Guilfoyle T J
University of Missouri, Department of Biochemistry, Columbia 65203, USA.
ASGSB Bull. 1995 Oct;8(2):39-45.
Transcription of two gene families, SAURs and GH3, in soybean has been shown to be specifically induced by the plant hormone auxin. The SAUR mRNAs have been shown to accumulate on the lower half and disappear from the upper half of soybean hypocotyls during gravitropic curvature. The SAUR and GH3 promoters have been fused to the beta-glucuronidase (GUS) reporter gene and shown to be specifically induced by auxins in transgenic tobacco plants. Histochemical staining and quantitative GUS assays indicate that these auxin inducible promoters are activated on the lower half of transgenic tobacco stems undergoing gravitropic curvature. The auxin transport inhibitors, TIBA and NPA, block both gravitropic curvature and the activation of the auxin responsive promoters in transgenic tobacco stems. The auxin responsive elements (AuxREs) within the SAUR and GH3 promoters have been identified, and these AuxREs are likely to be the elements that are responsible for the increased expression of the SAUR and GH3 genes during gravitropism.
大豆中两个基因家族SAURs和GH3的转录已被证明受到植物激素生长素的特异性诱导。SAUR mRNA已被证明在大豆下胚轴重力弯曲过程中在下半部分积累并从上半部分消失。SAUR和GH3启动子已与β-葡萄糖醛酸酶（GUS）报告基因融合，并在转基因烟草植株中显示出受生长素特异性诱导。组织化学染色和定量GUS分析表明，这些生长素诱导型启动子在经历重力弯曲的转基因烟草茎的下半部分被激活。生长素运输抑制剂TIBA和NPA可阻断转基因烟草茎中的重力弯曲和生长素响应启动子的激活。SAUR和GH3启动子中的生长素响应元件（AuxREs）已被鉴定，这些AuxREs可能是重力作用期间SAUR和GH3基因表达增加的原因。
