Molecular Cloning Of PeGSK1 Gene From Phyllostachys Edulis And Its Function In Plant Fast Growth

As one of the fastest growing species in the world,Phyllostac hys edulis is the most important economic bamboo species in China.It has high economic,cultural and ecological values.In several m onths,the bamboo will be able to finish its bamboo stalk-shaped gr owth,its length up to more than 20 meters.However,there are fe w studies on the internal regulation mechanism and molecular biolo gy of the fast-growing stem in Phyllostachys edulis.So far,we ha ve not known much about the underlying regulatory mechanisms of bamboo and its molecular biology.In the study of molecular mecha nism of rapid growth of Phyllostachys edulis,we screened out one of the glycogen synthase kinase?GSK3?kinases that inhibit the gro wth of Arabidopsis thaliana by ectopic expression of the cDNA libr ary of Phyllostachys edulis to the model plant Arabidopsis thaliana Protein-coding gene,named PeGSK1.In this study,a GSK3-like k inases family gene,which inhibits the growth of Arabidopsis thalia na,in Phyllostachys edulis,was obtained by screening the study an d named as PeGSKl.This study investigated the function of PeGS K1 to explore its function during the rapid growth period of Arabid opsis thaliana and Phyllostachys edulis.It has been reported that glycogen synthase kinase 3?GSK3?is a highly conserved serine kinase belonging to MAPK family of cy toplasmic kinases.Arabidopsis GSKs are involved in the plant osm otic stress response,which is involved in the regulation of multiple signaling pathways.Plant GSKs are involved in important life-activ ity processes such as plant osmotic stress response,brassinosteroid s ignal transduction,injury response and flower developmental regulati on.More importantly,Arabidopsis GSKs regulate the expression of BR response pathway genes through phosphorylation of BZR1,thus playing an important role in Brassinosteroids?BR?signaling pathw ay.In this project,the full-length cDNA library of Phyllostachys e dulis was used to screen and clone the PeGSK1 gene from Phyllost achys edulis,and its function was analyzed in Arabidopsis and Phyl lostachys edulis.First,using bioinformatics software and phylogeneti c tree analysis to identify ATGSK1 and PeGSK1 have homology.T he PeGSK1 gene was cloned from Phyllostachys edulis and transfor med into the model plant Arabidopsis for ectopic expression:Ectopi c expression of the PeGSK1 gene showed a BR-associated phenotyp e,specifically:phenotypes such as smaller leaves,shorter stems,an d slower plant growth.At the same time overexpression of the plan t also appeared to inhibit leaf cell division and stem extension and other phenotypes.Then a protein deletion related experiment was pe rformed:a mutant?SALK₀43420?of Arabidopsis thaliana ATGSK1 gene deletion function was ordered from the Arabidopsis SALKAB RC official website,Both mutants were T-DNA insertions in the int ron region of the ATGSK1 gene,and the mutant atgskl plants sho wed faster growth rates than the over-expressed PeGSK1 and the e mpty vector control,including leaf size and stem height.Loss of A TGSK1 protein will lose its inhibitory effect on Arabidopsis growth.Yeast two-hybrid experiments showed that PeGSK1 could interact w ith the BZR1 homologous genes of Phyllostachys edulis.The quanti tative results showed that the over-expression of PeGSK1 enhanced the transcriptional expression of BR-related genes.Quantitative resul ts of different growth periods of Phyllostachys edulis showed that P eGSK1 had the highest expression level in bamboo shoots and the lower expression level in the bamboo shoot growth period.These r esults indicated that PeGSK1 plays an important role in the growth process of Arabidopsis thaliana and Phyllostachys edulis.