The Cloning And Functional Analysis Of Transcrip Tion Factor Gene SiNAC45 And SiMYB9 From Foxtail Millet

NAC(nascent polypeptide-associated complex) and MYB transcription factors play an important role in regulating plant growth and development, and abiotic stress response, and other processes. Millet has drought resistance, barren characteristics, it is an ideal material for crop resistance research. In this study we found two millet transcription factors gene SiNAC45 and SiMYB9 that expression had been upregulated under potassium stress on the basis of transcriptome sequence analysis of low potassium stress had been completed in previous work. and around the gene to do the characteristic analysis and resistance identification, to obtain the following results:1. SiNAC45 belonged in the first subfamily of NAC gene family. The full-length of SiNAC45 is 1383 bp, encoding 461 amino acids, and molecular weight and isoelectric point of SiNAC45 protein are 50.7 kD and 6.92, respectively. There is a conserved NAM domain between 20–100 amino acids of SiNAC45; SiMYB9 is a R2R3 MYB transcription factors. The full-length of SiMYB9 is 948 bp, it hastwo exons and three introns, encoding 316 amino acids.2. The gene expression profile results indicated that SiNAC45 was localized in the nucleus, mainly expressed in root and was induced by ABA and low potassium treatment, but did not other treatment such as NaCl and PEG. In seed germination, SiNAC45 maybe negative regulate ABA signal pathway; SiMYB9 was localized in the nucleus, it was induced by low nitrogen and low potassium treatment, but not ABA, NaCl and PEG.3. Gene resistance analysis showed that, under treatment with different concentrations of potassium, root length and fresh weight of SiNAC45 overexpression Arabidopsis significant increased compared with wild-type Arabidopsis, under treatment with different concentrations of potassium, nitrogen and phosphorus treatment, the root length of SiMYB9 overexpression Arabidopsis significant increased compared with wild-type Arabidopsis, no significant difference in the number of lateral roots between transgenic and wild-type Arabidopsis.4. Expression of two important potassium transporter genes AKT1 and HAK1 increased significantly in SiNAC45 transgenic plants, it same as CBL9 and CIPK23 in SiMYB9 transgenic plants.In conclusion: SiNAC45 transgenic plants can enhance tolerance to low potassium stress and maybe negative regulate ABA signal pathway; SiMYB9 overexpression Arabidopsis significant enhance tolerance to low potassium,low nitrogen, low phosphours stress. The functional analysis of SiNAC45 and SiMYB9 is a foundation for research molecular mechanisms of millet, and provides a new crop genetic improvement candidate genes.