Gene expression of ascorbic acid biosynthesis related enzymes of the Smirnoff-Wheeler pathway in acerola (Malpighia glabra)
Gene expression of ascorbic acid biosynthesis related enzymes of the Smirnoff-Wheeler pathway in acerola (Malpighia glabra)
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DOI：
10.1016/j.jplph.2008.09.004
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发表时间：
2009-01-01
影响因子：
4.3
通讯作者：
Esaka, Muneharu
中科院分区：
文献类型：
--
作者：
Badejo, Adebanjo A.;Fujikawa, Yukichi;Esaka, Muneharu
Smirnoff-Wheeler（SW）途径已被证明是模式植物拟南芥幼苗中L-抗坏血酸（阿萨;维生素C）的唯一重要来源。目前还不确定是否同样的途径适用于所有其他植物及其各种器官，因为AsA也可能通过其他途径合成。在这项研究中，我们克隆了一些涉及的SW-途径的基因，从针叶树（Malpighia glabra），含有大量的阿萨植物，并检查这些基因在植物中的表达模式。针叶树叶片中的阿萨含量比拟南芥高8倍左右，AsA合成基因的mRNA丰度比拟南芥高5-700倍。未成熟的果实具有最高的阿萨含量，但随着果实过渡到成熟，积累基本上受到抑制。这些基因的表达与果实中阿萨含量相关。虽然在种子中记录到非常少的阿萨，但在未成熟果实的种子中清楚地检测到编码所有基因的mRNA，除了位于果实中的L-半乳糖酸-1，4-内酯脱氢酶。在针叶树幼叶中，多数基因的表达受到黑暗的抑制，而受到光照的诱导。GDP-D-甘露糖焦磷酸化酶的表达与A.在黑暗中诱导拟南芥VTC 1。伤后24 h，各基因的表达量均出现高峰。这些发现将为研究金虎尾中丰富的阿萨生物合成的分子调控因子提供理论依据。(C)2008年Elsevier GmbH。All rights reserved.
The Smirnoff-Wheeler (SW) pathway has been proven to be the only significant source Of L-ascorbic acid (AsA; vitamin C) in the seedlings of the model plant Arabidopsis thaliana. It is yet uncertain whether the same pathway holds for all other plants and their various organs as AsA may also be synthesized through atternative pathways. In this study, we have cloned some of the genes involved in the SW-pathway from acerola (Malpighia glabra), a plant containing enormous amount of AsA, and examined the expression patterns of these genes in the plant. The AsA contents of acerola Leaves were about 8-fold more than that of Arabidopsis with 5-700-fold higher mRNA abundance in AsA-biosynthesizing genes. The unripe fruits have the highest AsA content but the accumulation was substantially repressed as the fruit transitions to maturation. The mRNAs encoding these genes showed correlation in their expression with the AsA contents of the fruits. Although very little AsA was recorded in the seeds the mRNAs encoding all the genes, with the exception of the mitochondrially Located L-galactono-1,4-lactone dehydrogenase, were clearly detected in the seeds of the unripe fruits. In young leaves of acerola, the expression of most genes were repressed by the dark and induced by light. However, the expression of GDP-D-mannose pyrophosphorylase similar to that encoded by A. thaliana VTC1 was induced in the dark. The expressions of all the genes surged after 24 h following wounding stress on the young Leaves. These findings will advance the investigation into the molecular factors regulating the biosynthesis of abundant AsA in acerola. (C) 2008 Elsevier GmbH. All rights reserved.