SlGLK2转录因子在番茄品种Heirloom果实中的功能及变异分析

Variation Analysis and Functions in Heirloom Fruits of Tomato(Solanum lycopersicum)Goldern2-Like(GLK2)Transcription Factor

Goldern2-Like(SlGLK2)基因是调控未成熟果实叶绿体发育重要的转录因子。番茄(Solanum lycopersicum)未成熟果实中叶绿体对成熟果实的糖类、风味物质积累和提高番茄品质具有一定的作用。Heirloom品系作为优异的种质资源,在果实颜色、大小、形状和风味等方面有很大差异。以32个Heirloom品种为研究材料,通过表型调查研究果实表型性状,检测果实不同部位和不同发育时期叶绿素含量,筛选20个Heirloom品种克隆SlGLK2基因和启动子序列,运用荧光定量PCR分析调控果实叶绿体发育的相关基因,从而分析基因间的调控关系,以期研究SlGLK2转录因子对Heirloom品种叶绿体发育的影响。结果表明:含有SlGLK2基因的品种,未成熟果实拥有深绿色果肩,其不同发育时期绿色果实果肩的叶绿素含量明显高于果实底部。在SlGLK2基因上游非编码区和编码区共发现21个单核苷酸多态性(SNPs),经聚类分析发现,部分SNPs与未成熟果实的表型相关。果实叶绿体发育相关基因的表达分析表明TKN2、TKN4和在番茄果实的果肩部表达量明显高于果实底部,且TKN2、TKN4位于SlGLK2上游并调控SlGLK2基因的表达。

The chloroplasts of immature green fruit,including tomato (Solanum lycopersicum),significantly contribute to the quantity and composition of ripe fruit sugars and metabolites,and thus,impact the quality and favor of the mature fruit.Traditional heirloom tomato varieties differ widely in the fruit color,size,shapeandflavors and these varieties have genetic,and perhaps epigenetic,diversity,which could be appropriate resources forimproving the fruit quality.The Golden 2-like transcription factor (SlGLK2) has an important role in regulating chlorophyll and plastid development in unripe tomato fruit.First,the phenotype of 32 Heirloomswere analyzed,then the chlorophyll from different fruit parts and development stages were detected.20 Heirlooms were selected by analyzing those traits.Coding and promoter sequence of those 20 Heirlooms were cloned.Following the expression profiling of genes regulating chloroplast development was analyzed by qPCR.The results showed that the Golden 2-like transcription factor (SlGLK2) had an important role in regulating chlorophyll and plastid developmentin unripetomato fruit.The chlorophyll concentration on the stem end was much higher than the bottom ofthefruits.Twenty-one single nucleotide polymorphisms (SNPs) in the SlGLK2 gene intron and promoter regions and three coding region SNPs were identified.The cluster of SNPs showed connection with the phenotype of Heirlooms.Expression of genes related chloroplast development showed that the TKN2,TKN4 and SlGLK2 gene expression was greater in the shoulders than at the blossom end of the fruit.TKN2,TKN4 up-regulate the expression of SlGLK2.