Function Research Of ZmWRKY114 Gene In Regulating Rice Plant Height

Plant height is an important agronomic trait in modern maize breeding.Dwarfing or semi-dwarfing traits give crops lots of advantages,such as enhanced lodging resistance,suitable for dense planting,improved harvest index,etc.,which are of great significance to increase and stabilize crop yield.WRKY transcription factor is one of the largest transcription regulatory factor families in plants and constitutes an important part of plant signal network.It was found that WRKY family members are not only extensively involved in plant abiotic stress defense response,but also play an important role in plant growth and development,morphogenesis,plant height and plant type regulation.Based on previous work in the laboratory,this study focused on rice overexpressing ZmWRKY114,and explored the function and molecular mechanism of ZmWRKY114 in regulating plant height by using genetics,molecular biology and cell biology.The main results are as follows:1.The results of phenotypic analysis showed that ZmWRKY114 transgenic rice was obviously dwarfing compared with the wild type during the whole growth period.The results of paraffin section analysis of stem node tissue showed that the semi-dwarfing phenotype of ZmWRKY114 transgenic rice was caused by the decrease of the number of stem internode cells.Phylogenetic tree and sequence analysis showed that ZmWRKY114 contained a typical WRKY domain,a nuclear localization signal,and a C2H2 zinc finger structure,which belonged to theⅡd subfamily of WRKY transcription factors.ZmWRKY114 and OsWRKY51 are in the same evolutionary branch,and OsWRKY51 can interact with OsWRKY71 to inhibit GA biosynthesis.2.Content of GA₁ and GA₃ in ZmWRKY114 transgenic rice were significantly lower than those of the wild type by GA content determination,GA₃ sensitivity test and GA₃replenishment test.Overexpression of ZmWRKY114 reduced the sensitivity of transgenic rice to GA₃,and exogenous GA₃ replenishment treatment could restore the plant height of transgenic rice.These results suggest that ZmWRKY114 may regulate plant height by regulating gibberellin biosynthesis in rice.3.Transcriptomic sequencing of 4-week-old wild-type and ZmWRKY114 transgenic rice showed that overexpression of ZmWRKY114 in rice altered the expression of some plant height related genes,including OsEUI1,OsGA2ox4,OsYAB1 and OsLOL2.4.EMSA and dual luciferase reporter assay results showed that ZmWRKY114 was activated by directly binding to the W-box cis-element in the OsGA2ox4 promoter region,suggesting that OsGA2ox4 is a direct target of ZmWRKY114.In conclusion,this study found that the semi-dwarf phenotype of ZmWRKY114 transgenic rice was caused by GA deletion.In transgenic rice,ZmWRKY114 binds to the OsGA2ox4promoter region and activates its expression.The increased expression of OsGA2ox4 leads to the decrease of GA expression level in the plant,which leads to the dwarfing of rice plants.This study revealed the key role of maize WRKY gene in rice growth and development and plant height morphogenesis,and provided theoretical reference for exploring maize plant height related functional genes and breeding maize dwarf germplasm resources.