论文部分内容阅读
以‘金童6号’和‘金童8号’黄肉桃为试材,于花后60 d时套袋对果实进行遮光处理,研究遮光对果实叶绿素和类胡萝卜素积累的影响,以及类胡萝卜素合成关键基因的表达差异。结果表明:伴随果实成熟,叶绿素含量逐渐降低,且3个采样时期套袋果实中的叶绿素含量均显著低于不套袋的对照;类胡萝卜素含量逐渐升高,但未成熟期套袋果实低于对照,成熟期则显著高于对照。利用高效液相色谱(HPLC)对果肉类胡萝卜素组分的分析表明:在黄肉桃果实未成熟期,类胡萝卜素以叶黄素和β–胡萝卜素积累为主,表现出叶绿体合成途径特征;进入成熟期,有色体类胡萝卜素合成途径占据优势,形成更为稳定的酯化类隐黄质和紫黄质,并且套袋果实中酯化类胡萝卜素的积累水平明显高于对照果实。此外,分子证据表明伴随果实成熟,类胡萝卜素合成关键基因HDR(羟甲基丁烯基–4–二磷酸还原酶)、PSY1(八氢番茄红素合成酶1)、PSY2(八氢番茄红素合成酶2)、PDS(八氢番茄红素脱氢酶)和HYB(β–胡萝卜素羟化酶基因)在套袋和不套袋果实中均呈现上调表达趋势。值得注意的是,DXS(1–脱氧–D–木酮糖–5–磷酸合成酶基因)、PSY2和PDS基因在成熟期套袋果实中的表达水平低于对照,而HYB基因的表达水平显著高于对照。
The golden peach of ’Golden Boy 6’ and ’Golden Boy’ 8 were used as test materials, and the fruits were shaded 60 days after anthesis to study the effects of shading on the accumulation of chlorophyll and carotenoids, Differences in expression of key genes for carotenoid synthesis. The results showed that the content of chlorophyll decreased gradually with the ripening of fruits, and the content of chlorophyll in bagged fruits was significantly lower than that of no-bag control in three sampling periods; the content of carotenoids increased gradually, but the immature bagged fruits were low In the control, maturity was significantly higher than the control. The analysis of the carotenoid components by high performance liquid chromatography (HPLC) showed that the carotenoids mainly accumulated lutein and β-carotene in the immature stage of the yellow peach fruit and showed the characteristics of chloroplast synthesis pathway. At maturity, the carotenoid biosynthesis pathway dominated, forming more stable esterified cryptoxanthin and violaxanthin, and the accumulation of esterified carotenoids in bagged fruits was significantly higher than that of control fruits. In addition, molecular evidence indicates that HDR (hydroxymethylbutene-4-diphosphate reductase), PSY1 (phytoene synthase 1), PSY2 (phytoene red), a key gene for the synthesis of carotenoids, The results showed that the expression of all the three enzymes, such as PDS (phytoene dehydrogenase) and HYB (beta-carotene hydroxylase) genes, were up-regulated in both bagged and non-bagged fruits. It is noteworthy that the expression level of DXS (1-deoxy-D-xylulose-5-phosphate synthase gene), PSY2 and PDS genes in bagged bagged fruit at maturity was lower than that of control, while the expression level of HYB gene was significant Higher than the control.