Lewis David, Bradley Marie, Bloor Stephen, Swinny Ewald, Deroles Simon, Winefield Chris, Davies Kevin
New Zealand Institute for Crop & Food Research Limited, Private Bag 11-600, Palmerston North, New Zealand.
New Zealand Institute for Industrial Research and Development, Gracefield Research Centre, PO Box 31-310, Lower Hutt, New Zealand.
Funct Plant Biol. 2006 Dec;33(12):1141-1152. doi: 10.1071/FP06181.
Antisense technology was successfully used to reduce flavonoid 3'-hydroxylase (F3'H) gene expression and enzyme activity and to promote the accumulation of monohydroxylated flavonols in petunia flower tissue. The hydroxylation pattern of specific flavonoid groups is a target for modification because of the possible associated changes in a range of factors including colour, stress tolerance and reproductive viability. Petunia (cv. Mitchell) plants were transformed to express in the antisense orientation the sequences encoding the F3'H (asF3'H). Transformants showed a range of responses, in terms of the level of endogenous F3'H gene expression and the relative proportion of the monohydroxylated flavonol (kaempferol) glycosides that accumulated. Kaempferol glycosides increased from 7% of the total flavonols in flower limb tissue of the wild type plants, to 45% in the flower limb tissue of line 114, the transgenic line that also showed the greatest decrease in F3'H expression in flower tissue. In leaf tissue, the trend was for a decrease in total flavonol concentration, with the relative proportion of kaempferol glycosides varying from ~40 to 80% of the total flavonols. The changes in leaf tissue were not consistent with the changes observed in flower tissue of the same lines. Endogenous F3'H activity in flower limb tissue was not completely shut down, although an 80% decrease in enzyme activity was recorded for line 114. The residual F3'H activity was still sufficient that quercetin glycosides remained as the major flavonol form. Alteration of F3'H activity appears to have affected overall flavonoid biosynthesis. A decrease in total flavonol concentration was observed in leaf tissue and two other flavonoid biosynthetic genes were down-regulated. No morphological changes were observed in the transgenic plants; however, up to a 60% decrease in pollen germination was observed in line 13. Thus, the relatively small change in flavonoid biosynthesis induced by the asF3'H transgene, correlated with several other effects beyond just the specific biosynthetic step regulated by this enzyme.
反义技术已成功用于降低矮牵牛花朵组织中黄酮类3'-羟化酶（F3'H）基因的表达和酶活性，并促进单羟基黄酮醇的积累。特定黄酮类基团的羟基化模式是修饰的目标，因为一系列因素（包括颜色、胁迫耐受性和繁殖活力）可能会发生相关变化。将矮牵牛（品种Mitchell）植株进行转化，使其以反义方向表达编码F3'H的序列（asF3'H）。就内源F3'H基因表达水平和积累的单羟基黄酮醇（山奈酚）糖苷的相对比例而言，转化体表现出一系列反应。山奈酚糖苷在野生型植株花朵边缘组织中的黄酮醇总量中占7%，在114系（该转基因系在花朵组织中F3'H表达下降幅度最大）的花朵边缘组织中增至45%。在叶片组织中，总黄酮醇浓度呈下降趋势，山奈酚糖苷的相对比例在总黄酮醇的约40%至80%之间变化。叶片组织中的变化与同系花朵组织中观察到的变化不一致。花朵边缘组织中的内源F3'H活性并未完全关闭，尽管114系的酶活性下降了80%。剩余的F3'H活性仍然足以使槲皮素糖苷作为主要的黄酮醇形式保留下来。F3'H活性的改变似乎影响了整体黄酮类生物合成。在叶片组织中观察到总黄酮醇浓度下降，另外两个黄酮类生物合成基因也被下调。转基因植株未观察到形态变化；然而，13系的花粉萌发率下降了60%。因此，asF3'H转基因诱导的黄酮类生物合成相对较小的变化，与除该酶调控的特定生物合成步骤之外的其他几种效应相关。
