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Maurya PK, Kumar V, Mondal S, Singh SP. Photoautotrophic black-colored cyanobacterial soil crust biosynthesizes photoprotective compounds and is capable of using blue, green, and red wavelengths of light for its growth. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:16756-16769. [PMID: 36576619 DOI: 10.1007/s11356-022-24993-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
Several cyanobacteria can adjust their light-harvesting machinery in response to existing light signals in a process called chromatic acclimation (CA) which permits the utilization of available light resources for photosynthesis. CA involves alteration in the pigment composition of a major light-harvesting complex called phycobilisome (PBS) and allows some cyanobacteria to utilize green light (GL) to drive photosynthesis. However, cyanobacteria, in contrast with eukaryotic algae and higher plants, can not utilize blue light (BL) for photosynthesis due to their dependency on PBS. Here, we studied a black-colored soil crust that was composed of a single cyanobacterium identified and named Oscillatoria sp. Malviya-1 after phenotypic and phylogenetic analyses. The black-colored crust can absorb light from almost all parts of photosynthetically active radiation (400-700 nm) and ultraviolet radiation (280-400 nm) due to the presence of photosynthetic pigments and microbial sunscreens such as chlorophyll ɑ, carotenoids, phycoerythrin, phycocyanin, allophycocyanin, mycosporine-like amino acids, and scytonemin. Unlike other cyanobacteria, Oscillatoria sp. Malviya-1 can grow using GL, BL, and red light (RL) in addition to white light (WL) which was accompanied by the different colors of the mat under different light conditions. The presence of CA and sunscreens compounds can maximize the fitness of soil crust under a dynamic light environment, UVR, and desiccation. Detailed study of Oscillatoria sp. Malviya-1 will provide information on the mechanism of CA in cyanobacterial soil crust and its unique ability to use both GL and BL.
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Affiliation(s)
- Pankaj K Maurya
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Vinod Kumar
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
- Institute of Forest Biodiversity (ICFRE), Ministry of Environment Forests and Climate Change, Hyderabad-500100, India
| | - Soumila Mondal
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Shailendra P Singh
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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Oh S, Kong Q, Montgomery BL. Guard-cell phytochromes impact seedling photomorphogenesis and rosette leaf morphology. MICROPUBLICATION BIOLOGY 2022; 2022. [PMID: 35128344 PMCID: PMC8808294 DOI: 10.17912/micropub.biology.000521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/17/2022] [Accepted: 01/24/2022] [Indexed: 11/06/2022]
Abstract
Using a previously established transgenic approach to inactivate phytochrome chromophore synthesis in specific organs or tissues, we used a guard cell-specific promoter to induce phytochrome deficiencies in guard cells of Arabidopsis thaliana. Analyses of multiple homozygous lines depleted of phytochromes in stomatal guard cells indicated elongated hypocotyls specifically in red and far-red growth conditions. Furthermore, rosette leaves of adult plants with guard cell-specific phytochrome deficiencies showed enhanced serration compared to the wild-type Col-0 parent. Thus, we demonstrate that guard cell-localized phytochromes impact the inhibition of hypocotyl elongation, as well as leaf margin morphology of adult rosette leaves in A. thaliana.
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Affiliation(s)
- Sookyung Oh
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Que Kong
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Beronda L Montgomery
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.,Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
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3
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Goetz M, Rabinovich M, Smith HM. The role of auxin and sugar signaling in dominance inhibition of inflorescence growth by fruit load. PLANT PHYSIOLOGY 2021; 187:1189-1201. [PMID: 34734274 PMCID: PMC8566266 DOI: 10.1093/plphys/kiab237] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/03/2021] [Indexed: 05/29/2023]
Abstract
Dominance inhibition of shoot growth by fruit load is a major factor that regulates shoot architecture and limits yield in agriculture and horticulture crops. In annual plants, the inhibition of inflorescence growth by fruit load occurs at a late stage of inflorescence development termed the end of flowering transition. Physiological studies show this transition is mediated by production and export of auxin from developing fruits in close proximity to the inflorescence apex. In the meristem, cessation of inflorescence growth is controlled in part by the age-dependent pathway, which regulates the timing of arrest. Here, we show the end of flowering transition is a two-step process in Arabidopsis (Arabidopsis thaliana). The first stage is characterized by a cessation of inflorescence growth, while immature fruit continues to develop. At this stage, dominance inhibition of inflorescence growth by fruit load is associated with a selective dampening of auxin transport in the apical region of the stem. Subsequently, an increase in auxin response in the vascular tissues of the apical stem where developing fruits are attached marks the second stage for the end of flowering transition. Similar to the vegetative and floral transition, the end of flowering transition is associated with a change in sugar signaling and metabolism in the inflorescence apex. Taken together, our results suggest that during the end of flowering transition, dominance inhibition of inflorescence shoot growth by fruit load is mediated by auxin and sugar signaling.
