roots, increased endogenous ABA levels, and reduced endogenous H2O2 content. The specific ABA signaling module during
the PPD process was identified as MePYL6–MePP2C16–MeSnRK2.1–MebZIP5/34.
MebZIP5/MebZIP34 directly binds to and activates the promoters of MeGRX6/MeMDAR1 through ABRE elements. Exogenous ABA significantly
induced the expression of genes involved in this module, glutaredoxin
content, and monodehydroascorbate reductase activity. We presented
a hypothesis suggesting that MePYL6–MePP2C16–MeSnRK2.1–MebZIP5/34–MeGRX6/MeMDAR1
is involved in ABA-induced antioxidative capacity, thus alleviating
PPD symptoms in cassava tuberous roots. The identification of the
specific signaling module involved in ABA’s control of PPD
provides a basis and potential targets for extending the shelf life
of cassava tuberous roots.