PCE:南开大学王宁宁团队揭示N7-SSPP融合基因通过清除活性氧提高转基因拟南芥和大豆的耐盐性

今天介绍的是南开大学生命科学学院王宁宁团队在PCE上发表的研究论文《N 7 -SSPP fusion gene improves salt stress tolerance in transgenic Arabidopsis and soybean through ROS scavenging》。

叶片衰老是一个基因程序化和与年龄相关的活动过程，导致叶绿素降解、光合效率降低和活性氧物质（ROS）积累。它受到许多与衰老相关的基因（SAG）的高度调节，而许多SAG也参与了盐胁迫反应。SSPP（叶片衰老的负调节因子）的过表达通过增加拟南芥和大豆中 ROS 的清除来显着提高植物的耐盐性。然而，SSPP 的过表达会严重抑制植物的正常生长，限制了其在农业中的直接使用。

在本研究中，作者团队之前发现 ACS7 的 N 末端 1-14 个残基（称为“N7”）通过泛素/蛋白酶体途径负调节其蛋白质稳定性，并且 N7 介导的蛋白质降解受到环境和衰老信号的抑制。为了避免SSPP的不利影响，将N7元素融合到SSPP的N端。本研究证实 N7-SSPP 融合基因有效地挽救了 SSPP 诱导的生长抑制，但在拟南芥和大豆中保持了增强的耐盐性。更重要的是，N7-SSPP 增强了大豆对长期盐胁迫的耐受性并增加了种子产量。

综上所述，N7-SSPP通过增强ROS清除能力有效提高耐盐性，克服了SSPP抑制植物生长的缺点。将N7融合到 SSPP 可能会为基因工程增强作物耐盐胁迫、为利用翻译后调控元件进行耐盐作物育种提供有效策略。

Leaf senescence is a genetically programmed and age-related active process that causes chlorophyll degradation, reduction of photosynthetic efficiency, and reactive oxygen species (ROS) accumulation. It is highly regulated by numerous senescence-associated genes (SAGs). Interestingly, many SAGs are also involved in salt-stress responses in plants. But overexpression of SSPP, a negative regulator of leaf senescence, significantly improved plant salt tolerance by increasing ROS scavenging in both Arabidopsis and soybean. However, overexpression of SSPP severely suppressed normal plant growth, limiting its direct use in agriculture. In this study, the author previously revealed that the N-terminal 1-14 residues of ACS7 (termed “ N7”) negatively regulated its protein stability through ubiquitin/proteasome pathway, and the N7-mediated protein degradation was suppressed by environmental and senescence signals. To avoid the adverse effects of SSPP, N7element was fused to the N-terminus of SSPP. This study demonstrated that N7-SSPP fusion gene effectively rescued SSPP-induced growth suppression but maintained enhanced salt tolerance in Arabidopsis and soybean. Particularly, N7-SSPP enhanced tolerance to long-term salt stress and increased seed yield in soybean. In a word, N7-SSPP overcomes the disadvantages of SSPP on plant growth inhibition and effectively improves salt tolerance through enhanced ROS scavenging. And fusing N7 to SSPP may offer an effective strategy for enhancing crop salt stress tolerance by genetic engineering. It is also providing an effective strategy of using post-translational regulatory element for salt-tolerant crop breeding.

原文链接：https://doi.org/10.1111/pce.14392 

转自：植物科学SCI

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