Correlation Between The Distribution Of Zm13 And The Expression Of Catalase Gene In Tropical And Temperate Maize

Maize(Zea mays L.)belongs to gramineous plants and is an important food crop.In recent years,the contradiction between supply and demand of maize in China has intensified,mainly because the yield per unit area ofmaize in China is not high.Breeding high-quality and high-yield new species is the fundamental way to solve this problem.However,the lack of temperate maize germplasm resources and serious genetic vulnerability are the status quo in China.Therefore,the use of abundant tropical germplasm is an effective way to change this situation.However,tropical maize has a strong photoperiod sensitivity,which limits its cultivation and utilization in temperate regions.Studies have reported that a 143 bp Zm13 transposon is deleted in the upstream region of the maize Zmcat3 gene promoter,and maize may be insensitive to photoperiod.The expression of this gene is affected by transposon insertion.In order to study the molecular mechanism of maize sensitivity to photoperiod,we distributed the Zm13 transposon in 133 kinds of temperate and tropical maize germplasms,and 3 catalase genes(Zmcat1,Zmcat2 and of Zmcat3)Difference expression in 102 kinds of temperate and tropical maize germplasms,diurnal expression of three catalase genes(Zmcat1,Zmcat2 and Zmcat3)in 30 kinds of temperate and tropical maize germplasms and copy number of Zmcat1 and Zmcat3 in 15 kinds of temperate and 12 kinds of tropical maize germplasm genomes.The main results are as follows:1.Bioinformatics analysis showed that there are three catalase-encoding genes in maize,which are distributed on three different chromosomes,with molecular weights ranging from 56.51 to 56.76 kDa and belongs Stable protein.By constructing a protein evolution relationship of catalase in four species(maize,rice,Arabidopsis and sorghum),it was found that catalase can be divided into three subfamilies:cat1,cat2 and cat3,and three catalase of the maize the three catalase enzymes in sorghum have high protein homology.Protein network interaction analysis revealed that three catalase enzymes were involved in embryonic development,inflorescence formation,cell morphogenesis and signal transduction pathways.2.This study used 133 kinds of geramplasms as materials,including 72 kinds of temperate maize germplasm and 61 kiinds of tropical maize germplasm.There are 16 kinds of temperate maize and 3 kinds of tropical maize with Zm13 transposon in the upstream region of Zmcat3 gene.It is speculated that this transposable element may not be the key site for the regulation of photoperiod sensitive gene expression.3.Sequencing the Zm13 transposon in the above 19 kinds of maize germplasms,and found that there is a base difference site in the upstream of the Zm13 transposon that only occurs in temperate maize,and base 524th of C is mutated to T;One base difference site is only found in tropical maize,and base 392th is mutated to C;one base difference site is present in both temperate and tropical maize,and base A is mutated to C..4.By analyzing the difference in the expression levels of catalase-encoding genes Zmcat1,Zmcat2 and Zmcat3 in 59 kinds of temperate and 43 kinds of tropical maize,it was found that there were large Differences of three genes expression in temperate and tropical maize.Combined with the insertion of the genomic transposon,the insertion of the transposon can affect the expression of the Zmcat3 gene to a certain extent,and the insertion of the Zm13 transposon will result in a decrease in the expression of the Zmcat3 gene.In temperate maize with transposon insertion,the expression level of Zmcat3 gene may be significantly or significantly reduced.The occurrence of the 75th base,the 424th base mutation,and the base insertion of two base sites in maize can reduce the expression level of the Zmcat3 gene to some extent.5.The copy number of Zmcatl and Zmcat3 in the genome is quite different in temperate and tropical maize,but the expression of these two genes is not directly related to their copy number variation.6.By analyzing the changes of day and night expression of catalase-encoding genes Zmcat1,Zmcat2 and Zmcat3 in 22 kinds of temperate and 8 kinds of tropical maize,it was found that the diurnal expression of Zmcat1 gene in different maize germplasms was different in different germplasms.The same trend is observed;Zmcat2 is higher in expression during daytime(lighting)than at night(darkness),which is consistent with previous conclusions,that is,Zmcat2’s response to light is at the transcriptional and translational level.Positive;Zmcat3 expression showed the same trend in all temperate maize and tropical maize,peaking at 18:00,which is consistent with previous studies showing that the expression of catalase gene Zmcat3 is regulated by circadian rhythm.The rate of decline in expression of Zmcat3 in temperate maize between 00:00 and 06:00 and 18:00 to 22:00 was less than that of tropical maize,which may be affected by differences in photoperiod sensitivity between germplasm.The presence of the transposon has a certain influence on the rhythm expression of the temperate maize Zmcat3 gene,leading to its peak in advance.At the same time,there are other mechanisms and factors that regulate and affect the expression of Zmcat3 gene rhythm,which can attenuate the effect of transposon on the peak time of the gene.In tropical maize,the rhythm expression of the Zmcat3 gene was not affected by the transposon.