吡咯啉-5-羧酸合成酶(P5CS)是植物中由P5CS基因编码的一种与干旱胁迫响应紧密联系的关键酶，它主要负责调节脯氨酸的生物合成。研究胡麻P5CS基因家族进化模式对进一步探索其在胡麻耐旱过程中的作用机制具有重要意义。本研究以拟南芥的2个P5CS基因作为查询序列，从胡麻、油菜、大豆、花生、向日葵、水稻、小麦等主要粮油作物的基因组中筛选获得P5CS基因家族成员。并通过分析不同作物P5CS基因受选择压力的大小、位点及功能分化潜力等阐明其进化模式，并在拟南芥中对其进行功能验证。研究结果显示，与其他作物的同源基因相比，胡麻P5CS基因家族成员在基因结构和进化模式上存在显著差异。在拟南芥中过表达受正向选择的胡麻LusP5CS1基因可以显著增加转基因拟南芥脯氨酸的积累并增强其耐旱性；在非干旱胁迫下过表达转基因拟南芥也表现出明显的适合度优势。本研究为胡麻耐旱分子机制和抗旱育种提供了理论基础。

Pyrroline-5-carboxylate synthetase (P5CS), a crucial enzyme encoded by the P5CS gene, plays a key role in the drought stress response in plants, primarily by regulating proline biosynthesis. In this study, we used two P5CS genes from Arabidopsis thaliana as query sequences to meticulously screen and identify members of the P5CS gene family from the genomes of various important grain and oil crops, including linseed, rapeseed, soybean, peanut, sunflower, rice, and wheat. By thoroughly analyzing the selection pressure, specific sites, and functional differentiation potential of P5CS genes across these diverse crops, we gained a comprehensive understanding of their evolutionary patterns. Furthermore, we validated the functions of these genes in Arabidopsis thaliana, a model organism. Our findings revealed significant differences in gene structure and evolutionary patterns among members of the linseed P5CS gene family compared to their homologs in other crops. Notably, overexpressing the positively selected linseed LusP5CS1 gene in Arabidopsis thaliana resulted in a substantial increase in proline accumulation and enhanced drought resistance in the transgenic plants. Interestingly, even under non-drought stress conditions, the transgenic Arabidopsis thaliana exhibited a notable fitness advantage. This groundbreaking study not only enhances our understanding of the molecular mechanisms underlying drought resistance but also provides a solid theoretical foundation for breeding drought-tolerant linseed varieties.