Smolikova Galina, Strygina Ksenia, Krylova Ekaterina, Leonova Tatiana, Frolov Andrej, Khlestkina Elena, Medvedev Sergei
Department of Plant Physiology and Biochemistry, St. Petersburg State University, 199034 St. Petersburg, Russia.
Postgenomic Studies Laboratory, Federal Research Center N.I. Vavilov All-Russian Institute of Plant Genetic Resources, 190121 St. Petersburg, Russia.
Plants (Basel). 2021 Sep 11;10(9):1884. doi: 10.3390/plants10091884.
Transition from seed to seedling is one of the critical developmental steps, dramatically affecting plant growth and viability. Before plants enter the vegetative phase of their ontogenesis, massive rearrangements of signaling pathways and switching of gene expression programs are required. This results in suppression of the genes controlling seed maturation and activation of those involved in regulation of vegetative growth. At the level of hormonal regulation, these events are controlled by the balance of abscisic acid and gibberellins, although ethylene, auxins, brassinosteroids, cytokinins, and jasmonates are also involved. The key players include the members of the LAFL network-the transcription factors LEAFY COTYLEDON1 and 2 (LEC 1 and 2), ABSCISIC ACID INSENSITIVE3 (ABI3), and FUSCA3 (FUS3), as well as DELAY OF GERMINATION1 (DOG1). They are the negative regulators of seed germination and need to be suppressed before seedling development can be initiated. This repressive signal is mediated by chromatin remodeling complexes-POLYCOMB REPRESSIVE COMPLEX 1 and 2 (PRC1 and PRC2), as well as PICKLE (PKL) and PICKLE-RELATED2 (PKR2) proteins. Finally, epigenetic methylation of cytosine residues in DNA, histone post-translational modifications, and post-transcriptional downregulation of seed maturation genes with miRNA are discussed. Here, we summarize recent updates in the study of hormonal and epigenetic switches involved in regulation of the transition from seed germination to the post-germination stage.
从种子到幼苗的转变是关键的发育步骤之一，极大地影响植物的生长和活力。在植物进入个体发育的营养阶段之前，信号通路需要进行大规模重排，基因表达程序也需要切换。这导致控制种子成熟的基因受到抑制，而参与营养生长调节的基因被激活。在激素调节层面，这些事件由脱落酸和赤霉素的平衡控制，不过乙烯、生长素、油菜素内酯、细胞分裂素和茉莉酸也参与其中。关键参与者包括LAFL网络的成员——转录因子LEAFY COTYLEDON1和2（LEC 1和2）、ABSCISIC ACID INSENSITIVE3（ABI3）、FUSCA3（FUS3）以及DELAY OF GERMINATION1（DOG1）。它们是种子萌发的负调控因子，在幼苗发育开始之前需要被抑制。这种抑制信号由染色质重塑复合物——多梳抑制复合物1和2（PRC1和PRC2）以及PICKLE（PKL）和PICKLE-RELATED2（PKR2）蛋白介导。最后，还讨论了DNA中胞嘧啶残基的表观遗传甲基化、组蛋白翻译后修饰以及通过miRNA对种子成熟基因进行转录后下调。在此，我们总结了激素和表观遗传开关在调控从种子萌发到萌发后阶段转变研究中的最新进展。
