Function Study Of Histone Deacetylase ZmHDT102 In Maize Resistance To Fusarium Graminearum

Histone deacetylases(HDACs)are key factors regulating the level of histone deacetylation and play an important role in chromosome structure modification and gene expression regulation.ZmHDT102,a maize histone deacetylase homologous to Arabidopsis AtHDT3 and rice OsHDT701,was obtained in previous laboratory studies.It was confirmed that the expression level of ZmHDT102 was significantly changed after treatment with salicylic acid and jasmonic acid,and showed a significant trend of inducing expression during the infection of Fusarium graminearum.It is speculated that ZmHDT102 plays an important role in maize resistance to F.graminearum.In order to further clarify its function and mechanism of action,the mutants of ZmHDT102 gene,Zmhdt102-1(initiation codon mutation),Zmhdt102-2(encoding codon mutation)and Zmhdt102-3(Mu transposon insertion mutation),were obtained in this study.The disease resistance of the mutants were testing to clarify the function of ZmHDT102 gene in maize disease resistance.The interacting proteins of ZmHDT102 were screened and identified by yeast library,IP-MS and Y2H technique.The downstream target genes of ZmHDT102 were screened and identified by RNA-Seq and qRT-PCR,which laid a foundation for elucidation of the function and mechanism of ZmHDT102 in maize resistance to biological and abiotic stress.The main results are as follows:1.Bioinformatics and expression pattern analysis of ZmHDT102 in maize.In this study,phylogenetic tree and domain analysis were performed on the plant-specific HD2 subfamilies of the HDAC family in maize,Arabidopsis and rice,and it was found that they do not have the HDAC domain specific to the HD AC family,and most of them have only a zinc finger structure.Maize ZmHDT102 is homologous with Arabidopsis AtHDT3 and rice OsHDT701.The promoter region of ZmHDT102 contains sequence elements that are responsive to stress and plant hormones.The expression regularity of ZmHDT102 gene was different in different tissues,which had certain time sequence and specificity.The expression of ZmHDT102 gene was significantly down-regulated under heat stress,cold stress and ultraviolet treatment.The expression of ZmHDT102 gene was significantly up-regulated under drought stress.The expression level of ZmHDT102 was increased continuously under the infection of F.graminearum.The expression level of ZmHDT102 was first increased and then decreased after ABA treatment,suggesting that ZmHDT102 was involved in the resistance of maize to biological and abiotic stresses.2.Subcellular localization analysis of maize ZmHDT102.Gateway technology was used to construct the vector ZmHDT102-103 for the fusion expression of ZmHDT102 and GFP.By means of Agrobacterium-mediated genetic transformation,ZmHDT102-103 was transformed into tobacco leaf cells for transient expression.The green fluorescence signal of GFP was observed in the nucleus under laser confocal microscope,indicating that ZmHDT102 was localized in the nucleus.3.Function studies of maize ZmHDT102 during growth and disease resistance.Compared with the inbred line B73,the mutant plants Zmhdt102-1,Zmhdt102-2 and Zmhdt102-3 were significantly shorter,with shorter fruit panicle,more desiccated seeds,and lower 1000-grain weight;After inoculation with F.graminearum,Setosphaeria turcica,Cochliobolus heterostrophus,Cochliobolus carbonum and Curvularia lunata,the mutants showed increased sensitivity.The expression level of ZmPRs gene in the mutant was significantly lower than that of the inbred line B73.These results indicated that ZmHDT102 played a positive regulatory role in maize growth and disease resistance.4.Screening and identification of ZmHDT102 interacting proteins in maize.18 potential candidate interaction proteins of ZmHDT102 were obtained by screening ZmHDT102 interaction proteins by species homologous relationship,yeast library and IPMS.The interaction between ZmHDT102 and ZmHDT108,ZmRpp30,ZmPIP1A,ZmMAP4K,ZmZnFl and ZmHDA101 was verified by yeast two-hybridization test,and the results were all negative.5.Screening and identification of ZmHDT102 target gene in maize.The downstream target genes of ZmHDT102 were analyzed by RNA-Seq,and 40 candidate target genes were obtained.Candidate target genes were identified by qRT-PCR.ZmZIM9,ZmETR1,ZmEIL8,ZmETR5,ZmPRP14,ZmPRP4,ZmMKK1,ZmAIC2,ZmZIM19,ZmAIC3,ZmIAA5,ZmARFTF29,ZmCML36,ZmEREB198 and ZmRPS3 were predicted to be possible downstream target genes of ZmHDT102.