玉米素
生物
细胞分裂素
生物化学
代谢物
新陈代谢
酶
嘌呤
糖基转移酶
生长素
植物
基因
作者
Tomáš Hluska,Petre I. Dobrev,Danuše Tarkowská,Jitka Frébortová,David Zalabák,David Kopečný,Ondřej Plíhal,Filip Kokáš,Pierre Briozzo,Marek Zatloukal,Václav Motyka,Petr Galuszka
出处
期刊:Plant Science
[Elsevier]
日期:2016-06-01
卷期号:247: 127-137
被引量:24
标识
DOI:10.1016/j.plantsci.2016.03.014
摘要
Cytokinins (CKs) are an important group of phytohormones. Their tightly regulated and balanced levels are essential for proper cell division and plant organ development. Here we report precise quantification of CK metabolites and other phytohormones in maize reproductive organs in the course of pollination and kernel maturation. A novel enzymatic activity dependent on NADP(+) converting trans-zeatin (tZ) to 6-(3-methylpyrrol-1-yl)purine (MPP) was detected. MPP shows weak anticytokinin properties and inhibition of CK dehydrogenases due to their ability to bind to an active site in the opposite orientation than substrates. Although the physiological significance of tZ side-chain cyclization is not anticipated as the MPP occurrence in maize tissue is very low, properties of the novel CK metabolite indicate its potential for utilization in plant in vitro tissue culture. Furthermore, feeding experiments with different isoprenoid CKs revealed distinct preferences in glycosylation of tZ and cis-zeatin (cZ). While tZ is preferentially glucosylated at the N9 position, cZ forms mainly O-glucosides. Since O-glucosides, in contrast to N9-glucosides, are resistant to irreversible cleavage catalyzed by CK dehydrogenases, the observed preference of maize CK glycosyltransferases to O-glycosylate zeatin in the cis-position might be a reason why cZ derivatives are over-accumulated in different maize tissues and organs.
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