Gilroy S.
Biology Department, Pennsylvania State University, 208 Mueller Laboratory, University Park, Pennsylvania 16802.
Plant Cell. 1996 Dec;8(12):2193-2209. doi: 10.1105/tpc.8.12.2193.
Gibberellic acid (GA) increases Ca2+ and calmodulin (CaM) levels in barley aleurone cells, and abscisic acid (ABA) antagonizes the GA effect. These alterations in cytoplasmic Ca2+ and CaM have been suggested to be central regulators of the secretory response of the barley aleurone. Using microinjection of caged Ca2+, Ca2+ chelators, and CaM, we mimicked or blocked these hormonally induced changes in Ca2+ and CaM and assessed their effects on GA and ABA action. Although mimicking GA-induced changes in Ca2+ and CaM did not mimic GA action, blocking these changes did prevent GA stimulation of secretion. The induction of the amylase gene by GA was, however, unaffected. Similarly, blocking the decrease in Ca2+ normally caused by ABA in these cells blocked ABA action, except that induction of Em gene transcription by ABA was unaffected. These results suggest that GA and ABA signals are transduced by Ca2+- and CaM-dependent and Ca2+- and CaM-independent systems in the aleurone cell.
赤霉素（GA）可提高大麦糊粉层细胞中的钙离子（Ca2+）和钙调蛋白（CaM）水平，而脱落酸（ABA）则拮抗GA的作用。细胞质中Ca2+和CaM的这些变化被认为是大麦糊粉层分泌反应的核心调节因子。通过显微注射笼形Ca2+、Ca2+螯合剂和CaM，我们模拟或阻断了这些激素诱导的Ca2+和CaM变化，并评估了它们对GA和ABA作用的影响。尽管模拟GA诱导的Ca2+和CaM变化并不能模拟GA的作用，但阻断这些变化确实能阻止GA对分泌的刺激。然而，GA对淀粉酶基因的诱导不受影响。同样，阻断这些细胞中通常由ABA引起的Ca2+减少会阻断ABA的作用，不过ABA对Em基因转录的诱导不受影响。这些结果表明，GA和ABA信号在糊粉层细胞中通过Ca2+和CaM依赖以及Ca2+和CaM非依赖系统进行转导。
