水稻OsHKT基因表达模式分析

Expression Patterns of OsHKT Genes in Rice

【目的】OsHKT(High-affinity K^+transporter)是与水稻耐盐胁迫有关的一类Na^+或K^+转运体或Na^+-K^+共转运体,对水稻体内Na^+再循环,维持植株地上部特别是叶片中的低Na^+浓度和低Na^+/K^+比具有重要作用。本研究的目的是分析OsHKT基因家族表达的组织特异性、昼夜节律性以及盐、ABA对其表达的影响。【方法】利用荧光定量PCR技术分析OsHKT家族基因的表达模式。【结果】OsHKT基因家族中不同成员的表达具有明显的组织特异性,OsHKT1;1、OsHKT1;3、OsHKT2;3以及OsHKT2;4主要在水稻的叶片中表达,其余基因在根中表达水平较高。分析盐处理后OsHKT家族基因在水稻根和叶中的表达模式,结果表明OsHKT家族基因的表达均受盐胁迫的影响,但是不同OsHKT家族成员对盐胁迫反应不同。盐处理后OsHKT1;5、Os HKT2;1和OsHKT2;2基因在根和叶中的表达模式是一致的,而其他家族成员在根和叶中存在差异。所有OsHKT基因的表达在根或叶片中均受ABA调控,其中只有OsHKT1;3和OsHKT1;5在根和叶片中表达模式相似。光周期表达模式结果表明,OsHKT基因家族成员的表达具有相似的昼夜节律性。【结论】本研究结果表明水稻OsHKT家族不同成员的表达具有组织特异性和相似的昼夜节律性,并且不同成员对盐胁迫和ABA应答反应不同。这种表达模式可能与水稻在不同环境下的盐胁迫反应相适应。本研究结果为进一步揭示OsHKT基因的作用机制奠定了基础。

【Objective】OsHKTs （High Affinity K＋ Transporter） encode Na＋ or K＋ transporter or Na＋-K＋ co-transporters that play an important role in Na＋ recirculation and maintaining the low concentration of Na＋ and low Na＋ / K＋ ratio in above-ground tissues, especially leaves. Therefore, OsHKT family is related to salt stress tolerance in rice. In this study, we analyzed the tissue specificity and diurnal rhythm of OsHKTs gene expression and expression patterns in rice seedlings treated with either salt or ABA. 【Method】 qRT-PCR technique was used to analyze OsHKTs expression patterns. 【Result】Individual member of OsHKT family genes had different expression levels in root and leaf. OsHKT1;1, OsHKT1;3, OsHKT2;3, and OsHKT2;4 mainly expressed in leaves, whereas other members had higher transcript levels in roots relative to those in leaves. Salt treatment affected transcript levels of OsHKT family genes both in leaves and roots. OsHKT1;5, OsHKT2;1, and OsHKT2;2 had similar expression patterns in both leaves and roots of seedlings treated with NaCl, whereas other members did not. Transcript levels of OsHKT family genes were regulated by ABA treatment either in leaves or in roots. OsHKT1;3 and OsHKT1;5 had similar expression patterns in both leaves and roots. In addition, expression patterns of OsHKT genes exhibited similar diurnal rhythm. 【Conclusion】Our results suggest that expression of OsHKT family genes has tissue-specificity and similar diurnal rhythm. Exogenous NaCl and ABA treatment have different influences on OsHKT transcripts, depending on individual member of the family. Our findings lay a foundation for further revealing the functional mechanism of OsHKT genes in rice.