Cloning And Expression Analysis Of Transcription Factors Gene PpNAC In Poa Pratensis L.

Kentucky bluegrass (Poa pratensis L.) widely distributed in the northern cold temperate humid regions is one of a perennial cool-season turf grass. Because of its beautiful leaf appearance and thin rhizome, Kentucky bluegrass is not only a fine forage grass, but also a turf grass. Kentucky bluegrass likes the cold and humid climate and endures a strong cold, but was intolerant of drought and susceptible to disease especially in hot and humid conditions. NAC proteins are a class of plant-specific transcription factor, which played an important role in several aspects including plant growth and development, organ formation, hormone regulation and a variety of biotic and abiotic stress. A NAC transcription factor gene was isolated from Kentucky bluegrass by RACE, and primary research on its functions was carried out. Main results are as follows:(1) A NAC gene was cloned by RACE from 200mM NaCl treated Poa pratensis L. leaves. It is 1147bp in length, including an open reading frame of 837bp, encoding a predicted polypeptide chain of 278 amino acid, and its molecular weight is 31.43 kD. The alignment result of nucleotide sequence suggest it belongs to NAC transcription factor, named PpNAC.(2) The pBI-PpNAC-GFP fluorescence expression vector of the PpNAC was constructed. Transient expression of onion bulb epidermal cells showed that PpNAC mainly localized in the nucleus.(3)Southern Blot was performed with DIG-taped cDNA as a probe. Result showed that PpNAC mainly exists in the genome as a single copy.(4) Real-time PCR results show that the expression of PpNAC was promoted significantly by 4℃,37℃,NaCl,ABA and SA,whearas inhibited by PEG,MeJA and ET.