Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
The Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
Cells. 2021 Mar 6;10(3):582. doi: 10.3390/cells10030582.
It has been challenging to simultaneously improve photosynthesis and stress tolerance in plants. Crassulacean acid metabolism (CAM) is a CO-concentrating mechanism that facilitates plant adaptation to water-limited environments. We hypothesized that the ectopic expression of a CAM-specific phosphopyruvate carboxylase (PEPC), an enzyme that catalyzes primary CO fixation in CAM plants, would enhance both photosynthesis and abiotic stress tolerance. To test this hypothesis, we engineered a CAM-specific gene (named ) from into tobacco. In comparison with wild-type and empty vector controls, transgenic tobacco plants constitutively expressing showed a higher photosynthetic rate and biomass production under normal conditions, along with significant carbon metabolism changes in malate accumulation, the carbon isotope ratio δC, and the expression of multiple orthologs of CAM-related genes. Furthermore, overexpression enhanced proline biosynthesis, and improved salt and drought tolerance in the transgenic plants. Under salt and drought stress conditions, the dry weight of transgenic tobacco plants overexpressing was increased by up to 81.8% and 37.2%, respectively, in comparison with wild-type plants. Our findings open a new door to the simultaneous improvement of photosynthesis and stress tolerance in plants.
同时提高植物的光合作用和抗逆性一直具有挑战性。景天酸代谢（CAM）是一种 CO 浓缩机制，有助于植物适应水分受限的环境。我们假设异位表达 CAM 特异性磷酸烯醇丙酮酸羧化酶（PEPC），一种在 CAM 植物中催化初级 CO 固定的酶，将同时提高光合作用和非生物胁迫耐受性。为了验证这一假设，我们将来自 的 CAM 特异性基因（命名为 ）工程化到烟草中。与野生型和空载体对照相比，组成型表达 的转基因烟草植物在正常条件下表现出更高的光合速率和生物量生产，同时在苹果酸积累、碳同位素比 δC 和多个 CAM 相关基因的同源物的表达方面发生了显著的碳代谢变化。此外，过表达 增强了脯氨酸的生物合成，并提高了转基因植物的耐盐性和耐旱性。在盐和干旱胁迫条件下，与野生型植物相比，过表达 的转基因烟草植物的干重分别增加了 81.8%和 37.2%。我们的研究结果为同时提高植物的光合作用和抗逆性开辟了新的途径。
