Chandler PM, Robertson M
Commonwealth Scientific and Industrial Research Organization Plant Industry, G.P.O. Box 1600, Canberra, ACT 2601, Australia.
Plant Physiol. 1999 Jun;120(2):623-32. doi: 10.1104/pp.120.2.623.
Dose-response curves relating gibberellin (GA) concentration to the maximal leaf-elongation rate (LERmax) defined three classes of recessive dwarf mutants in the barley (Hordeum vulgare L.) 'Himalaya. ' The first class responded to low (10(-8)-10(-6) M) [GA3] (as did the wild type). These grd (GA-responsive dwarf) mutants are likely to be GA-biosynthesis mutants. The second class of mutant, gse (GA sensitivity), differed principally in GA sensitivity, requiring approximately 100-fold higher [GA3] for both leaf elongation and alpha-amylase production by aleurone. This novel class may have impaired recognition between the components that are involved in GA signaling. The third class of mutant showed no effect of GA3 on the LERmax. When further dwarfed by treatment with a GA-biosynthesis inhibitor, mutants in this class did respond to GA3, although the LERmax never exceeded that of the untreated dwarf. These mutants, called elo (elongation), appeared to be defective in the specific processes that are required for elongation rather than in GA signaling. When sln1 (slender1) was introduced into these different genetic backgrounds, sln was epistatic to grd and gse but hypostatic to elo. Because the rapid leaf elongation typical of sln was observed in the grd and gse backgrounds, we inferred that rapid leaf elongation is the default state and suggest that GA action is mediated through the activity of the product of the Sln gene.
将赤霉素（GA）浓度与大麦（Hordeum vulgare L.）“喜马拉雅”品种中最大叶片伸长率（LERmax）相关的剂量反应曲线定义了三类隐性矮化突变体。第一类对低浓度（10^(-8)-10^(-6) M）的[GA3]有反应（野生型也是如此）。这些grd（GA反应性矮化）突变体可能是GA生物合成突变体。第二类突变体gse（GA敏感性），主要在GA敏感性方面有所不同，叶片伸长和糊粉层产生α-淀粉酶都需要大约高100倍的[GA3]。这一新类可能在GA信号传导所涉及的成分之间的识别上存在缺陷。第三类突变体显示GA3对LERmax没有影响。当用GA生物合成抑制剂处理使其进一步矮化时，这类突变体确实对GA3有反应，尽管LERmax从未超过未处理矮化植株的LERmax。这些被称为elo（伸长）的突变体，似乎在伸长所需的特定过程中存在缺陷，而不是在GA信号传导方面。当将sln1（slender1）导入这些不同的遗传背景时，sln对grd和gse是上位性的，但对elo是下位性的。因为在grd和gse背景中观察到了典型的sln快速叶片伸长，我们推断快速叶片伸长是默认状态，并表明GA作用是通过Sln基因产物的活性介导的。
