Analysis Of ERF Transcription Factor OPBP1

The ERFs (ethylene-responsive factors) is unique to plants, containg a conserved DNA domain. Recently, it was approved that the expression of many ERF genes is involved in plant development metabolisms pathogen infection, as well as response to environmental stress, such as high salt cold drought et al. Recently, ERFs have been evidenced to regulate different plant signaling pathways. It has been a hot topic to understand the interaction of differdent plant signaling pathways.Osmotin promoter binding protein 1 (OPBPl), was isolated using a yeast one-hybrid system. RNA gel blot and RT-PCR analysis indicated that expression of the OPBPl gene was induced by elicitor cryptogein, NaCl, ethephon, methyl jasmonate, cycloheximide, as well as pathogen attack. It indicate that OPBPl is an immediate early gene, and maybe involved in plant response to biotic and abiotic stress. Transient expression analysis using an OPBPl-eGFP fusion gene in onion epidermal cells revealed that the OPBP1 protein was targeted to the nuclear. Further, electrophoretic mobility shift assays demonstrated that the recombinant OPBPl protein could bind to an oligonucleotide containing the GCC-box cis element. Transgenic tobacco plants with an overexpression of the OPBPl gene accumulated high levels of PR-la and PR-5d genes and exhibited enhance resistance to infection by Pseudomonas syringae pv tabaci and Phytophthora parasitica var nicotianae pathogens. They alao exhibited increase tolerance to salt stress at the seed-germination/ seedling stage as reflected by the percentage of germination/green seedlings, the fresh weight of seedlings, and their developmental pattern. On the other hand, the antisense transgenic lines, whose expression of OPBPl gene was inhibited, became more sensitive to salt stress and pathogen attack.Transgenic rice plants with an overexpression of the OPBPl gene accumulated higher levels of wsil8, OsNHXl, OsP5CS and OsGSTul, which were reported to be involved in salt tolerant signaling pathway. The overexprssion rice lines exhibited enhanced resistance to infection of Magnaporthe grisea, more tolerant to salt stress and oxidase stress.Thus, OPBPl seems to be an important determinant of biotic and abiotic stress response in plants. However, it would be of interest to know whether pathogen resistance and stress tolerance in rice is either due to ectopic expression or the natural function of OPBPl.