GIGANTEA regulates transcription to promote pathogen defense against in .

Plants have evolved a network of complex signaling pathways that allow them to cope with the fluctuations of internal and external environmental cues. GIGANTEA (GI), a well-known, highly conserved plant nuclear protein, has been shown to regulate multiple biological functions in plants such as circadian rhythm, light signaling, cold tolerance, hormone signaling, and photoperiodic flowering. Recently, the role of GI in disease tolerance against different pathogens has come to light; however, a detailed mechanism to understand the role of GI in pathogen defense remains largely unexplained. Here, we report that is upregulated upon infection with a virulent oomycete pathogen, (), in accession Col-0. To investigate the role of GI in defense, we examined the pathogen infection phenotype of mutant plants and found that mutant was highly susceptible to Noco2 infection. Notably, the quantitative real-time PCR showed that () and several PAD4-regulated downstream genes were downregulated upon Noco2 infection in mutant as compared to Col-0 plants. Furthermore, the chromatin immunoprecipitation results show that GI can directly bind to the intronic region of the gene, which might explain the mechanism of GI function in regulating disease resistance in plants. Taken together, our results suggest that expression is induced upon pathogen infection and GI can regulate the expression of to promote resistance against the oomycete pathogen in .