Institute of Plant Sciences, University of Bern, Switzerland.
Amino Acids. 2010 Oct;39(4):949-62. doi: 10.1007/s00726-010-0525-3. Epub 2010 Mar 5.
Proline fulfils diverse functions in plants. As amino acid it is a structural component of proteins, but it also plays a role as compatible solute under environmental stress conditions. Proline metabolism involves several subcellular compartments and contributes to the redox balance of the cell. Proline synthesis has been associated with tissues undergoing rapid cell divisions, such as shoot apical meristems, and appears to be involved in floral transition and embryo development. High levels of proline can be found in pollen and seeds, where it serves as compatible solute, protecting cellular structures during dehydration. The proline concentrations of cells, tissues and plant organs are regulated by the interplay of biosynthesis, degradation and intra- as well as intercellular transport processes. Among the proline transport proteins characterized so far, both general amino acid permeases and selective compatible solute transporters were identified, reflecting the versatile role of proline under stress and non-stress situations. The review summarizes our current knowledge on proline metabolism and transport in view of plant development, discussing regulatory aspects such as the influence of metabolites and hormones. Additional information from animals, fungi and bacteria is included, showing similarities and differences to proline metabolism and transport in plants.
脯氨酸在植物中具有多种功能。作为一种氨基酸，它是蛋白质的结构组成部分，但在环境胁迫条件下，它也作为相容性溶质发挥作用。脯氨酸代谢涉及多个亚细胞区室，并有助于细胞的氧化还原平衡。脯氨酸的合成与经历快速细胞分裂的组织有关，如茎尖分生组织，并且似乎参与花发育和胚胎发育。脯氨酸的含量在花粉和种子中很高，在那里它作为相容性溶质，在脱水过程中保护细胞结构。细胞、组织和植物器官中的脯氨酸浓度受生物合成、降解以及细胞内和细胞间运输过程的相互作用调节。在迄今为止表征的脯氨酸转运蛋白中，鉴定了一般氨基酸通透酶和选择性相容性溶质转运体，反映了脯氨酸在应激和非应激情况下的多功能作用。该综述根据植物发育总结了我们对脯氨酸代谢和运输的现有认识，讨论了代谢物和激素等调节方面的影响。还包括来自动物、真菌和细菌的信息，显示了与植物中脯氨酸代谢和运输的相似性和差异性。
