OsGSK2与OsGLK1互作调控水稻叶绿素合成与叶绿体发育

OsGSK2 Interacts with OsGLK1 to Regulate Chlorophyll Synthesis and Chloroplast Development in Rice

叶绿素是水稻光合作用的重要色素,叶绿素的合成决定光合作用的效率,影响植物的产量和品质。在本研究中,发现糖原合成酶激酶OsGSK2过表达植株Go-2成熟期呈现叶片深绿色的表型。相比野生型,Go-2植株叶绿素a、叶绿素b以及类胡萝卜素含量显著升高。透射电镜观察结果显示,相比野生型,Go-2植株叶绿体类囊体片层增多。酵母双杂交“一对一”实验证实OsGSK2与Golden2-Like转录因子OsGLK1存在互作,并进一步通过双分子荧光互补实验确认OsGSK2与OsGLK1存在互作。在水稻原生质体中检测双荧光素酶活性发现,相比单转OsGLK1,OsGSK2与OsGLK1共转显著提高下游靶基因的表达水平。荧光定量PCR结果表明,相比野生型,在Go-2植株中OsGLK1直接调控的靶基因OsPORB、OsCAO1、LHCB6等转录水平显著上调。研究结果初步揭示了OsGSK2与OsGLK1互作调控水稻叶绿素合成和叶绿体发育的分子机理,进一步拓展了水稻糖原合成酶激酶的分子功能,丰富了水稻叶色调控的分子网络,为水稻高光合分子育种提供了理论依据。

Chlorophyll is an important pigment in rice photosynthesis,and its synthesis determines the efficiency of photosynthesis,ultimately affecting plant yield and quality.In this study,it was found that the glycogen synthase kinase OsGSK2 overexpressed Go-2 plants exhibited a dark green leaf phenotype at heading date.Compared to the wild type,the contents of chlorophyll a,chlorophyll b,and carotenoids in Go-2 plants significantly increased.The observation results of transmission electron microscopy showed that compared to the wild type,the chloroplast thylakoid layers of Go-2 plants increased.Yeast two hybrid"one-to-one"experiment confirmed the interaction between OsGSK2 and the Golden2-Like transcription factor OsGLK1,and further confirmed the interaction between OsGSK2 and OsGLK1 through bimolecular fluorescence complementarity experiments.By detecting dual luciferase activity in rice protoplasts,it was found that compared to single transgenic OsGLK1,co transfection of OsGSK2 and OsGLK1 significantly increased the expression level of downstream target genes.The fluorescence quantitative PCR results showed that compared to the wild-type,the transcription levels of target genes(OsPORB,OsCAO1,LHCB6,etc)directly regulated by OsGLK1 were significantly up-regulated in Go-2 plants.These results provided preliminarily insights on the molecular mechanism of the interaction between OsGSK2 and OsGLK1 in regulating rice chlorophyll synthesis and chloroplast development,extending the molecular function of rice glycogen synthase kinase,enriching the regulation network of rice leaf color,and providing theoretical basis for high photosynthetic molecular breeding in rice.