MacNicol Peter K., Jacobsen John V.
CSIRO Division of Plant Industry, P.O. Box 1600, Canberra, ACT 2601, Australia.
Physiol Plant. 2001 Apr;111(4):533-539. doi: 10.1034/j.1399-3054.2001.1110414.x.
The expression of the Adh1 gene (alcohol dehydrogenase, EC 1.1.1.1) was studied in the aleurone layer of barley (Hordeum vulgare cv. Himalaya). Expression increased markedly during grain development at the levels of activity, enzyme protein and mRNA. mRNA content, but not enzyme activity, could be increased further by exogenous abscisic acid (ABA) when isolated, de-embryonated developing grains were pre-treated with gibberellic acid (GA3) or fluridone. In isolated mature aleurone layers incubated with exogenous hormones, ADH mRNA was strongly up-regulated by ABA and down-regulated by GA3 within 6 h. With ABA, this increase in mRNA was followed by an increase in ADH protein and activity, peaking at 18 h. With GA3, the decrease in mRNA was accompanied by simultaneous decreases in protein and activity. In general, GA3 counteracted the effect of ABA and vice versa. In the aleurone of germinating grain, ADH activity decayed in a distal direction from the embryo, consistent with down-regulation by gibberellin(s) diffusing from it. It was concluded that ADH gene expression in the aleurone of the intact grain is regulated by an ABA/gibberellin interaction.
对大麦（青稞品种喜马拉雅）糊粉层中乙醇脱氢酶1基因（Adh1，乙醇脱氢酶，EC 1.1.1.1）的表达进行了研究。在籽粒发育过程中，该基因在活性、酶蛋白和mRNA水平上的表达均显著增加。当用赤霉素（GA3）或氟啶酮对分离的、去胚的发育籽粒进行预处理后，外源脱落酸（ABA）可进一步提高mRNA含量，但不能提高酶活性。在与外源激素一起孵育的分离成熟糊粉层中，ABA在6小时内强烈上调ADH mRNA，而GA3则下调ADH mRNA。使用ABA时，mRNA的这种增加随后是ADH蛋白和活性的增加，在18小时达到峰值。使用GA3时，mRNA的减少伴随着蛋白质和活性的同时降低。一般来说，GA3抵消了ABA的作用，反之亦然。在发芽籽粒的糊粉层中，ADH活性从胚部向远端衰减，这与从胚部扩散的赤霉素对其下调作用一致。研究得出结论，完整籽粒糊粉层中ADH基因的表达受ABA/赤霉素相互作用的调控。
