The Role of Phytochromes in Triggering Plant Developmental Transitions

Abstract

Light is an essential stimulus for energy production, plant growth, development and adaptation to constantly changing environmental conditions. Plants sense different wavelengths of light through the action of specialised families of photoreceptor proteins. The molecular and physiological role of the phytochrome family of red/far‐red light receptors is well characterised. Upon light activation, phytochromes trigger multicomponent signalling cascades to induce fundamental cellular processes ranging from gene expression to protein abundance and nuclear architecture to regulate various aspects of plant development. Phytochrome responses are cell autonomous but in some cases mediate interorgan communication to control major developmental and adaptive responses such as flowering initiation and shade avoidance. Reciprocal interactions and integration between phytochrome and circadian signalling pathways are essential for optimising growth and reproductive success during the life cycle of the model plant Arabidopsis thaliana . Key Concepts Light is a vital informational signal for plant survival and growth. The phytochrome family of plant photoreceptors acts as molecular photoswitches in response to red and far‐red light. Plant phytochrome signal transduction regulates molecular and cellular processes. Phytochromes induce cell‐autonomous responses and interorgan communication. Phytochromes regulate light‐induced developmental transitions as well as adaptation to growth under dense canopy. Plant phytochromes have antagonistic and synergistic roles in regulating photoperiodic flowering in Arabidopsis . Phytochromes inform the endogenous clock about seasonal and daily changes to optimise plant growth and establish reproductive success.

The influence of light regime on the growth data and pigment composition of the plant Gentiana lutea cultured in vitro

“…Це пов'я-зано з тим, що світло здатне переключати механізми ендогенної регуляції та реалізувати відповідні програми морфогенезу. Його фізіологічне значення для рослин не обмежується лише фото-синтезом, а поширюється на численні системи контролю за ростом і розвитком організму (Karnachuk et al, 1990;Kaiserli & Chory, 2016). При цьому доведено, що ріст рослин визначає од-ночасне поєднання трьох параметрів: якості світла, його інтен-сивності та тривалості дії (Folta & Childers, 2008).…”

Light behind the curtain: photoregulation of nuclear architecture and chromatin dynamics in plants

“…Dynamic changes in chromatin structure and architecture through large‐scale genome reorganization or localized modifications on histone tails provide excellent tools for conferring specificity to gene expression in response to environmental and endogenous stimuli at diverse tissues and at different developmental stages (Kouzarides, ; Barneche et al ., ). Light has direct and indirect roles in mediating histone modifications and chromatin reorganization as a means of regulating gene expression to trigger major developmental transitions, ranging from de‐etiolation to shade avoidance and flowering (Kaiserli & Chory, ). Early studies demonstrating a direct association between one of the major light signalling components, DE‐ETIOLATED‐1 (DET1), with histones (H2B) provided evidence supporting the involvement of chromatin remodelling in light signalling (Benvenuto et al ., ).…”

“…Plant development is determined by the presence or absence of light. In particular, light drives one of the most life‐changing developmental transitions in plant development: photomorphogenesis or de‐etiolation, the ‘birth of body formation’, occurs as soon as a seedling emerges from soil and sees light for the first time (Kaiserli & Chory, ). De‐etiolation is characterized by a series of responses: the opening and greening of the cotyledons (embryonic leaves) and the inhibition of hypocotyl (embryonic stem) growth (Chen & Chory, ).…”

TANDEM ZINC-FINGER/PLUS3 regulates phytochrome B abundance and signaling to fine-tune hypocotyl growth

“…In addition to providing the main source of energy for photosynthesis, light also acts as a stimulus that triggers signaling cascades to optimize plant adaptation to fluctuating environmental regimes. Plant photoreceptors and downstream signaling components integrate information on changes in light quality, intensity, direction, and duration within a 24-h period (photoperiod), which is key for modulating major developmental transitions such as seed germination, de-etiolation, and flowering ( Quail, 2002 ; Chory, 2010 ; Chen and Chory, 2011 ; Kaiserli and Chory, 2016 ).…”