College of Horticulture, Nanjing Agricultural University, Nanjing, China.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.
BMC Plant Biol. 2022 Jun 27;22(1):310. doi: 10.1186/s12870-022-03658-x.
Glucose can be involved in metabolic activities as a structural substance or signaling molecule and plays an important regulatory role in fruit development. Glucose metabolism is closely related to the phenylpropanoid pathway, but the specific role of glucose in regulating lignin biosynthesis in pear fruit is still unclear. The transcriptome of pear calli generated from fruit and treated with glucose was analyzed to investigate the role of glucose in lignin biosynthesis.
The treatment of exogenous glucose significantly enhanced the accumulation of lignin in pear calli. A total of 6566 differentially expressed genes were obtained by transcriptome sequencing. Glycolysis was found to be the pathway with significant changes. Many differentially expressed genes were enriched in secondary metabolic pathways, especially the phenylpropanoid pathway. Expression of structural genes (PbPAL, PbHCT, PbCOMT, PbPRX) in lignin biosynthesis was up-regulated after glucose treatment. In addition, glucose might regulate lignin biosynthesis through interactions with ABA, GA, and SA signaling. Several candidate MYB transcription factors involved in glucose-induced lignin biosynthesis have also been revealed. The qRT-PCR analyses showed that the expression pattern of PbPFP at early developmental stage in 'Dangshansuli' fruits was consistent with the trend of lignin content. Transient expression of PbPFP resulted in a significant increase of lignin content in 'Dangshansuli' fruits at 35 days after full bloom (DAB) and tobacco leaves, indicating that PbPFP (Pbr015118.1) might be associated with the enhancement of lignin biosynthesis in response to glucose treatment.
PbPFP plays a positive role in regulating lignin biosynthesis in response to glucose treatment. This study may reveal the regulatory pathway related to lignin accumulation in pear calli induced by glucose.
葡萄糖可以作为结构物质或信号分子参与代谢活动，在果实发育中发挥重要的调节作用。葡萄糖代谢与苯丙烷代谢途径密切相关，但葡萄糖在调节梨果实木质素生物合成中的具体作用尚不清楚。本研究通过分析外源葡萄糖处理梨愈伤组织后的转录组，探讨葡萄糖在木质素生物合成中的作用。
外源葡萄糖处理显著增强了梨愈伤组织中木质素的积累。通过转录组测序共获得 6566 个差异表达基因。发现糖酵解途径变化显著。许多差异表达基因富集在次生代谢途径中，特别是苯丙烷代谢途径。木质素生物合成结构基因（PbPAL、PbHCT、PbCOMT、PbPRX）的表达在葡萄糖处理后上调。此外，葡萄糖可能通过与 ABA、GA 和 SA 信号的相互作用来调节木质素生物合成。还揭示了几个参与葡萄糖诱导木质素生物合成的候选 MYB 转录因子。qRT-PCR 分析表明，‘砀山酥梨’果实早期发育阶段 PbPFP 的表达模式与木质素含量的变化趋势一致。在 35 天（DA）和烟草叶片中瞬时表达 PbPFP 导致‘砀山酥梨’果实木质素含量显著增加，表明 PbPFP（Pbr015118.1）可能与葡萄糖处理诱导的木质素生物合成增强有关。
PbPFP 在响应葡萄糖处理调节木质素生物合成中发挥积极作用。本研究可能揭示了葡萄糖诱导梨愈伤组织木质素积累的调控途径。
