| Wheat albino strain is a natural mutant strain from the parent dwarf wheat Aibian 1,it shows the stage albinism phenomena from interior leaves to total aerial parts,and need continued low temperature conditions.This characters is controlled by both nuclear and cytoplasm factors.In order to study the expression alteration of chloroplast genes in different wheat cultivars and development stages,and to reveal the molecular mechanism of albinism leaves,we using semi-quantitative RT-PCR compared the chloroplast genes expression profiles of interior and expanding leaves of albinism strain,albinio transfer wheat and control wheat materials at room temperature;with the low temperature treatment of 2d,10d,20d between albinism strain and its parent aibian No.1.Differentially expression chloroplast genes in different tissues of transcription level was screened in albino strain and related materials,for further study of wheat chloroplast gene expression and regulation and the relationship with the albino leaf color,and laid the foundation for further clarify the molecular mechanism of returning white albino.The main findings in this research were as follows:1、39 differentially expressed chloroplast genes was detected by semi-quantitative PCR at room temperature in the following seven wheat cultivars:the albinism line(F)and its control Aibian 1(A),albinio transfer wheat and Chinese spring.What is more,most of the 39 differentially expressed genes have higher expressed levels in interior leaves than that in expanding leaves.2、33 differentially expressed genes were found between albinism line and its control Aibian 1 by the profiling of chloroplast genomics.17 genes or gene clusters was found having higher expression levels in albinism line.Compared to the albinism materials,there are 5 genes or clusters have over expressed in our test.3、After long time of 4℃ low temperature treatment,Expression of plastid genes in wheat is not consistent in response to the short-term low temperature treatment and long-term low temperature treatment.It is a dynamic process.Such as petD10 shows down-regulate after 2d low temperature,after 10d low temperature,petD shows up-regulate,after 20d low temperature,petD shows down-regulate.chloroplast genes show a same expression pattern in albinism line and its control Aibian 1.4、15 genes or gene clusters shows down-regulated expression in interior leaves of albinism line after 20d of 4℃ low temperature treatment,the down-regulated genes are relative to transcription of chloroplast gene,translation,the assembly of photosystem,the electron transport chain and heme binding protein.In this study,CcsA is a gene associated with pigment metabolism down-regulated,retroaction inhibit the synthesis of chlorophyll precursors,affect the synthesis of chlorophyll,may be closely related to leaf albino;ycf3 is associated with optical system,the gene down-regulated affect the assembly of PS I,damage the chloroplast thylakoid membrane,destroyed the chloroplast structure.We think,these two genes may be associated with albinism albino leaf color is more closely,but requires further validation.These differentially expressed chloroplast genes induced by low tempreture may be influence the expression of chloroplast genes in albinism line,and structure,growth,metabolism and function of chloroplast,may be associated with leaf albino of albinism line. |
