University of Angers, Institut de Recherche en Horticulture et Semences UMR 1345, SFR 4207 QUASAV, 2 Bd Lavoisier, F-49045 Angers, France.
J Plant Physiol. 2013 Jun 15;170(9):874-7. doi: 10.1016/j.jplph.2013.01.008. Epub 2013 Feb 9.
Stress associated proteins (SAP) have been already reported to play a role in tolerance acquisition of some abiotic stresses. In the present study, the role of MtSAP1 (Medicago truncatula) in tolerance to temperature, osmotic and salt stresses has been studied in tobacco transgenic seedlings. Compared to wild type, MtSAP1 overexpressors were less affected in their growth and development under all tested stress conditions. These results confirm that MtSAP1 is involved in the response processes to various abiotic constraints. In parallel, we have performed studies on an eventual link between MtSAP1 overexpression and proline, a major player in stress response. In an interesting way, the results for the transgenic lines did not show any increase of proline content under osmotic and salt stress, contrary to the WT which usually accumulated proline in response to stress. These data strongly suggest that MtSAP1 is not involved in signaling pathway responsible for the proline accumulation in stress conditions. This could be due to the fact that the overexpression of MtSAP1 provides sufficient tolerance to seedlings to cope with stress without requiring the free proline action. Beyond that, the processes by which the MtSAP1 overexpression lead to the suppression of proline accumulation will be discussed in relation with data from our previous study involving nitric oxide.
应激相关蛋白（SAP）已被报道在一些非生物胁迫的耐受获得中发挥作用。在本研究中，研究了烟草转基因幼苗中 MtSAP1（Medicago truncatula）在耐受温度、渗透和盐胁迫中的作用。与野生型相比，MtSAP1 过表达株系在所有测试的胁迫条件下，其生长和发育受影响较小。这些结果证实 MtSAP1 参与了对各种非生物胁迫的响应过程。同时，我们还研究了 MtSAP1 过表达与脯氨酸之间的潜在联系，脯氨酸是应激响应中的主要参与者。有趣的是，转基因株系的结果显示，在渗透和盐胁迫下，脯氨酸含量没有增加，而 WT 通常会在应激时积累脯氨酸。这些数据强烈表明 MtSAP1 不参与脯氨酸积累的信号通路。这可能是因为 MtSAP1 的过表达为幼苗提供了足够的耐受能力，使其能够在不依赖游离脯氨酸作用的情况下应对胁迫。此外，还将结合我们之前涉及一氧化氮的研究数据，讨论 MtSAP1 过表达导致脯氨酸积累抑制的机制。