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Affiliation(s)
- Marc Goetz
- CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA 5064, Australia
| | - Maia Rabinovich
- CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA 5064, Australia
| | - Harley M Smith
- CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA 5064, Australia
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Hu L, Liu P, Jin Z, Sun J, Weng Y, Chen P, Du S, Wei A, Li Y. A mutation in CsHY2 encoding a phytochromobilin (PΦB) synthase leads to an elongated hypocotyl 1(elh1) phenotype in cucumber (Cucumis sativus L.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2021; 134:2639-2652. [PMID: 34091695 DOI: 10.1007/s00122-021-03849-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/29/2021] [Indexed: 06/12/2023]
Abstract
The elongated hypocotyl1 (elh1) mutant in cucumber is due to a mutation in CsHY2, which is a homolog of the Arabidopsis HY2 encoding the phytochromobilin (PΦB) synthase for phytochrome biosynthesis Hypocotyl length is a critical determinant in establishing high quality seedlings for successful cucumber production, but knowledge on the molecular regulation of hypocotyl growth in cucumber is very limited. Here, we reported identification and characterization of a cucumber elongated hypocotyl 1 (elh1) mutant. We found that the longer hypocotyl in elh1 was due to longitudinal growth of hypocotyl cells. With fine mapping, the elh1 locus was delimited to a 20.9-kb region containing three annotated genes; only one polymorphism was identified in this region between two parental lines, which was a non-synonymous SNP (G28153633A) in the third exon of CsHY2 (CsGy1G030000) that encodes a phytochromobilin (PΦB) synthase. Uniqueness of the mutant allele at CsHY2 was verified in natural cucumber populations. Ectopic expression of CsHY2 in Arabidopsis hy2-1 long-hypocotyl mutant led to reduced hypocotyl length. The PΦB protein was targeted to the chloroplast. The expression levels of CsHY2 and five phytochrome genes CsPHYA1, CsPHYA2, CsPHYB, CsPHYC and CsPHYE were all significantly down-regulated while several cell elongation related genes were up-regulated in elh1 mutant compared to wild-type cucumber, which are correlated with dynamic hypocotyl elongation in the mutant. RNA-seq analysis in the WT and mutant revealed differentially expressed genes involved in porphyrin and chlorophyll metabolisms, cell elongation and plant hormone signal transduction pathways. This is the first report to characterize and clone the CsHY2 gene in cucumber. This work reveals the important of CsHY2 in regulating hypocotyl length and extends our understanding of the roles of CsHY2 in cucumber.
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Affiliation(s)
- Liangliang Hu
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Peng Liu
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Zhuoshuai Jin
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Jing Sun
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Yiqun Weng
- Horticulture Department, USDA-ARS Vegetable Crops Research Unit, University of Wisconsin, Madison, WI, 53706, USA
| | - Peng Chen
- College of Life Science, Northwest A & F University, Yangling, 712100, Shaanxi,, China
| | - Shengli Du
- Tianjin Vegetable Research Center, Tianjin, 300192, China
- National Key Laboratory of Vegetable Germplasm Innovation, Tianjin, 300192, China
| | - Aimin Wei
- Tianjin Vegetable Research Center, Tianjin, 300192, China.
