Analysis Of Salt Resistance Of ZmPIF3 Over-expressed Transgenic Arabidopsis Thaliana L

Soil salinization as a kind of natural stress causes soil desertification.High level of Na+ ion in soil will induce the disorder of internal environment,slow cellular metabolic and alter cellular architecture,it severely affects the yield and variety of crop.Maize as a salt-susceptible crop,is always injured by salt stress.So it has guiding significance for maize breeding to study the molecular mechanism.It has been reported that PIF3 was involved in freezing tolerance,however the relationship between PIF3 and stress tolerance is little known.In this study,two transcription version of Zm PIF3 was used for analysis of phenotype,physiology and biochemistry index,and transcriptome.Based on transcriptome analysis,we studied the function of DEGs related to salt tolerance.Here are the main results.1.Two transcript versions of Zm PIF3 and WT(wildtype)under salt treatment was used for phenotype analysis,it shown that germination rate and relative root length of Zm PIF3.1 over-expressed Arabidopsis are higher than Zm PIF3.2.Thus we selected Zm PIF3.1 over-expressed Arabidopsis at seeding stage as material for phenotype analysis,the result showed that WT plants was more severely inhibited by salinity,with severe dehydrations and dried leaves.It shown that Zm PIF3 over-expressed transgenic Arabidopsis has better salt tolerance.2.We analyzed the levels of proline,CAT and MDA in transgenic Arabidopsis and WT under salt treatment.Compared to WT,the level of MDA in transgenic Arabidopsis is lower and rise more slowly,the levels of proline and CAT is higher and increase significantly.It proved that transgenic Arabidopsis has better ability to decomposeperoxide and membrane damage is lower.3 We examined gene expression in over-expressed Zm PIF3 transgenic Arabidopsis and WT using transcriptome analysis,and respectively identified 6152 and 3983 differentially expression genes(DEGs).Among them,3167 and 2056 was upregulated,2985 and 1927 was downregulated.Through the comparative analysis of DEGs in two samples,we found that 276 DEGs only existed in WT,2445 DEGs only existed transgenic Arabidopsis,and 3707 DEGs were overlapped in two samples.Based on GO enrichment analysis,we found DEGs was enriched in cellular process,metabolic process,and catalytic activity.And through mapping DEGs to the reference canonical pathways in the KEGG,the maximum amount of DEGs was discovered in metabolic pathways,followed by Biosynthesis of secondary metabolites,Biosynthesis of antibiotics,plant hormone signal transduction and so on.We randomly selected 10 genes for q RT-PCR analysis,which demonstrated the reliability of transcriptome analysis.4.The functional annotation showed that top 50 DEGs of I(DEGs only in wildtype after salt stress)?II(DEGs only in transgenic Arabidopsis after salt stress)and III(DEGs in both two samples after salt stress)identified in this study were associated with hormone,Ca2+signalingand transcription factor regulation.There are 32 DEGs related to hormone,which are involved in regulation of ethylene(ET),auxin(IAA)and abscisic acid(ABA),with the percent of 30%,32% and 10%.Furthermore,10 DEGs in IIand III are involved in Ca2+ signaling.Among them,the maximum amount was CMLs with the percent of 30%,and 70% of DEGs related to Ca2+ signaling.It suggested that these DEGs may have positive regulation in salt tolerance.15 DEGs including MYB?b HLH?CBF?b ZIP and WRKY are transcription factors.MYB?ERF and CBF are relatively higher,with the percent of 27%?27% and 20%.MYB existed in three types,which are significant upregulated or downregulated.ERF existed in II and III types,which are all downregulated.CBF existed in II types,which are upregulated.It showed that these transcription factors may have positive regulation in salt tolerance.Zm PIF3 may involve in response to salt tolerance by interact with hormone,Ca2+ signaling and transcription factor regulation.