Isolation And Molecular Characterization Of Quinoa SPL Family Genes

Quinoa（Chenopodium quinoa Willd.）is an internationally recognized whole-nutrient crop,which has attracted wide attention because of its super high nutritional value.In addition,quinoa can resist a variety of stresses and can be grown in areas such as alpine and high salinity.Therefore,it is very important to study the molecular mechanism of quinoa’s resistance to stress.SBP-box genes are a type of plant-specific transcription factor gene family（SPL genes family）,which play a vital role in plant development.Studies have found that SPL genes are involved in many aspects of plant developmental processes,such as transition from vegetative to flowering,integration of light signals during flowering,bud maturity,anther development,and maintenance of plant copper homeostasis.However,the function of SPL gene in quinoa has not been reported.Therefore,this article uses bioinformatics and PCR to isolate the quinoa SPL gene and analyzes the expression pattern of quinoa SPL gene and its relationship with drought resistance.To this end,we carried out the experiments and the main results are as follows:1.The quinoa SPL family genes were isolated and related bioinformatics analysis was performed.23 SPL genes were identified in the quinoa genome,and named CqSPL1～CqSPL18.Among them,21 SPL gene products have a complete SBP-box conserved domain,which contains two Zn²⁺-binding structures and a functional nuclear localization signal.While the SBP-box domains of CqSPL7-1 and CqSPL7-2 coded products lack the Zn²⁺-binding structures.The subcellular localization prediction results showed that these CqSPLs are all localized in the nucleus.Among 23 CqSPL genes,12 CqSPL genes are regulated by mi R156 genes.According to the phylogenetic tree constructed based on the SPLs of quinoa,Arabidopsis and tomato,the quinoa SPL genes can be divided into five groups,named G1～G5.2.The expression level of quinoa SPL gene in different tissues was analyzed.We have clarified the tissue expression pattern of CqSPL gene.The expression levels of the members of the quinoa SPL gene family in different tissues are quite different.CqSPL10,CqSPL16,CqSPL17,CqSPL18 these 4 SPL genes are expressed in extremely low levels in all tissues.More than half of the SPL genes have the highest expression levels in inflorescences.Among them,CqSPL8-1 and CqSPL8-2 are specifically expressed in inflorescences,In addition,the three SPL genes,CqSPL7-1,CqSPL7-2,and CqSPL9-1,have the highest expression levels in seeds,and the three SPL genes,CqSPL2-1,CqSPL2-2,and CqSPL15,have the highest expression levels in leaves.3.The expression of SPL gene in quinoa seedlings under drought stress was analyzed.Using various concentration of PEG-400 to simulate drought conditions,and finally 3%PEG-400 was selected to do drought treatment.The results showed that the expression of the two genes CqSPL1 and CqSPL12-1 was increased by about 50%,respectively,after treatment with 3%PFG-400.We assumed that these two SPL genes may play important roles in drought stress.4.The activity of the quinoa CqSPL8 promoter was analyzed in detail.The subcellular localizations of CqSPL8-1 and CqSPL8-2 were found to be located in the nucleus.The active position of the CqSPL8-1promoter is in the pistil.These research results lay a foundation for further exploring the function of quinoa SPL genes,and provide a scientific basis for the future development and utilization of these SPL genes as well.