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.

中文翻译：

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转录组和加权相关网络分析提供了对芍药花序茎直度的见解。

缺乏结构成分导致花序茎弯曲。参与木质素和半纤维素生物合成的差异表达基因至关重要。参与纤维素和聚糖生物合成的基因也是相关的。直立的花序茎对于高质量的切花草本牡丹花来说是必不可少的。为了探索花序茎弯曲的影响因素，测量了两个具有对比茎直性特征的草本牡丹品种（'大富贵'，直立；'垂头红'，弯曲）的主要细胞壁含量，并观察了茎结构。此外，进行了Illumina测序，并使用加权相关网络分析（WGCNA）对结果进行了分析。结果表明，木质素、半纤维素和可溶性糖含量存在显着差异，在 S3 阶段，当弯曲开始时，硬化和木质部区域以及髓中细胞壁的增厚。此外，还发现了44,182个显着差异表达基因（DEGs），这些DEGs主要富集在36个途径中。在 DEG 中，WGCNA 鉴定了参与木质素、纤维素和木聚糖生物合成的中枢基因以及调节这些过程的转录因子。这些结果表明，提供细胞壁刚性的化合物的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的生物合成的基因很重要。木质素和半纤维素引起了人们极大的兴趣，纤维素和聚糖也不容忽视。