The coloration in the skin of red pears differs between varieties, 'Hongxing' (Pyrus communis) and 'Mantianhong' {Pyrus pyrifolia). To elucidate the basis of red coloration, the transcription profiles of ten flavonoid-related genes in the skin of the two varieties were investigated by semiquanatitative RT-PCR and Real-time PCR. In this study, the transcription levels were higher in 'Mantianhong' than 'Hongxing' for the upstream genes (CHS,CHI) ,but they were on the contrary for the downstream genes (F3H,DFR,ANS) and the genes (FLS,LAR,ANR) required for flavonols and proanthocynins biosynthesis. Expression of all the tested genes in the skin of covered fruits were reduced with light intensity decreasing and those of F3GT and FLS were 20 ~ 30-fold in the skin of fruits uncovered than that of covered. However,although the fruits of 'Hongxing' were covered, the transcription of the genes (PAL, F3H, DFR,ANS,LAR,ANR) were still more abundant than that of uncovered 'Mantianhong'. Therefore, it might be concluded that the different red coloration between two varieties is due to the differential expression of the downstream genes in the anthocyanin biosynthesis and F3GT is the key gene for light regulation of coloration of 'Hongxing'.%采用半定量和荧光定量PCR方法,分析10个类黄酮合成基因在梨品种‘红星’和‘满天红’成熟果皮中的转录特性以及光照对基因表达的影响.结果表明:‘满天红’花色苷合成上游基因(CHS、CHI)的表达量高于‘红星',而下游基因(F3H、DFR、ANS)以及黄酮醇(FLS)和原花色素(LAR、ANR)合成相关基因的表达量却正好相反.套袋去除光照可使所有被检测基因的转录水平降低,F3GT和FLS最明显,表达量差异达20～30倍以上,且套袋‘红星’中PAL、F3H、DFR、ANS、LAR、ANR基因的表达量仍高于不套袋‘满天红’.研究认为,花色苷合成下游基因转录水平的差异是2个红色梨品种间着色不同的主要原因,而F3GT是光照调控‘红星’着色的关键基因.
展开▼
