Key Laboratory of Plant Stress Biology, School of Life Sciences, Henan University, 475004, Kaifeng, China.
State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, 475004, Kaifeng, China.
Nat Commun. 2019 Apr 16;10(1):1768. doi: 10.1038/s41467-019-09467-5.
Seed germination and photoautotrophic establishment are controlled by the antagonistic activity of the phytohormones gibberellins (GAs) and abscisic acid (ABA). Here we show that Arabidopsis thaliana GAS2 (Gain of Function in ABA-modulated Seed Germination 2), a protein belonging to the Fe-dependent 2-oxoglutarate dioxygenase superfamily, catalyzes the stereospecific hydration of GA to produce GA 16, 17-dihydro-16α-ol (DHGA). We show that DHGA, a C-GA has an atypical structure compared to known active GAs but can bind to the GA receptor (GID1c). DHGA can promote seed germination, hypocotyl elongation and cotyledon greening. Silencing and over-expression of GAS2 alters the ABA/GA ratio and sensitivity to ABA during seed germination and photoautotrophic establishment. Hence, we propose that GAS2 acts to modulate hormonal balance during early seedling development.
种子萌发和自养建立受植物激素赤霉素(GAs)和脱落酸(ABA)的拮抗活性控制。在这里,我们表明拟南芥 GAS2(ABA 调节种子萌发的功能增益 2),一种属于 Fe 依赖性 2-氧戊二酸双加氧酶超家族的蛋白质,催化 GA 的立体特异性水合生成 GA 16,17-二氢-16α-醇(DHGA)。我们表明,与已知的活性 GAs 相比,DHGA,一种 C-GA 具有非典型的结构,但可以与 GA 受体(GID1c)结合。DHGA 可以促进种子萌发、下胚轴伸长和子叶变绿。GAS2 的沉默和过表达会改变种子萌发和自养建立过程中的 ABA/GA 比值和对 ABA 的敏感性。因此,我们提出 GAS2 在早期幼苗发育过程中起调节激素平衡的作用。