- National Key Laboratory of Vegetable Germplasm Innovation, Tianjin, 300192, China.
| | - Yuhong Li
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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Oh S, Montgomery BL. Mesophyll-specific phytochromes impact chlorophyll light-harvesting complexes (LHCs) and non-photochemical quenching. PLANT SIGNALING & BEHAVIOR 2019; 14:1609857. [PMID: 31037997 PMCID: PMC6619949 DOI: 10.1080/15592324.2019.1609857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Phytochromes regulate light-dependent plastid development and plant growth and development. Prior analyses demonstrated that phytochromes regulate expression of Sigma factor 2 (SIG2), which is involved in plastid transcription and coordinates expression of plastid- and nuclear-encoded genes involved in plastid development, as well as plant growth and development. Mutation of SIG2 impacts distinct aspects of photosynthesis, resulting in elevated levels of cyclic electron flow and nonphotochemical quenching (NPQ). As we initially identified SIG2 expression as misregulated in a line lacking phytochromes in mesophyll tissues (i.e., CAB3::pBVR lines), here we report on an investigation of whether photosynthetic parameters such as NPQ are also disrupted in CAB3::pBVR lines. We determined that a specific parameter of NPQ, i.e., energy-dependent quenching (qE) which is a rapidly induced photoprotective mechanism that dissipates stressful absorption of excess light energy during photosynthesis, is disrupted when mesophyll phytochromes are significantly depleted. The observed reduction in NPQ levels in strong CAB3::pBVR lines is associated with a reduction in the accumulation of Lhcb1 proteins and assembly or stability of light-harvesting complexes (LHCs), especially trimeric LHC. These results implicate mesophyll-localized phytochromes in a specific aspect of phytochrome-mediated NPQ, likely through regulation of chlorophyll synthesis and accumulation and the associated impacts on chlorophyll-protein complexes. This role is distinct from the impact of mesophyll phytochrome-dependent control of SIG2 and associated NPQ regulation.
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Affiliation(s)
- Sookyung Oh
- Department of Energy — Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - Beronda L. Montgomery
- Department of Energy — Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
- CONTACT Beronda L. Montgomery Department of Energy — Plant Research Laboratory, Michigan State University, 612 Wilson Road, Room 106, East Lansing, MI 48824, USA
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Montgomery BL. Spatiotemporal Phytochrome Signaling during Photomorphogenesis: From Physiology to Molecular Mechanisms and Back. FRONTIERS IN PLANT SCIENCE 2016; 7:480. [PMID: 27148307 PMCID: PMC4826876 DOI: 10.3389/fpls.2016.00480] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 03/24/2016] [Indexed: 05/21/2023]
Abstract
Light exposure results in distinct responses in specific seedling tissues during photomorphogenesis. Light promotes growth of cotyledons and leaves, as well as development and elongation of roots, whereas light inhibits elongation of hypocotyls. For distinct plant responses such as shade avoidance, far-red light or shifts in spectral light quality similarly have disparate impacts on distinct plant tissues, resulting in elongation of stems or petioles and a reduction in growth of leaf blades for many species. The physiological bases of such tissue- and organ-specific light responses were initially studied using localized irradiation of specific tissues and organs, or irradiation of dissected plant parts. These historical approaches were used to identify spatial-specific pools of photoreceptors responsible for regulating local, i.e., tissue- or organ-specific, or distal, i.e., interorgan, plant responses. The red/far-red responsive phytochromes have been the most widely studied among photoreceptors in this regard. Whereas, the spatial localization of photoreceptors regulating many tissue- or organ-specific light responses were identified, the underlying signaling networks responsible for mediating the observed responses have not been well defined. Recent approaches used to investigate the molecular bases of spatiotemporal light responses include selective irradiation of plants harboring mutations in specific photoreceptors, tissue-specific expression of photoreceptors, primarily in photoreceptor mutant backgrounds, or tissue-specific biochemical ablation of photoreceptor accumulation. Progressive integration of such approaches for regulating the availability of localized pools of phytochromes with the use of transcriptomic or proteomic analyses for assessing the genes or proteins which these spatially discrete pools of phytochrome regulate is yielding emergent insight into the molecular bases of spatiotemporal phytochrome signaling pathways responsible for regulating spatiotemporal light responses of which we have been aware of at the physiological level for decades. Here, I discuss historical and emerging approaches to elucidating spatiotemporal signaling mediated by phytochromes during photomorphogenesis.
