Sadka A., DeWald D. B., May G. D., Park W. D., Mullet J. E.
Department of Biochemistry and Biophysics, Texas A & M University, College Station, Texas 77843-2128.
Plant Cell. 1994 May;6(5):737-749. doi: 10.1105/tpc.6.5.737.
The soybean vegetative storage protein genes VspA and VspB encode vacuolar glycoprotein acid phosphatases. Transcription of the Vsp is synergistically activated by jasmonic acid or methyl jasmonate (MeJA) and soluble sugars. The action of these modulators is mediated by two different DNA domains in the VspB promoter. In this study, we present new data regarding VspB regulation by sucrose and inorganic phosphate, which suggest a common mechanism of transcriptional control for Vsp and other sugar-inducible genes. We found that the sugar-mediated activation of VspB expression was inhibited by phosphate. Deletion analysis and transient assays in tobacco protoplasts identified a 130-bp DNA domain in the VspB promoter that mediates both sucrose induction and phosphate inhibition. Transcription mediated by this DNA domain was induced by phosphate elimination from the protoplast incubation medium, even in the absence of sucrose. The effect of sucrose and phosphate on VspB expression was studied in vivo in several ways. Depletion of phosphate from soybean cell cultures by the addition of mannose stimulated VspB expression, even in the absence of sucrose or MeJA. In illuminated soybean leaves treated with MeJA, inhibition of photosynthetic electron transport by DCMU decreased VspB expression. In contrast, VspB expression in soybean leaves stimulated by phosphate depletion was not influenced by DCMU. Moreover, sucrose-stimulated expression of the sugar-responsive genes lipoxygenase A and chalcone synthase of soybean and proteinase inhibitor II and class I patatin of potato was inhibited by phosphate. Like VspB, these genes were stimulated by phosphate depletion in the absence of exogenous sucrose. We propose that sugar-responsive genes are activated, in part, by accumulation of sugar-phosphates and concomitant reduction of cellular phosphate levels. These data may help explain recruitment of the Vsp, which encode acid phosphatases, as vegetative storage proteins.
大豆营养贮藏蛋白基因VspA和VspB编码液泡糖蛋白酸性磷酸酶。Vsp的转录由茉莉酸或茉莉酸甲酯（MeJA）和可溶性糖协同激活。这些调节剂的作用由VspB启动子中的两个不同DNA结构域介导。在本研究中，我们提供了关于蔗糖和无机磷酸盐对VspB调控的新数据，这表明Vsp和其他糖诱导基因存在共同的转录控制机制。我们发现磷酸盐抑制了糖介导的VspB表达激活。烟草原生质体中的缺失分析和瞬时分析确定了VspB启动子中的一个130 bp DNA结构域，该结构域介导蔗糖诱导和磷酸盐抑制。即使在没有蔗糖的情况下，从原生质体孵育培养基中去除磷酸盐也能诱导该DNA结构域介导的转录。通过几种方式在体内研究了蔗糖和磷酸盐对VspB表达的影响。通过添加甘露糖耗尽大豆细胞培养物中的磷酸盐，即使在没有蔗糖或MeJA的情况下也能刺激VspB表达。在用MeJA处理的光照大豆叶片中，DCMU对光合电子传递的抑制降低了VspB表达。相反，磷酸盐耗尽刺激的大豆叶片中VspB表达不受DCMU影响。此外，磷酸盐抑制了大豆糖响应基因脂氧合酶A和查尔酮合酶以及马铃薯蛋白酶抑制剂II和I类patatin的蔗糖刺激表达。与VspB一样，在没有外源蔗糖的情况下，这些基因受到磷酸盐耗尽的刺激。我们提出，糖响应基因部分地通过糖磷酸盐的积累和细胞磷酸盐水平的相应降低而被激活。这些数据可能有助于解释编码酸性磷酸酶的Vsp作为营养贮藏蛋白的募集。
