Preliminary Study On The Function Of Rice BZIP Gene OsNIF1and OsNIF2

The bZIP family genes have been implicated in diverse physiological processes in eukaryotes,such as seed maturation and germination, flower development, light and stress signaling,hormone signaling and defense against biotic and abiotic stress responses.89bZIPtranscription factors have been found in rice, and16of them have been functionallycharacterized, most of them plays a crucial role in the adaptive response to abiotic stressessuch as drought, cold and high salinity. However their function in rice defense responses remainscompletely elusive. In this paper the expression and function of rice blast resistance relatedgene bZIP were studied, and the results are as follow:(1) bZIP genes take a crucial role in response to biotic and abiotic stress in plant. In thispaper, expression profiles of13genes in Pi36-mediated resistance were compared by usingreal-time RT-PCR. The results indicated OsNIF1and OsNIF2were greatly up-regulated in theresistant cultivar while not in the susceptible cultivar. This suggests the two genes mayfunctional participate in Pi36-mediated resistance.(2) In order to further study on the function of bZIP gene in rice blast resistance response,OsNIF1and OsNIF2were regarded as the target of the study, RNAi vector andover-expression vector were constructed respectively. A number of transgenic plants wereobtained by Agrobacterium-mediated transformation to the Q61cultivar. In T0plants, theexpression level in RNAi transgenic plants were down-regulated in different degree andobviously up-regulated in over-expression ones. T1plants were inoculated with an avirulentisolates RB11, and the results showed the Pi36-mediated resistance responses may not relyon the OsNIF1and OsNIF2signal pathway(3) In order to analyze whether the OsNIF1and OsNIF2gene stimulates plants basicresistance after overexpression, The expression level of defense related genes PBZ and PR1bwere detected as well as the SA marker gene WRKY45. Results showed that, after OsNIF1andOsNIF2constitutively overexpressed salicylic acid signaling pathway was stimulated, theymay involved in plant basic defense response.(4) Whether OsNIF1and OsNIF2gene are involved in rice drought stress? Water lossrate of transgenic plants was measured as well as wild type. The results indicated that loss rate of overexpression transgenic plants OsNIF1and OsNIF2were lower than that of thewildtype. So, it is deduced that the two genes may be involved in the responses to droughtstress in rice.(5) Subcellular localization of OsNIF1and OsNIF2genes was predicted by usingbioinformatics methods. The results revealed that they localized in the nucleus. Thensubcellular localization vector of OsNIF1and OsNIF2genes were constructed respectively,using a GFP fusion vectors. The constructions laid the foundation to protoplast transformationand observation of subcellular localization.