| Carya cathayensis Sarg.is a monoecious plant of Carya in the Juglandaceae.The differentiation of male and female flowers of Carya cathayensis has temporal and spatial differences[1,2],which make it to be a good material for exploring the key genes of flower differentiation in monoecious plants.The MADS-box gene family is a gene family closely related to the formation of flowers,and is bound to participate in the flowering network of male and female flower differentiation.The relationship between MADS-box gene family members and floral organ development in 30 angiosperms and two exogenous plants was analyzed by using a large number of genomic and transcriptome data and bioinformatics methods.MADS-box gene in Carya cathayensis was also identified and analyzed.By using the two transcriptome data of male and female flowers of Carya cathayensis,the candidate genes that may be related to the male and female differentiation of Carya cathayensis were obtained through screening differential expression genes and go enrichment.The relationship between hormone related genes and MADS box genes and the male and female differentiation of Carya cathayensis was analyzed.The main results are as follows:1.According to the statistics of the members of the MADS-box family of 32 species,it is found that in angiosperms,the number of genes in the MADS-box gene family is not proportional to the size of the plant genome.Although there are obvious differences in the morphology of flower organs between hermaphroditic and unisexual flowering plants,the number of genes in four subfamilies related to flower organ development has not been found.The increase in the number of type II genes in the MADS-box gene family mainly follows the whole genome replication events of the species,while the increase of type I gene number is due to recent small-scale repetitive events.2.According to the transcriptome data of five plant floral organs,it was found that the expression of ABCDE functional genes related to flowering in male,female and bisexual flowers basically conformed to ABCDE model,which indicated that ABCDE model was not only suitable for bisexual flower model plants,but also for monoecious and dioecious higher plants.3.A total of 66 MADS box genes were identified in Hickory.Through cluster analysis,it was found that there were 16 type I genes and 50 type II genes in Hickory.Among them,type II genes can be divided into 13 subfamilies.There are obvious differences in gene structure among MADS box genes of Carya cathayensis,but they generally have long introns.The promoter region contains more light response,anaerobic induction and hormone response promoter elements.4.Based on the analysis of transcriptome data of the second generation sequencing of male and female flowers of Carya cathayensis,the differential genes of different developmental stages of male and female flowers were discovered.Through the analysis of pathway enrichment,it was found that the differential genes mainly focused on the synthesis of secondary metabolites,plant hormone signal transduction,sugar metabolism,linoleic acid metabolism and other pathways.Through the analysis of the expression level of 62 genes related to plant hormone synthesis and metabolism in the three development stages of female and male flowers,it is found that JA may play a role in promoting male,while BR and GA may play a role in promoting female.5.Based on the transcriptional isomers and expression of MADS box gene family in the three generations of transcriptome data,it is speculated that AP1 subfamily gene may have functional differentiation and redundancy in Hickory,while SEP subfamily gene may have an important relationship with the formation of special flower types of hickory male and female flowers.It is speculated that the differentiation of hickory male and female flowers is controlled by different floral regulation pathways and the development of hickory male flowers It may be related to hormone,thermal induction and photoperiod pathway. |
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