Cloning And Function Analysis Of SINAC6 And SINAC7 Genes In Suaeda Liaotungensis K

NAC transcription factors play an important role in regulation of plant growth, development and resistance to drought, high salt, low temperature, damage, virus and other physiological processes.As one of the important halophytes, there are a lot of salt-tolerant genes in Suaeda liaotungensis K. to be researched. In this study, two EST sequences are identified from the transcriptome sequencing database of S. liaotungensis, and named as SlNAC6 and SlNAC7. And we do study on their gene cloning and function analyzing.RACE was used to amplify whole length of SlNAC6 and SlNAC7 cDNA. The whole length of SlNAC6 cDNA is 1301 base pair(bp) and encodes 353 amino acids, and the GenBank with the accession number is KR002106. The whole length of SlNAC7 cDNA is 1863 bp and encodes 573 amino acids, and the GenBank with the accession number is KR002107. Multiple sequence alignment and phylogenetic tree showed that SlNAC6 belongs to ONAC003 subfamily, and SlNAC7 belongs to ANAC011 subfamily.By using qRT-PCR method,we analyzed the expression patterns of these two genes. The results showed that the two genes express in different tissues in S. liaotungensis and the expression is the highest in leaves, lower in stems, the lowest in roots. SlNAC6 and SlNAC7 response to salt, low temperature and ABA stress.The transcription activation assay in yeast demonstrated that SlNAC6、SlANC7 and their C-terminal have the transcription activation activity,while the conserved N-terminal not. This study prove that SlNAC6 and SlNAC7 are transcription factors and the transcription activation domain is in C-terminal.The SlNAC6-GFP and SlNAC7-GFP were transfered into onion epidermal cells by using gene gun. Subcellular location assay showed that SlNAC6, SlNAC7 protein are targeted to the nucleus and cytoplasm. This study proved that SlNAC6 and SlNAC7 localized in nucleus are transcription factors and SlNAC6 and SlNAC7 localized in cytoplasm may have other functions.The SlNAC6 and SlNAC7 were transfered into Arabidopsis by inflorescence infection method. Through screening, the homozygous diploid of SlNAC6 and SlNAC7 transgenic Arabidopsis were obtained. The resistance analysis under different abiotic stress of transgenic Arabidopsis indicated that SlNAC6 and SlNAC7 are excellent genes to resist salt cold and drought stress.The study on abiotic stress-related NAC transcription factors in Suaeda liaotungensis K., not only promotes to understand plant stress-resistance mechanisms, but also establishes the foundation for stress-resistance crop cultivation.