Cloning and activity analysis of promoter of an AP2/ERF transcription factor gene OsERF096 in rice

Enhancing chilling resistance is of significance to high and stable yield in rice.AP2/ERF transcription factor can resist the cold stress.Our previous study found that rice OsERF096 gene expression was significantly induced by cold stress.In this study, we cloned the OsERF096 promoter (-1~-1 215 bp) and found several cis-elements related to cold and hormone responses.Based on the distribution of cis-elements in OsERF096 promoter, four 5′-truncated fragments were designed and cloned into the pCAMBIA3301 vector, resulting in P_{OsERF096-1215}-GUS, P_{OsERF096-1102}-GUS, P_OsERF096-827-GUS, P_OsERF096-501-GUS constructs, which were then transformed into Arabidopsis.By comparing the GUS staining and GUS gene expression analyzed by qRT-PCR, we found that under control conditions, among the four OsERF096 promoter fragments, P_{OsERF096-1215} and P_{OsERF096-1102} displayed the highest and lowest activity, respectively.Unexpectedly, no significant difference was observed in the activity of four OsERF096 promoter fragments under cold stress, which was contradictory to previous qRT-PCR result showing that OsERF096 expression was greatly induced by cold stress.The findings will facilitate further research on the regulatory mechanism of OsERF096 expression and biological function.