Study On NACL1 Regulated Root Stem Cell And Biomass

The developed and robust root system is an important guarantee for the growth and development of plants under various environmental conditions.Root stem cells can form different types of tissue starting cells and then form various root tissues through division and differentiation,which play an important role in the root development process.Therefore,studying the molecular regulation mechanism of root stem cells provides an important theoretical basis for elucidating the regulatory network of plant growth and development,stress adaptation and nutrient absorption.In order to explore the regulation mechanism of root tip stem cells,we conducted an analysis of the phenotype of atnacll mutants and found that the quiescent center(Quencent center,QC)division and the differentiation of distal stem cells(Distal Stem Cell,DSC)were enhanced.The root length of this mutant is similar to the wild type,indicating that the gene is not involved in the regulation of root length.Analysis of spatiotemporal expression using pNACL::NACL1-GUS and pNACL1::GFP transgenic lines showed that AtNACL1 is mainly expressed in the middle column,QC,endothelial layer,and cortical endothelial starting cells.Transient expression analysis using tobacco leaves showed that AtNACLl is mainly in the nucleus,indicating that the gene encodes a nuclear localization protein.In order to clarify the molecular mechanism of AtNACL1 regulating root stem cell niche(the general term for QC and surrounding stem cells),we examined the expression of key genes involved in the regulation of root stem cell niche in atnacl1 mutants.The results showed that the key regulatory genes PLT1 and PLT2 involved in the root tip stem cell niche were significantly reduced in the atnacll mutant,indicating that may be involved in the transcriptional regulation of PLT1 and PLT2;Although the GRAS transcription factors SCR and SHR decreased at the transcription level,the expression levels of SCR::GFP and SHR::GFP increased in atnacll mutants,indicating that AtNACL1 may negatively regulate the protein levels of SCR and SHR.The results of yeast two-hybrid and BiFC experiments show that AtNACL1 can interact with SHR,which suggests that AtNACL1 may participate in the transcriptional regulation of downstream genes through protein interaction with SHR and ultimately affect the maintenance of the root stem cells nicheIn order to further elucidate whether AtNACLl regulated root stem cell niche is involved in the regulation of plant growth and development,we overexpressed AtNACL1 in Arabidopsis and maize and tested its effect on plant growth and development.The results showed that the overexpression of AtNACL1 in Arabidopsis can significantly increase the biomass.The transgenic plants showed a phenotype with an increased number of rosette leaves and increased plant height.Transgenic maize over-expressing AtNACL1 also showed a larger seed grain and a stronger phenotype.The biomass of AtNACL1 over-expressing transgenic maize was significantly higher than that of non-transgenic controls.This result indicates that AtNACL1 is likely to participate in the regulation of plant biomass by regulated stem cells.In summary,AtNACL1 is a regulatory factor that regulates the root stem cells niche.On the one hand,it can maintain the steady state of root stem cells by regulated the transcription of AP2 transcription factors PLT1 and PLT2;on the other hand,AtNACLl may interact with SHR proteins.Work to regulate the root stem cells niche.The results of overexpression transgenic analysis using AtNA CL1 in Arabidopsis and corn showed that overexpression of AtNACL1 can significantly increase the biomass of Arabidopsis or corn,indicating that this gene is an important factor for plant growth regulation and can be based on the increase in the future.The new varieties of biomass have certain application value.