Shanghai Key Lab of Protected Horticultural Technology, Horticulture Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201403, China.
College of Agriculture, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing 210095, China.
Int J Mol Sci. 2022 Sep 4;23(17):10140. doi: 10.3390/ijms231710140.
Celery seed is known to be difficult to germinate due to its morphological dormancy. Light is the key signal to release morphological dormancy and promote seed germination. However, this mechanism has rarely been studied. We performed physiological, transcriptome analyses on celery seed exposed to light and dark to decipher the mechanism by which light promotes germination of celery seed. The results showed that light significantly enhanced the expression of gibberellin synthesis genes and abscisic acid degradation genes and inhibited the expression of abscisic acid synthesis genes and gibberellin degradation genes. Moreover, gibberellin synthesis inhibitor could completely inhibit the germination capacity of celery seed, indicating that gibberellin is indispensable in the process of celery seed germination. Compared with dark, light also increased the activity of α-amylase and β-amylase and the expression of related coding genes and promoted the degradation of starch and the increase of soluble sugar content, suggesting that light enhanced the sugar metabolism of celery seed. In addition, transcriptome analysis revealed that many genes related to endosperm weakening (cell wall remodeling enzymes, extension proteins) were up-regulated under light. It was also found that light promoted the accumulation of hydrogen peroxide in the radicle, which promoted the endosperm weakening process of celery seed. Our results thus indicated that light signal may promote the release of morphological dormancy through the simultaneous action of multiple factors.
由于形态休眠，芹菜种子难以发芽。光是解除形态休眠和促进种子发芽的关键信号。然而，这种机制很少被研究。我们对暴露在光照和黑暗中的芹菜种子进行了生理和转录组分析，以揭示光促进芹菜种子发芽的机制。结果表明，光照显著增强了赤霉素合成基因和脱落酸降解基因的表达，抑制了脱落酸合成基因和赤霉素降解基因的表达。此外，赤霉素合成抑制剂能完全抑制芹菜种子的发芽能力，表明赤霉素在芹菜种子发芽过程中是必不可少的。与黑暗相比，光照还增加了α-淀粉酶和β-淀粉酶的活性以及相关编码基因的表达，促进了淀粉的降解和可溶性糖含量的增加，表明光照增强了芹菜种子的糖代谢。此外，转录组分析显示，许多与胚乳弱化（细胞壁重塑酶、延伸蛋白）相关的基因在光照下上调。还发现光照促进了胚根中过氧化氢的积累，从而促进了芹菜种子胚乳的弱化过程。因此，我们的研究结果表明，光信号可能通过多种因素的共同作用来促进形态休眠的解除。
