紫斑牡丹种子发育期油脂合成积累的源汇基因协同表达

Coordinate Expression of Source and Sink Genes Involved in Lipid Biosynthesis and Accumulation during Seed Development of Paeonia suffruticosa

为研究紫斑牡丹种子油脂合成积累与相关基因(GPD1, DGAT1和DGAT2)表达间的关系,以四个不同发育期(6月20日, 7月7日, 7月17日和7月27日)的种子为材料,氯仿甲醇法测定种子含油率,实时荧光定量PCR方法分析基因的表达模式,分析相关基因在不同发育期种子中的表达差异及其对油脂合成积累的影响。结果表明:(1)不同发育期紫斑牡丹种子含油率呈不断升高趋势,在6月20日至7月27日的38 d内,从4.21%上升到18.38%;(2)调控油脂合成的源基因GPD1和汇基因DGAT1与DGAT2在发育前期的紫斑牡丹种子中的表达呈快速上升趋势,且表达量均在7月7日达到最高值;随后源汇基因的表达均不断降低。紫斑牡丹发育前期种子中源(GPD1)汇(DGAT1和DGAT2)基因的协同高表达,既促进合成了更多的TAG前体G3P,又促进了TAG积累。源基因GPD1表达量增加了2.44倍,汇基因DGAT1和DGAT2分别增加5.16倍和3.83倍,促成种子含油量增加了2.77倍。这可为深入理解紫斑牡丹种子油脂合成积累提供理论依据,对后续开展高油紫斑牡丹的分子育种具有重要意义。

In order to explore the relationship between the oil biosynthesis and accumulation and the expression of related genes in seeds of Paeonia suffruticosa,the seeds harvested at four different developmental stages (Jun.e 20,July 7,July 17 and July 27)were selected as the material.The seed oil contents were tested by the method of chloroforrn methanol.The different expression patterns of genes were determined using qRT-PCR,and the effects of these genes on lipid biosynthesis and accumulation were analyzed.The results showed that the seed oil contents appeared in continuous increase during seed development,and it increased from 4.21%to 18.38%in only 38 days from June 20 to July 27.The expression of source gene 'GPDI'and sink genes 'DGA TI'and 'DGA 72'increased rapidly during early seed development,which reached the highest values at July 7.After this,the expression of source and sink genes decreased gradually.The high coordinate expressions of source gene GPD1 and sink genesDGA T1 and DGA T2 not only promoted the synthesis of more TAG precursors G3P,but also promoted the accumulation of TAG.The expression of GPD1 increased by 2.44 times,the expression of DGA T1 and DGA T2 increased by 5.16 times and 3.83 times respectively,resulting in the increase of seed oil content by 2.77 times.These results could provide a theoretical basis for further understanding of oil synthesis and accumulation in seeds of Paeonia suffruticosa,and would be of great significance for subsequent molecular breeding of Paeonia suffruticosa with high oil content.DGA T1 and DGA T2 not only promoted the synthesis of more TAG precursors G3P,but also promoted the accumu- lation of TAG.The expression of GPD1 increased by 2.44 times,the expression of DGA T1 and DGA T2 increased by 5.16 times and 3.83 times respectively,resulting in the increase of seed oil content by 2.77 times.These results could provide a theoretical basis for further understanding of oil synthesis and accumulation in seeds of Paeonia suffruticosa,and would be of great significance for subsequent molecular breeding of Paeonia suffruticosa with high oil content.