An Integrative Analysis Of The Transcriptome And Proteome Of 'Wuzi Ougan' (Citrus Suavissima Hort.Ex Tanaka 'Seedless') And The Wild Type Improves Our Understanding Of Male Sterility

‘Wuzi Ougan'(Citrus suavissima Hort.ex Tanaka ‘seedless'),a bud variation of Ougan,whose fruit is seedless and has all of the same excellent characters as Ougan.Seedless fruits now occupy an important position in the domestic and international market.It is meaningful to explore the male sterility in order to provide theoretical guiding for the development of seedless citrus species.In the study,the anthers of ‘Wuzi Ougan' and its wild type were observed and the mature pollen were squashed.RNA-Seq were carried out using the anthers during the period of microsporocyte,i TRAQ were carried out using the flower buds of the sporogenous period,the anthers of early microsporocyte and microsporocyte to meiosis,from which we obtained a large amount of information.some differentially expressed genes(DEGs)were selected to verify the relative expression by q RT-PCR,the main research results were as follows:The result of squashed were listed: the mature pollen grains are empty and basically inactive in ‘Wuzi Ougan',While the pollen grain basically active in Ougan.There were no obvious different in anthers of two citrus species throughout development of floral organ.In mature pollen,the normal of anther dehiscence in Ougan,the failure of anther dehiscence and ‘Wuzi Ougan' by stereoscope.The gene profiling was performed by the RNA-seq method and 13496 high-confidence genes were identified,among which there were 212 DEPs(FC>2,FDR<0.01)in developmental stages of anthers between ‘Wuzi Ougan' and its wild type.The KEGG enrichment of DEGs showed as follows: phenylpropanoid biosynthesis,flavonoid biosynthesis and phenylalanine metabolism.The GO annotation of DEGs showed as follows: In biological process,the metabolic process,cellular process,single-organism process and organic substance metabolic process were in the majority.In molecular function,the catalytic activity and binding were in the majority;In cell component,the cell and cell part were in the majority.Meanwhile,part of DEGs were collected to verify the relative expression.The proteome profiling was performed by the i TRAQ method and 6201 high-confidence proteins were identified,among which there were 487 DEPs(FC>1.2,FDR<0.05)in one or more developmental stages of anthers between ‘Wuzi Ougan' and its wild type.The KEGG enrichment of DEGs showed as follows: phenylpropanoid biosynthesis,flavonoid biosynthesis,and phenylalanine metabolism.The main functional subcategories associated with the main category biological process into which the DEPs were classified were sporopollenin biosynthesis process and pollen exine formation.Some DEGs related to phenylpropanoid metabolism were also validated by q RT-PCR analysis.An integrative analysis of the fold change at the transcript(log2 FPKM ratios)and protein(log1.2 i TRAQ ratios)levels was positively correlated,in which the correlation coefficients were 0.3414(all genes vs.all proteins)and 0.5686(DEGs vs.DEPs).The KEGG enrichment of DEGs showed as follows: phenylpropanoid biosynthesis,flavonoid biosynthesis,and phenylalanine metabolism.Analysis bioinformatics of the phenylpropanoid metabolism combine with q RT-PCR result.As result,the abnormal expression of key genes 4CL,PAL,COMT,CCo AOMT and CAD involve in the network of phenylalanine metabolism resulted in the male sterility in ‘Wuzi Ougan'.