海滨锦葵早期盐胁迫应答基因表达

Gene Expression of Kosteletzkya virginica in Response to Salt Stress at Early Stage

利用cDNA扩增片段长度多态性(cDNA amplified fragment length polymorphism,cDNA-AFLP)对盐胁迫下海滨锦葵早期根和叶片的基因差异表达进行了分析.结果表明,海滨锦葵早期盐胁迫应答基因的表达模式可以分为4类:抑制表达、重新诱导、上调表达和下调表达.对38个差异表达的盐胁迫应答基因片段进行了回收测序和BLASTX比对,其中34个差异表达片段与其他物种有高度同源性,4个差异表达片段为新基因片段.进一步对其中的6个差异表达基因的转录水平进行的实时RT-PCR相对定量分析,Avp1,Nhx1和Oat在根和叶中都上调表达;Gapdh和Pmp在根中下调表达而在叶中却上调表达;Chx1在根中上调表达而在叶中却下调表达.盐生植物海滨锦葵在盐胁迫的早期阶段可能通过细胞离子区域化以调节离子平衡外,还可能在整株水平上把钠离子区域化到根部.

Gene differential expression of Kosteletzkya virginica （L.） Presl seedling under salt stress in roots and leaves was analyzed using the cDNA-amplified fragment length polymorphism （cDNA-AFLP） technique. Polymorphic transcript-derived fragments （TDFs） between the control plants and salt-treated plants were grouped into four main differential expression patterns： repression, de novo induction, up-regulation, and down-regulation. Among them, 34 differentially expressed gene fragments were homologous to the known genes from other species and 4 were new sequences with unknown functions. These differen- tially expressed genes of K. virginica seedlings under salt stress can be classified into four groups according to their putative functions. The changes of six differentially expressed genes were selected and confirmed by quantitative real-time RT-PCR. The transcription of Avpl, Nhx1 and Oat is up-regulated in roots and leaves, mRNAs of Gapdh and Prop in leaves are up-regulated while down-regulated in roots. The transcription of Chx1 is up-regulated in roots while down-regulated in leaves. From the above results, it is speculated that salt tolerance in K. virginica seedlings is related with limiting Na^＋ level in leaves and accumulating Na^＋ in roots.