Fruit Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350013, China.
Int J Mol Sci. 2024 Jul 8;25(13):7481. doi: 10.3390/ijms25137481.
Sand pear is the main cultivated pear species in China, and brown peel is a unique feature of sand pear. The formation of brown peel is related to the activity of the cork layer, of which lignin is an important component. The formation of brown peel is intimately associated with the biosynthesis and accumulation of lignin; however, the regulatory mechanism of lignin biosynthesis in pear peel remains unclear. In this study, we used a newly bred sand pear cultivar 'Xinyu' as the material to investigate the biosynthesis and accumulation of lignin at nine developmental stages using metabolomic and transcriptomic methods. Our results showed that the 30 days after flowering (DAF) to 50DAF were the key periods of lignin accumulation according to data analysis from the assays of lignin measurement, scanning electron microscope (SEM) observation, metabolomics, and transcriptomics. Through weighted gene co-expression network analysis (WGCNA), positively correlated modules with lignin were identified. A total of nine difference lignin components were identified and 148 differentially expressed genes (DEGs), including 10 structural genes (PAL1, C4H, two 4CL genes, HCT, CSE, two COMT genes, and two CCR genes) and MYB, NAC, ERF, and TCP transcription factor genes were involved in lignin metabolism. An analysis of RT-qPCR confirmed that these DEGs were involved in the biosynthesis and regulation of lignin. These findings further help us understand the mechanisms of lignin biosynthesis and provide a theoretical basis for peel color control and quality improvement in pear breeding and cultivation.
砂梨是中国主要的栽培梨品种，褐色果皮是砂梨的独特特征。褐色果皮的形成与栓皮层的活性有关，其中木质素是重要成分。褐色果皮的形成与木质素的生物合成和积累密切相关；然而，梨果皮中木质素生物合成的调控机制尚不清楚。本研究以新育成的砂梨品种‘新玉’为试材，采用代谢组学和转录组学方法，在九个发育阶段研究木质素的生物合成和积累。结果表明，根据木质素测定、扫描电子显微镜（SEM）观察、代谢组学和转录组学分析，花后 30 天（DAF）至 50DAF 是木质素积累的关键时期。通过加权基因共表达网络分析（WGCNA），鉴定出与木质素呈正相关的模块。共鉴定出 9 种差异木质素成分和 148 个差异表达基因（DEGs），包括 10 个结构基因（PAL1、C4H、两个 4CL 基因、HCT、CSE、两个 COMT 基因和两个 CCR 基因）和 MYB、NAC、ERF 和 TCP 转录因子基因，参与木质素代谢。RT-qPCR 分析证实这些 DEGs 参与木质素的生物合成和调控。这些发现进一步帮助我们理解木质素生物合成的机制，并为梨育种和栽培中果皮颜色控制和品质改良提供理论基础。
