National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, 35 East Tsinghua Road, Haidian District, Beijing 100083, China.
Horticulture Science, College of Horticulture, Hebei Agricultural University, 2596 Lekai South Street, Lianchi District, Baoding, Hebei 071001, China.
Tree Physiol. 2020 Aug 29;40(9):1292-1311. doi: 10.1093/treephys/tpaa050.
ZINC FINGER OF ARABIDOPSIS THALIANA12 (ZAT12) plays an important role in stress responses, but the transcriptional regulation of ZAT12 in response to abiotic stress remains unclear. In this study, we confirmed that a SALT TOLERANCE ZINC FINGER1 transcription factor from Populus euphratica (PeSTZ1) could regulate the expression of PeZAT12 by dual-luciferase reporter (DLR) assay and electrophoretic mobility shift assay. The expression of PeSTZ1 was rapidly induced by NaCl and hydrogen peroxide (H2O2) treatments. Overexpressing PeSTZ1 in poplar 84K (Populus alba × Populus glandulosa) plant was endowed with a strong tolerance to salt stress. Under salt stress, transgenic poplar exhibited higher expression levels of PeZAT12 and accumulated a larger amount of antioxidant than the wild-type plants. Meanwhile, ASCORBATE PEROXIDASE2 (PeAPX2) can be activated by PeZAT12 and PeSTZ1, promoting the accumulation of cytosolic ascorbate peroxidase (APX) to scavenge reactive oxygen species (ROS) under salt stress. This new regulatory model (PeSTZ1-PeZAT12-PeAPX2) was found in poplar, providing a new idea and insight for the interpretation of poplar resistance. Transgenic poplar reduced the accumulation of ROS, restrained the degradation of chlorophyll and guaranteed the photosynthesis and electron transport system. On the other hand, transgenic poplar slickly adjusted K+/Na+ homeostasis to alleviate salt toxicity in photosynthetic organs of plants under salt stress and then increased biomass accumulation. In summary, PeSTZ1 confers salt stress tolerance by scavenging the accumulation of ROS through regulating the expression of PeZAT12 and PeAPX2 in poplar.
拟南芥锌指蛋白 12（ZAT12）在应激反应中发挥重要作用，但 ZAT12 对非生物胁迫的转录调控尚不清楚。本研究通过双荧光素酶报告（DLR）测定和电泳迁移率变动分析（EMSA）证实了来自胡杨的盐胁迫锌指蛋白 1（PeSTZ1）可以调节 PeZAT12 的表达。PeSTZ1 的表达被 NaCl 和过氧化氢（H2O2）处理迅速诱导。在杨树 84K（白杨×腺柳）植物中超表达 PeSTZ1 使其具有较强的耐盐性。在盐胁迫下，转基因杨树的 PeZAT12 表达水平较高，抗氧化剂积累量也大于野生型植物。同时，抗坏血酸过氧化物酶 2（PeAPX2）可以被 PeZAT12 和 PeSTZ1 激活，在盐胁迫下促进细胞质抗坏血酸过氧化物酶（APX）的积累以清除活性氧（ROS）。在杨树中发现了这种新的调控模型（PeSTZ1-PeZAT12-PeAPX2），为解释杨树的抗性提供了新的思路和见解。转基因杨树减少了 ROS 的积累，抑制了叶绿素的降解，并保证了光合作用和电子传递系统的正常运转。另一方面，转基因杨树在盐胁迫下通过调节 PeZAT12 和 PeAPX2 的表达来维持光合器官中 K+/Na+的平衡，从而减轻盐毒性，并增加生物量积累。总之，PeSTZ1 通过调节 PeZAT12 和 PeAPX2 的表达来清除 ROS 的积累，从而赋予杨树耐盐性。
