脯氨酸代谢途径在调控水稻phyB突变体干旱胁迫耐性中的作用

摘要

The expression levels of key genes involved in proline metabolic pathway were compared in rice wild type (WT)and phyB mutant.The results showed that dehydration treatment induced the expression of proline biosynthetic gene OsP5CS1 and OsOAT,but suppressed the expression of proline catabolic gene OsP5CDH.And the expression level of OsP5CS1 gene in phyB mutant was obviously higher than that in WT, which suggesting that phyB negatively regulated its expression.To explore the relation between high OsP5CS1 transcript level and stronger drought tolerance in phyB mutant,the OsP5CS1 transgenic tobacco was obtained. Water loss rate assays of detached leaves revealed that transgenic tobacco showed a slower water loss rate com-pared to non-transgenic tobacco.In addition,the leaf disk differentiation rate under high salinity of transgen-ic tobacco was higher than that of non -transgenic tobacco.These findings suggested that the regulation of phyB on proline metabolic pathway was one of the important factors contributing to stronger drought tolerance in phyB mutant.%本研究分析了水稻野生型和phyB突变体中脯氨酸代谢途径关键基因的表达水平。结果显示，干旱处理能够诱导脯氨酸生物合成相关基因OsP5CS1和OsOAT的表达，抑制脯氨酸生物降解基因OsP5CDH的表达。且phyB突变体中OsP5CS1基因的表达水平明显高于野生型，据此推测phyB负调控OsP5CS1基因的表达。为了分析OsP5CS1基因的高水平表达是否与phyB突变体较强的干旱胁迫耐性有关，本研究进一步培育了转OsP5CS1基因烟草。离体叶片失水速率结果表明，转基因烟草的失水速率小于野生型；盐胁迫条件下，转基因烟草的分化率明显高于野生型。综上所述，phyB对脯氨酸代谢途径的调控是phyB突变体具有较强干旱胁迫耐性的重要因素之一。