Ezura H, Harberd N P
Department of Molecular Genetics, John Innes Centre, Norwich, UK.
Planta. 1995;197(2):301-5. doi: 10.1007/BF00202651.
The regeneration of shoot buds from callus cells in vitro is an important technique in modern plant genetic manipulation. Whilst it is clear that genetic factors play a major role in determining the ability of callus cells to become organized into regenerating shoot buds, the precise nature of these factors remains unknown. Here we show that callus derived from mutants of Arabidopsis thaliana which have reduced levels of endogenous bioactive gibberellins (GAs), or reduced responsivity to GAs, regenerates shoot buds more readily than does callus derived from wild-type controls. In addition, exogenous GA reduces, and exogenous paclobutrazol (a GA-bio-synthesis inhibitor) increases, the frequency of shoot bud regeneration from wild-type callus. These results show that GA levels play a role in regulating shoot bud regeneration from callus, and suggest that variation in endogenous GA levels or responsivity may account for a major component of the genetic variation in shoot bud regeneration frequency described in other species.
体外从愈伤组织细胞再生出芽是现代植物基因操作中的一项重要技术。虽然很明显遗传因素在决定愈伤组织细胞形成再生芽的能力方面起主要作用，但这些因素的确切性质仍然未知。在这里我们表明，来自拟南芥突变体的愈伤组织，其内源生物活性赤霉素（GA）水平降低，或对GA的反应性降低，比来自野生型对照的愈伤组织更容易再生出芽。此外，外源GA降低了野生型愈伤组织的出芽频率，而外源多效唑（一种GA生物合成抑制剂）则增加了出芽频率。这些结果表明GA水平在调节愈伤组织的出芽再生中起作用，并表明内源GA水平或反应性的变化可能是其他物种中描述的出芽再生频率遗传变异的主要组成部分。