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Affiliation(s)
- Beronda L. Montgomery
- Department of Energy — Plant Research Laboratory, Michigan State UniversityEast Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State UniversityEast Lansing, MI, USA
- *Correspondence: Beronda L. Montgomery,
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Mahmood K, Kannangara R, Jørgensen K, Fuglsang AT. Analysis of peptide PSY1 responding transcripts in the two Arabidopsis plant lines: wild type and psy1r receptor mutant. BMC Genomics 2014; 15:441. [PMID: 24906416 PMCID: PMC4070568 DOI: 10.1186/1471-2164-15-441] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 05/20/2014] [Indexed: 11/21/2022] Open
Abstract
Background Small-secreted peptides are emerging as important components in cell-cell communication during basic developmental stages of plant cell growth and development. Plant peptide containing sulfated tyrosine 1 (PSY1) has been reported to promote cell expansion and differentiation in the elongation zone of roots. PSY1 action is dependent on a receptor PSY1R that triggers a signaling cascade leading to cell elongation. However little is known about cellular functions and the components involved in PSY1-based signaling cascade. Results Differentially expressed genes were identified in a wild type plant line and in a psy1r receptor mutant line of Arabidopsis thaliana after treatment with PSY1. Seventy-seven genes were found to be responsive to the PSY1 peptide in wild type plants while 154 genes were responsive in the receptor mutant plants. PSY1 activates the transcripts of genes involved in cell wall modification. Gene enrichment analysis revealed that PSY1-responsive genes are involved in responses to stimuli, metabolic processes and biosynthetic processes. The significant enrichment terms of PSY1-responsive genes were higher in psy1r mutant plants compared to in wild type plants. Two parallel responses to PSY1 were identified, differing in their dependency on the PSY1R receptor. Promoter analysis of the differentially expressed genes identified a light regulatory motif in some of these. Conclusion PSY1-responsive genes are involved in cellular functions and stimuli responses suggesting a crosstalk between developmental cues and environmental stimuli. Possibly, two parallel responses to PSY1 exist. A motif involved in light regulation was identified in the promoter region of the differentially expressed genes. Reduced hypocotyl growth was observed in etiolated receptor mutant seedlings. Electronic supplementary material The online version of this article (doi: 10.1186/1471-2164-15-441) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Anja T Fuglsang
- Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark.
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Hopkins JA, Kiss JZ. Phototropism and gravitropism in transgenic lines of Arabidopsis altered in the phytochrome pathway. PHYSIOLOGIA PLANTARUM 2012; 145:461-73. [PMID: 22380624 DOI: 10.1111/j.1399-3054.2012.01607.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Phytochromes are a family of photoreceptor molecules, absorbing primarily in red and far-red, that are important in many aspects of plant development. These studies investigated the role of phytochromes in phototropism and gravitropism of seedlings of Arabidopsis thaliana. We used two transgenic lines, one which lacked phytochromes specifically in the roots (M0062/UASBVR) and the other lacked phytochromes in the shoots (CAB3::pBVR). These transgenic plants are deficient in the phytochrome chromophore in specific tissues due the expression of biliverdin IXa reductase (BVR), which binds to precursors of the chromophore. Experiments were performed in both light and dark conditions to determine whether roots directly perceive light signals or if the signal is perceived in the shoot and then transmitted to the root during tropistic curvature. Kinetics of tropisms and growth were assayed by standard methods or with a computer-based feedback system. We found that the perception of red light occurs directly in the root during phototropism in this organ and that signaling also may occur from root to shoot in gravitropism.
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Affiliation(s)
- Jane A Hopkins
- Department of Botany, Miami University, Oxford, OH 45056, USA
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Warnasooriya SN, Montgomery BL. Spatial-specific regulation of root development by phytochromes in Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2011; 6:2047-50. [PMID: 22112446 PMCID: PMC3337204 DOI: 10.4161/psb.6.12.18267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Distinct tissues and organs of plants exhibit dissimilar responses to light exposure--cotyledon growth is promoted by light, whereas hypocotyl growth is inhibited by light. Light can have different impacts on root development, including impacting root elongation, morphology, lateral root proliferation and root tropisms. In many cases, light inhibits root elongation. There has been much attention given to whether roots themselves are the sites of photoperception for light that impacts light-dependent growth and development of roots. A number of approaches including photoreceptor localization in planta, localized irradiation and exposure of dissected roots to light have been used to explore the site(s) of light perception for the photoregulation of root development. Such approaches have led to the observation that photoreceptors are localized to roots in many plant species, and that roots are capable of light absorption that can alter morphology and/or gene expression. Our recent results show that localized depletion of phytochrome photoreceptors in Arabidopsis thaliana disrupts root development and root responsiveness to the plant hormone jasmonic acid. Thus, root-localized light perception appears central to organ-specific, photoregulation of growth and development in roots.
