Identification of a novel rice bZIP-type transcription factor gene,OsbZIP1, involved in response to infection ofMagnaporthe grisea

Abstract

The basic leucine zipper (bZIP) proteins belong to a large family of transcriptional factors, some of which are thought to be involved in plant responses to biotic and abiotic stimuli. In this work, we cloned a novel bZIP gene from rice, designatedOsbZIP1, which is inducible in response to infection withMagnaporthe grisea. Sequence analysis showed that the deduced protein had a potential nuclear localization signal and 2 possible acidic activation domains. Results of transient expression experiments demonstrated that OsbZIP1 is localized in the nucleus. The ability of OsbZIP1 to activate the transcription of the reporter gene was also determined in yeast. Northern blotting analysis showed thatOsbZIP1 was constitutively expressed in the roots and strongly induced in rice leaves in response to infection with both the compatible race MS220 and incompatible race 131 ofM. grisea. Furthermore, OsbZIP1 expression could be rapidly induced in leaves treated with salicylic acid, jasmonic acid, and abscisic acid. These results indicate that the OsbZIP1 may function as a transcription factor and may play a role in salicylic acid-dependent signal transduction pathway for defense of rice against pathogens.