Thompson Michael, Gamage Dananjali, Hirotsu Naoki, Martin Anke, Seneweera Saman
Faculty of Health, Engineering and Sciences, Centre for Crop Health, University of Southern QueenslandToowoomba, QLD, Australia.
Faculty of Life Sciences, Toyo UniversityItakura-machi, Japan.
Front Physiol. 2017 Aug 8;8:578. doi: 10.3389/fphys.2017.00578. eCollection 2017.
Plant responses to atmospheric carbon dioxide will be of great concern in the future, as carbon dioxide concentrations ([CO]) are predicted to continue to rise. Elevated [CO] causes increased photosynthesis in plants, which leads to greater production of carbohydrates and biomass. Which organ the extra carbohydrates are allocated to varies between species, but also within species. These carbohydrates are a major energy source for plant growth, but they also act as signaling molecules and have a range of uses beyond being a source of carbon and energy. Currently, there is a lack of information on how the sugar sensing and signaling pathways of plants are affected by the higher content of carbohydrates produced under elevated [CO]. Particularly, the sugar signaling pathways of roots are not well understood, along with how they are affected by elevated [CO]. At elevated [CO], some plants allocate greater amounts of sugars to roots where they are likely to act on gene regulation and therefore modify nutrient uptake and transport. Glucose and sucrose also promote root growth, an effect similar to what occurs under elevated [CO]. Sugars also crosstalk with hormones to regulate root growth, but also affect hormone biosynthesis. This review provides an update on the role of sugars as signaling molecules in plant roots and thus explores the currently known functions that may be affected by elevated [CO].
未来，植物对大气二氧化碳的响应将备受关注，因为预计二氧化碳浓度（[CO₂]）会持续上升。升高的[CO₂]会使植物光合作用增强，进而导致碳水化合物和生物量产量增加。额外的碳水化合物分配到哪个器官因物种而异，即使在同一物种内也存在差异。这些碳水化合物是植物生长的主要能量来源，但它们也作为信号分子，除了作为碳和能量来源外还有一系列用途。目前，关于植物的糖感知和信号传导途径如何受到升高的[CO₂]条件下产生的更高碳水化合物含量影响的信息还很缺乏。特别是，根系的糖信号传导途径以及它们如何受到升高的[CO₂]影响还不太清楚。在升高的[CO₂]条件下，一些植物会将更多的糖分分配到根系，在那里它们可能作用于基因调控，从而改变养分吸收和运输。葡萄糖和蔗糖也能促进根系生长，这一效应与在升高的[CO₂]条件下发生的情况类似。糖还与激素相互作用来调节根系生长，同时也影响激素生物合成。本文综述了糖作为植物根系信号分子的作用，并探讨了目前已知的可能受升高的[CO₂]影响的功能。
