Figure 9.

Preliminary model summarizing how OsWRKY53 regulates herbivore-induced signaling pathways and defenses. Plants recognize signals from wounding and herbivore infestation and quickly transduce these to MPK cascades, which leads to the activation of OsMPK3/OsMPK6. Active OsMPK3/OsMPK6 activates some WRKYs, and thus both OsMPK3/OsMPK6 and WRKYs regulate the biosynthesis of defense-related signals, such as JA, JA-Ile, and ET. The activated OsMPK3/OsMPK6 gradually elicits OsWRKY53 by phosphorylating it. Moreover, the ET pathway may also positively mediate the activity of OsWRKY53. OsWRKY53 can inhibit the activity of OsMPK3/OsMPK6 directly and indirectly by the interaction of the two MPKs and may mediate other WRKYs with an unknown way, which keeps the defense response at an appropriate level. Arrows represent regulation negatively or positively; barred lines represent negative regulation; and arrows with a plus symbol represent positive regulation. Lines in green represent the OsWRKY53-ET regulation loop.