Elucidation of modification mechanism of secondary metabolites in plant vacuoles.

在单子叶植物长春花中发现了AAGT基因，拟南芥的AAGT基因与红叶中的糖基残基作用于花青素，表明AAGT反应在植物界中普遍存在。在飞燕草的萼片中，花青素的7位修饰时，对羟基苄基葡萄糖(PHBG)作为葡萄糖供体。紫草酚花色苷由三个糖基和两个对羟基苯基(PHBA)残基组成，由糖基和PHBA-残基交替串联和线性连接而成。在生成紫草酚的反应中，pHBG作为酰基葡萄糖依赖的酰基转移酶的酰基供体和葡萄糖供体，AAGT作为Zwitter的供体。鉴定了UDP-葡萄糖依赖的pHBA葡萄糖基转移酶基因，该酶活性的丧失导致花青素的7位不发生修饰。

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.