Disruption of Adenosine-5′-Phosphosulfate Kinase in Arabidopsis Reduces Levels of Sulfated Secondary Metabolites
Disruption of Adenosine-5′-Phosphosulfate Kinase in Arabidopsis Reduces Levels of Sulfated Secondary Metabolites
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DOI：
10.1105/tpc.109.065581
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发表时间：
2009-03-01
期刊：
影响因子：
11.6
通讯作者：
Kopriva, Stanislav
中科院分区：
文献类型：
--
作者：
Mugford, Sarah G.;Yoshimoto, Naoko;Kopriva, Stanislav
植物对硫酸盐的代谢主要有两条途径，其中分支为5 '-磷酸硫酸腺苷（APS）。APS可以被还原成硫化物并在初级硫酸盐同化途径中掺入Cys中，或者被APS激酶磷酸化为3 '-磷酸腺苷5'-磷酸硫酸盐，这是硫酸化反应的活化硫酸盐形式。为了评估APS激酶在多大程度上调节硫酸化化合物的积累，我们分析了拟南芥中相应的基因家族。对四种亚型中的每一种的T-DNA插入敲除系的分析未揭示任何表型改变。然而，当比较所有六种双突变体组合时，apk 1/apk 2植物显著小于野生型植物。硫代葡萄糖苷的水平，硫酸化的次生代谢产物的主要类别，和硫酸化的12-羟基茉莉酮酸酯在apk 1 apk 2植物减少约5倍。虽然生长素水平增加apk 1 apk 2突变体，是大多数植物的情况下与受损的芥子油苷合成，典型的高生长素表型没有观察到。硫代葡萄糖苷的减少导致参与硫代葡萄糖苷生物合成和代谢前体积累的基因的转录水平增加。它也导致硫代谢的巨大改变：apk 1和apk 2植物中硫酸盐和硫醇的水平增加。这些数据表明，APK 1和APK 2的APS激酶亚型发挥了重要作用，在合成的次生硫酸代谢产物和所需的正常生长率。
Plants can metabolize sulfate by two pathways, which branch at the level of adenosine 5'-phosphosulfate (APS). APS can be reduced to sulfide and incorporated into Cys in the primary sulfate assimilation pathway or phosphorylated by APS kinase to 3'-phosphoadenosine 5'-phosphosulfate, which is the activated sulfate form for sulfation reactions. To assess to what extent APS kinase regulates accumulation of sulfated compounds, we analyzed the corresponding gene family in Arabidopsis thaliana. Analysis of T-DNA insertion knockout lines for each of the four isoforms did not reveal any phenotypical alterations. However, when all six combinations of double mutants were compared, the apk1 apk2 plants were significantly smaller than wild-type plants. The levels of glucosinolates, a major class of sulfated secondary metabolites, and the sulfated 12-hydroxyjasmonate were reduced approximately fivefold in apk1 apk2 plants. Although auxin levels were increased in the apk1 apk2 mutants, as is the case for most plants with compromised glucosinolate synthesis, typical high auxin phenotypes were not observed. The reduction in glucosinolates resulted in increased transcript levels for genes involved in glucosinolate biosynthesis and accumulation of desulfated precursors. It also led to great alterations in sulfur metabolism: the levels of sulfate and thiols increased in the apk1 apk2 plants. The data indicate that the APK1 and APK2 isoforms of APS kinase play a major role in the synthesis of secondary sulfated metabolites and are required for normal growth rates.