Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, 100083, People's Republic of China.
Management Office of Caozhou Peony Garden, Heze, 274000, Shandong, People's Republic of China.
Plant Mol Biol. 2020 Feb;102(3):239-252. doi: 10.1007/s11103-019-00945-4. Epub 2019 Dec 12.
Lack of structural components results in inflorescence stem bending. Differentially expressed genes involved in lignin and hemicellulose biosynthesis are vital; genes involved in cellulose and glycan biosynthesis are also relevant. An erect inflorescence stem is essential for high-quality cut herbaceous peony flowers. To explore the factors underlying inflorescence stem bending, major cell walls contents were measured, and stem structure was observed in two herbaceous peony varieties with contrasting stem straightness traits ('Da Fugui', upright; 'Chui Touhong', bending). In addition, Illumina sequencing was performed and weighted correlation network analysis (WGCNA) was used to analyze the results. The results showed significant differences in lignin, hemicellulose and soluble sugar contents, sclerenchyma and xylem areas and thickening in cell walls in pith at stage S3, when bending begins. In addition, 44,182 significantly differentially expressed genes (DEGs) were found, and these DEGs were mainly enriched in 36 pathways. Among the DEGs, hub genes involved in lignin, cellulose, and xylan biosynthesis and transcription factors that regulated these process were identified by WGCNA. These results suggested that the contents of compounds that provided cell wall rigidity were vital factors affecting inflorescence stem straightness in herbaceous peony. Genes involved in or regulating the biosynthesis of these compounds are thus important; lignin and hemicellulose are of great interest, and cellulose and glycan should not be ignored. This paper lays a foundation for developing new herbaceous peony varieties suitable for cut flowers by molecular-assisted breeding.
结构成分的缺乏导致花序茎弯曲。参与木质素和半纤维素生物合成的差异表达基因是至关重要的；参与纤维素和聚糖生物合成的基因也相关。直立的花序茎对于高品质的切花芍药花是必不可少的。为了探索花序茎弯曲的原因，我们测量了两个具有不同茎直度特征的芍药品种（“大富贵”，直立；“垂头红”，弯曲）的主要细胞壁含量，并观察了茎的结构。此外，我们进行了 Illumina 测序，并使用加权相关网络分析（WGCNA）分析结果。结果表明，在弯曲开始时的 S3 阶段，木质素、半纤维素和可溶性糖含量、厚壁组织和木质部面积以及髓心细胞壁加厚存在显著差异。此外，发现了 44182 个显著差异表达基因（DEGs），这些 DEGs 主要富集在 36 条途径中。在 DEGs 中，通过 WGCNA 鉴定出参与木质素、纤维素和木聚糖生物合成以及调节这些过程的转录因子的关键基因。这些结果表明，提供细胞壁刚性的化合物含量是影响芍药花序茎直度的重要因素。因此，参与或调节这些化合物生物合成的基因是重要的；木质素和半纤维素是非常重要的，而纤维素和聚糖也不容忽视。本文为通过分子辅助育种开发适合切花的新型芍药品种奠定了基础。
