Regulating Of Plant Growth And Development By The SlCDT1 Gene In Tomato

The proliferation,differentiation,aging and apoptosis and other life activities in eukaryotic cells is the basis for the survival and reproduction of organisms.Interphase in cell division is an important stage in the process of plant and animal cell cycle,and mainly to complete DNA replication and related protein synthesis.Replication licensing factor CDT1 is a component of the pre-replication complex that is an essential regulator of eukaryotic DNA replication.Although CDT1 plays an important role in eukaryotic cell division and other processes,its function in tomato has not been reported.Therefore,this study provides the theoretical basis for genetical engineered tomato.In this study,Sl CDT1 gene was cloned from tomato leaves by homologous cloning.In order to study the expression pattern of Sl CDT1 in tomato the green fluorescent transient expression vector p ART27::Sl CDT1-GFP was constructed and injected in tobacco leaves to determine the subcellular localization of Sl CDT1 protein.The result displayed Sl CDT1 protein is expressed in the nucleus.Meanwhile,the overexpression vector p BI121::Sl CDT1 HA was constructed by using molecular biology techniques and introduced into wild-type tomato(AC).The stable positive transgenic plants were screened and used as genetic material to study the biological function of Sl CDT1 gene.These results showed that Sl CDT1 overexpression transgenic plants were shorter than wild type,and chlorophyll content of tomato fruit in Sl CDT1 overexpression transgenic plants was lower than wild type tomato fruit,but chlorophyll content of leaves was not change.This result indicated that Sl CDT1 gene may be involved in regulating chlorophyll synthesis.Furthermore,the results of semi-quantitative PCR analysis also showed that the transcription level of Cyclin B gene in the Sl CDT1 overexpressing plants was significantly higher than wild type,and the transcription level of the plastid development-related gene(Min E)was significantly lower than that of the wild type.This result showed that Sl CDT1 maybe play a key role in cell cycle and plastid development.As E3 ubiquitin ligase,CUL4-DDB1-DET1 complex is involved in many important growth and development processes,including plastid development and so on.Co-immunoprecipitation experiments showed that Sl CDT1 had strong interaction with CUL4,DDB1,DET1 and Ub.These results indicated that tomato Sl CDT1 gene could be involved in plant growth and development,and may be regulated and ubiquitinated by CUL4,DDB1,DET1.This study laid an important foundation for understanding the role of Sl CDT1 in tomato growth and development.