College of Animal Science and Technology, China Agricultural University, Beijing, China.
Beijing Key Laboratory for Grassland Science, China Agricultural University, Beijing, China.
PLoS One. 2019 Jul 16;14(7):e0219669. doi: 10.1371/journal.pone.0219669. eCollection 2019.
In plants, Δ1-pyrroline- 5-carboxylate synthase (P5CS) is the rate-limiting enzyme in proline biosynthesis. In this study, we introduced the LpP5CS (Lolium perenne L.) gene into switchgrass by Agrobacterium-mediated transformation. The transgenic lines (TG) were classified into two groups based on their phenotypes and proline levels. The group I lines (TG4 and TG6) had relatively high proline levels and improved biomass yield. The group II lines (TG1 and TG2) showed low proline levels, severely delayed flowering, stunted growth and reduced biomass yield. Additionally, we used RNA-seq analysis to detect the most significant molecular changes, and we analyzed differentially expressed genes, such as flowering-related and CYP450 family genes. Moreover, the biomass yield, physiological parameters, and expression levels of reactive oxygen species scavenger-related genes under salt stress all indicated that the group I plants exhibited significantly increased salt tolerance compared with that of the control plants, in contrast to the group II plants. Thus, genetic improvement of switchgrass by overexpressing LpP5CS to increase proline levels is feasible for increasing plant stress tolerance.
在植物中，Δ1-吡咯啉-5-羧酸合成酶（P5CS）是脯氨酸生物合成的限速酶。本研究通过农杆菌介导的转化将柳枝稷的 LpP5CS（Lolium perenne L.）基因导入到柳枝稷中。根据表型和脯氨酸水平，将转基因株系（TG）分为两组。第 I 组（TG4 和 TG6）的脯氨酸水平相对较高，生物量产量也有所提高。第 II 组（TG1 和 TG2）的脯氨酸水平较低，开花严重延迟，生长受阻，生物量产量降低。此外，我们使用 RNA-seq 分析检测到最显著的分子变化，并分析了差异表达基因，如花相关和 CYP450 家族基因。此外，在盐胁迫下，生物量产量、生理参数和活性氧清除剂相关基因的表达水平均表明，与对照植物相比，第 I 组植物的耐盐性显著提高，而第 II 组植物则相反。因此，通过过表达 LpP5CS 来提高脯氨酸水平，从而改良柳枝稷，提高植物的抗逆性是可行的。
