State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.
Hainan Yazhou Bay Seed Lab, Sanya, China.
Physiol Plant. 2022 May;174(3):e13700. doi: 10.1111/ppl.13700.
Cellulose, a key component of the cell wall, plays an important role in maintaining the growth of pollen tubes. However, the molecular mechanism of cellulose participating in the cessation of pear pollen tube growth remains unclear. Here, we reported that at 15 h post-cultured (HPC), the slow-growth pear pollen tubes showed thickened cell walls and cellulose accumulation in the inner wall. Transcriptome data and quantitative real-time PCR analysis showed that PbrCSLD5, a cellulose synthesis-like gene, was highly expressed in the 15 HPC pear pollen tubes. Knockdown of PbrCSLD5 caused a decrease in cellulose content in pear pollen tubes. Moreover, PbrCSLD5 overexpression in Arabidopsis resulted in the accumulation of cellulose and disruption of normal pollen tube growth. Transcription factor PbrMADS52 was found to bind to the promoter of PbrCSLD5 and enhanced its expression. Our results suggested that the PbrMADS52-PbrCSLD5 signaling pathway led to increased cellulose content in the pear pollen tube cell wall, thereby inhibiting pollen tube growth. These results provided new insights into the regulation of pollen tube growth.
纤维素是细胞壁的主要成分之一，在维持花粉管生长方面发挥着重要作用。然而，纤维素参与梨花粉管生长停止的分子机制尚不清楚。本研究报道，在培养 15 小时后（HPC），生长缓慢的梨花粉管表现出细胞壁增厚和内壁纤维素积累。转录组数据和定量实时 PCR 分析显示，纤维素合成样基因 PbrCSLD5 在 15 HPC 梨花粉管中高度表达。敲低 PbrCSLD5 导致梨花粉管中纤维素含量减少。此外，在拟南芥中过表达 PbrCSLD5 导致纤维素积累和花粉管生长正常受到破坏。发现转录因子 PbrMADS52 与 PbrCSLD5 的启动子结合并增强其表达。我们的结果表明，PbrMADS52-PbrCSLD5 信号通路导致梨花粉管细胞壁中纤维素含量增加，从而抑制花粉管生长。这些结果为花粉管生长的调控提供了新的见解。
