Cryptochromes: How Blue Light Perception Influences Plant Physiology


Light plays a pivotal role in several physiological processes during plant growth, development and adaptation. Plants sense and respond to fluctuating light conditions using various photoreceptors such as phytochromes, cryptochromes and phototropins. In particular, cryptochromes are able to monitor, capture and transmit the stimuli of UVA/blue light in order to promote photomorphogenesis and regulate many aspects of plant development and growth including seed germination and seedling de‐etiolation, flowering induction, circadian rhythms and stress responses. Cryptochromes influence all these processes by modulating the expression pattern of several genes; such massive regulation is fundamental for optimising all physiological properties of plants throughout their life cycle.

Key Concepts

  • Light is essential for plant life.
  • Plants use photoreceptors to sense and monitor quality, direction, intensity and length of light stimulus.
  • Cryptochromes play fundamental roles in plant development.
  • Cryptochromes are highly conserved among plant species.
  • Cryptochromes regulate many light‐dependent physiological processes.

Keywords: cryptochromes; blue light; photomorphogenesis; photoreceptors; plant development

Figure 1. Plant cryptochromes structure. (a) Domain structure of cry1 and cry2 subfamilies' members. (b) Domain structure of cry3 subfamily members. Blue bars indicate the photolyase‐homologous region, orange bar indicates the C‐terminal extension, green bars indicate chromophores binding regions and red bars indicate the conserved DAS domain.
Figure 2. Plant cryptochromes activation, signalling and physiological responses. Cryptochrome homodimers formation occurs upon exposure to blue light. Homodimers interact with transcription factors (TF) and transcription regulators (TR) promoting gene expression. Cryptochrome signalling cascade regulates physiological processes such as de‐etiolation, stomatal opening, photoperiodic flowering and fruit metabolic composition.


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Further Reading

Ahmad M (2016) Photocycle and signaling mechanisms of plant cryptochromes. Current Opinion in Plant Biology 33: 108–115.

Fiorucci A‐S and Fankhauser C (2017) Plant strategies for enhancing access to sunlight. Current Biology 27: R931–R940.

de Wit M, Keuskamp DH, Bongers FJ, et al. (2016) Integration of phytochrome and cryptochrome signals determines plant growth during competition for light. Current Biology 26: 3320–3326.

Yang Z, Liu B, Su J, et al. (2017) Cryptochromes orchestrate transcription regulation of diverse blue light responses in plants. Photochemistry and Photobiology 93: 112–127.

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Fantini, Elio, and Facella, Paolo(Jan 2020) Cryptochromes: How Blue Light Perception Influences Plant Physiology. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0028355]