Analysis Of Differentially Expressed Genes Of Female And Male In Ginkgo Biloba L. And Identification Of Genes Involved In Sex

Ginkgo biloba has been called “living fossil” in academia, as the only surviving relictseed plant after the Quaternary Glaciation in China. Ginkgo biloba is considered as animportant economic and ornamental tree, its female and male plants tend to have the differenteconomic value. The male plants are usually used as timber or ornamental tree, and thefemale plants are not suitable for as ornamental tree, because the bad taste of the fruit and thepollution caused by decay of fallen friut and other reasons, however a large number of femaleplants are needed to product the ginkgo. So the sex identification especially early sexidentification, has important meaning for scientific planning of the production and economicbenefits of ginkgo biloba.The male and female flowers of ginkgo biloba were studied as the material in this paper.The differentially expressed genes of male and female flowers were isolated by SuppressionSubtraction Hybridisation (SSH), and the subtractive hybrization library of the reproductiveorgans of ginkgo biloba was constructed. A large number of specific genes related with sexregulation of ginkgo biloba were selected through the sequencing, and the differentiallyexpressed genes were analyzed on the homologous sequence and function of NCBI. Theresults were as follows:1. The subtractive hybrization library of the male and female flowers of ginkgo bilobawas constructed. The differentially expressed sequence were300-1200bp after screening ofsubtractive hybrization library by colony PCR, which included47were sequenced successful.2. The BLAST showed the homology between the specific gene library screening ESTsand GenBank sequences, while a preliminary analysis of biological information followed byKEGG metabolic pathway database and the COG functional classification. The biologicalfunction of the obtained ESTs can be divided into8categories: Energy production andmetabolism; Photosynthesis and chloroplast gene; Transcriptional regulation; Signaltransduction and metabolisms; Protein metabolism; Meiosis; Secondary metabolitebiosynthesis and catabolism.3. The chloroplast gene related with Photosynthesis can be found in the female not maleflowers of ginkgo biloba. through function analysis, which fit with the morphology that thecolor of the female flowers present dark green, and the male flowers present peak greenduring the development, which indicated the speed of the development female flowers isfaster than the male. Transcriptional regulation genes related with predominant expression exist in the sequences of female flowers, so the development of the female flowers is morecomplicated compared to the male flowers.4. Strictosidine synthase confirmed as the correlated genes with sex identification ofplants can be found in the differentially expressed sequence of the male flowers, whichprovide the important theory foundation for the study of sex determination mechanism andsex identification of ginkgo biloba.5. The unknown of the special evolutionary, the appearance of the genes that related withdevelopment of flowers and sex determination of ginkgo biloba is later and the evolution isfaster, and the great difference between materials, suggesting the homology between thedifferentially genes sequences of female and male flowers of ginkgo biloba and NCBIsequences. And some specific expression gene sequences may be include the key genes of sexdetermination, can be found in the female and male flowers though its function is unknown.