Identification Of Genes Involved In Photoperiod Insensitivity Of Oat Based On Hybrid Sequencing

Light is an important environmental factor that regulates plant growth and development which participates in different physiological processes.Physiological responses of plants to the length of day and night are defined as photoperiodism.According to the relationship between day length and flowering time,plants can be divided into long-day plant,short-day plant and day-neutral plant.Oat is a crop for food and feed that distribute worldwide.As a long-day plant,oat needs day length longer than critical day length to heading.The demand for day length limits the maturity and suitable range of oat,and affects the yield of oat.In this study,photoperiod insensitive cultivar gp012 and photoperiod sensitive cultivar HONGQI2 were used as experimental materials to observe the main stem apex(MSA)morphology of two cultivars under short day-length conditions.Illumina RNA-seq and Iso-seq transcriptome database was constructed from leaf and MSA,and candidate genes involved in photoperiod insensitive of oats were analyzed and identified.The main conclusions are as follows:1.Under short light,the main stem apex of photoperiod-insensitive variety gp012 did not change significantly;however,the MSA of photoperiod-sensitive cultivar HONGQI2 gradually shrank during its development,which resulted in the failure of heading and fruiting.2.The full-length transcriptome database of oats was constructed using the leaf and MSA of oat variety gp012 and HONGQI2.63.63GB clean data were obtained by RNA-seq,with Q30 reaching 90.32%.11.62GB data were generated by Iso-seq,which were corrected by RNA-seq data and differentially expressed transcripts(DET)were screened out.60,673 de-redundant transcript sequences were obtained.3.A total of 7932 transcripts were differentially expressed in two oat cultivars.Through functional annotation of differentially expressed transcripts,7394 differentially expressed transcripts were annotated.Through analysis of annotation results,PRR,a photoperiod insensitive gene family in oats,were identified.4.Predicting the photoperiod insensitive regulation model of oat:The up-regulated expression of AsCRE1 in gp012 maintains that promotes the accumulation of AsARR4.AsARR4 maintains the activation form of AsPHYB,and induces strong light reaction.AsTOC1 and AsPRR5 were up-regulated,which changed the transcriptional level of AsPRR37,caused the downstream MADS-box genes expression change and maintained the MSA morphology.5.The expression peaks of AsTOC1,AsPRR5 and AsPRR37,members of AsPRR family,appeared at different time in one photoperiod in two oat varieties.The member of AsPRR family contain two conservative domains,including the N-terminal REC domain and the C-terminal CCT domain.The difference of expression patterns of AsPRR family in two oat varieties may be the reason why gp012 is insensitive to photoperiod.6.The gene AsPRR37 was cloned and belongs to the AsPRR family.The length of the gene is 4568 bp that contains eight exons and seven introns.