When plants are entirely submerged, photosynthesis and respiration are severely restricted, affecting plant growth and potentially even causing plant death. The AP2/ERF superfamily has been widely reported to play a vital role in plant growth, development and resistance to biotic and abiotic stresses. However, no relevant studies exist on flooding stress in pecan. In this investigation, we observed that CiAP2/ERF65 positively modulated the hypoxia response during submergence, whereas CiAP2/ERF106 was sensitive to submergence. The levels of physiological and biochemical indicators, such as POD, CAT and among others, in CiAP2/ERF65-OE lines were significantly higher than those in wild-type Arabidopsis thaliana, indicating that the antioxidant capacity of CiAP2/ERF65-OE lines was enhanced under submergence. The RNA-seq results revealed that the maintenance of the expression levels of the antenna protein gene, different signaling pathways for regulation, as well as the storage and consumption of ATP, might account for the opposite phenotypes of CiAP2/ERF65 and CiAP2/ERF106. Furthermore, the expression of some stress-related genes was altered during submergence and reoxygenation. Overall, these findings enhance our understanding of submergence stress in pecan, providing important candidate genes for the molecular design and breeding of hypoxia resistant in plants.

当植物完全淹没时，光合作用和呼吸作用受到严重限制，影响植物生长，甚至可能导致植物死亡。AP2/ERF 超家族已被广泛报道在植物生长、发育以及对生物和非生物胁迫的抵抗力中发挥着至关重要的作用。然而，目前还没有关于山核桃洪水胁迫的相关研究。在这项研究中，我们观察到CiAP2/ERF65正向调节浸水期间​​的缺氧反应，而CiAP2/ERF106对浸水敏感。CiAP2/ERF65 -OE品系的POD 、CAT等生理生化指标水平显着高于野生型拟南芥，表明CiAP2/ERF65 -OE品系的抗氧化能力增强淹没之下。RNA-seq结果表明，天线蛋白基因表达水平的维持、调节的不同信号通路以及ATP的储存和消耗可能是CiAP2/ERF65和CiAP2/ERF106相反表型的原因。此外，一些与应激相关的基因的表达在淹没和复氧过程中发生了改变。总的来说，这些发现增强了我们对山核桃淹没胁迫的理解，为植物抗缺氧的分子设计和育种提供了重要的候选基因。