Elucidation of modification mechanism of secondary metabolites in plant vacuoles.

在单子叶植物Agapanthus中发现了酰基葡萄糖依赖性葡萄糖基转移酶（AAGT）基因，拟南芥AAGT在变红叶片中通过葡萄糖基残基作用于酰基修饰的花青素，表明AAGT反应在植物界很常见。在飞鸽萼片中，对羟基苄基葡萄糖（pHBG）在花青素7位的修饰上起葡萄糖基供体的作用。花青素violdelphin由3个糖基和2个对羟基苯基（pHBA）残基组成，通过糖基和pHBA残基交替串联和线性偶联的方式偶联。在形成violdelphin的反应中，发现pHBG作为酰基-葡萄糖依赖性酰基转移酶的酰基供体和葡萄糖供体具有双重功能，AAGT作为Zwitter供体。发现了udp -葡萄糖依赖性pHBA葡萄糖基转移酶的基因，该基因的丧失导致花青素7位不修饰。

Acyl-glucose dependent glucosyltransfrase (AAGT) gene was found in a monocot plant, Agapanthus, and Arabidopsis AAGT acted to acyl-modified anthocyanin with glucosyl residues in red turning leaves, indicating that AAGT reaction is common in the plant kingdom. In delphinium sepals, p-hydroxybenzyl-glucose (pHBG) acted as a glucosyl-donor at modification at the 7 position of anthocyanidin. The anthocyanin, violdelphin, consisted of three glycosyl and two p-hydroxybenzyl (pHBA)-residues, conjugated with alternately tandem and linear conjugation of glycosyl and pHBA-residues. In the reaction to form violdelphin, it was revealed that pHBG played a bi-functional role to be acyl donors and glucosyl donors for acyl-glucose dependent acyl-transferase and AAGT as Zwitter donor. The gene for UDP-glucose dependent pHBA glucosyltransferase was identified and the loss of this activity resulted not to modify at the 7 position of anthocyanidin.