Analysis Of Rice Core Genes Response To Ozone Stress And Its Effect On Transposon Expression

Ozone?O₃?,as a harmful greenhouse gas,induces the production of reactive oxygen species after entering the plant,therefor affecting the normal growth of plants and causing a decline in agricultural productivity.In recent years,as the content of ozone precursors increases,the concentration of ozone in the air also increases.The rice growing season coincides with the peak ozone season,putting this region and high risk for ozone induced rice yield losses,so it is particularly important to fully understand the series of molecular response mechanisms caused by ozone stress.Rice?Oryza sativa L.?,as an important food crop,is the main food source for more than half of the world's population.At present,the whole genome sequencing of rice has been completed.Its genome is small,and the annotation information is comprehensive.It is a model plant in crops.In this study,the rice variety Nipponbare were exposed to three different ozone concentrations in open-top chambers?OTCs?.The treatment concentrations were 80 nmol·mol^-1,160 nmol·mol^-11 and 200nmol·mol^-1,and the unfiltered air was used as control.To analyze the transcriptome data of rice leaves in the vegetative growth period,the following results were obtained:1.In the functional enrichment classification of differentially expressed genes?DEGs?,up-regulated DEGs are significantly enriched in cell death,signal transduction,response to abiotic stimulation,response to stress,oxygen binding,kinase activity,cell wall components.Down-regulated DEGs are significantly enriched in the functions of photosynthesis,cell membrane,cytoplasm,membrane structure organelles,and thylakoids.Among the DEGs in stress response,we found 14DEGs that responded to other abiotic stresses.It is important significance for breeding resistant varieties.2.Among the DEGs,we found significantly enriched metabolic pathways under ozone stress treatments.The tricarboxylic acid cycle,porphyrin and chlorophyll metabolism,carbon fixation in photosynthetic organisms,photosynthetic antenna protein,photosynthesis,and other metabolic pathways are supressed.Phytohormone signal transduction,phenylpropanoid biosynthesis,diterpenoid biosynthesis,and plant-pathogen interactions are activated.3.By comparing the expression patterns of concentration-specific genes on the same day,we found that the phenomenons of rice response to different concentrations of ozone stress are different.The concentration-specific genes expression pattern of80 nmol·mol^-11 was different from 160 nmol·mol^-11 and 200 nmol·mol^-1.The function of these concentration-specific genes are concentrated on the stress response.4.Epigenetic modification related gene data were analyzed in each group of differentially expressed genes.We found that a total of 56 epigenetic modification related genes were differentially expressed during ozone stress.These genes involved intheepigeneticcodingsystem,includingDNAmethyltransferases/demethyltransferases directly altering DNA methylation levels,and histone acetylase/deacetylase directly altering histone acetylation levels.It indicated that the level and pattern of epigenetic modification of rice under ozone stress treatment may change.5.We performed statistics on all differentially expressed transposons,involving10 categories,for a total of 205 transposons.Up-regulated differentially expressed transposons are concentrated in the Ty3-gypsy retrotransposons,and down-regulated differentially expressed transposons are concentrated in Ty1-copia retrotransposons,Ty3-gypsy retrotransposons and CACTA transposons.In addition,a fully inserted DEG with mPing was found,which was down-regulated after ozone stress.It is indicated that the transposons can respond to ozone stress treatment,and the change of its expression pattern may have some influence on the expression of nearby genes.