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Zeng SM, Lo EKW, Hazelton BJ, Morales MF, Torii KU. Effective range of non-cell autonomous activator and inhibitor peptides specifying plant stomatal patterning. Development 2020; 147:dev192237. [PMID: 32816968 PMCID: PMC7502594 DOI: 10.1242/dev.192237] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/27/2020] [Indexed: 12/15/2022]
Abstract
Stomata are epidermal valves that facilitate gas exchange between plants and their environment. Stomatal patterning is regulated by the EPIDERMAL PATTERING FACTOR (EPF) family of secreted peptides: EPF1 enforces stomatal spacing, whereas EPIDERMAL PATTERNING FACTOR-LIKE9 (EPFL9), also known as Stomagen, promotes stomatal development. It remains unknown, however, how far these signaling peptides act. Utilizing Cre-lox recombination-based mosaic sectors that overexpress either EPF1 or Stomagen in Arabidopsis cotyledons, we reveal a range within the epidermis and across the cell layers in which these peptides influence patterns. To determine their effective ranges quantitatively, we developed a computational pipeline, SPACE (stomata patterning autocorrelation on epidermis), that describes probabilistic two-dimensional stomatal distributions based upon spatial autocorrelation statistics used in astrophysics. The SPACE analysis shows that, whereas both peptides act locally, the inhibitor EPF1 exerts longer range effects than the activator Stomagen. Furthermore, local perturbation of stomatal development has little influence on global two-dimensional stomatal patterning. Our findings conclusively demonstrate the nature and extent of EPF peptides as non-cell autonomous local signals and provide a means for quantitative characterization of complex spatial patterns in development.This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Scott M Zeng
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | - Emily K W Lo
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Bryna J Hazelton
- Department of Physics, University of Washington, Seattle, WA 98195, USA
- eScience Institute, University of Washington, Seattle, WA 98195 USA
| | - Miguel F Morales
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | - Keiko U Torii
- Department of Biology, University of Washington, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, University of Texas at Austin, Austin, TX 78712, USA
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
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Borghi M, Fernie AR. Outstanding questions in flower metabolism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1275-1288. [PMID: 32410253 DOI: 10.1111/tpj.14814] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/29/2020] [Accepted: 05/05/2020] [Indexed: 06/11/2023]
Abstract
The great diversity of flowers, their color, odor, taste, and shape, is mostly a result of the metabolic processes that occur in this reproductive organ when the flower and its tissues develop, grow, and finally die. Some of these metabolites serve to advertise flowers to animal pollinators, other confer protection towards abiotic stresses, and a large proportion of the molecules of the central metabolic pathways have bioenergetic and signaling functions that support growth and the transition to fruits and seeds. Although recent studies have advanced our general understanding of flower metabolism, several questions still await an answer. Here, we have compiled a list of open questions on flower metabolism encompassing molecular aspects, as well as topics of relevance for agriculture and the ecosystem. These questions include the study of flower metabolism through development, the biochemistry of nectar and its relevance to promoting plant-pollinator interaction, recycling of metabolic resources after flowers whiter and die, as well as the manipulation of flower metabolism by pathogens. We hope with this review to stimulate discussion on the topic of flower metabolism and set a reference point to return to in the future when assessing progress in the field.
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Affiliation(s)
- Monica Borghi
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam, 14476, Germany
| | - Alisdair R Fernie
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam, 14476, Germany
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MYB repressors and MBW activation complex collaborate to fine-tune flower coloration in Freesia hybrida. Commun Biol 2020; 3:396. [PMID: 32719499 PMCID: PMC7385123 DOI: 10.1038/s42003-020-01134-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 07/01/2020] [Indexed: 12/28/2022] Open
Abstract
Floral anthocyanin has multiple ecological and economic values, its biosynthesis largely depends on the conserved MYB-bHLH-WD40 (MBW) activation complex and MYB repressors hierarchically with the MBW complex. In contrast to eudicots, the MBW regulatory network model has not been addressed in monocots because of the lack of a suitable system, as grass plants exhibit monotonous floral pigmentation patterns. Presently, the MBW regulatory network was investigated in a non-grass monocot plant, Freesia hybrida. FhMYB27 and FhMYBx with different functional manners were confirmed to be anthocyanin related R2R3 and R3 MYB repressors, respectively. Particularly, FhMYBx could obstruct the formation of positive MBW complex by titrating bHLH proteins, whereas FhMYB27 mainly defected the activator complex into suppressor via its repression domains in C-terminus. Furthermore, the hierarchical and feedback regulatory loop was verified, indicating the synergistic and sophisticated regulatory network underlying Freesia anthocyanin biosynthesis was quite similar to that reported in eudicot plants. Yueqing Li, Xiaotong Shan, et al. study the MYB-bHLH-WD40 (MBW) regulatory network in a non-grass monocot plant, Freesia hybrida. They report two anthocyanin related MYB repressors FhMYB27 and FhMYBx and verified their involvement in a functional feedback loop with MBW to regulate anthocyanin biosynthesis.
