沙棘种子形成发育过程中油脂合成积累关键基因的表达分析

Expression of Key Genes Involved in Lipid Biosynthesis and Accumulation during Seeds Formation and Development in Hippophae rhamnoides

为探讨沙棘种子油脂积累与相关基因表达的关系,以不同发育期间（6月25日、7月6日、7月17日、7月28日、8月8日和8月19日）的近缘高油品系‘新俄3号’和低油品系‘绥棘1号’种子为试材,利用氯仿甲醇法测定含油率,采用实时荧光定量PCR方法分析限速酶基因的表达模式,验证各基因在天然高低油种子间的表达差异。结果表明：（1）除7月17日外,其他时期‘新俄3号’的种子含油率均高于‘绥棘1号’;7月6日～7月28日期间油脂迅速积累,而且‘新俄3号’种子含油率增速大于‘绥棘1号’。（2）油脂迅速积累期的GPD1基因高表达,可能通过促进3-磷酸甘油合成进而加速‘新俄3号’种子油脂高积累;油脂积累过程中DGAT1和DGAT2基因在‘新俄3号’种子中的表达量一直高于‘绥棘1号’。研究认为,GPD1、DGAT1和DGAT2基因可能与‘新俄3号’种子油脂的相对高积累有关。本研究结果为进一步深入验证沙棘油脂合成限速酶基因功能奠定基础。

To explore the relationship between lipid biosynthesis and relevant gene expression in sea buckthorn seeds,we harvested the developing seeds of the line ‘Xin＇e 3＇with high oil content and the line‘Suiji 1＇with low oil content as experimental materials on June 25,July 6,17,28,August 8and 19.These two lines had closed genetic relationship.The oil content in seeds was determined by the method of chloroform methanol,and the expression profiles of GPD1,DGAT1 and DGAT2genes involved in lipid biosynthesis were tested using real-time quantitative PCR.The results showed that：（1）the oil content in the seeds of‘Xin＇e 3＇was higher than that in‘Suiji 1＇except for July 17.The rapid accumulations of seed lipid of these two lines were during July 6to 28,and the increasing rates in ‘Xin＇e 3＇were higher than that in‘Suiji 1＇;（2）the high expression of GPD1 gene occurred in the period of rapid lipid accumulation,which may speed up lipid biosynthesis in‘Xin＇e 3＇seeds through promoting the biosynthesis of glycerol-3-phosphate.The expression levels of DGAT1 and DGAT2genes in line‘Xin＇e 3＇were higher than that inline‘Suiji 1＇during lipid accumulation.Thus,GPD1,DGAT1 and DGAT2genes may be associated with the high accumulation of lipid in‘Xin＇e 3＇seeds.These results provided scientific bases for validating the function of genes encoding for rate-limiting enzymes involved in sea buckthorn lipid biosynthesis and accumulation.