Overexpression of transketolase gene promotes chilling tolerance by increasing the activities of photosynthetic enzymes, alleviating oxidative damage and stabilizing cell structure in Cucumis sativus L.
Overexpression of transketolase gene promotes chilling tolerance by increasing the activities of photosynthetic enzymes, alleviating oxidative damage and stabilizing cell structure in Cucumis sativus L.
复制标题
转酮醇酶基因的过表达通过增加光合酶的活性、减轻氧化损伤和稳定细胞结构来促进黄瓜的耐冷性。
DOI：
10.1111/ppl.12903
复制
发表时间：
2019-12-01
影响因子：
6.4
通讯作者：
Ai, Xizhen
中科院分区：
文献类型：
--
作者：
Bi, Huangai;Li, Fude;Ai, Xizhen
转酮醇酶（TK）是Cavin循环的关键酶，被认为与高等植物的非生物抗性有关。然而，传统知识如何影响耐冷性仍然在很大程度上是未知的。在这里，我们描述了超表达黄瓜TK基因（CsTK）的生长，光合作用，活性氧代谢和细胞超微结构在低温胁迫下的影响。结果表明，低温处理导致叶片光合速率（Pn）、气孔导度（Gs）、实际光化学效率（ΦPSII）和蔗糖含量下降，而胞间CO2浓度（Ci）和MDA含量升高。在低温胁迫5 d后，CsTK植株的这些变化得到缓解，而抑制CsTK则表现出相反的结果。在低温胁迫下，转CsTK基因黄瓜植株的叶面积和干物质增加幅度较大，相关酶活性较高，参与卡尔文循环和活性氧清除系统的代谢物质含量增加较多，而· OH、H2 O2含量和超氧阴离子产生速率较低。在低温胁迫结束时，与野生型相比，CsTK正义植株的细胞超微结构完整，叶绿体膨胀，细胞膜和叶绿体膜破裂，基粒片层消失，而CsTK反义植株的细胞超微结构损伤加重。综上所述，CsTK主要通过提高黄瓜植株的碳同化能力、减轻氧化损伤和稳定细胞结构来提高黄瓜的耐冷性。
Despite being a key enzyme of Cavin cycle, transketolase (TK) is believed to be related to abiotic resistance in higher plants. However, how TK affects chilling tolerance still remains largely unknown. Here, we describe the effect of overexpression of the Cucumis sativa TK gene (CsTK) on growth, photosynthesis, ROS metabolism and cell ultrastructure under chilling stress. Low temperature led to a decrease of the photosynthetic rate (Pn), the stomatal conductance (Gs), the actual photochemical efficiency (ΦPSII) and the sucrose content, whereas there was an increase of the intercellular CO2 concentration (Ci) and MDA content. These changes were alleviated in the CsTK plants after 5 days of chilling stress, however, inhibition of CsTK showed the opposite results. Furthermore, transgenic plants with overexpression of CsTK showed higher increase in leaf area and dry matter, higher activity of the enzymes and higher increase in the contents of metabolism substance involved in Calvin cycle and reactive oxygen scavenging system as well as lower • OH and H2 O2 content, superoxide anion production rate compared with the control cucumber plants under chilling stress. At the end of the chilling stress, compared to wild-type (WT) which exhibited dramatically destroyed cell ultrastructure, expanded chloroplast, broken cell and chloroplast membranes as well as the disappeared grana lamella, the CsTK sense plants showed a more complete cell ultrastructure, whereas, the damage of the cell ultrastructure was aggravated in CsTK antisense plants. Taken together, these results imply that CsTK promoted chilling tolerance in cucumber plants mainly through increasing the capacity to assimilate carbon, alleviating oxidative damage and stabilizing cell structure.