Transcriptome And DNA Methylation Analysis Of Arabidopsis Flower Development Under Exogenous H₂O₂ Conditions

Under stress conditions,shortening the growth period and early flower development of plants is one way to adapt to the stress mechanism of stress.The most common result of plants responding to stress is the production of ROS.The study founded that ROS can be used as a signal molecule to participate in the signal transduction of cellular processes,thereby regulating some important cellular activities and plant physiological processes.Therefore,active oxygen plays an important role in plant flower bud differentiation.In order to investigate the regulation mechanism of ROS on plant flowering,this study used Arabidopsis as experimental material.The pot experiment was carried out by spraying H₂O₂ solution to study the effects of exogenous H₂O₂ on the metabolism of reactive oxygen species,transcriptional expression of flowering genes,methylation of flower genes and flower bud differentiation in Arabidopsis.The results are as follows:?1?The application of exogenous H₂O₂ sprayed the active oxygen peroxide and superoxide anion in the experimental group of Arabidopsis thaliana rapidly,which was significantly higher than that of the control group and changed the oxidative equilibrium state of the plant.Endogenous reactive oxygen species act as a signaling molecule to activate a series of downstream transcription factors that regulate the growth and development of Arabidopsis.?2?Through the statistics of the phenotypes of the test group and the control group,the results showed that the buds and convulsions of the experimental group were earlier than the control group,and the bud rate and convulsion rate of the experimental group were higher than those of the control group.The total number of leaves formed was significantly lower than that of the control group,and the plant height of the test group was significantly lower than that of the control group,and the mature fruit pods were significantly smaller than the control group.This indicates that exogenous H2O2 accelerated the transformation of Arabidopsis from vegetative growth to reproductive growth,prompted Arabidopsis to complete the life cycle ahead of time,and also affected plant and organ growth.?3?Analysis of flowering-related gene expression in Arabidopsis thaliana showed that spraying H2O2 promoted the expression of flowering integration genes FT?SOC1and LFY,and inhibited the expression of flowering inhibitory gene FLC.Exogenous exogenous H2O2 was significantly different after 8 days of spraying,which was basically consistent with morphological observation.It indicated that the application of hydrogen peroxide 8d in this experiment was the key point of flower bud differentiation in the experimental group,which was an important period for the transformation of Arabidopsis from vegetative growth to reproductive growth.It is indicated that reactive oxygen species act as a signaling molecule involved in the regulation of the flowering pathway.?4?Analysis of the gene expression of methylated cytosine methyltransferases MET1?MET2,the domain rearrangement methyltransferase DRM2 and the chromatin methyltransferase CMT3 by fluorescent quantitative PCR showed that the gene expression of was significantly decreased.Analysis of total DNA methylation level by HPLC showed that the total DNA methylation level of the test group was significantly lower than that of the control group,which was consistent with the expression trend of the methyltransferase gene.At 8d,the methylation level of the test group decreased significantly,while the control group rose to the highest level at 10d,which was significantly higher than the test group.It is indicated that 8d is the key period of flower bud differentiation in the experimental group in this experiment,which is consistent with the expression of flowering genes and the observation of flower bud differentiation.Sequencing analysis of the 1500 bp methylation-enriched locus in the promoter region of the upstream flowering region of FT and the flowering inhibitory gene FLC of 8-12d was performed by MethylTarget sequencing technology.The results showed that the total methylation level of the flowering inhibitory gene FLC in the experimental group was higher than that in the control group,while the total methylation level of the FT in the experimental group was lower than that in the control group.It indicated that the treatment of H₂O₂ promoted the FLC methylation level of Arabidopsis thaliana flowering inhibitory gene,decreased the expression of FLC,and relieved the inhibition of downstream flowering positive regulatory factors by FLC.At the same time,it also reduced the methylation level of the flowering factor gene FT to promote its expression to make the Arabidopsis flower start in advance.The response regions of FLC and FT to hydrogen peroxide are mainly in the third analysis fragment of the FLC promoter region and the third analysis fragment in the FT promoter region,and the mechanism of responding to the active oxygen signal needs further study.The experimental results indicate that H2O2 has a genetic methylation modification epigenetic regulation pathway for the promotion of Arabidopsis flower bud differentiation.?5?Transcriptome sequencing of Arabidopsis thaliana shoot tips treated with exogenous H2O2 for 8-10d,we screened 27,416 differentially expressed genes,including 302 differentially expressed genes,178 up-regulated genes,and 124down-regulated genes.Significant changes in the expression levels of many transcription factors and methyltransferases have occurred.Through the GO and KEGG Pathway functions,differentially expressed genes and pathways related to ROS signaling and flower induction were enriched,and further understanding of the possible pathways of transcriptional regulation of ROS-responsive flowering-related genes was provided for subsequent transcriptomes.The combination of basic analysis and H2O2 provides a reliable experimental basis for the regulation of Arabidopsis flower development.This experiment combined with stem tip anatomical structure observation,transcriptome sequencing analysis,total DNA methylation and FLC,FT gene methylation detection.The effects of gene transcriptional expression and DNA methylation modification on the flowering transformation of Arabidopsis thaliana under the treatment of exogenous H2O2 were analyzed.It provides a theoretical reference and experimental basis for further discussion on the regulation mechanism and regulation pathway of reactive oxygen species regulation of Arabidopsis thaliana flower transformation.In this experiment,we combined the observation of stem tip anatomy,transcriptome sequencing analysis,total DNA methylation and FLC?FT gene methylation detection to analyze the gene transcription and DNA methylation modification of exogenous H₂O₂ treatment.The effect of mustard flower transformation,It provides a theoretical reference and experimental basis for further discussion on the regulation mechanism and regulation pathway of reactive oxygen species regulation of Arabidopsis thaliana flower transformation.