Xie Yang, Zhang Wei, Wang Yan, Xu Liang, Zhu Xianwen, Muleke Everlyne M, Liu Liwang
National Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
Department of Plant Sciences, North Dakota State University, Fargo, ND, 58105, USA.
Funct Integr Genomics. 2016 Sep;16(5):529-43. doi: 10.1007/s10142-016-0504-1. Epub 2016 Jul 27.
Microsporogenesis is an indispensable period for investigating microspore development and cytoplasmic male sterility (CMS) occurrence. Radish CMS line plays a critical role in elite F1 hybrid seed production and heterosis utilization. However, the molecular mechanisms of microspore development and CMS occurrence have not been thoroughly uncovered in radish. In this study, a comparative analysis of radish floral buds from a CMS line (NAU-WA) and its maintainer (NAU-WB) was conducted using next generation sequencing (NGS) technology. Digital gene expression (DGE) profiling revealed that 3504 genes were significantly differentially expressed between NAU-WA and NAU-WB library, among which 1910 were upregulated and 1594 were downregulated. Gene ontology (GO) analysis showed that these differentially expressed genes (DEGs) were mainly enriched in extracellular region, catalytic activity, and response to stimulus. KEGG enrichment analysis revealed that the DEGs were predominantly associated with flavonoid biosynthesis, glycolysis, and biosynthesis of secondary metabolites. Real-time quantitative PCR analysis showed that the expression profiles of 13 randomly selected DEGs were in high agreement with results from Illumina sequencing. Several candidate genes encoding ATP synthase, auxin response factor (ARF), transcription factors (TFs), chalcone synthase (CHS), and male sterility (MS) were responsible for microsporogenesis. Furthermore, a schematic diagram for functional interaction of DEGs from NAU-WA vs. NAU-WB library in radish plants was proposed. These results could provide new information on the dissection of the molecular mechanisms underlying microspore development and CMS occurrence in radish.
小孢子发生是研究小孢子发育和细胞质雄性不育（CMS）发生不可或缺的时期。萝卜CMS系在优良F1杂交种子生产和杂种优势利用中起着关键作用。然而，萝卜中小孢子发育和CMS发生的分子机制尚未完全揭示。在本研究中，利用下一代测序（NGS）技术对萝卜CMS系（NAU-WA）及其保持系（NAU-WB）的花芽进行了比较分析。数字基因表达（DGE）谱分析显示，NAU-WA和NAU-WB文库之间有3504个基因显著差异表达，其中1910个上调，1594个下调。基因本体（GO）分析表明，这些差异表达基因（DEGs）主要富集在细胞外区域、催化活性和对刺激的反应。KEGG富集分析表明，DEGs主要与类黄酮生物合成、糖酵解和次生代谢物生物合成有关。实时定量PCR分析表明，随机选择的13个DEGs的表达谱与Illumina测序结果高度一致。几个编码ATP合酶、生长素反应因子（ARF）、转录因子（TFs）、查尔酮合酶（CHS）和雄性不育（MS）的候选基因参与了小孢子发生。此外，还提出了萝卜植株中NAU-WA与NAU-WB文库DEGs功能相互作用的示意图。这些结果可为剖析萝卜小孢子发育和CMS发生的分子机制提供新的信息。