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Li Y, Shan X, Tong L, Wei C, Lu K, Li S, Kimani S, Wang S, Wang L, Gao X. The Conserved and Particular Roles of the R2R3-MYB Regulator FhPAP1 from Freesia hybrida in Flower Anthocyanin Biosynthesis. PLANT & CELL PHYSIOLOGY 2020; 61:1365-1380. [PMID: 32392327 DOI: 10.1093/pcp/pcaa065] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
Anthocyanin biosynthesis is mainly controlled by MYB-bHLH-WD40 (MBW) complexes that modulate the expression of anthocyanin biosynthetic genes (ABGs). The MYB regulators involved in anthocyanin biosynthesis arose early during plant evolution and thus might function divergently in different evolutionary lineages. Although the anthocyanin-promoting R2R3-MYB regulators in eudicots have been comprehensively explored, little consensus has been reached about functional discrepancies versus conservation among MYB regulators from different plant lineages. Here, we integrated transcriptome analysis, gene expression profiles, gain-of-function experiments and transient protoplast transfection assays to functionally characterize the monocot Freesia hybrida anthocyanin MYB regulator gene FhPAP1, which showed correlations with late ABGs. FhPAP1 could activate ABGs as well as TT8-clade genes FhTT8L, AtTT8 and NtAN1 when overexpressed in Freesia, Arabidopsis and tobacco, respectively. Consistently, FhPAP1 could interact with FhTT8L and FhTTG1 to form the conserved MBW complex and shared similar target genes with its orthologs from Arabidopsis. Most prominently, FhPAP1 displayed higher transactivation capacity than its homologs in Arabidopsis and tobacco, which was instantiated in its powerful regulation on ABGs. Moreover, we found that FhPAP1 might be the selected gene during the domestication and rapid evolution of the wild Freesia species to generate intensive flower pigmentation. These results showed that while the MBW complex was highly evolutionarily conserved between tested monocot and core eudicot plants, participating MYB regulators showed functional differences in transactivation capacity according to their activation domain and played important roles in the flower coloration domestication and evolution of angiosperms.
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Affiliation(s)
- Yueqing Li
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China
| | - Xiaotong Shan
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China
| | - Linna Tong
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China
| | - Chao Wei
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China
| | - Keyu Lu
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China
| | - Shuying Li
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China
| | - Shadrack Kimani
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China
- Department of Biological and Physical Sciences, Karatina University, P.O. Box 1957, 10101 Karatina, Kenya
| | - Shucai Wang
- School of Life Sciences, Linyi University, Linyi, China
| | - Li Wang
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China
| | - Xiang Gao
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China
- National Demonstration Center for Experimental Biology Education, Northeast Normal University, Changchun, China
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Koski MH. Macroevolution of Flower Color Patterning: Biased Transition Rates and Correlated Evolution with Flower Size. FRONTIERS IN PLANT SCIENCE 2020; 11:945. [PMID: 32714351 PMCID: PMC7344184 DOI: 10.3389/fpls.2020.00945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/10/2020] [Indexed: 06/11/2023]
Abstract
Floral pigmentation patterns can both mediate plant-pollinator interactions and modify the abiotic environment of reproductive structures. To date, there have been no inquiries into the rate and directionality of macroevolutionary transitions between patterned and non-patterned petals despite their ecological importance and ubiquity across angiosperms. Petals in the Potentilleae tribe (Rosaceae) display color patterns in the ultraviolet (UV) and human-visible spectrum, or can be uniform in color (i.e., patternless). Using a phylogeny of Potentilleae, I test whether evolutionary transition rates between patterned and non-patterned petals are biased in either direction. I then examine whether UV and human-visible floral patterns are phylogenetically correlated and test the prediction that color patterns will evolve in concert with larger flowers if they function as guides to orient pollinators to floral rewards. I found that transition rates were biased toward petals that were uniform in color. Transition rates from patterned to uniformly colored petals were two and six times higher than the reverse for UV and human-visible pattern, respectively. The presence of UV and human-visible pattern evolved independently from one another. However, the evolution of human-visible pattern was associated with the evolution of larger flowers but the evolution of UV pattern was correlated with the evolution of smaller flowers. I posit that the transition bias toward non-patterned flowers may reflect developmental constraints on spatial regulation of pigments required to produce floral color patterning. The correlated evolution of larger flowers and human-visible pigmentation patterns support the hypothesis that nectar or pollen guides are more likely to evolve in larger-flowered species. This work provides insight into how transition rate bias and trait correlations can shape phylogenetic patterns of floral color pattern diversity.
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Ünalan M, Müller P. Development: Painting Flowers with MYBs. Curr Biol 2020; 30:R227-R229. [PMID: 32155427 DOI: 10.1016/j.cub.2020.01.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Color patterns influence how attractive flowers are to bees, butterflies, and birds. By combining experiments and theory, a new study shows how a pair of MYB transcription factors orchestrates the formation of pigmentation patterns on monkeyflowers.
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Affiliation(s)
- Murat Ünalan
- Systems Biology of Development Group, Friedrich Miescher Laboratory of the Max Planck Society, Max-Planck-Ring 9, 72076 Tübingen, Germany
| | - Patrick Müller
- Systems Biology of Development Group, Friedrich Miescher Laboratory of the Max Planck Society, Max-Planck-Ring 9, 72076 Tübingen, Germany; Modeling Tumorigenesis Group, Translational Oncology Division, Eberhard Karls University Tübingen, Otfried-Müller-Straße 10, 72076 Tübingen, Germany.
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