Transcriptome Analysis and Differential Gene Screening of Male Flower Buds in Three Age Stages of <i>Ginkgo biloba</i>

Abstract

In this paper, the key genes of flowering regulation among three age stages was screened and the molecular mechanism of the flowering pathway was revealed in  Ginkgo biloba . It can provide scientific basis for promoting early flowering, molecular breeding and spreading planting of  Ginkgo biloba . High throughput sequencing technology and bioinformatics tools were used to sequence the transcriptome of male flower buds of  Ginkgo biloba  in three age stages. By analyzed the sequencing data, we screened out the key differential expression genes of age pathway. A total of 57.45 Gb of raw data was generated by transcriptome sequencing. The total number of Unigenes was 35 058 and annotated in the 8 functional databases (GO, COG, KEGG, KOG, NR, Pfam, Swiss-Prot, and eggNOG). The Unigenes were classified into 55 GO categories and 126 metabolic pathways. Analysis of differentially expressed genes revealed that 37 genes were up-regulated and 75 genes were down-regulated during the flower bud undifferentiated stage vs. initial stage of flower bud differentiation. A total of 592 genes were up-regulated and 871 genes were down-regulated during the initial stage of flower bud differentiation vs. flower bud differentiation stage. The flower bud undifferentiated stage vs. flower bud differentiation stage，961 genes were up-regulated and 1 203 genes were down-regulated. A large number of flowering related genes were discovered and finally screened out 11 key genes of flowering regulation in age pathway. including  SPL (gene.Gb_23724, gene.Gb_03922),  AP2 (gene.Gb_00766),  MADS-box (gene.Gb_01886, gene.Gb_15398, gene.Gb_28337, Gingko_newGene_2213), Gibberellin-regulated protein(gene.Gb_34467, gene.Gb_28606, gene.Gb_33214)and DELLAs protein(gene.Gb_34644).