Gil K-E, Ha J-H, Park C-M
a Department of Chemistry , Seoul National University , Seoul , Korea.
b Plant Genomics and Breeding Institute , Seoul National University , Seoul , Korea.
Plant Signal Behav. 2018;13(5):e1473684. doi: 10.1080/15592324.2018.1473684. Epub 2018 Jun 25.
Plant photomorphogenic responses have been studied mostly using the shoots, the core part of plant architecture that perceives light for photosynthesis and influences the overall processes of growth and development. While the roots are also known to respond to aboveground light through multiple routes of light signal transduction, root photomorphogenesis has been less highlighted until recently. A long-standing, critical question was how the underground roots are capable of sensing aerial light and how the root-sensed light signals trigger root photomorphogenesis. When the roots are directly exposed to light, reactive oxygen species (ROS) are rapidly produced to promote primary root elongation, which helps the roots to escape from the abnormal growth conditions. However, severe or long-term exposure of the roots to light causes ROS burst, which impose oxidative damages, leading to a reduction of root growth. We have recently found that phytochrome B (phyB) promotes abscisic acid (ABA) biosynthesis in the shoots and the shoot-derived ABA signals mediate ROS detoxification in the roots, lessening the detrimental effects of light on root growth. On the basis of these observations we propose that the phyB-mediated ABA signaling contributes to the shoot-root synchronization that is essential for optimal growth and performance in plants.
植物的光形态建成反应大多是利用地上部分进行研究的，地上部分是植物结构的核心部分，负责感知光照以进行光合作用，并影响生长和发育的整体过程。虽然已知根系也能通过多种光信号转导途径对地上光照做出反应，但直到最近，根系光形态建成才受到较少关注。一个长期存在的关键问题是，地下根系如何能够感知地上光照，以及根系感知到的光信号如何触发根系光形态建成。当根系直接暴露在光照下时，会迅速产生活性氧（ROS）以促进主根伸长，这有助于根系摆脱异常生长条件。然而，根系长时间或严重暴露在光照下会导致ROS爆发，造成氧化损伤，从而导致根系生长减缓。我们最近发现，光敏色素B（phyB）促进地上部分脱落酸（ABA）的生物合成，而地上部分产生的ABA信号介导根系中的ROS解毒，减轻光照对根系生长的不利影响。基于这些观察结果，我们提出phyB介导的ABA信号传导有助于地上-地下同步，这对植物的最佳生长和性能至关重要。
