Abstract

Pollen tube growth is critical for the sexual reproduction of flowering plants. Catharanthus roseus receptor-like kinases (CrRLK1L) play an important role in plant sexual reproduction, pollen tube growth, and male and female gametophyte recognition. Here, we identified a CrRLK1L protein in pear (Pyrus bretschneideri), PbrCrRLK1L13, which is necessary for normal tip growth of the pollen tube. When PbrCrRLK1L13 was knocked down, the pollen tube grew faster. Interaction analysis showed that the kinase domain of PbrCrRLK1L13 interacted with the C-terminal region of PbrGEF8, and PbrCrRLK1L13 activated the phosphorylation of PbrGEF8 in vitro. Furthermore, PbrROP1 and PbrROP2 were the downstream targets of PbrCrRLK1L13-PbrGEF8. When we knocked down the expression of PbrCrRLK1L13, PbrGEF8, or PbrROP1/2, the balance of cellulose deposition in the pollen tube wall was disrupted. Considering these factors, we proposed a model for a signaling event regulating pear pollen tube growth. During pear pollen tube elongation, PbrCrRLK1L13 acted as a surface regulator of the PbrROP1 and PbrROP2 signaling pathway via PbrGEF8 to affect the balance of cellulose deposition and regulate pear pollen tube growth.

中文翻译：

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PbrROP1/2 引起的纤维素沉积失衡由 Pyrus 花粉管中的 CrRLK1L-ROPGEF 模块介导

摘要

花粉管的生长对开花植物的有性繁殖至关重要。Catharanthus roseus 受体样激酶 (CrRLK1L) 在植物有性繁殖、花粉管生长以及雄性和雌性配子体识别中发挥重要作用。在这里，我们在梨 ( Pyrus bretschneideri )中鉴定了一个 CrRLK1L 蛋白PbrCrRLK1L13，它是花粉管正常尖端生长所必需的。当PbrCrRLK1L13被击倒时，花粉管生长得更快。相互作用分析表明，PbrCrRLK1L13的激酶结构域与PbrGEF8的C端区域相互作用，PbrCrRLK1L13在体外激活了PbrGEF8的磷酸化. 此外，PbrROP1 和 PbrROP2 是 PbrCrRLK1L13-PbrGEF8 的下游目标。当我们敲除PbrCrRLK1L13、PbrGEF8或PbrROP1/2的表达时，花粉管壁中纤维素沉积的平衡被破坏。考虑到这些因素，我们提出了一个调节梨花粉管生长的信号事件模型。在梨花粉管伸长过程中，PbrCrRLK1L13通过PbrGEF8作为PbrROP1和PbrROP2信号通路的表面调节剂，影响纤维素沉积平衡，调节梨花粉管生长。