Feng Nan, Song Gaoyuan, Guan Jiantao, Chen Kai, Jia Meiling, Huang Dehua, Wu Jiajie, Zhang Lichao, Kong Xiuying, Geng Shuaifeng, Liu Jun, Li Aili, Mao Long
National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, China.
Plant Physiol. 2017 Jul;174(3):1779-1794. doi: 10.1104/pp.17.00310. Epub 2017 May 17.
Early reproductive development in cereals is crucial for final grain number per spike and hence the yield potential of the crop. To date, however, no systematic analyses of gene expression profiles during this important process have been conducted for common wheat (). Here, we studied the transcriptome profiles at four stages of early wheat reproductive development, from spikelet initiation to floral organ differentiation. -means clustering and stage-specific transcript identification detected dynamically expressed homeologs of important transcription regulators in spikelet and floral meristems that may be involved in spikelet initiation, floret meristem specification, and floral organ patterning, as inferred from their homologs in model plants. Small RNA transcriptome sequencing discovered key microRNAs that were differentially expressed during wheat inflorescence development alongside their target genes, suggesting that miRNA-mediated regulatory mechanisms for floral development may be conserved in cereals and Arabidopsis. Our analysis was further substantiated by the functional characterization of the () gene, which was initially expressed in stamen primordia and later in the tapetum during anther maturation. In agreement with its stage-specific expression pattern, the loss of function of the predominantly expressed B homeolog of in a tetraploid durum wheat mutant resulted in smaller anthers with more infertile pollens than the wild type and a reduced grain number per spike. Together, our work provides a first glimpse of the gene regulatory networks in wheat inflorescence development that may be pivotal for floral and grain development, highlighting potential targets for genetic manipulation to improve future wheat yields.
谷物的早期生殖发育对于每穗最终粒数至关重要，进而决定了作物的产量潜力。然而，迄今为止，尚未对普通小麦在这一重要过程中的基因表达谱进行系统分析。在此，我们研究了小麦早期生殖发育四个阶段的转录组图谱，从颖花原基起始到花器官分化。通过均值聚类和阶段特异性转录本鉴定，检测到在颖花和花分生组织中动态表达的重要转录调节因子的同源基因，根据它们在模式植物中的同源物推断，这些基因可能参与颖花起始、小花分生组织特化和花器官模式形成。小RNA转录组测序发现了在小麦花序发育过程中差异表达的关键微小RNA及其靶基因，表明miRNA介导的花发育调控机制在谷物和拟南芥中可能是保守的。我们的分析通过对（）基因的功能表征得到进一步证实，该基因最初在雄蕊原基中表达，随后在花药成熟过程中在绒毡层中表达。与其阶段特异性表达模式一致，四倍体硬粒小麦突变体中主要表达的B同源基因功能缺失导致花药比野生型更小，不育花粉更多，每穗粒数减少。总之，我们的工作首次揭示了小麦花序发育中的基因调控网络，这可能对花和籽粒发育至关重要，突出了遗传操作的潜在靶点，以提高未来小麦产量。
