Norizuki Takuya, Minamino Naoki, Sato Miyuki, Ueda Takashi
Division of Cellular Dynamics, National Institute for Basic Biology, Okazaki, Japan.
Laboratory of Molecular Membrane Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan.
Front Plant Sci. 2023 Feb 9;14:1101983. doi: 10.3389/fpls.2023.1101983. eCollection 2023.
Autophagy is a highly conserved system that delivers cytoplasmic components to lysosomes/vacuoles. Plastids are also degraded through autophagy for nutrient recycling and quality control; however, the involvement of autophagic degradation of plastids in plant cellular differentiation remains unclear. Here, we investigated whether spermiogenesis, the differentiation of spermatids into spermatozoids, in the liverwort involves autophagic degradation of plastids. Spermatozoids of possess one cylindrical plastid at the posterior end of the cell body. By fluorescently labeling and visualizing plastids, we detected dynamic morphological changes during spermiogenesis. We found that a portion of the plastid was degraded in the vacuole in an autophagy-dependent manner during spermiogenesis, and impaired autophagy resulted in defective morphological transformation and starch accumulation in the plastid. Furthermore, we found that autophagy was dispensable for the reduction in plastid number and plastid DNA elimination. These results demonstrate a critical but selective role of autophagy in plastid reorganization during spermiogenesis in .
自噬是一种高度保守的系统，可将细胞质成分输送到溶酶体/液泡中。质体也通过自噬进行降解，以实现营养物质循环利用和质量控制；然而，质体的自噬降解在植物细胞分化中的作用仍不清楚。在这里，我们研究了地钱中精子发生（即精细胞分化为精子）过程是否涉及质体的自噬降解。地钱的精子在细胞体后端有一个圆柱形质体。通过对质体进行荧光标记和可视化，我们检测到精子发生过程中质体动态的形态变化。我们发现，在精子发生过程中，一部分质体以自噬依赖的方式在液泡中被降解，自噬受损会导致质体形态转变缺陷和淀粉积累。此外，我们发现自噬对于质体数量的减少和质体DNA的消除并非必需。这些结果表明，自噬在地钱精子发生过程中的质体重组中起关键但具有选择性的作用。