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Affiliation(s)
| | - Beronda L. Montgomery
- Department of Energy Plant Research Laboratory; Michigan State University; East Lansing, MI USA
- Department of Biochemistry and Molecular Biology; Michigan State University; East Lansing, MI USA
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Warnasooriya SN, Montgomery BL. Using transgenic modulation of protein synthesis and accumulation to probe protein signaling networks in Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2011; 6:1312-21. [PMID: 21862868 PMCID: PMC3258059 DOI: 10.4161/psb.6.9.16437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Deployment of new model species in the plant biology community requires the development and/or improvement of numerous genetic tools. Sequencing of the Arabidopsis thaliana genome opened up a new challenge of assigning biological function to each gene. As many genes exhibit spatiotemporal or other conditional regulation of biological processes, probing for gene function necessitates applications that can be geared toward temporal, spatial and quantitative functional analysis in vivo. The continuing quest to establish new platforms to examine plant gene function has resulted in the availability of numerous genomic and proteomic tools. Classical and more recent genome-wide experimental approaches include conventional mutagenesis, tagged DNA insertional mutagenesis, ectopic expression of transgenes, activation tagging, RNA interference and two-component transactivation systems. The utilization of these molecular tools has resulted in conclusive evidence for the existence of many genes, and expanded knowledge on gene structure and function. This review covers several molecular tools that have become increasingly useful in basic plant research. We discuss their advantages and limitations for probing cellular protein function while emphasizing the contributions made to lay the fundamental groundwork for genetic manipulation of crops using plant biotechnology.
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Affiliation(s)
- Sankalpi N Warnasooriya
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
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Ranjan A, Fiene G, Fackendahl P, Hoecker U. The Arabidopsis repressor of light signaling SPA1 acts in the phloem to regulate seedling de-etiolation, leaf expansion and flowering time. Development 2011; 138:1851-62. [DOI: 10.1242/dev.061036] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Plants adjust their growth and development in response to the ambient light environment. These light responses involve systemic signals that coordinate differentiation of different tissues and organs. Here, we have investigated the function of the key repressor of photomorphogenesis SPA1 in different tissues of the plant by expressing GUS-SPA1 under the control of tissue-specific promoters in a spa mutant background. We show that SPA1 expression in the phloem vasculature is sufficient to rescue the spa1 mutant phenotype in dark-grown spa mutant seedlings. Expression of SPA1 in mesophyll, epidermis or root tissues of the seedling, by contrast, has no or only slight effects. In the leaf, SPA1 expression in both the phloem and the mesophyll is required for full complementation of the defect in leaf expansion. SPA1 in phloem and mesophyll tissues affected division and expansion of cells in the epidermal layer, indicating that SPA1 induces non-cell-autonomous responses also in the leaf. Photoperiodic flowering is exclusively controlled by SPA1 expression in the phloem, which is consistent with previous results showing that the direct substrate of the COP1/SPA complex, CONSTANS, also acts in the phloem. Taken together, our results highlight the importance of phloem vascular tissue in coordinating growth and development. Because the SPA1 protein itself is incapable of moving from cell to cell, we suggest that SPA1 regulates the activity of downstream component(s) of light signaling that subsequently act in a non-cell-autonomous manner. SPA1 action in the phloem may also result in mechanical stimuli that affect cell elongation and cell division in other tissues.
