Six NAC transcription factors involved in response to TYLCV infection in resistant and susceptible tomato cultivars.

NAC transcription factors (TFs) belong to plant-specific TFs, which have been identified in many plant species. The NAC TFs act as the nodes of a regulatory network in plant's response to abiotic and biotic stresses. Till now, response of tomato NAC TFs involved in Tomato yellow leaf curl virus (TYLCV) infection is unknown. In the present study, six NAC TFs were identified to respond to TYLCV infection in tomato. We observed that transcripts of four NAC genes (SlNAC20, SlNAC24, SlNAC47, and SlNAC61) were induced after TYLCV infection in resistant tomato cultivar. Virus-induced gene silencing analysis (VIGS) indicated that SlNAC61 played positive roles in response to TYLCV infection. Tomato NAC TFs were not only involved in defense regulation but in development and stress progress. These NAC TFs interacted with other proteins, including protein phosphatase and mitogen-activated protein kinase. Some defense response TFs, such as WRKY, TGA, MYB, NAC, could interact with NAC proteins by binding cis-elements in promoter regions of NAC TFs. These identified tomato NAC TFs cooperated with other TFs and proteins, indicating the complex response mechanism of described NAC TFs involved in TYLCV infection. The results will offer new evidence to further understand the NAC TFs involved in response to TYLCV infection in tomato.