Chu Chiung-Chih, Han Chia-Ying, Li Hsou-Min
Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
Nat Plants. 2025 Jun 13. doi: 10.1038/s41477-025-02020-x.
Plastids develop into nutrient-storing leucoplasts in seeds and roots. Efficient protein delivery is essential to modify biosynthetic processes in leucoplasts for human needs, but no effective transit peptide for leucoplasts is currently available. Here, using an in vitro leucoplast import system, we have identified six high-efficiency transit peptides. Compared with a widely used chloroplast transit peptide, these peptides delivered similar amounts of GFP into chloroplasts, but two to seven times more GFP into root and petal leucoplasts, attesting to the advantage of screening using leucoplasts. When used to deliver bacterial phytoene synthase (crtB) into rice calli and glyphosate-resistant EPSP synthase into Arabidopsis, these peptides enhanced carotenoid production and herbicide resistance, respectively. The correlation among levels of GFP delivery, carotenoid production and herbicide resistance indicates that the efficiency of these transit peptides is consistent across plant species and passenger proteins. Transit peptide selection therefore offers an effective way to modulate production levels of engineered proteins.
质体在种子和根中发育成储存营养的白色体。高效的蛋白质递送对于根据人类需求改造白色体中的生物合成过程至关重要，但目前尚无有效的白色体转运肽。在此，我们利用体外白色体导入系统鉴定出了六种高效转运肽。与广泛使用的叶绿体转运肽相比，这些肽向叶绿体中递送的绿色荧光蛋白（GFP）量相似，但向根和花瓣白色体中递送的GFP量多出两到七倍，这证明了使用白色体进行筛选的优势。当用于将细菌八氢番茄红素合成酶（crtB）递送至水稻愈伤组织以及将抗草甘膦的5-烯醇丙酮酰莽草酸-3-磷酸合酶（EPSP合酶）递送至拟南芥时，这些肽分别提高了类胡萝卜素产量和除草剂抗性。GFP递送水平、类胡萝卜素产量和除草剂抗性之间的相关性表明，这些转运肽的效率在不同植物物种和客体蛋白中是一致的。因此，转运肽的选择为调节工程蛋白的生产水平提供了一种有效方法。
