Abstract
Trichothecenes are a family of closely related phytotoxins produced by several phytopathogenic fungi, and acts on eukaryotic ribosome as inhibitors of protein synthesis. We revealed that T-2 toxin, one of trichothecenes induce defense response in Arabidopsis plants. We also found that the AtNF-X1 gene, which is an Arabidopsis homolog of the human transcriptional repressor NF-X1, was up-regulated in T-2 toxin-treated plants. The AtNF-X1 protein contains a RING finger domain and a NF-X1-type Zn finger domains. An atnf-x1 mutant was highly sensitive to T-2 toxin compared with the wild type. Western blot analysis revealed that AtNF-X1 protein levels increased by T-2 toxin treatment. Expected molecular weight of AtNF-X1 protein is about 130 kD , but protein bands of 80 kD and 62 kD were detected by αAtNF-X1-N (60-142 a.a.) and αAtNF-X1-C (766-1188) antibody, respectively. These results suggest that the AtNF-X1 protein was cleaved by a protease.
