木薯品种(系)类胡萝卜素代谢相关基因和蛋白表达水平分析

以白心木薯华南6068、华南9号、紫叶黄心木薯BGM019和粉红木薯Mirasol为材料,探究木薯块根膨大期和成熟期与类胡萝卜素代谢通路相关的14个基因和4种蛋白质表达水平变化。用HPLC检测块根β-胡萝卜素含量的变化,分别用qRT-PCR和Western blot方法对类胡萝卜素代谢通路相关基因和蛋白酶的表达水平进行分析。以华南6068为对照,研究结果表明:华南9号和紫叶黄心木薯BGM019成熟期中的类胡萝卜素合成途径关键基因PSY2、LCYB基因显著高于膨大期,而降解相关的关键基因CCD1、NCED3在成熟期的表达量显著低于膨大期(P0.05)。粉红木薯Mirasol成熟期中PSY2、LCYB的显著下调与CCD1、NCED3的显著上调(P0.05)是造成β-胡萝卜素含量差异的原因之一。通过分析不同木薯品种(系)在膨大期和成熟期块根类胡萝卜素代谢途径相关基因的表达水平,有助于解析β-胡萝卜素积累的分子机理。此外,Western blot结果显示抗坏血酸过氧化物酶、谷胱甘肽还原酶、超氧化物歧化酶和HSP70虽然和块根类胡萝卜素代谢途径没有直接关联,但它们在木薯膨大期和成熟期块根表达水平有显著差异(P0.05)。

Analysis of genes and enzymes associated with carotenoid metabolism in cassava

The expressions of genes and enzymes related with carotenoid metabolic pathway in the storage roots of cassava swelling and mature periods was validated using white cassava SC6068,yellow cassava SC9,purple-leaf and yellow cassava BGM019 and pink cassava Mirasol as research materials.HPLC method was used to detect the changes of β-carotene contents,qRT-PCR and Western blot methods were applied to analyze the expressed changes of the genes and proteins regarding carotenoid pathway,respectively.In the present study,SC6068 was used as a control,the results showed that in mature period the SC9 and BGM019 carotenoid biosynthesis pathway genes PSY2 and LCYB expression was significantly higher than swelling period (P ＜ 0.05).On the contrary,the degradation genes CCD1 and NCED3 was significantly lower than swelling period.During the mature period,the Mirasol carotenoid biosynthesis genes PSY2 and LCYB was down-regulation and the CCD1and NCED3 was up-regulation (P ＜ 0.05) which was the one reason resulted in carotenoid content change.These data regarding the analysis of the gene expressions related with carotenoid metabolic pathway of storage roots in swelling and mature periods,will be helpful to understand the mechanism of β-carotene accumulation.Furthermore,the Western blot results showed that there was no correlation relationship between β-carotene accumulation and ascorbate peroxidase,glutathione reductase,FeSOD and HSP70.However,their expression was significantly differed during swelling and mature periods (P ＜0.05).