Figure 2.

Hypothetical model for APX6-regulated ROS/redox signaling in seeds. APX6 function in seeds to reduce the levels of ROS and redox imbalances during stress, protecting seeds and maintain their vigor. ROS and redox signals generated in the absence of functional APX6 or during sever stress conditions lead to increased levels of ABA and auxin and promote their inhibitory effect on germination. APX6 effect the balance between the AA pool and DHA pool.⁵ Decreased availability of AA result in activation of ABA biosynthesis genes including NECD leading accumulation of ABA.¹⁵ ABI4 expression and pathway are activated in response to the increase in oxidative load and the level of ABA. It is not clear yet if ABI4 responds directly to auxin or indirectly by enhancing the ABA-mediate response.