The Transcription Factor PwNF-YB3 Plays Role In Response To Abiotic Stresses In Arabidopsis Thaliana

NUCLEAR FACTOR-Y (NF-Y), also known as heme-associated protein (HAP) or CCAAT-binding factor (CBF), is one of the most ubiquitous transcription factors found in eukaryotes. The NF-Y complex includes three subunits:NF-Y A, NF-YB, and NF-YC. The interaction among the three subunits resulted in a large number of NF-YA/YB/YC heterotrimer combinations in plants, and thereby provides the potential for the NF-Y complex to be implicated in a wide range of processes and play diverse roles in gene transcription in higher plants. In recently years, with the functional dissection of NF-Y family, NF-Y members appears to be vital integrators of various regulatory events, involving the transcription factor itself as well as plant developmental process and stress response. Here, we identified another NF-Y subuint fromPicea wilsonii, PwNF-YB3 gene, and transformed it into Arabidopsis to detect its function in plant. Our data showed that overexpression of PwNF-YB3 altered the flowering time and conferred an enhanced tolerance to salt and drought stress in Arabidopsis. The results were showed as follows:1 To investigate the potential role of PwNF-YB3, we first evaluated its expressions in different organs such as root, stem, needle, pollen, and abiotic stresses by quantitative RT-PCR (RT-qPCR). The results suggest that PwNF-YB3 was significantly enhanced by treatment with NaCl, heat, PEG and slightly induced by ABA and cold treatment.2 To determine whetherPwNF-YB3 functions as a transcription factor, we observed the localization of PwNF-YB3 by transient expression in Arabidopsis. The PwNF-YB3-GFP fusion protein was predominately localized in the cell nucleus, while the GFP protein alone was detected both in cytoplasm and nucleus, as expected.3 To investigate whether PwNF-YB3 functions in plants response to salinity and osmotic tolerance, PwNF-YB3 was transformed into Arabidopsis. Overexpression of PwNF-YB3 in Arabidopsis seedlings increased tolerance to salinity stress and Mannitol treatment during seed germination and seedling stage.4 To investigate the mechanism of PwNF-YB3involved in stress response, we selected several stress related genesand examined their expression level by RT-qPCR in PwNF-YB3 overexpression line and wild type plants. Our results suggest PwNF-YB3 is more likely to be involved in the CBF-dependent dehydration response than ABA.5 Transactivation of PwNF-YB3 was not detected in yeast, suggesting that PwNF-YB3 is likely to act as transcription inhibitor. PwNF-YB3 and PwHAP5 can interaction in vitro through the method of Yeast Two Hybrid System, suggesting that PwNF-YB3 act as transcription activator by interacting with other genes or transcription factors.