甘薯生长期间块根β-胡萝卜素合成基因的表达分析

Study on the Relationship Between Accumulation of β-carotene and Expression of Genes for β-carotene Biosynthesis in the Storage Roots of Sweet potato[Ipomoea batatas L.(Lam)]

以β-胡萝卜素含量高的优质红心甘薯金山72和高产优质的黄心甘薯金山57为材料,栽后60～120 d4个生长时期提取块根总RNA和β-胡萝卜素,用RT-PCR分析psy、pds、zds、lyc-b 4个酶基因的表达,用HPLC测定同一时期块根β-胡萝卜素的含量。结果显示,在金山57中,随着块根的生长,4个基因表达逐渐减弱,相应地,块根β-胡萝卜素含量逐渐降低;在金山72中,4个基因的表达随着块根生长总体呈现逐渐增强趋势,块根β-胡萝卜素含量相应地逐渐提高。整体而言,在块根生长过程中,4个基因在金山72中表达比在金山57中强。该合成途径的4个基因中,lyc-b的表达相对稳定,其表达强弱与块根β-胡萝卜素含量关系密切。表明甘薯块根β-胡萝卜素生物合成与积累受基因调控,其含量与不同品种及不同块根膨大时期4个酶基因的表达密切相关,lyc-b是甘薯块根β-胡萝卜素生物合成途径的关键酶基因。

Unveil the relationship between β-carotene content and expression of the genes for synthesis of β- carotene in the tuberous roots. β-carotenes were isolated from the tuberous roots of Jinshan72 （orange-flesh） and Jinshan57 （yellow-flesh） at various developmental stages and measured by HPLC, respectively, and total RNA were isolated synchronously and were used for RT-PCR. In yellow-flesh Jinshan57, all of the four genes expressed gradually weaker throughout the tuberous root developmental stages, the β-carotene content in the tuberous roots decreased correspondingly, whereas in orange-flesh cultivar Jinshan72, all of the four genes expressed gradually stronger throughout the tuberous root developmental stages, the β-carotene content in the tuberous roots increased correspondingly. As the whole, most of the four genes in Jinshan72 expressed stronger than that in Jinshan57 over the whole developmental period. Among the four genes, the expression of lyc-b were more steadily than the others, therefore showed more related to the content of β-carotene in the tuberous roots. Synthesis and accumulation of β-carotene in tuberous roots of sweet potato were developmentally regulated, and were closely related to the expression of four genes at different developmental stages and different cultivars, lyc-b might be the key gene in β-carotene synthesis pathway.