Dudareva N, Raguso R A, Wang J, Ross J R, Pichersky E
Department of Biology, University of Michigan, Ann Arbor 48109-1048, USA.
Plant Physiol. 1998 Feb;116(2):599-604. doi: 10.1104/pp.116.2.599.
The fragrance of Clarkia breweri (Onagraceae), a California annual plant, includes three benzenoid esters: benzylacetate, benzylbenzoate, and methylsalicylate. Here we report that petal tissue was responsible for the benzylacetate and methylsalicylate emission, whereas the pistil was the main source of benzylbenzoate. The activities of two novel enzymes, acetyl-coenzyme A:benzylalcohol acetyltransferase (BEAT), which catalyzes the acetyl esterification of benzylalcohol, and S-adenosyl-L-methionine:salicylic acid carboxyl methyltransferase, which catalyzes the methyl esterification of salicylic acid, were also highest in petal tissue and absent in leaves. In addition, the activity of both enzymes in the various floral organs was developmentally and differentially regulated. S-Adenosyl-L-methionine:salicylic acid carboxyl methyltransferase activity in petals peaked in mature buds and declined during the next few days after anthesis, and it showed a strong, positive correlation with the emission of methylsalicylate. The levels of BEAT activity and benzylacetate emission in petals also increased in parallel as the buds matured and the flowers opened, but as emission began to decline on the 2nd d after anthesis, BEAT activity continued to increase and remained high until the end of the lifespan of the flower.
加州一年生植物布鲁尔氏蝇子草（柳叶菜科）的花香包含三种苯酯类物质：乙酸苄酯、苯甲酸苄酯和水杨酸甲酯。在此我们报告，花瓣组织负责乙酸苄酯和水杨酸甲酯的释放，而雌蕊是苯甲酸苄酯的主要来源。两种新酶的活性，即催化苄醇乙酰酯化反应的乙酰辅酶A：苄醇乙酰转移酶（BEAT）和催化水杨酸甲酯酯化反应的S-腺苷-L-甲硫氨酸：水杨酸羧基甲基转移酶，在花瓣组织中也最高，而在叶片中不存在。此外，这两种酶在不同花器官中的活性受到发育调控且存在差异。花瓣中S-腺苷-L-甲硫氨酸：水杨酸羧基甲基转移酶的活性在成熟花蕾中达到峰值，并在开花后的接下来几天内下降，且与水杨酸甲酯的释放呈强烈正相关。随着花蕾成熟和花朵开放，花瓣中BEAT活性水平和乙酸苄酯释放也同步增加，但在开花后第2天释放开始下降时，BEAT活性继续增加并一直保持高水平，直到花朵寿命结束。
