Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557, USA.
Department of Chemistry, University of Nevada, Reno, NV 89557, USA.
Int J Mol Sci. 2021 Nov 12;22(22):12230. doi: 10.3390/ijms222212230.
In angiosperms, double fertilization requires pollen tubes to transport non-motile sperm to distant egg cells housed in a specialized female structure known as the pistil, mediating the ultimate fusion between male and female gametes. During this journey, the pollen tube encounters numerous physical barriers that must be mechanically circumvented, including the penetration of the stigmatic papillae, style, transmitting tract, and synergid cells as well as the ultimate fusion of sperm cells to the egg or central cell. Additionally, the pollen tube must maintain structural integrity in these compact environments, while responding to positional guidance cues that lead the pollen tube to its destination. Here, we discuss the nature of these physical barriers as well as efforts to genetically and cellularly identify the factors that allow pollen tubes to successfully, specifically, and quickly circumnavigate them.
在被子植物中，双受精需要花粉管将非运动精子运输到位于专门的雌性结构——雌蕊中的远卵细胞，介导雌雄配子的最终融合。在这个过程中，花粉管遇到了许多物理障碍，必须通过机械手段绕过，包括穿透柱头乳突、花柱、传递道和助细胞，以及最终使精子细胞与卵或中央细胞融合。此外，花粉管必须在这些紧凑的环境中保持结构完整性，同时响应位置导向信号，引导花粉管到达目的地。在这里，我们讨论这些物理障碍的性质，并努力从遗传和细胞水平上确定使花粉管成功、特异性和快速绕过它们的因素。
