Cloning And Function Analysis Of S/NAC4、S/NAC10 Transcription Factors In Suaeda Liaotungensis K.

NAC transcription factor is the plant transcription regulatory factor which has been newly discovered in the past decade, and plays a crucial role in organ formation,plant growth and defense a variety of stresses. The study of abiotic stress related NAC transcription factors, helps to understand the mechanism of plants, and lays a foundation for the crop cultivation.In this paper, two sequences with NAC domain structure, named SlNAC4 and SlNAC10 from the Suaeda liaotungensis K. transcriptome database, are cloned and analyzed. The main results and conclusions are as follows:Based on the known EST sequence, the length sequences of SlNAC4/10 are obtained by RACE technology. SlNAC4(GenBank login number: KJ933531) has 1450 bp, which encodes 331 amino acids. SlNAC10(GenBank login number: KJ933532) has 1584 bp, which encodes 369 amino acids. Accroding to biological information analysis, two genes have conservative NAC structure domains in the N-terminal, and have higher diversities in the C-terminal.NCBI(http://www.ncbi.cn) online Blast and the construction of the evolutionary tree show that, SlNAC4 has high similarity with ThNAC1, SlNAC10 is similar with AtNAC19, AtNAM and AtATAF. According to references, it is speculated that SlNAC4 belongs to NAP subfamily and SlNAC10 belongs to NAM subfamily, and they are also associated with abiotic stress responses.The expressions of SlNAC4 and SlNAC10 in roots, stems and leaves of Suaeda liaotungensis K. are analyzed through qRT-polymerase chain reaction(PCR) analysis, and also analyzed under the conditons, such as drought, high salt, low temperature and ABA abiotic stress. The results show that the SlNAC4 expresses in stem most numerously, while SlNAC10 in leaves. The amount of the expressions of SlNAC4 and SlNAC10 rises first and falls later under different stress treatment suggesting that SlNAC4, SlNAC10 can response to stress and are affected by abiotic stress.By constructing GFP-SlNAC4/10, and transforming into onion epidermal cells by gene gun. It is found that GFP-Sl NAC4 is located in the nucleus and the cytoplasm, while GFP-SlNAC10 is located in the nucleus under the confocal microscope.We guess that they may be transcription factors. SlNAC4 also distributes in the cytoplasm and may have other important functions.By constructing yeast hybrid expression vectors with SlNAC4/10 full length, N terminal and C terminal, and transform yeast AH109 by using lithium acetate mediation, which are respectively nurtured in SD /-Trp(short) and SD /-Trp-His-Ade nurturing medium. Beta galactose glucoside result shows that SlNAC4 and SlNAC10 both have transcriptional activation activity, and the structure of transcription activation locates in the C terminal, which are further determined as the transcription factors.By constructing plant expression vectors, transforming Arabidopsis thaliana, the exogenous homozygous lines T3 generation are obtained and identified by PT-PCR. After various abiotic stress treatments of the transgenic lines T3 generation, the results show that they have higher resistance to drought, high salt and low freezing. SlNAC4 and SlNAC10 play a certain role in resisting abiotic stress in plants, and thus can be used for cultivation of the plants resisting abiotic stress.