Asian Natural Environmental Science Center (ANESC), The University of Tokyo, 1-1-1 Midori-cho, Nishitokyo-shi, Tokyo, 188-0002, Japan; Laboratory of Crop Physiology, Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9 Kita-ku, Sapporo-shi, Hokkaido, 060-8589, Japan.
Laboratory of Crop Physiology, Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9 Kita-ku, Sapporo-shi, Hokkaido, 060-8589, Japan.
Biochem Biophys Res Commun. 2020 Jun 11;526(4):1036-1041. doi: 10.1016/j.bbrc.2020.03.179. Epub 2020 Apr 15.
Pollen wall characteristics are dramatically changed during pollen maturation. Many genes have been identified as regulators of such changes in pollen wall characteristics, but mechanisms of such changes have not been completely understood. Here, a GDSL-type esterase/lipase gene, GELP77, is shown to regulate such changes in Arabidopsis thaliana. GELP77-deficient (gelp77) plants exhibited male sterility, and this phenotype was suppressed by introduction of a GELP77 genomic fragment. Mature pollen grains of wild-type Arabidopsis plants have an organized reticulate surface structure and are dissociated from each other. In contrast, pollen grains of gelp77 lacked such a structure and were shrunken and stuck to each other. Nuclei were not detectable in gelp77 microspores at a putative uninucleate stage, suggesting that GELP77 is required as early as this stage. In plants that have the GELP77 promoter-GELP77-GFP transgene, the GELP77-GFP fusion protein was detected in microspores, tapetal cells and middle layer cells in anthers at post-meiotic stages, whereas not anthers at pre-meiotic stages. Analysis of amino acid sequences suggests that GELP77 is phylogenetically distant from the other 104 GDSL-type esterase/lipase genes in Arabidopsis and that GELP77 orthologs are present in various plant species. Together, these results indicate that GELP77 regulates pollen wall characteristics in Arabidopsis.
花粉壁特性在花粉成熟过程中发生显著变化。许多基因已被鉴定为调节花粉壁特性变化的调控因子，但这些变化的机制尚未完全理解。在这里，我们发现 GDSL 型酯酶/脂肪酶基因 GELP77 调控拟南芥花粉壁特性的变化。GELP77 缺失（gelp77）的植物表现出雄性不育，而这种表型可以通过引入 GELP77 基因组片段得到抑制。野生型拟南芥植物的成熟花粉粒具有有组织的网状表面结构，彼此分离。相比之下，gelp77 的花粉粒缺乏这种结构，并且皱缩并粘在一起。在拟南芥 gelp77 小孢子的假定单核阶段，无法检测到核，表明 GELP77 早在这个阶段就需要。在具有 GELP77 启动子-GELP77-GFP 转基因植物中，在减数分裂后阶段的花药中的小孢子、绒毡层细胞和中层细胞中检测到 GELP77-GFP 融合蛋白，而在减数分裂前阶段的花药中则没有。氨基酸序列分析表明，GELP77 在系统发育上与拟南芥中的其他 104 个 GDSL 型酯酶/脂肪酶基因相距甚远，并且 GELP77 同源物存在于各种植物物种中。总之，这些结果表明 GELP77 调节拟南芥花粉壁特性。
