Signorelli Santiago, Monza Jorge
a Department of Agriculture, The School of Agriculture and Environment , The University of Western Australia , Perth , WA , Australia.
b Department of Plant Biology, The School of Molecular Sciences , The University of Western Australia , Perth , WA , Australia.
Plant Signal Behav. 2017 Nov 2;12(11):e1367464. doi: 10.1080/15592324.2017.1367464. Epub 2017 Oct 6.
Proline accumulation is a common response of plants to different biotic and abiotic stresses. In the model legume Lotus japonicus, osmotic stress-induced proline accumulation is one of the first responses of the plant, converting proline in a reliable stress marker. The main biosynthetic pathway of proline is from glutamate and the reaction catalyzed by the enzyme Δ-pyrroline 5-carboxylate synthase (P5CS) is the rate limiting step. L. japonicus has been suggested to have three different P5CS genes. Here the predicted P5CS genes of L. japonicus were analyzed in silico and their expression under osmotic stress was determined. Contrary to previous suggestions this study demonstrated that L. japonicus has two different P5CS genes, as most dicotyledonous plants do. The gene that is inducible by osmotic stress and is located on chromosome 1, was called LjP5CS1, and the one located on chromosome 2 and not inducible by osmotic stress was called LjP5CS2.
脯氨酸积累是植物对不同生物和非生物胁迫的常见反应。在豆科模式植物百脉根中，渗透胁迫诱导的脯氨酸积累是植物的早期反应之一，脯氨酸可作为可靠的胁迫标志物。脯氨酸的主要生物合成途径是由谷氨酸合成，由Δ-吡咯啉5-羧酸合成酶（P5CS）催化的反应是限速步骤。有人提出百脉根有三个不同的P5CS基因。本文对百脉根预测的P5CS基因进行了电子分析，并测定了它们在渗透胁迫下的表达。与之前的观点相反，本研究表明，和大多数双子叶植物一样，百脉根有两个不同的P5CS基因。其中一个受渗透胁迫诱导且位于1号染色体上的基因被命名为LjP5CS1，另一个位于2号染色体上且不受渗透胁迫诱导的基因被命名为LjP5CS2。
