Characterizition And Function Analysis Of Wheat Transcription Factors TaNAC2 Response To Puccinia Striiformis F.Sp.Tritici

Wheat stripe rust, caused by Puccinia striiformis f.sp.tritici(Pst), is one of the most devastating diseases in the world. Due to its fast spread and high frequent occurrences, the disease has attracted much global attention. Therefore, analyzing the interaction and molecular mechnism between wheat and stripe rust is important for the sustainable control of wheat stripe rust. Especially, understanding the molecular signaling pathways of resistance genes response to biotic stress and abiotic stress can provide theoretical basis and practical value for breeding new disease-resistant varieties. Plant-specific NAC comprises one of the largest plant transcription factor(TF) families. The NAC proteins have been found to play important roles in plant development and regulation, responses to viral infections, environmental stimuli and pathogens. In this study, a TaNAC2 gene was characterized in the wheat-stripe rust fungus pathosystem. The main results and conclusions are as follows:Through searching the wheat cDNA libraries constructed by our lab, We obtained a 1457 bp coding sequence through RT-PCR, which contained an open reading frame(ORF) 990 bp and encoded a polypeptide of 329 amino acids. Besides, through analyzing its amino acid sequence of TaNAC2, We found that N-terminal contains a plant-specific NAC conservative domain structure belongs to NAM, which is the subfamily of NAC family. The quantitative real-time polymerase chain reaction(qRT-PCR) analyses revealed that TaNAC2 in the compatible interaction challenged by the virulent Pst race CYR31 and increased following 48 h post inoculation(hpi), so it may be a disease gene. After exogenous application of JA, SA and ABA treatment, the up-regulation of the TaNAC2 transcript was immediately observed following 2h post treatment. However, ETH had no obvious effect on TaNAC2 expression. Yeast one-hybrid assay revealed that the C-terminal region of the TaNAC2 protein had transcriptional activity. To test the subcellular localization of TaNAC2, We carried out transient expression analysis of TaNAC2-GFP fusion protein in Arabidopsis leaf protoplasts and found that TaNAC2 is localized in the nucleus. To further obtain the function of TaNAC2 during the wheat-Pst interaction, BSMV-VIGS system was used to decrease the transcript level of TaNAC2, which enhanced the resistance of wheat to the virulent race CYR31. Therfore, We speculated that TaNAC2 is a sense of disease genes. The results indicated that the TaNAC2 gene functioned as a transcriptional activator involving in wheat response to biotic and abiotic stresses.