BACKGROUND WS24-3A is a newly bred non-heading Chinese cabbage genic male-sterile line, in which sterility is controlled by a recessive gene, designated as Bra2ms. WS24-3A has been used for hybrid breeding. OBJECTIVE To reveal the underlying molecular mechanisms responsible for the sterility of WS24-3A. METHODS Cytological observation of the process of sterile/fertile anther development was performed to determine the tissue and stage in which sterility occurs. Phenotyping and transcriptomic analyses were performed to identify differentially expressed genes (DEGs) between sterile and fertile flower buds at different stages. RESULTS Cytological analysis revealed no tetrads at stage 7 or at later stages of anther development, and the degradation of callose was delayed. Abnormal meiocytes were surrounded by sustaining callose that degenerated gradually in WS24-3A. Comparative transcript profiling identified 3282 DEGs during three anther developmental stages, namely, pre-meiotic anther, meiotic anther, and anthers with single-celled pollen stage. The difference in DEG percentage between up-regulated and down-regulated at meiotic anther stage was obviously larger than at the other two stages; further, most DEGs are important for male meiosis, callose synthesis and dissolution, and tapetum development. Ten DEGs were found to be involved in anther and pollen development, which were analyzed by quantitative PCR. CONCLUSION Bra2ms affected gene expression in meiocytes and associated with callose synthesis, degradation and tapetum development. Our results provide clues to elucidate the molecular mechanism of genic male sterility in non-heading Chinese cabbage.

中文翻译：

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新育成的隐性基因雄性不育大白菜WS24-3A的比较转录谱分析和细胞学观察。

背景技术WS24-3A是一种新近育成的非抽穗大白菜基因雄性不育系，其不育由隐性基因控制，即Bra2ms。WS24-3A已用于杂交育种。目的揭示造成WS24-3A不育的潜在分子机制。方法进行不育/可育花药发育过程的细胞学观察，以确定发生不育的组织和阶段。进行了表型和转录组分析，以鉴定不育和可育花芽在不同阶段之间的差异表达基因（DEG）。结果细胞学分析显示在花药发育的第7阶段或以后阶段没有四分体，并且of的降解被延迟。在WS24-3A中，异常的肌细胞被维持的愈伤组织包围，该愈伤组织逐渐退化。比较转录谱分析在三个花药发育阶段，即减数分裂前的花药，减数分裂的花药和单细胞花粉期的花药中鉴定了3282个DEG。在减数分裂花药阶段上调和下调之间的DEG百分比差异明显大于其他两个阶段。此外，大多数DEG对雄性减数分裂，ose的合成和溶解以及绒毡层发育都很重要。发现有十个DEG与花药和花粉发育有关，并通过定量PCR进行了分析。结论Bra2ms影响了肌细胞中的基因表达，并与call的合成，降解和绒毡层发育有关。