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Incident light is a central modulator of plant growth and development. However, there are still open questions surrounding wavelength-specific plant proteomic responses. Here we applied tandem mass tag based quantitative proteomics technology to acquire an in-depth view of proteome changes in Arabidopsis thaliana response to narrow wavelength blue (B; 450 nm), amber (A; 595 nm), and red (R; 650 nm) light treatments. A total of 16,707 proteins were identified with 9120 proteins quantified across all three light treatments in three biological replicates. This enabled examination of changes in the abundance for proteins with low abundance and important regulatory roles including transcription factors and hormone signaling. Importantly, 18% (1631 proteins) of the A. thaliana proteome is differentially abundant in response to narrow wavelength lights, and changes in proteome correlate well with different morphologies exhibited by plants. To showcase the usefulness of this resource, data were placed in the context of more than thirty published datasets, providing orthogonal validation and further insights into light-specific biological pathways, including Systemic Acquired Resistance and Shade Avoidance Syndrome. This high-resolution resource for A. thaliana provides baseline data and a tool for defining molecular mechanisms that control fundamental aspects of plant response to changing light conditions, with implications in plant development and adaptation. SIGNIFICANCE: Understanding of molecular mechanisms involved in wavelength-specific response of plant is question of widespread interest both to basic researchers and to those interested in applying such knowledge to the engineering of novel proteins, as well as targeted lighting systems. Here we sought to generate a high-resolution proteomic profile of plant leaves, based on exposure to specific narrow-wavelength lights. Although changes in plant physiology in response to light spectral composition is well documented, there is limited knowledge on the roles of specific light wavelengths and their impact. Most previous studies have utilized relatively broad wavebands in their experiments. Such multi-wavelengths lights trigger diverse and complex signaling networks that pose major challenges in inference of wavelength-specific molecular processes that underly the plant response. Moreover, most studies have compared the effect of blue and red wavelengths comparing with FL, as control. As FL light consists the mixed spectra composition of both red and blue as well as numerous other wavelengths, comparing undeniably results in inconsistent and overlapping responses that will hamper effects to elucidate the plant response to specific wavelengths [1, 2]. Monitoring plant proteome response to specific wavelengths and further contrasting the changes with one another, rather than comparing plants proteome to FL, is thus necessary to gain detailed insights on underlying biological pathways and their consequences in plant physiology. Here, we employed narrow wavelength LED lights in our design to eliminate a potential overlap in molecular responses by ensuring non-overlapping wavelengths in the light treatments. We further applied TMT-labeling technology to gain a high-resolution view on the proteome changes. Our proteomics data provides an in-depth coverage suitable for system-wide analyses, providing deep insights on plant molecular response particularly because of the tremendous increase in the coverage of identified proteins which outreach the other biological data., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In vegetation stands, plants receive red to far-red ratio (R:FR) signals of varying strength from all directions. However, plant responses to variations in R:FR reflected from below have been largely ignored despite their potential consequences for plant performance. Using a heterogeneous rose canopy, which consists of bent shoots down in the canopy and vertically growing upright shoots, we quantified upward far-red reflection by bent shoots and its consequences for upright shoot architecture. With a three-dimensional plant model, we assessed consequences of responses to R:FR from below for plant photosynthesis. Bent shoots reflected substantially more far-red than red light, causing reduced R:FR in light reflected upwards. Leaf inclination angles increased in upright shoots which received low R:FR reflected from below. The increased leaf angle led to an increase in simulated plant photosynthesis only when this low R:FR was reflected off their own bent shoots and not when it reflected off neighbour bent shoots. We conclude that plant response to R:FR from below is an under-explored phenomenon which may have contrasting consequences for plant performance depending on the type of vegetation or crop system. The responses are beneficial for performance only when R:FR is reflected by lower foliage of the same plants., (© 2020 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.)

Background: In cereal crops such as wheat, an optimal timing of developmental transitions is required to maximize grain yield. Many of these developmental changes are precisely regulated by changes in the duration, intensity or quality of light. Phytochromes are dimeric photoreceptors that absorb light maximally in the red and far-red wavelengths and induce large-scale transcriptional changes in response to variation in light quality. In wheat, PHYC is required for early flowering under long days. However, it is currently unknown whether this function requires the presence of PHYB. In this study, we characterized the role of PHYB in wheat development and used RNA-seq to analyze and compare the transcriptomes of phyB-null and phyC-null TILLING mutants., Results: Under long-day photoperiods, phyB-null plants exhibit a severe delay in flowering comparable to the delay observed in phyC-null plants. These results demonstrate that both genes are required for the induction of wheat flowering under long days. Using replicated RNA-seq studies we identified 82 genes that are significantly up or down regulated in both the phyB-null and phyC-null mutant relative to their respective wild-type controls. Among these genes are several well-characterized positive regulators of flowering, including PPD1, FT1 and VRN1. Eight-fold more genes were differentially regulated only in the phyB-null mutant (2202) than only in the phyC-null mutant (261). The PHYB-regulated genes were enriched in components of the auxin, gibberellin and brassinosteroid biosynthesis and signaling pathways, and in transcription factors with putative roles in regulating vegetative development and shade-avoidance responses. Several genes involved in abiotic stress tolerance pathways were also found to be regulated by PHYB., Conclusions: PHYB and PHYC are both required for the photoperiodic induction of wheat flowering, whereas PHYB alone regulates a large number of genes involved in hormone biosynthesis and signaling, shade-avoidance response, and abiotic stress tolerance. Our analysis provides a comprehensive overview of the PHYB- and PHYC-mediated transcriptional changes during light signaling, and an initial step towards the dissection of this regulatory gene network in wheat. This further dissection will be required to explore the individual phytochrome-mediated developmental responses and to evaluate their potential to improve wheat adaptation to changing environments.