A Novel Transcription Factor Gene Negatively Regulates the Defense Response against in Pepper ( L.).

SBP-box (Squamosa-promoter binding protein) genes are a type of plant-specific transcription factor and play important roles in plant growth, signal transduction and stress response. However, little is known about the SBP-box genes in pepper (), especially in the process of infection. In this study, a novel gene () was selected from the gene family, which was isolated from the pepper genome database in our previous study. The gene was located in the nucleus of the cell and its silencing in the pepper plant enhanced the defense response against infection. After inoculation with , the root activity of the -silenced plants is compared to control plants, while malondialdehyde (MDA) content is compared viceversa. Additionally, the expression of defense related genes (, , and ) in the silenced plants were induced to different degrees and the peak of and were higher than that of The over-expressed plants were more susceptible to infection with higher EC (electrical conductivity) and MDA contents as compared to the wild-type. The relative expression of defense related genes (, , and ) in transgenic and wild-type plants were induced, especially the and . In conclusion, these results indicate that gene negative regulates the defense response against infection which suggests their potentially significant role in plant defense. To our knowledge, this is the first report on gene which negative regulate defense response.