PHYTOCHROME INTERACTING FACTOR1 interactions leading to the completion or prolongation of seed germination
PHYTOCHROME INTERACTING FACTOR1 interactions leading to the completion or prolongation of seed germination
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DOI：
10.1080/15592324.2018.1525999
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发表时间：
2018-01-01
影响因子：
2.9
通讯作者：
Downie, A. Bruce
中科院分区：
文献类型：
--
作者：
Dirk, Lynnette M. A.;Kumar, Santosh;Downie, A. Bruce
在拟南芥中，已知基本的受阻环受阻转录因子植物色素相互作用因子1（PIF 1）协调种子转录组，使得最终在黑暗中产生抑制萌发完成的蛋白质。虽然PIF 1介导的脱落酸（阿坝）和赤霉酸（GA）的抑制/催化作用是间接的PIF 1行动有利于阿坝，而歧视GA，坚定地建立阿坝的抑制影响完成发芽。结果是组织对ABA更敏感并产生更多的阿坝;并且对GA的反应较低且缺乏GA。适当波长的光照激活光敏色素，光敏色素进入细胞核，并与PIF 1结合，启动PIF 1通过不同激酶的磷酸化，随后的多聚泛素化和水解。在光照下，磷酸化的PIF 1从种子细胞中消除的一种机制涉及F-BOX蛋白，冷温发芽10（CTG 10）。在无偏筛选的激活标记的品系中发现，在10 ° C下加速种子萌发的完成，CTG 10在降低PIF 1滴度中的作用的一个间接结果应该是增强其产物起作用以增加生物活性GA滴度的基因的转录，将细胞内环境从抑制性环境转变为有利于种子萌发完成的环境。我们已经使用CTG 10量改变的多种拟南芥品系测试了这一假设。在这里，我们证明了使用双分子荧光互补，PIF 1与CTG 10相互作用，并表明，在光暴露的种子，PIF 1是更持久的ctg 70相对于野生型种子，而它是不太稳定的种子过表达CTG 10。这些结果与来自三个基因的相对转录本丰度一致，所述三个基因的产物参与生物活性GA积累。我们提出了一个模型，PIF 1相互作用在吸胀的种子在萌发过程中的变化，以及如何一个允许的光信号影响这些变化，导致这些积极的光胚繁殖体的萌发完成。
In Arabidopsis thaliana, the basic Helix Loop Helix transcription factor, PHYTOCHROME INTERACTING FACTOR1 (PIF1) is known to orchestrate the seed transcriptome such that, ultimately, proteins repressing the completion of germination are produced in darkness. While PIF1-mediated control of abscisic acid (ABA) and gibberellic acid (GA) anabolism/catabolism is indirect PIF1 action favors ABA while discriminating against GA, firmly establishing ABA's repressive influence on the completion of germination. The result is tissue that is more sensitive to and producing more ABA; and is less responsive to and deficient in GA. Illumination of the appropriate wavelength activates phytochrome which enters the nucleus, and binds to PIF1, initiating PIF1's phosphorylation by diverse kinases, subsequent polyubiquitination, and hydrolysis. One mechanism by which phosphorylated PIF1 is eliminated from the cells of the seed upon illumination involves an F-BOX protein, COLD TEMPERATURE GERMINATING10 (CTG10). Discovered in an unbiased screen of activation tagged lines hastening the completion of seed germination at 10 degrees C, one indirect consequence of CTG10 action in reducing PIF1 titer, should be to enhance the transcription of genes whose products work to increase bioactive GA titer, shifting the intracellular milieu from one that is repressive to, toward one conducive to, the completion of seed germination. We have tested this hypothesis using a variety of Arabidopsis lines altered in CTG10 amounts. Here we demonstrate using bimolecular fluorescence complementation that PIF1 interacts with CTG10 and show that, in light exposed seeds, PIF1 is more persistent in ctg70 relative to WT seeds while it is less stable in seeds over-expressing CTG10. These results are congruent with the relative transcript abundance from three genes whose products are involved in bioactive GA accumulation. We put forth a model of how PIF1 interactions in imbibed seeds change during germination and how a permissive light signal influences these changes, leading to the completion of germination of these positively photoblastic propagules.