Genes that help plants grow in the dark
Light significantly influences plant growth and physiology, from supplying an energy source during photosynthesis to acting as an environmental clock through which plants perceive seasons. Plants monitor changes in light through light-sensitive pigments called photoreceptors that, along with other environmental signals, help to regulate growth and development. Seedlings sown underground, for example, grow vigorously upwards, but upon reaching the soil surface their development changes in response to perceived light. The EU-funded DARK GROWTH project aimed to find such regulators of plant growth in the dark, unravelling complex, light-influenced networks in the process. Researchers identified genes that are regulated by a class of proteins (known as PIF) that promote growth in the dark (underground). Upon light exposure, plant photoreceptors (Phy) interact with PIF proteins to switch from dark-grown, which appears yellow and spindly, to light-grown, which displays increased girth and greening. They also discovered how PIF proteins regulate seedlings growing under day/night (diurnal) conditions, by activating genes involved in growth at the end of the night. Phy proteins repress growth by degrading PIF proteins, as part of a Phy/PIF regulatory network that ensures optimal growth in response to different light conditions. This study has highlighted PIF proteins as key plant growth regulators that integrate light, temperature, circadian rhythm and hormonal signals, as well as germination and flowering. Because efficient plant growth is important for agriculture, this work could provide mechanisms to improve crop production.
Keywords
Light conditions, plant growth, photoreceptors, PIF proteins, growth regulators
