Botany, Ahead of Print.
Pollination drop (PD) plays a crucial role in the sexual reproduction of gymnosperms. However, the molecular mechanism regulating PD secretion has not been reported. In our study, we successfully constructed cDNA libraries in ovules between PD secretion and PD withdrawal stages, and identified 2975 differentially expressed genes (DEGs). These genes were involved in biosynthesis of secondary metabolites, fatty acid biosynthesis, fatty acid metabolism, and hormone-related pathways. We especially identified DEGs related to jasmonic acid (JA) metabolism and signal transduction, including Gb_39942 (SDP1), Gb_03931 (OPR2), and Gb_18696 (4CLL4), which were all upregulated at the stage of PD secretion in Ginkgo biloba L. Gb_17431 (TIF3B) and Gb_17432 (TIF9), which encode the negative regulator JAZ protein, were downregulated during this period. We also found that KO1 (Gb_05787 and Gb_38576) and GA20ox1 (Gb_16591), which are related to gibberellin (GA) synthesis, were upregulated, whereas Gb_17754, encoding the GA receptor GID1, was downregulated during PD secretion. From these results, we predicted that JA and GA may play important roles in the regulation of PD secretion in G. biloba ovules.

中文翻译：

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银杏胚珠中授粉滴分泌的植物激素需求量

植物学，提前印刷。
授粉下降（PD）在裸子植物的有性生殖中起着至关重要的作用。然而，尚未报道调节PD分泌的分子机制。在我们的研究中，我们成功地在PD分泌和PD退缩阶段之间的胚珠中构建了cDNA文库，并鉴定了2975个差异表达基因（DEG）。这些基因参与次级代谢产物的生物合成，脂肪酸的生物合成，脂肪酸的代谢以及激素相关的途径。我们特别确定了与茉莉酸（JA）代谢和信号转导相关的DEG，包括Gb_39942（SDP1），Gb_03931（OPR2）和Gb_18696（4CLL4），它们在银杏的PD分泌阶段均被上调。Gb_17431（在此期间，编码负调控因子JAZ蛋白的TIF3B和Gb_17432（TIF9）被下调。我们还发现与赤霉素（GA）合成有关的KO1（Gb_05787和Gb_38576）和GA20ox1（Gb_16591）被上调，而编码GA受体GID1的Gb_17754在PD分泌过程中被下调。从这些结果，我们预测JA和GA可能在银杏胚珠的PD分泌的调节中起重要作用。