Functional Studies Of Rice Histone Deacetylase OsHDA706 And OsHDA714 In Rice

The main research contents of epigenetics include DNA methylation,histone modification and chromatin remodeling factors,histone modification includes various modifications of amino acid residues on the N-terminal of histones,such as methylation,acetylation and phosphorylation.By affecting the state of chromatin,these modiflcations play an important role in regulating gene expression and are one of the important mechanisms of epigenetic regulation.Histone acetylation is one of the most studied modifications.The addition and removal of Histone lysine acetylation is eo-coordinated with Histone acetyltransferases(HATs)and Histone deacetylases(HDACs),respectively.Histone deacetylase can be divided into three subfamilies:RPD3/HDA1 family,HD2 family and SIR2 family.Our previous studies indicated that that OsSRTI of rice histone was deacetylated in the glycolytic pathway(OsGAPDHI)to inhibit its transcriptional activity,and the OsSRTl inhibit the accumulation of OsGAPDHl protein in the cell nucleus,thus regulating the metabolism of saccharide and eventually OsSRTl affected the energy metabolism in rice.To investigate whether other histone deacetylases are associated with energy metabolism,we use two groups in the RPD3/HDAI family to take the histone deacetylase OsHDA706 and OsHDA714 for the study,and by reverse genetics,bioinformatics and molecular biology,to study the biological functions and the metabolic pathways of OsHDA706 and OsHDA714,and try to illustrate the mechanism of their function in plant growth,gene expression,and metabolic control.The main results of this paper are as follows:1.The expression profile of OsHDA706 and OsHDA714 analyze that the two genes were high in expression in green parts,such as leaves,flag leaf and stem of rice,and were low in the non-green parts,such as callus,endosperm and young ear.Genetic rhythm analysis revealed that OsDA706 had a certain circadian rhythm,while OsHDA714 had no circadian rhythm.2.OsHDA706 and OsHAD7I4 mutants were created using Crispr/Cas9 technology.Phenotypic study showed that the seeds ofhda706 showed early maturation,and the overexpression plant(OX706)showed reduced plant height and less tiller.While OsHDA714 CRISPR/Cas9 mutant plants(hda714)a lower seed setting rate,a more compact plant phenotype,and overexpression plants(OX714)displayed no obvious phenotype.3.The prediction of subcellular software indicates that these two proteins are cytoplasmic proteins,which are further conflrmed by the transient transformation of protoplastsof rice and tobacco leaves.OsHDA706 is located in the cytoplasm,and OsHDA714 is located in the cytoplasm and in the endoplasmic reticulum.This suggests that these HDAC may regulate lysine acetylation of non-histone proteins.4.The expression levels of OsHDA706 and OsHDA714 were detected by different stress treatments on wild-type rice materials.The results showed that after 3 hours of 300 mM NaCI and 42? heat treatments,OsHDA706 RNA expression is induced,but at 4?(cold),the expression of OsHDA706 is suppressed.5.The wild type rice material was subjected to energy stress treatment to detect the expression levels of OsHDA706 and OsHDA714,the results showed that OsHDA706 expression is induced by treatments with 2%Glucose(Glucose)dark during 3 h and nitrogen deprivation during eight days.With 2%of glucose and the lack of nitrogen,the OsHDA714 expression is not much changed,but is suppressed in the dark.These qRT-PCR results were also verified in hda706 and hda714 plants.It indicates that OsHDA706 is induced by carbon(dark)and nitrogen(complete lack of nitrogen)status.6.Yeast two-hybrid experiments were performed to screen two proteins that interact with OsHDA706 and OsHDA714,enoyl-CoA hydratase and glucose-6-phosphate dehydrogenase(G6PDH).In addition,the results of subcellular localization indicate that OsHDA706 and OsHDA714 co-localize with the interaction proteins enoyl-CoA hydratase and G6PDH,respectively.