Functional Analysis Of Maize Transcription Factor ZmBBX2

Maize（Zea mays L.）belongs to annual graminaceae herb.Globally,corn yields more than any other food crop.In addition to being used as food,corn can also be used as animal feed and industrial feedstock to produce biomass clean fuels.After a long time of development of traditional breeding,although the improvement of traditional varieties has greatly increased the corn yield,the current global demand for corn has far exceeded the increase rate.In the past 20 years,with the in-depth understanding of plant genome and gene function,coupled with the rapid development of genetic engineering technology,people began to try to use genetic engineering to improve maize varieties,in order to achieve the purpose of high yield and superior yield.In order to improve maize from the level of genetic engineering,it is necessary to fully understand the function and mechanism of genes in maize.The BBX transcription factor family is a subfamily of the zinc finger protein family,which plays an important role in plant growth and development,flowering time,and response to biotic and abiotic stresses.The BBX family is well known in Arabidopsis,but relatively little studied in maize.In this study,maize ZmBBX2 transcription factor was selected,and the function and upstream and downstream interaction genes of ZmBBX2 were explained by means of Ch IP-Seq data,yeast single hybridization,Dual-Luciferase,and stable genetic transformation in Stella setaria.Here are the main findings:（1）Stable genetic transformation was carried out on the C₄ photosynthetic type model plant,Stella stellata,using Agrobacterium infection on plant callus as the core method,combined with plant tissue culture technology,and the overexpressed strains of ZmBBX2 were obtained.The overexpressed strains showed high growth,delayed flowering,and high grain yield.（2）Using yeast single hybrid system,the 1030 bp upstream promoter of ZmBBX2 transcription initiation region was divided into 11 segments,and the upstream gene of ZmBBX2 was screened from the existing transcription factor expression library in the laboratory.After the preliminary screening results are confirmed,detailed point-to-point verification is performed,The results showed that Zm NAC could bind to the promoter segment 7 of ZmBBX2.The binding site of Zm NAC was predicted by the binding website,and it was speculated that Zm NAC might bind to the AAAAAAAA or AGAGGA sites in the seventh segment of the promoter of ZmBBX2.（3）Based on the double luciferase report test,tobacco instantaneous transformation was used as material and means.The interaction between Zm NAC and ZmBBX2 was analyzed.The results showed that Zm NAC could activate the transcriptional expression of ZmBBX2.（4）Based on the double luciferase report test,maize protoplasts were transformed into materials and means by instantaneous transformation,supplemented by Ch IP-Seq data analysis.The downstream gene of ZmBBX2 was identified and validated,and it was found that ZmBBX2 could activate the transcriptional expression of ZmRbcS.This project preliminarily analyzed the function of maize ZmBBX2 and phenotype of model plant Staria setaria.The upstream and downstream genes of ZmBBX2 were excavated to supplement and explain the function of BBX family in maize,which also laid a theoretical foundation for the improvement of maize genetic engineering to a certain extent.