L-Ascorbic acid accumulation in fruit of Ribes nigrum occurs by in situ biosynthesis via the L-galactose pathway
L-Ascorbic acid accumulation in fruit of Ribes nigrum occurs by in situ biosynthesis via the L-galactose pathway
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DOI：
10.1071/fp07221
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发表时间：
2007-01-01
影响因子：
3
通讯作者：
Viola, Roberto
中科院分区：
文献类型：
--
作者：
Hancock, Robert D.;Walker, Paul G.;Viola, Roberto
黑加仑(Ribes ngrum L.)是一种广泛种植的经济作物，因其维生素C(L-抗坏血酸)含量高而珍贵。本研究对果实的积累机理进行了系统的分析。AsA的积累发生在果实膨大期间，并与高的L-半乳糖途径的原位生物合成能力和低的周转速率有关。停止AsA的积累与生物合成减少和周转增加有关。光合作用或营养组织中AsA的转运对果实AsA的积累贡献不大。落叶处理对果实AsA浓度没有影响，但显著降低了果实产量。向完好的果实供应抗坏血酸前体L-半乳糖基-1，4-内酯可瞬间提高果实抗坏血酸浓度，在去除该化合物后迅速恢复到对照水平。这些数据表明，黑加仑果实中AsA的积累受到很强的发育、代谢和遗传控制，并预示着培育高AsA品种的潜力。
Blackcurrant (Ribes nigrum L.) is a widely grown commercial crop valued for its high vitamin C (L-ascorbic acid, AsA) content. In the present study, a systematic analysis of the mechanism of fruit AsA accumulation was undertaken. AsA accumulation occurred during fruit expansion and was associated with high in situ biosynthetic capacity via the L-galactose pathway and low rates of turnover. Cessation of AsA accumulation was associated with reduced biosynthesis and increased turnover. Translocation of AsA from photosynthetic or vegetative tissues contributed little to fruit AsA accumulation. Manipulation of substrate availability by defoliation had no effect on fruit AsA concentration but significantly reduced fruit yields. Supply of the AsA precursor L-galactono-1,4-lactone to intact, attached fruit transiently increased fruit AsA concentration which rapidly returned to control levels after removal of the compound. These data suggest strong developmental, metabolic and genetic control of AsA accumulation in blackcurrant fruit and indicate the potential for breeding high AsA cultivars.