Study On Epigenetic Effector DRW1 In Regulation Of Growth And Development And Establishment Of Epigenomic Database In Rice

Both genetic regulators and epigenetic modifications play essential roles in regulation of gene expression,developmental cues and environmental stimuli,resulting in bio-diversity fundament.During cell division,genetic and epigenetic information must be exactly transferred from mother to daughter cells in eukaryotes.But these epigenetic regulation processes transferring from mother cells to daughter cells during cell-cycle progression are less unknown in plants,especially for crops.Here,this study revealed that the yeast CTF4(CHROMOSOME TRANSMISSION FIDELITY PROTEIN 4)homologous protein in rice,DRW1(DWARF-RELATED WD40 PROTEIN 1),which participate in the recruitment of Polycomb(Pc G)complex members Os LHP1(LIKEHETEROCHROMATIN PROTEIN 1)and Os CLF(CURLY LEAF),forms “epigenetic molecular module” to maintain H3K27me3 modification.In rice,DRW1 specifically regulates the cell cycle inhibitors KIP-RELATED PROTEIN 1 and KRP5 to delay S phase in the cell cycle.Further protein-toprotein interaction assays verified that DRW1 interacts with the DNA helicase complex component GINS(Go,Ichi,Nii,and San)and DNA polymerase ?(DNAP)as a “replication molecular module” to regulate DNA replication and damage repair.It has been shown that DRW1 is similar to molecular function of yeast CTF4 that influence the DNA helicase activity,DNA replication and damage repair in the S phase of the cell cycle,but also specifically affects the transmission of epigenetic information during cell division,remains elusive in yeast CTF4.Loss-of-function DRW1 causes significantly yield-related phenotypes,i.e.,dwarf,reduced seed size,while mutation of CTF4 homologous EOL1(ENHANCER OF LHP1 1)in Arabidopsis thaliana,has no remarkable phenotype.It was found that both rice DRW1 and Arabidopsis EOL1 are expressed in the dividing cells,directly interact with the members of the Pc G complex promoting the deposition of H3K27me3 modification levels;however,the downstream biological processes act antagonistically.In rice,drw1 does not affect heading date(flowering time in rice),involve in control of cell cycle and DNA damage repair;while Arabidopsis EOL1 is involved in the regulation of photoperiod flowering pathways,and non-responsive to ell cycle and DNA damage mechanisms.This study states that the biological function of CTF4/EOL1/DRW1 is not only conserved,but also divergent during the evolutionary events.In addition,DRW1 modulates yield-related traits including plant height and seed size.Further research on the function of DRW1 provides clues for subsequent genetic improvement of rice growth,yield,and stress resistance related traits and improvement.Currently,no report for species-specific epigenomic database is available hindering epigenetic studies in rice.Thus,integration of high-quality japonica rice "Nipponbare" and indica rice("93-11")genomic annotations,DNA N6-adenine methylation(6m A)and 5-cytosine methylation(5m C)and transcriptomic data reported by our research group,and Ch IP-seq(Chromatin Immunoprecipitation sequencing)data for histone modification downloaded from NCBI,combined with deep-learning approaches for 6m A prediction,the rice epigenomic database “e Rice” was established(http://www.elabcaas.cn/rice/index.html).The integration of epigenomic and genomic data improves data utilization and in-depth mining capabilities,and realizes systematic query and integrated display of gene sequence and annotation information,DNA methylation,histone modification,and intelligent prediction data of DNA methylation.Thus,e Rice provides a variety of big data including genome and epigenome and AI(Artificial Intelligence)prediction data and users can access,query and obtain data with a friendly interface,providing a data platform for rice breeding programs by molecular design.