FAR-RED ELONGATED HYPOCOTYLS3 Negatively Regulates Shade Avoidance Responses in Arabidopsis.

  title={FAR-RED ELONGATED HYPOCOTYLS3 Negatively Regulates Shade Avoidance Responses in Arabidopsis.},
  author={Lin Ma and Yang Li and Xiuxiu Li and Di Xu and Xueqiao Lin and Mingmei Liu and Gang Li and Xiaochun Qin},
  journal={Plant, cell \& environment},
  • Lin Ma, Yang Li, X. Qin
  • Published 12 August 2019
  • Environmental Science
  • Plant, cell & environment
Light is a key limiting factor of plant growth and development under the canopy. Specific light signals such as a low ratio of red: far-red (R:FR) light, trigger the shade avoidance response, which affects hypocotyl, stem, and leaf growth. Although multiple components mediating shade avoidance responses have been identified in the past few decades, the underlying regulatory mechanism remains unclear. In this study, we found that the far-red elongated hypocotyls 3 (fhy3) mutant exhibited longer… 

Arabidopsis FAR-RED ELONGATED HYPOCOTYL3 Integrates Age and Light Signals to Negatively Regulate Leaf Senescence

This study discovered that the light-signaling protein FAR-RED ELONGATED HYPOCOTYL3 (FHY3) negatively regulates age-induced and light-mediated leaf senescence in Arabidopsis (Arabidopsis thaliana); FHY3 directly binds to the promoter region of transcription factor gene WRKY28 to repress its expression, thus negatively regulating salicylic acid biosynthesis and senescences.

Light and Abscisic Acid Coordinately Regulate Greening of Seedlings1[OPEN]

This study reveals the physiological and molecular function of DET1 and FHY3 in the greening of seedlings and provides insights into the regulatory mechanism by which plants integrate light and ABA signals to fine-tune early seedling establishment.

PIFs coordinate shade avoidance by inhibiting auxin repressor ARF18 and metabolic regulator QQS.

The results suggest that PIFs-dependent gene regulation coordinates multiple SAS responses, including altered stem growth via ARF18, as well as altered leaf growth and metabolism via QQS, which controls the allocation of carbon and nitrogen.

FHY3 interacts with phytochrome B and regulates seed dormancy and germination.

A transcriptional cascade consisting of phyB-FHY3-RVE2/RVE7/SPT-GA3ox2 that relays environmental light signals and thereby controls seed dormancy and germination is revealed.

Integration of Light and Auxin Signaling in Shade Plants: From Mechanisms to Opportunities in Urban Agriculture

With intensification of urbanization throughout the world, food security is being threatened by the population surge, frequent occurrence of extreme climate events, limited area of available

Light and abscisic acid interplay in early seedling development.

The role of ABA-light crosstalk in regulating seedling establishment in crops is enlisted, and open questions for future investigations are highlighted.



The Shade Avoidance Syndrome in Arabidopsis: The Antagonistic Role of Phytochrome A and B Differentiates Vegetation Proximity and Canopy Shade

The data indicate that the R:FR signal distinguishes between the presence of proximal, but non-shading, neighbors and direct foliar shade, via a intrafamily photosensory attenuation mechanism that acts to suppress excessive reversion toward skotomorphogenic development under prolonged direct vegetation shade.

Interaction of shade avoidance and auxin responses: a role for two novel atypical bHLH proteins

It is shown that PAR1 and PAR2 act in the nucleus to broadly control plant development, acting as negative regulators of a variety of SAS responses, including seedling elongation and photosynthetic pigment accumulation.

Phytochrome interacting factors 4 and 5 control seedling growth in changing light conditions by directly controlling auxin signaling.

The identification of genome-wide PIF5-binding sites during shade avoidance revealed that this bHLH transcription factor regulates the expression of a subset of previously identified SAS genes, and this study suggests that PIF4 and Pif5 regulate elongation growth by controlling directly the expression for auxin biosynthesis and auxin signaling components.

The shade avoidance syndrome in Arabidopsis: a fundamental role for atypical basic helix-loop-helix proteins as transcriptional cofactors.

It is concluded that protein-protein interactions involving the HLH domain of PAR1 and HFR1 are a fundamental aspect of the mechanism by which these proteins regulate gene expression, most likely through interaction with true transcription factors that do bind to the target genes and eventually unleash the observed SAS responses.

Interactions between HLH and bHLH factors modulate light-regulated plant development.

It is shown that light signal stabilizes PAR1 protein and PAR1 interacts with Pif4 and inhibits PIF4-mediated gene activation, and a complex HLH/bHLH network regulating cell elongation and plant development in response to light and hormones is formed.

Inhibition of the shade avoidance response by formation of non‐DNA binding bHLH heterodimers

The data indicate that PIF4 and PIF5 promote SAS by directly binding to G‐boxes present in the promoter of shade marker genes, but their action is limited later in the shade when HFR1 accumulates and forms non‐DNA‐binding heterodimers.

Phytochrome-mediated inhibition of shade avoidance involves degradation of growth-promoting bHLH transcription factors.

It is suggested that, in dense vegetation, which is rich in far-red light, shade avoidance is triggered, at least partially, as a consequence of reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.

The shade-avoidance syndrome: multiple signals and ecological consequences.

It is suggested that it might be possible to improve crop health at high planting densities by targeting links between phyB and JA signalling, in particular salicylic acid and jasmonic acid.

Photoreceptor signaling networks in plant responses to shade.

  • J. Casal
  • Environmental Science
    Annual review of plant biology
  • 2013
Multiple regulatory loops and the input of the circadian clock create a complex network able to respond even to subtle threats of competition with neighbors while still compensating for major environmental fluctuations such as the day-night cycles.