盐处理下ZxSOS1调控旱生植物霸王Na~＋、K~＋转运蛋白基因的表达

ZxSOS1 Regulates the Expression of Genes Encoding Na^+, K^+ Channels or Transporters in the Xerophyte Zygophyllum xanthoxylum under Salt Condition

本研究以多浆旱生植物霸王(Zygophyllum xanthoxylum)野生型(WT)及质膜Na+/H+逆向转运蛋白基因ZxSOS1-RNAi(RNA干扰)株系(L9)为材料,采用实时荧光定量PCR的方法分析了ZxSOS1被干扰后,霸王各组织中参与Na+、K+转运的重要通道或转运蛋白编码基因表达丰度的变化。结果显示,50 mmol·L-1 NaCl处理下,随处理时间延长,WT和L9根和茎中ZxSOS1和ZxSKOR、叶中ZxSOS1、ZxNHX和ZxVP1的表达丰度逐渐增加;ZxHKT1;1和ZxAKT1在WT根中的表达丰度呈增加趋势,而在L9根中则呈降低趋势;盐处理48 h后,L9株系中上述各基因的表达丰度均显著低于WT。由此从基因表达水平解析了ZxSOS1-RNAi株系叶和茎中Na+的分配比例显著下降、根中显著增加,而K+在其叶和根中的分配比例下降、茎中显著增加的调控机制。可见,ZxSOS1可通过调节各组织中参与Na+、K+转运的重要通道或转运蛋白编码基因的表达以调控霸王体内Na+、K+转运、空间分配和稳态平衡,进而调节植株的生长。

Wild type （WT） and ZxSOS1-RNAi plants of the succulent xerophyte Zygophyllum xanthoxylum, were used to examine the changes of genes encoding important Na＋, K＋ channels or transporters in different tissues. The results showed that, under 50 mmol·L^-1 NaC1, the expression levels of ZxSOS1 and ZxSKOR in roots and stems, ZxSOS1, ZxNHX and ZxVP1 in leaves in both WT and L9 were gradually increased; the expression levels of ZxHKT1;1 and ZxAKT1 were gradually increased in roots of WT but decreased in roots of L9; the expression levels of above genes were significantly lower in L9 than that in WT at 48 h under 50 mmol·L^-1 NaCl. These results provide an adequate explanation of why ZxSOSl-silenced plants accumulated more Na~ in their roots but less Na~ in leaves and stems and also showed a decreased spatial distribution of K~ in leaves and roots but an increased K＋ spatial distribution in stems than WT under 50 mmol·L^-1 NaCl at gene expression level, and meanwhile, demonstrate that, under salt treatment, ZxSOS1 is involved in the long-distance transport, spatial distribution and homeostasis of Na＋, K＋ by regulating the expression level of genes encoding important Na＋, K＋ channels or transporters in Z. xanthoxylum.