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中科院:发现调控果实花青苷着色新机制
摘要 : 中国科学院武汉植物园果树分子育种科学组博士研究生周晖在研究员韩月彭的指导下开展了血桃着色性状遗传机理研究,相关成果已在线发表于《The Plant Journal》。
 
中国科学院武汉植物园果树分子育种科学组博士研究生周晖在研究员韩月彭的指导下开展了血桃着色性状遗传机理研究,相关成果已在线发表于《The plant Journal》。
 
“血桃”不仅外观艳丽夺目,而且富含花青苷具备清除体内自由基、抗癌防老等保健功效,深受消费者青睐。研究人员通过遗传作图将控制血桃呈色基因定位于一个200kb区间,然后结合比较转录组学研究,克隆了控制血桃着色基因BL,该基因位于花青苷MYB调节基因的上游,在果实发育后期能与其他NAC基因形成异质二聚体激活MYB基因的转录,进而促进花青苷代谢相关基因的表达,最终导致果肉大量积累花青苷呈血色。但在果实发育前期SPL1基因抑制BL基因的表达,因而果实不现红色。
 
该研究开辟了我国果树功能基因图位克隆研究的先河,研究成果揭示了植物花青苷合成调控新机制,为今后植物花青素着色的遗传改良提供了理论基础与分子工具。

控制血桃着色的模式示意图
 
原文链接:Molecular genetics of blood-fleshed peach reveals activation of anthocyanin biosynthesis by NAC transcription factors
 
Anthocyanin pigmentation is an important consumer trait in peach (Prunus persica). In this study, the genetic basis of the blood-flesh trait was investigated using the cultivar Dahongpao, which shows high levels of cyanidin-3-glucoside in the mesocarp. Elevation of anthocyanin levels in the flesh was correlated with the expression of an R2R3 MYB transcription factor, PpMYB10.1. However, PpMYB10.1 did not co-segregate with the blood-flesh trait. The blood-flesh trait was mapped to a 200-kb interval on peach Linkage Group (LG)5. Within this interval, a gene encoding a NAC domain transcription factor (TF) was found to be highly up-regulated in blood-fleshed peaches when compared with non-red-fleshed peaches. This NAC TF, designated BLOOD (BL), acts as a heterodimer with PpNAC1 which shows high levels of expression in fruit at late developmental stages. We show that the heterodimer of BL and PpNAC1 can activate the transcription of PpMYB10.1, resulting in anthocyanin pigmentation in tobacco. Furthermore, silencing the BL gene reduces anthocyanin pigmentation in blood-fleshed peaches. The transactivation activity of the BL-PpNAC1 heterodimer is repressed by a SQUAMOSA promoter-binding protein-like transcription factor, PpSPL1. Low levels of PpMYB10.1 expression in fruit at early developmental stages is likely attributed to lower levels of expression of PpNAC1, plus the presence of high levels of repressors such as PpSPL1. We present a mechanism whereby BL is the key gene for blood-flesh trait in peach, via its activation of PpMYB10.1 in maturing fruit. Partner TFs such as bHLHs and NAC1 are required, as are the removal of transcriptional repressors.(DOI: 10.1111/tpj.12792)

日期:2015-03-03     来源:The Plant Journal
转载:http://www.bio1000.com/gnjz/botany/503228.html