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Affiliation(s)
- Aashish Ranjan
- Botanical Institute, Cologne Biocenter, University of Cologne, Zuelpicher Strasse 47b, 50674 Cologne, Germany
| | - Gabriele Fiene
- Botanical Institute, Cologne Biocenter, University of Cologne, Zuelpicher Strasse 47b, 50674 Cologne, Germany
| | - Petra Fackendahl
- Botanical Institute, Cologne Biocenter, University of Cologne, Zuelpicher Strasse 47b, 50674 Cologne, Germany
| | - Ute Hoecker
- Botanical Institute, Cologne Biocenter, University of Cologne, Zuelpicher Strasse 47b, 50674 Cologne, Germany
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Shin DH, Cho MH, Kim TL, Yoo J, Kim JI, Han YJ, Song PS, Jeon JS, Bhoo SH, Hahn TR. A small GTPase activator protein interacts with cytoplasmic phytochromes in regulating root development. J Biol Chem 2010; 285:32151-9. [PMID: 20551316 PMCID: PMC2952216 DOI: 10.1074/jbc.m110.133710] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 06/14/2010] [Indexed: 11/06/2022] Open
Abstract
Phytochromes enable plants to sense light information and regulate developmental responses. Phytochromes interact with partner proteins to transmit light signals to downstream components for plant development. PIRF1 (phytochrome-interacting ROP guanine-nucleotide exchange factor (RopGEF 1)) functions as a light-signaling switch regulating root development through the activation of ROPs (Rho-like GTPase of plant) in the cytoplasm. In vitro pulldown and yeast two-hybrid assays confirmed the interaction between PIRF1 and phytochromes. PIRF1 interacted with the N-terminal domain of phytochromes through its conserved PRONE (plant-specific ROP nucleotide exchanger) region. PIRF1 also interacted with ROPs and activated them in a phytochrome-dependent manner. The Pr form of phytochrome A enhanced the RopGEF activity of PIRF1, whereas the Pfr form inhibited it. A bimolecular fluorescence complementation analysis demonstrated that PIRF1 was localized in the cytoplasm and bound to the phytochromes in darkness but not in light. PIRF1 loss of function mutants (pirf1) of Arabidopsis thaliana showed a longer root phenotype in the dark. In addition, both PIRF1 overexpression mutants (PIRF1-OX) and phytochrome-null mutants (phyA-211 and phyB-9) showed retarded root elongation and irregular root hair formation, suggesting that PIRF1 is a negative regulator of phytochrome-mediated primary root development. We propose that phytochrome and ROP signaling are interconnected through PIRF1 in regulating the root growth and development in Arabidopsis.
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Affiliation(s)
- Dong Ho Shin
- From the Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 446-701
| | - Man-Ho Cho
- From the Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 446-701
| | - Tae-Lim Kim
- From the Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 446-701
| | - Jihye Yoo
- From the Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 446-701
| | - Jeong-Il Kim
- the Department of Biotechnology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 500-757, and
| | - Yun-Jeong Han
- the Department of Biotechnology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 500-757, and
| | - Pill-Soon Song
- the Faculty of Biotechnology, Jeju National University, Jeju 690-756, Korea
| | - Jong-Seong Jeon
- From the Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 446-701
| | - Seong Hee Bhoo
- From the Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 446-701
| | - Tae-Ryong Hahn
- From the Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 446-701
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Rosa BA, Oh S, Montgomery BL, Chen J, Qin W. Computing gene expression data with a knowledge-based gene clustering approach. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2010; 1:51-68. [PMID: 21968910 PMCID: PMC3180043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Accepted: 06/11/2010] [Indexed: 05/31/2023]
Abstract
Computational analysis methods for gene expression data gathered in microarray experiments can be used to identify the functions of previously unstudied genes. While obtaining the expression data is not a difficult task, interpreting and extracting the information from the datasets is challenging. In this study, a knowledge-based approach which identifies and saves important functional genes before filtering based on variability and fold change differences was utilized to study light regulation. Two clustering methods were used to cluster the filtered datasets, and clusters containing a key light regulatory gene were located. The common genes to both of these clusters were identified, and the genes in the common cluster were ranked based on their coexpression to the key gene. This process was repeated for 11 key genes in 3 treatment combinations. The initial filtering method reduced the dataset size from 22,814 probes to an average of 1134 genes, and the resulting common cluster lists contained an average of only 14 genes. These common cluster lists scored higher gene enrichment scores than two individual clustering methods. In addition, the filtering method increased the proportion of light responsive genes in the dataset from 1.8% to 15.2%, and the cluster lists increased this proportion to 18.4%. The relatively short length of these common cluster lists compared to gene groups generated through typical clustering methods or coexpression networks narrows the search for novel functional genes while increasing the likelihood that they are biologically relevant.
