To identify the dynamic differences in transcriptome and gene expression in chinese bayberry flowers of different sex types, the female ‘Fugong-1’ (WT) and its monoecious mutant (MT) were used as experimental materials. Using Illumina HiSeq™ 2500, flowers at the inflorescence germination, inflorescence elongation, and initial flowering stages were sequenced by RNA-seq technology and 6 libraries were obtained. After sequence assemble, 84,945 unigenes greater than 200 bp were found and the total length was 71.66 Mb. Transcriptomic expression analysis of the six libraries indicated that there was only 297 genes showed different expression at the inflorescence germination stage between MT and WT, the difference of which was the minimum. At the elongation stage and the initial flowering stage, such numbers increased to 787 and 2722, respectively. Gene ontology (GO) functional enrichment analysis revealed that the enriched differentially expressed genes (DEGs) included those related with transcription in DNA-templated (GO: 0006355), pollen exine formation (GO: 0010584), plasma membrane (GO: 0005886), sequence-specific DNA binding transcription factor activity (GO: 0003700), and 2-alkenal reductase [NAD(P)] activity (GO: 0032440) GO categories, etc. Among these processes, pollen exine formation plays an important role in pollen cell wall synthesis and sporopollen participates in the biosynthesis of sporopollenin. High expression levels of these related genes were closely related to the MT’s male flower traits during the initial flowering stage, which resulted in the male characteristics in MT flower. This study provides important foundation for further mining important genes and regulating factors controlling the sex differentiation of flowers in chinese bayberry.
Zehuang Zhang, Qihua Lin and Qiuzhen Zhong
Wenting Wang, Chao Feng, Zehuang Zhang, Liju Yan, Maomao Ding, Changjie Xu and Kunsong Chen
Chinese bayberry (Morella rubra) is an economically important subtropical evergreen fruit crop native to China and other Asian countries. For facilitating cultivar discrimination and genetic diversity analysis, a total of 38 high-quality and highly polymorphic expressed sequence tags-simple sequence repeat (EST-SSR) markers, with little or no polymerase chain reaction (PCR) stutter bands, including 21 screened from those obtained previously and 17 newly developed markers, were developed. The average number of alleles (N a) per locus was 5.6, and polymorphism information content varied from 0.34 to 0.86, with a mean value of 0.57. With these markers, all 42 Chinese bayberry accessions analyzed were successfully discriminated and the phylogenetic relationship between accessions was revealed. The accessions can be separated into two groups with six subgroups. The grouping of four main cultivars in three subgroups and 12 white-fruited accessions, each with little or no anthocyanin accumulation in ripe fruit, into five subgroups suggested the preservation of broad diversity among cultivated populations. These EST-SSR markers and the findings obtained in this study can assist the discrimination of cultivars and lines and contribute to genetic and breeding studies in Chinese bayberry.