番茄糖基转移酶基因SlUGT75C1-like的功能研究及自然变异分析

Functional study and natural variation analysis of glycosyltransferase gene SlUGT75C1-like in tomato

为了解析番茄(Solanum lycopersicum)群体中与木犀草素葡萄糖苷含量相关的自然变异,以426份番茄为材料,进行了基于代谢组学的全基因组关联分析(metabolome Genome-Wide Association Study,mGWAS),发现番茄SlUGT75C1-like基因下游的存在一个与番茄木犀草素-7-O-葡萄糖苷含量紧密关联的突变位点。进一步在3个亚群的番茄群体中,进行全基因组核苷酸多态性计算,发现SlUGT75C1-like所处的区域在不同亚群中存在明显的差异;进一步分析代谢组和转录组数据相关性发现SlUGT75C1-like的转录水平与木犀草素-7-O-葡萄糖苷的相对含量存在极显著的正相关关系,最后,通过蛋白原核表达获得SlUGT75C1-like融合蛋白并利用体外酶活试验证明该基因催化木犀草素的糖基化反应。研究结果说明,番茄SlUGT75C1-like基因的自然变异造成了木犀草素-7-O-葡萄糖苷在番茄群体中的含量差异,mGWAS在识别新的植物代谢基因簇方面具有较大的优势和巨大潜力,在为植物精细育种提供分子基础方面具有重要的应用价值。

In order to analyze the natural variation related to luteolin glucoside content in tomato population,426 tomato samples were used as materials to performed metabolome genome-wide association study(mGWAS)analysis,and found that there was a mutation site downstream of tomato SlUGT75C1-like gene which was closely related to the content of luteolin-7-O-glucoside.Furthermore,the nucleotide polymorphism of the whole genome was calculated in three subgroups of tomato population,and it was found that the region where SlUGT75C1-like was located was obviously different among different subgroups.Further analysis of the correlation between metabolomics and transcriptome data showed that the transcription level of SlUGT75C1-like was positively correlated with the relative content of luteolin-7-O-glucoside.Finally,the fusion protein of SlUGT75C1-like was obtained by prokaryotic expression of the protein,and the enzyme activity test in vitro showed that SlUGT75C1-like catalyzed the glycosylation of luteolin.The results indicated that the natural variation of SlUGT75C1-like gene causes the content difference of luteolin-7-O-glucoside in tomato population.mGWAS has a large advantage and great potential in identifying new plant metabolic gene clusters,and is important in providing the molecular basis for fine plant breeding.