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Warnasooriya SN, Montgomery BL. Investigating tissue- and organ-specific phytochrome responses using FACS-assisted cell-type specific expression profiling in Arabidopsis thaliana. J Vis Exp 2010:1925. [PMID: 20517200 DOI: 10.3791/1925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Light mediates an array of developmental and adaptive processes throughout the life cycle of a plant. Plants utilize light-absorbing molecules called photoreceptors to sense and adapt to light. The red/far-red light-absorbing phytochrome photoreceptors have been studied extensively. Phytochromes exist as a family of proteins with distinct and overlapping functions in all higher plant systems in which they have been studied. Phytochrome-mediated light responses, which range from seed germination through flowering and senescence, are often localized to specific plant tissues or organs. Despite the discovery and elucidation of individual and redundant phytochrome functions through mutational analyses, conclusive reports on distinct sites of photoperception and the molecular mechanisms of localized pools of phytochromes that mediate spatial-specific phytochrome responses are limited. We designed experiments based on the hypotheses that specific sites of phytochrome photoperception regulate tissue- and organ-specific aspects of photomorphogenesis, and that localized phytochrome pools engage distinct subsets of downstream target genes in cell-to-cell signaling. We developed a biochemical approach to selectively reduce functional phytochromes in an organ- or tissue-specific manner within transgenic plants. Our studies are based on a bipartite enhancer-trap approach that results in transactivation of the expression of a gene under control of the Upstream Activation Sequence (UAS) element by the transcriptional activator GAL4. The biliverdin reductase (BVR) gene under the control of the UAS is silently maintained in the absence of GAL4 transactivation in the UAS-BVR parent. Genetic crosses between a UAS-BVR transgenic line and a GAL4-GFP enhancer trap line result in specific expression of the BVR gene in cells marked by GFP expression. BVR accumulation in Arabidopsis plants results in phytochrome chromophore deficiency in planta. Thus, transgenic plants that we have produced exhibit GAL4-dependent activation of the BVR gene, resulting in the biochemical inactivation of phytochrome, as well as GAL4-dependent GFP expression. Photobiological and molecular genetic analyses of BVR transgenic lines are yielding insight into tissue- and organ-specific phytochrome-mediated responses that have been associated with corresponding sites of photoperception. Fluorescence Activated Cell Sorting (FACS) of GFP-positive, enhancer-trap-induced BVR-expressing plant protoplasts coupled with cell-type-specific gene expression profiling through microarray analysis is being used to identify putative downstream target genes involved in mediating spatial-specific phytochrome responses. This research is expanding our understanding of sites of light perception, the mechanisms through which various tissues or organs cooperate in light-regulated plant growth and development, and advancing the molecular dissection of complex phytochrome-mediated cell-to-cell signaling cascades.
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Kami C, Lorrain S, Hornitschek P, Fankhauser C. Light-regulated plant growth and development. Curr Top Dev Biol 2010; 91:29-66. [PMID: 20705178 DOI: 10.1016/s0070-2153(10)91002-8] [Citation(s) in RCA: 428] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Plants are sessile and photo-autotrophic; their entire life cycle is thus strongly influenced by the ever-changing light environment. In order to sense and respond to those fluctuating conditions higher plants possess several families of photoreceptors that can monitor light from UV-B to the near infrared (far-red). The molecular nature of UV-B sensors remains unknown, red (R) and far-red (FR) light is sensed by the phytochromes (phyA-phyE in Arabidopsis) while three classes of UV-A/blue photoreceptors have been identified: cryptochromes, phototropins, and members of the Zeitlupe family (cry1, cry2, phot1, phot2, ZTL, FKF1, and LKP2 in Arabidopsis). Functional specialization within photoreceptor families gave rise to members optimized for a wide range of light intensities. Genetic and photobiological studies performed in Arabidopsis have shown that these light sensors mediate numerous adaptive responses (e.g., phototropism and shade avoidance) and developmental transitions (e.g., germination and flowering). Some physiological responses are specifically triggered by a single photoreceptor but in many cases multiple light sensors ensure a coordinated response. Recent studies also provide examples of crosstalk between the responses of Arabidopsis to different external factors, in particular among light, temperature, and pathogens. Although the different photoreceptors are unrelated in structure, in many cases they trigger similar signaling mechanisms including light-regulated protein-protein interactions or light-regulated stability of several transcription factors. The breath and complexity of this topic forced us to concentrate on specific aspects of photomorphogenesis and we point the readers to recent reviews for some aspects of light-mediated signaling (e.g., transition to flowering).
