State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, China.
Key Laboratory of Green Pesticide and Agricultural Bioengineering, Guizhou University, Guiyang, PR China.
J Plant Physiol. 2023 Aug;287:154037. doi: 10.1016/j.jplph.2023.154037. Epub 2023 Jun 9.
Reactive oxygen species (ROS) play an essential role as both signaling molecule and damage agent during salt stress. As a signaling molecule, proper accumulation of HO is crucial to trigger stress response and enhance stress tolerance. However, the dynamic regulation mechanism of HO remains unclear. Here, we show that MhCAT2 (catalase 2 in Malus hupehensis) undergoes oxidative modification in an O-dependent manner and that oxidation at His225 residue reduces the MhCAT2 activity. Furthermore, the substitution of His225 with Tyr weakens the activity of MhCAT2. The oxidation modification provides a post-translational brake mechanism for the excessive scavenging of HO caused by salt stress-induced catalase (CAT) over-expression. Overall, this finding provides mechanistic insights on stress tolerance augmentation by an O-mediated switch that regulates HO homeostasis in Malus hupehensis.
活性氧（ROS）在盐胁迫过程中既是信号分子又是损伤剂，起着至关重要的作用。作为一种信号分子，HO 的适当积累对于触发应激反应和增强应激耐受性至关重要。然而，HO 的动态调节机制尚不清楚。在这里，我们表明 MhCAT2（苹果属胡阳 CAT2）以 O 依赖性方式发生氧化修饰，并且 His225 残基的氧化降低了 MhCAT2 的活性。此外，用 Tyr 取代 His225 会削弱 MhCAT2 的活性。氧化修饰为盐胁迫诱导的过氧化氢酶（CAT）过表达引起的 HO 过度清除提供了一种翻译后制动机制。总的来说，这项发现为苹果属胡阳通过 O 介导的开关来调节 HO 动态平衡从而增强应激耐受性提供了机制见解。
