OsNACs Were Up-regulated By Cd In Rice And The Function Study Of OsNACs Domain Sequence

Cadmium(Cd)is a heavy metal that harm for animals and plants,and it is a contaminants in soil.Plants absorb and transfer Cd by root,thus enrichment in plants,and finally threat to human health.RNA-seq analysis shows that the expression level of NAC transcription factors have changed in rice leaves when exposed to Cd,and the rice leaves express not only the full-lenght NAC genes,but also NAC isoforms only with DNA binding domain.The expression level of OsNACs and OsNACs domain sequence were up-regulated by Cd,thus this study will focus on the research of the interaction between NAC transcription factors and their domain sequence.Then the expression of OsNACs in rice was confirmed by the qRT-PCR method,and the results show that the expression of OsNAC3、OsNAC5 and OsNAC6 were up-regulated by 50 μM Cd.The results of BiFC show that OsNACs can interaction with their corresponding NAC domain sequence in the nucleus.OsNAC5 domain sequence also displayed cross interaction with other OsNACs and itself in the nucleus.To testify whether OsNACs domains interfere their corresponding full-lenght NAC transcription factors,the expression of OsLEA3,which is regarded as the target of NACs,was analyzed by qRT-PCR in protoplast-based transient expression assays.The data showed that the NAC-regulated gene OsLEA3 is up-regulated by over-expression OsNACs in rice protoplasts,whereas the upregulated expression of OsLEA3 is down-regulated by co-transforming the OsNACs domain sequences.In a word,OsNACs gene were up-regulated by Cd in rice leaves,and OsNACs can interaction with OsNACs domain sequence,and co-localized in the nucleus,which was called the dimeration of OsNACs transcription factors in plant.Thus the OsNACs domain sequence can interfere with the full-lenght NAC transcription factors to regulate the expression of NAC-regulated gene by competitively binding the promoter region...