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Affiliation(s)
- Chitose Kami
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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Warnasooriya SN, Montgomery BL. Detection of spatial-specific phytochrome responses using targeted expression of biliverdin reductase in Arabidopsis. PLANT PHYSIOLOGY 2009; 149:424-33. [PMID: 18971430 PMCID: PMC2613748 DOI: 10.1104/pp.108.127050] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 10/26/2008] [Indexed: 05/21/2023]
Abstract
To regulate levels of holophytochrome in a spatial-specific manner and investigate the major sites of action of phytochromes during seedling development, we constructed transgenic Arabidopsis (Arabidopsis thaliana) plant lines expressing plastid-targeted mammalian biliverdin IXalpha reductase (pBVR) under regulatory control of CAB3 and MERI5 promoters. Comparative photobiological and phenotypic analyses indicated that spatial-specific expression of pBVR led to the disruption of distinct subsets of phytochrome-regulated responses for different promoters. pBVR expression in photosynthetic tissues (CAB3::pBVR lines) had intermediate effects on chlorophyll accumulation, carotenoid production, anthocyanin synthesis, and leaf development responses in white-light conditions. CAB3::pBVR expression, however, resulted in distinctive phenotypes in far-red (FR) conditions. A number of FR high irradiance responses were disrupted in CAB::pBVR lines, including FR-dependent inhibition of hypocotyl elongation and stimulation of anthocyanin accumulation. By contrast, preferential expression of pBVR in the shoot apical meristem in MERI5::pBVR lines resulted in a phytochrome-deficient, leaf development phenotype under short-day growth conditions. These results implicate leaf-localized phytochrome A as having a unique role in regulating FR-mediated hypocotyl elongation and meristem- and/or leaf primordia-localized phytochromes as having a novel role in phytochrome-dependent responses. Taken together, these studies demonstrate the efficacy of selectively inactivating distinct phytochrome-mediated responses by regulated expression of BVR in transgenic plants, a novel means to investigate the sites of phytochrome photoperception and to regulate specifically light-mediated plant growth and development.
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Affiliation(s)
- Sankalpi N Warnasooriya
- Department of Energy Plant Research Laboratory , Michigan State University, East Lansing, Michigan 48824-1312, USA
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Montgomery BL. Spatial-specific phytochrome responses during de-etiolation in Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2009; 4:47-9. [PMID: 19704706 PMCID: PMC2634071 DOI: 10.4161/psb.4.1.7271] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 10/27/2008] [Indexed: 05/21/2023]
Abstract
Photoreceptors exhibit complex regulation of many aspects of growth and development, including developmental-, spatial- and temporal-specific photoregulatory responses. Such diverse regulation has been noted for all major classes of photoreceptors in plants, including red/far-red (R/FR) absorbing phytochromes and blue/UV-A (B/UV-A) light-absorbing cryptochromes and phototropins. However, the most insight into spatiotemporal responses has been reported for phytochromes both at the physiological and, more recently, at the molecular levels. Through tissue-specific degradation of the phytochrome chromophore, my laboratory recently demonstrated that phytochromes exhibit light-dependent, spatiotemporal control over de-etiolation responses in Arabidopsis thaliana. Mesophyll-localized phytochrome A (phyA) controls numerous far-red high irradiance responses (FR-HIR) in Arabidopsis. Meristem- and/or leaf primordia-localized phytochromes are involved in the regulation of leaf development. In this addendum, I provide additional novel evidence for spatial-specific, blue-light-dependent signaling roles of phytochromes.
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Affiliation(s)
- Beronda L Montgomery
- Department of Energy Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA.
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