The Preliminary Analyses Of Olfactory Bulb And Olfactory Epithelium Transcriptome Of Two Kinds Of Ardeidae Birds

Olfactory epithelium and olfactory bulb are animals' main olfactory tissues.We have conducted the transcriptome sequencing of olfactory epithelium and olfactory bulb of little egrets and night herons and completed bioinformatics analyses.The results are as follows:1)For nestling night herons,there are 19 olfactory receptor gene expressions in developmental positions of the olfactory bulb,and 66 olfactory receptor gene expressions in olfactory epithelium tissues.For adult night herons,there are 14 olfactory receptor gene expressions in olfactory bulb tissues,and 41 olfactory receptor gene expressions in olfactory epithelium tissues.The researcher deduces that the number of adult night herons' olfactory receptor genes is less than that of the nestling herons',because of the epigenetic silence of olfactory receptor gene.In the development process of the olfactory bulb,there are 856 genes upregulated and 904 genes downregulated in total.The expression of DLX5 genes related to the olfactory neurons and the olfactory bulb rises significantly in the process of olfactory bulb development,which shows that differentiations of neurons are active in the process of olfactory bulb development.There are 26 genes upregulated and 9 genes downregulated in the development process of the olfactory epithelium.The results of KEGG pathway enrichments indicate that biological pathways related to olfactory are in enrichment.2)For nestling little egrets,there are totally 19 olfactory receptor gene expressions in the developmental positions of olfactory bulb,and 124 olfactory receptor gene expressions in olfactory epithelium.For adult little egrets,there are 16 olfactory receptor gene expressions in olfactory bulb and 115 olfactory receptor gene expressions in olfactory epithelium.There are 5 genes upregulated in the development process of egrets' olfactory bulb.There are only 2 genes downregulated in the development process of their olfactory epithelium.The transcription factors DLX5 gene in egrets'olfactory tissues related to olfactory neurons and olfactory bulb is absent of gene expressions.The reason is that it is hard to connect egrets'olfactory bulb neurons with the olfactory bulb when DLX5 gene is absent,which influences the gene expressions in the process of olfactory tissue development.3)Comparative transcriptome results of night herons and little egrets show that the number of night herons' olfactory receptor gene expressions is less than that of little egrets',which is consistent with the statistics of the genome.There are no significant differences of expression levels of olfactory receptor genes among the samples between the adults' olfactory bulb and the nestling birds' olfactory development of positions in the same kind through Nonparametric test and post hoc test.However,there are significant differences of expression levels of olfactory receptor genes among the olfactory epithelium tissues of each group between the adult and the nestling birds.The results of research show that ardeidae birds olfactory receptor genes have stable expressions in olfactory bulb,but have randomness of expressions in olfactory epithelium.4)There are a total of 9 genes which have positive selection phenomenon in the transcripts of night herons and egrets' olfactory tissues.The CCDC60 genes related to the response to biological stimulation in night herons have positive selection phenomenon.Yet,the CCDC60 genes have purification selection in little egrets,Dalmatian Pelican and Crested Ibis.There are 8 genes related to transcriptional regulation,shearing,protein folding and bacteria stimulation response genes which have positive selection phenomenon in night Herons,little egrets,Dalmatian Pelican and Crested Ibis.5)For Ardeidae birds,their Type 14 of olfactory receptor gene has many polymorphic loci,which are associated with Type 14 of olfactory receptor gene selection of gas molecules.Type 14 gene polymorphism loci are good for ardeidae birds' olfactory adaptation.