Differential Induction of PepTLP Expression via Complex Regulatory System against Fungal Infection, Wound, and Jasmonic Acid Treatment during Pre-and Post-Ripening of Nonclimacteric Pepper Fruit

Abstract

Ripe fruit of pepper (Capsicum annuum) showed resistance to Colletotrichum gloeoporioides, but unripe fruit was susceptible. We previously isolated the PepTLP gene that induced in both unripe and ripe fruit by fungal infection and wound, and only in ripe fruit by jasmonic acid (JA) treatment. To examine further regulation of PepTLP, the action of specific agonist and antagonists of known signaling effector on the .PepTLP expression by fungal infection, wound, and JA was investigated. A similar dephosphorylation event negatively activated all the PepTLP expression in the ripe fruit by fungal infection, wound, and JA. The induction of PepTLP expression by wound is differentially regulated via phosphorylation and dephosphorylation step during pre- and post-ripening, respectively. In addition, the induction of PepTLP expression in the ripe fruit by wound and JA is differentially regulated via dephosphorylation and phosphorylation step, respectively. Only both wound and JA treatment has synergistic effect on the PepTLP expression in the unripe fruit. Both SA and JA treatments on the unripe fruit, and both wound or JA and SA on the ripe fruit could not do any effect on the expression of PepTLP. These results suggest that the induction of PepTLP expression is differentially regulated via complex regulatory system against fungal infection, wound, and JA treatment during pre- and post-ripening of pepper fruit.