Galactone-γ-lactone-dependent ascorbate biosynthesis alters wheat kernel maturation
Galactone-γ-lactone-dependent ascorbate biosynthesis alters wheat kernel maturation
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DOI：
10.1111/j.1438-8677.2011.00543.x
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发表时间：
2012-07-01
期刊：
影响因子：
3.9
通讯作者：
De Gara, L.
中科院分区：
文献类型：
--
作者：
Paradiso, A.;de Pinto, M. C.;De Gara, L.
籽粒发育和成熟涉及几个特征性事件，如抗坏血酸（ASC）代谢，蛋白质合成和储存，淀粉胚乳的程序性细胞死亡（PCD）和组织脱水的变化。尽管有许多研究关注这些事件，但它们是否以及如何相互代谢相关，仍有待阐明。在本调查中，ASC相关的代谢，PCD发生，籽粒灌浆和脱水的变化进行了分析，在内核成熟，在正常条件下生长的植物和植物显示修改ASC合成超过3年的时间。所获得的结果表明，ASC起着关键的作用，在网络的事件表征内核成熟。在此过程中，ASC含量降低。当通过用其直接前体L-半乳糖内酯-γ-内酯（GL）喂养植物来改善籽粒中的ASC生物合成时，在籽粒成熟期间观察到的ASC的减少被延迟。因此，抗坏血酸过氧化物酶（APX）活性也增强。此外，延迟ASC减少允许延迟PCD发生在籽粒贮藏组织和籽粒脱水。有趣的是，从本研究中出现的数据表明，延迟ASC含量和APX活性的降低也改善了籽粒灌浆。相关的抗坏血酸依赖的氧化还原调节内核生产力进行了讨论。
Kernel development and maturation involve several well-characterised events, such as changes in ascorbate (ASC) metabolism, protein synthesis and storage, programmed cell death (PCD) of starchy endosperm and tissue dehydration. Despite many studies focusing on these events, whether and how they are metabolically related to each other, remains to be elucidated. In the present investigation, the changes in ASC-related metabolism, PCD occurrence, kernel filling and dehydration have been analysed during kernel maturation, over a 3-year period in plants grown under normal conditions and in plants displaying modified ASC synthesis. The obtained results suggest that ASC plays a pivotal role in the network of events characterising kernel maturation. During this process, a decrease in ASC content occurs. When ASC biosynthesis is improved in the kernel, by feeding the plants with its immediate precursor, L-galactone-gamma-lactone (GL), the decrease in ASC, observed during kernel maturation, is delayed. As a consequence, ascorbate peroxidase (APX) activity is also enhanced. Moreover, a delay in the ASC decrease permits a delay in PCD occurring in kernel storage tissues and in kernel dehydration. Interestingly, the data emerging from the present investigation suggest that the delay in the decrease in ASC content and APX activity also improves kernel filling. The relevance of the ascorbate-dependent redox regulation for kernel productivity is discussed.