Sainsbury Laboratory, Cambridge University, Cambridge, UK.
Sainsbury Laboratory, Cambridge University, Cambridge, UK.
Curr Opin Plant Biol. 2019 Feb;47:9-15. doi: 10.1016/j.pbi.2018.08.001. Epub 2018 Aug 30.
The gibberellin phytohormones regulate growth and development throughout the plant lifecycle. Upstream regulation and downstream responses to gibberellins vary across cells and tissues, developmental stages, environmental conditions, and plant species. The spatiotemporal distribution of gibberellins is the result of an ensemble of biosynthetic, catabolic and transport activities, each of which can be targeted to influence gibberellin levels in space and time. Understanding gibberellin distributions has recently benefited from discovery of transport proteins capable of importing gibberellins as well as novel methods for detecting gibberellins with high spatiotemporal resolution. For example, a genetically-encoded fluorescent biosensor for gibberellins was deployed in Arabidopsis and revealed gibberellin gradients in rapidly elongating tissues. Although cellular accumulations of gibberellins are hypothesized to regulate cell growth in developing embryos, germinating seeds, elongating stems and roots, and developing floral organs, understanding the quantitative relationship between cellular gibberellin levels and cellular growth awaits further investigation. It is also unclear how spatiotemporal gibberellin distributions result from myriad endogenous and environmental factors directing an ensemble of known gibberellin enzymatic and transport steps.
赤霉素植物激素在整个植物生命周期中调节生长和发育。赤霉素的上游调控和下游响应在细胞和组织、发育阶段、环境条件和植物物种之间存在差异。赤霉素的时空分布是生物合成、分解代谢和运输活动的综合结果，其中每一种活动都可以作为靶点，以影响空间和时间上的赤霉素水平。最近，得益于能够导入赤霉素的转运蛋白的发现，以及具有高时空分辨率检测赤霉素的新方法，对赤霉素分布的理解得到了改善。例如，在拟南芥中部署了一种用于赤霉素的遗传编码荧光生物传感器，揭示了快速伸长组织中的赤霉素梯度。尽管细胞内赤霉素的积累被假设可以调节发育中的胚胎、萌发的种子、伸长的茎和根以及发育中的花器官中的细胞生长，但要了解细胞内赤霉素水平与细胞生长之间的定量关系，还需要进一步研究。赤霉素时空分布如何由众多内源性和环境因素决定，从而导致一系列已知的赤霉素酶和运输步骤，目前也不清楚。
