School of Horticulture and Plant Protection, International Research Laboratory of Agriculture and Agri-Product Safety, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, 48 Wenhui East Road, Yangzhou 225009, China.
Int J Mol Sci. 2022 Feb 16;23(4):2186. doi: 10.3390/ijms23042186.
Seed dormancy transition is a vital developmental process for seedling propagation and agricultural production. The process is precisely regulated by diverse endogenous genetic factors and environmental cues. Callery pear ( Decne) is an important rootstock species that requires cold stratification to break seed dormancy, but the mechanisms underlying pear seed dormancy release are not yet fully understood. Here, we analyzed the transcriptome profiles at three different stages of cold stratification in callery pear seeds using RNA sequencing combined with phytohormone and sugar content measurements. Significant alterations in hormone contents and carbohydrate metabolism were observed and reflected the dormancy status of the seeds. The expressions of genes related to plant hormone metabolism and signaling transduction, including indole-3-acetic acid (IAA) biosynthesis (, , , , and ) genes as well as several abscisic acid (ABA) and gibberellic acid (GA) catabolism and signaling transduction genes (s, , and s), were consistent with endogenous hormone changes. We further found that several genes involved in cytokinin (CTK), ethylene (ETH), brassionolide (BR), and jasmonic acid (JA) metabolism and signaling transduction were differentially expressed and integrated in pear seed dormancy release. In accordance with changes in starch and soluble sugar contents, the genes associated with starch and sucrose metabolism were significantly up-regulated during seed dormancy release progression. Furthermore, the expression levels of genes involved in lipid metabolism pathways were also up-regulated. Finally, 447 transcription factor (TF) genes (including , , , , , and genes) were observed to be differentially expressed during seed cold stratification and might relate to pear seed dormancy release. Our results suggest that the mechanism underlying pear seed dormancy release is a complex, transcriptionally regulated process involving hormones, sugars, lipids, and TFs.
种子休眠的转变是幼苗繁殖和农业生产的重要发育过程。这个过程受到多种内源性遗传因素和环境线索的精确调节。西洋梨（Decne）是一种重要的砧木物种，需要经过低温层积来打破种子休眠，但梨种子休眠解除的机制尚不完全清楚。在这里，我们使用 RNA 测序结合植物激素和糖含量测量，分析了在三个不同低温层积阶段的西洋梨种子的转录组图谱。观察到激素含量和碳水化合物代谢的显著变化，反映了种子的休眠状态。与植物激素代谢和信号转导相关的基因的表达，包括吲哚-3-乙酸（IAA）生物合成（、、、、和）基因以及几种脱落酸（ABA）和赤霉素（GA）分解代谢和信号转导基因（s、、和 s），与内源激素变化一致。我们进一步发现，一些参与细胞分裂素（CTK）、乙烯（ETH）、油菜素内酯（BR）和茉莉酸（JA）代谢和信号转导的基因差异表达，并在梨种子休眠解除中整合。与淀粉和可溶性糖含量的变化一致，与淀粉和蔗糖代谢相关的基因在种子休眠解除过程中显著上调。此外，与脂质代谢途径相关的基因的表达水平也上调。最后，观察到 447 个转录因子（TF）基因（包括、、、、、和 基因）在种子低温层积过程中差异表达，可能与梨种子休眠解除有关。我们的研究结果表明，梨种子休眠解除的机制是一个复杂的、转录调控过程，涉及激素、糖、脂质和 TF。
