Crop Genetics, John Innes Centre, Norwich, UK.
Nat Plants. 2019 Feb;5(2):148-152. doi: 10.1038/s41477-018-0357-9. Epub 2019 Feb 4.
Plants modulate their growth rate according to seasonal and environmental cues using a suite of growth repressors known to interact directly with cellular machinery controlling cell division and growth. Mutants lacking growth repressors show increased growth rates, but the mechanism by which these plants ensure source availability for faster growth is unclear. Here, we undertake a comprehensive analysis of the fast-growth phenotype of a quintuple growth-repressor mutant, using a combination of theoretical and experimental approaches to understand the physiological basis of source-sink coordination. Our results show that, in addition to the control of tissue growth rates, growth repressors also affect tissue composition and leaf thickness, modulating the efficiency of production of new photosynthetic capacity. Modelling suggests that increases in growth efficiency underlie growth-rate differences between the wild type and spatula della growth-repressor mutant, with spatula della requiring less carbon to synthesize a comparable photosynthetic capability to the wild type, and fixing more carbon per unit mass. We conclude that through control of leaf development, growth repressors regulate both source availability and sink strength to achieve growth-rate variation without risking a carbon deficit.
植物根据季节和环境线索调节生长速度，使用一系列已知与控制细胞分裂和生长的细胞机制直接相互作用的生长抑制剂。缺乏生长抑制剂的突变体表现出生长速度加快，但这些植物如何确保为更快生长提供源的机制尚不清楚。在这里，我们使用理论和实验相结合的方法，对五重生长抑制剂突变体的快速生长表型进行了全面分析，以了解源库协调的生理基础。我们的结果表明，除了控制组织生长速度外，生长抑制剂还影响组织组成和叶片厚度，从而调节新光合作用能力的产生效率。模型表明，生长效率的提高是野生型和匙形突变体生长抑制剂之间生长速度差异的基础，匙形突变体需要更少的碳来合成与野生型相当的光合作用能力，并且每单位质量固定更多的碳。我们得出结论，通过控制叶片发育，生长抑制剂调节源可用性和库强度，以实现生长速度的变化，而不会冒着碳亏缺的风险。
