Swain S M, Tseng T S, Olszewski N E
Department of Plant Biology and Plant Molecular Genetics Institute, University of Minnesota, St. Paul, Minnesota 55108, USA.
Plant Physiol. 2001 Jul;126(3):1174-85. doi: 10.1104/pp.126.3.1174.
Gibberellins (GAs) are plant hormones with diverse roles in plant growth and development. SPINDLY (SPY) is one of several genes identified in Arabidopsis that are involved in GA response and it is thought to encode an O-GlcNAc transferase. Genetic analysis suggests that SPY negatively regulates GA response. To test the hypothesis that SPY acts specifically as a negatively acting component of GA signal transduction, spy mutants and plants containing a 35S:SPY construct have been examined. A detailed investigation of the spy mutant phenotype suggests that SPY may play a role in plant development beyond its role in GA signaling. Consistent with this suggestion, the analysis of spy er plants suggests that the ERECTA (ER) gene, which has not been implicated as having a role in GA signaling, appears to enhance the non-GA spy mutant phenotypes. Arabidopsis plants containing a 35S:SPY construct possess reduced GA response at seed germination, but also possess phenotypes consistent with increased GA response, although not identical to spy mutants, during later vegetative and reproductive development. Based on these results, the hypothesis that SPY is specific for GA signaling is rejected. Instead, it is proposed that SPY is a negative regulator of GA response that has additional roles in plant development.
赤霉素（GAs）是一类在植物生长和发育过程中具有多种作用的植物激素。SPINDLY（SPY）是在拟南芥中鉴定出的几个参与GA反应的基因之一，据认为它编码一种O-连接的N-乙酰葡糖胺转移酶。遗传分析表明，SPY对GA反应起负调控作用。为了验证SPY作为GA信号转导的负向作用成分这一假说，对spy突变体和含有35S:SPY构建体的植株进行了研究。对spy突变体表型的详细研究表明，SPY可能在植物发育中发挥作用，且超出了其在GA信号传导中的作用。与此观点一致，对spy er植株的分析表明，尚未发现参与GA信号传导的ERECTA（ER）基因似乎增强了非GA的spy突变体表型。含有35S:SPY构建体的拟南芥植株在种子萌发时GA反应降低，但在后期营养和生殖发育过程中也表现出与GA反应增强一致的表型，尽管与spy突变体不同。基于这些结果，SPY对GA信号传导具有特异性的假说被否定。相反，有人提出SPY是GA反应的负调控因子，在植物发育中还具有其他作用。
