肌醇多磷酸5-磷酸酶(5PTases)通过调节磷酸肌醇衍生物的分解代谢在肌醇信号传导中起作用。以前的报道表明,5PTase在植物发育和胁迫反应中起关键作用。在这项研究中,我们发现了一个新的5PTase基因,Gs5PTase8,来自野生大豆(甘氨酸大豆)3号染色体的耐盐基因座。Gs5PTase8在盐处理下高度上调。它位于细胞核和质膜中,在胞外体中具有强烈的信号。Gs5PTase8的异位表达显著提高了转基因BY-2细胞的耐盐性,大豆毛状根和拟南芥,表明Gs5PTase8可以提高植物的耐盐性。Gs5PTase8的过表达显著增强了盐胁迫下过氧化氢酶和抗坏血酸过氧化物酶的活性。在脱落酸处理下,转Gs5PTase8基因的拟南芥的种子比野生型早发芽,表明Gs5PTase8会改变ABA敏感性。此外,转录分析表明,应激反应基因,AtRD22、AtRD29A和AtRD29B,在盐胁迫下,Gs5PTase8转基因拟南芥植物的诱导水平高于野生型。这些结果表明,Gs5PTase8在耐盐性中起积极作用,可能是提高大豆对盐胁迫适应性的候选基因。
Inositol polyphosphate 5-phosphatases (5PTases) function in inositol signaling by regulating the catabolism of phosphoinositol derivatives. Previous reports showed that 5PTases play a critical role in plant development and stress responses. In this study, we identified a novel 5PTase gene, Gs5PTase8, from the salt-tolerance locus of chromosome 3 in wild soybean (Glycine soja). Gs5PTase8 is highly up-regulated under salt treatment. It is localized in the nucleus and plasma membrane with a strong signal in the apoplast. Ectopic expression of Gs5PTase8 significantly increased salt tolerance in transgenic BY-2 cells, soybean hairy roots and Arabidopsis, suggesting Gs5PTase8 could increase salt tolerance in plants. The overexpression of Gs5PTase8 significantly enhanced the activities of catalase and ascorbate peroxidase under salt stress. The seeds of Gs5PTase8-transgenic Arabidopsis germinated earlier than the wild type under abscisic acid treatment, indicating Gs5PTase8 would alter ABA sensitivity. Besides, transcriptional analyses showed that the stress-responsive genes, AtRD22, AtRD29A and AtRD29B, were induced with a higher level in the Gs5PTase8-transgenic Arabidopsis plants than in the wild type under salt stress. These results reveal that Gs5PTase8 play a positive role in salt tolerance and might be a candidate gene for improving soybean adaptation to salt stress.