Molecular mechanisms and ecological function of far‐red light signalling. (27th March 2017)

• Record Type: Journal Article
• Authors: Sheerin, David J.; Hiltbrunner, Andreas
• Is Part Of: Plant, cell and environment. Volume 40:Number 11(2017)
• Page Start: 2509
• Page End: 2529
• Publication Date: 2017-03-27
• Subjects: anthocyanin biosynthesis -- COP1 -- deetiolation -- flowering -- high irradiance response (HIR) -- phytochrome A -- seed germination -- SPA proteins -- very low fluence response (VLFR); Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.12915
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: Land plants possess the ability to sense and respond to far‐red light (700–760 nm), which serves as an important environmental cue. Due to the nature of far‐red light, it is not absorbed by chlorophyll and thus is enriched in canopy shade and will also penetrate deeper into soil than other visible wavelengths. Far‐red light responses include regulation of seed germination, suppression of hypocotyl growth, induction of flowering and accumulation of anthocyanins, which depend on one member of the phytochrome photoreceptor family, phytochrome A (phyA). Here, we review the current understanding of the underlying molecular mechanisms of how plants sense far‐red light through phyA and the physiological responses to this light quality. Light‐activated phytochromes act on two primary pathways within the nucleus; suppression of the E3 ubiquitin ligase complex CUL4/DDB1 COP1/SPA and inactivation of the PHYTOCHROME INTERACTING FACTOR (PIF) family of bHLH transcription factors. These pathways integrate with other signal transduction pathways, including phytohormones, for tissue and developmental stage specific responses. Unlike other phytochromes that mediate red‐light responses, phyA is transported from the cytoplasm to the nucleus in far‐red light by the shuttle proteins FAR‐RED ELONGATED HYPOCOTYL 1 (FHY1) and FHY1‐LIKE (FHL). However, additional mechanisms must exist that shift the action of phyA to far‐red light; current hypotheses are discussed. Summary Statement: Far‐red light regulates several responses in plants, including seed germination, suppression of hypocotyl growth, induction of flowering and accumulation of anthocyanins. Here, we review the current understanding of how plants sense far‐red light through phytochrome A and how downstream signalling works at the molecular level.