In situ expression of trehalose synthesizing genes, TPS1 and TPPB, in Arabidopsis thaliana using the GUS reporter gene
In situ expression of trehalose synthesizing genes, TPS1 and TPPB, in Arabidopsis thaliana using the GUS reporter gene
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DOI：
10.1007/s11240-009-9565-3
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发表时间：
2009-09-01
影响因子：
3
通讯作者：
Bailey, Bryan
中科院分区：
文献类型：
--
作者：
Bae, Hanhong;Sicher, Richard;Bailey, Bryan
使用含有β-葡萄糖醛酸酶（GUS）报告基因的构建体，获得了表达AtTPS 1（At 1g 78580）或AtTPPB（At 1g 78090）启动子区的两个转基因拟南芥品系。这两个基因的功能串联产生二糖，海藻糖，他们可能在高等植物中具有重要的调控和信号功能。这两个基因在拟南芥中几乎组成型表达，并且在较年轻的组织中表达较高，并且通常随着年龄的增长而减少。在黄化和光生长的幼苗中观察到两种启动子的相似表达模式。在第1天的萌发过程中观察到这两个基因的密集表达，但在3天后的下胚轴中没有表达。与AtTPS 1相反，AtTPPB的表达集中在7天龄光生长幼苗的根分生组织中。AtTPS 1和AtTPPB的表达主要观察到年轻的，积极分裂的组织，如茎尖，并在花的部分，包括花药，雌蕊，角果和发育中的种子。这两个基因的表达也清楚地与维管束，根下胚轴交界处，花梗角果交界处和相关结构参与散装溶质运输。AtTPS 1和AtTPPB的转录水平被抑制或很少受到外源蔗糖，葡萄糖，果糖或海藻糖的影响时，通过定量实时PCR测量。然而，这两个海藻糖生物合成基因被山梨醇、甘露醇和NaCl诱导2至10倍。AtTPS 1和AtTPPB对相同的化学和胁迫处理的反应没有检测到GUS活性的变化。这可能是由于GUS蛋白相对于转录水平的稳定性。由于AtTPS 1和AtTPPB串联功能产生海藻糖，因此这两个基因的表达在拟南芥组织中分布相似并不奇怪。
Two transgenic Arabidopsis lines were derived that expressed promoter regions for either AtTPS1 (At1g78580) or AtTPPB (At1g78090) using constructs containing the beta-glucuronidase (GUS) reporter gene. These two genes function in tandem to produce the disaccharide, trehalose, and they likely have important regulatory and signaling functions in higher plants. Both genes were expressed nearly constitutively in Arabidopsis and expression was high in younger tissue and typically diminished with age. Similar expression patterns for both promoters were observed in etiolated and in light grown seedlings. Dense expression of both genes was observed during germination on day 1 but expression was absent from hypocotyls 3 days later. In contrast to AtTPS1, the expression of AtTPPB was concentrated in the root meristem of 7-day old light grown seedlings. The expression of both AtTPS1 and AtTPPB was mainly observed in young, actively dividing tissues, such as the shoot apex, and in flower parts including anthers, pistils, siliques and developing seeds. Expression of both genes also was clearly associated with vascular bundles, the root-hypocotyl junction, the pedicel-silique junction and related structures involved in bulk solute transport. Transcript levels of AtTPS1 and AtTPPB were either repressed or were little affected by exogenous sucrose, glucose, fructose or trehalose when measured by quantitative real-time PCR. However, both trehalose biosynthesis genes were induced two to tenfold by sorbitol, mannitol and NaCl. Responses of AtTPS1 and AtTPPB to the same chemical and stress treatments were not detected by changes in GUS activity. This may be due to the stability of the GUS protein relative to transcript levels. Because AtTPS1 and AtTPPB function in tandem to produce trehalose it was not surprising that the expression of both genes was distributed similarly in Arabidopsis tissues.