51
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Chandler JW. Auxin response factors. PLANT, CELL & ENVIRONMENT 2016; 39:1014-28. [PMID: 26487015 DOI: 10.1111/pce.12662] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/22/2015] [Accepted: 10/05/2015] [Indexed: 05/03/2023]
Abstract
Auxin signalling involves the activation or repression of gene expression by a class of auxin response factor (ARF) proteins that bind to auxin response elements in auxin-responsive gene promoters. The release of ARF repression in the presence of auxin by the degradation of their cognate auxin/indole-3-acetic acid repressors forms a paradigm of transcriptional response to auxin. However, this mechanism only applies to activating ARFs, and further layers of complexity of ARF function and regulation are being revealed, which partly reflect their highly modular domain structure. This review summarizes our knowledge concerning ARF binding site specificity, homodimer and heterodimer multimeric ARF association and cooperative function and how activator ARFs activate target genes via chromatin remodelling and evolutionary information derived from phylogenetic comparisons from ARFs from diverse species. ARFs are regulated in diverse ways, and their importance in non-auxin-regulated pathways is becoming evident. They are also embedded within higher-order transcription factor complexes that integrate signalling pathways from other hormones and in response to the environment. The ways in which new information concerning ARFs on many levels is causing a revision of existing paradigms of auxin response are discussed.
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Affiliation(s)
- John William Chandler
- Institute of Developmental Biology, University of Cologne, Cologne Biocenter, Zuelpicher Strasse 47b, Cologne, D-50674, Germany
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52
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Abstract
Auxin is arguably the most important signaling molecule in plants, and the last few decades have seen remarkable breakthroughs in understanding its production, transport, and perception. Recent investigations have focused on transcriptional responses to auxin, providing novel insight into the functions of the domains of key transcription regulators in responses to the hormonal cue and prominently implicating chromatin regulation in these responses. In addition, studies are beginning to identify direct targets of the auxin-responsive transcription factors that underlie auxin modulation of development. Mechanisms to tune the response to different auxin levels are emerging, as are first insights into how this single hormone can trigger diverse responses. Key unanswered questions center on the mechanism for auxin-directed transcriptional repression and the identity of additional determinants of auxin response specificity. Much of what has been learned in model plants holds true in other species, including the earliest land plants.
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Affiliation(s)
- Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands;
| | - Doris Wagner
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104;
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53
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Zhang S, de Boer AH, van Duijn B. Auxin effects on ion transport in Chara corallina. JOURNAL OF PLANT PHYSIOLOGY 2016; 193:37-44. [PMID: 26943501 DOI: 10.1016/j.jplph.2016.02.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 05/26/2023]
Abstract
The plant hormone auxin has been widely studied with regard to synthesis, transport, signaling and functions among the land plants while there is still a lack of knowledge about the possible role for auxin regulation mechanisms in algae with "plant-like" structures. Here we use the alga Chara corallina as a model to study aspects of auxin signaling. In this respect we measured auxin on membrane potential changes and different ion fluxes (K(+), H(+)) through the plasma membrane. Results showed that auxin, mainly IAA, could hyperpolarize the membrane potential of C. corallina internodal cells. Ion flux measurements showed that the auxin-induced membrane potential change may be based on the change of K(+) permeability and/or channel activity rather than through the activation of proton pumps as known in land plants.
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Affiliation(s)
- Suyun Zhang
- Plant Biodynamics Laboratory, Institute Biology Leiden, Leiden University, Sylvius Laboratory, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Albertus H de Boer
- Department of Structural Biology, Faculty Earth and Life Sciences, Vrije Universiteit, De Boelelaan 1085-1087, 1081HV Amsterdam, The Netherlands
| | - Bert van Duijn
- Plant Biodynamics Laboratory, Institute Biology Leiden, Leiden University, Sylvius Laboratory, Sylviusweg 72, 2333 BE Leiden, The Netherlands; Fytagoras, Sylvius Laboratory, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
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54
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Huang Z, Duan W, Song X, Tang J, Wu P, Zhang B, Hou X. Retention, Molecular Evolution, and Expression Divergence of the Auxin/Indole Acetic Acid and Auxin Response Factor Gene Families in Brassica Rapa Shed Light on Their Evolution Patterns in Plants. Genome Biol Evol 2015; 8:302-16. [PMID: 26721260 PMCID: PMC4779605 DOI: 10.1093/gbe/evv259] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Auxin/indole acetic acids (Aux/IAAs) and auxin response factors (ARFs), major components of the Aux signaling network, are involved in many developmental processes in plants. Investigating their evolution will provide new sight on the relationship between the molecular evolution of these genes and the increasing morphotypes of plants. We constructed comparative analyses of the retention, structure, expansion, and expression patterns of Aux/IAAs and ARFs in Brassica rapa and their evolution in eight other plant species, including algae, bryophytes, lycophytes, and angiosperms. All 33 of the ARFs, including 1 ARF-like (AL) (a type of ARF-like protein) and 53 Aux/IAAs, were identified in the B. rapa genome. The genes mainly diverged approximately 13 Ma. After the split, no Aux/IAA was completely lost, and they were more preferentially retained than ARFs. In land plants, compared with ARFs, which increased in stability, Aux/IAAs expanded more rapidly and were under more relaxed selective pressure. Moreover, BraIAAs were expressed in a more tissue-specific fashion than BraARFs and demonstrated functional diversification during gene duplication under different treatments, which enhanced the cooperative interaction of homologs to help plants adapt to complex environments. In addition, ALs existed widely and had a closer relationship with ARFs, suggesting that ALs might be the initial structure of ARFs. Our results suggest that the rapid expansion and preferential retention of Aux/IAAs are likely paralleled by the increasingly complex morphotypes in Brassicas and even in land plants. Meanwhile, the data support the hypothesis that the PB1 domain plays a key role in the origin of both Aux/IAAs and ARFs.
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Affiliation(s)
- Zhinan Huang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture of Nanjing Agricultural University, Nanjing, P.R. China
| | - Weike Duan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture of Nanjing Agricultural University, Nanjing, P.R. China
| | - Xiaoming Song
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture of Nanjing Agricultural University, Nanjing, P.R. China Center of Genomics and Computational Biology, College of Life Sciences, North China University of Science and Technology, Tangshan, Hebei, China
| | - Jun Tang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture of Nanjing Agricultural University, Nanjing, P.R. China
| | - Peng Wu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture of Nanjing Agricultural University, Nanjing, P.R. China
| | - Bei Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture of Nanjing Agricultural University, Nanjing, P.R. China
| | - Xilin Hou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture of Nanjing Agricultural University, Nanjing, P.R. China
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55
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Gold DA, Runnegar B, Gehling JG, Jacobs DK. Ancestral state reconstruction of ontogeny supports a bilaterian affinity for
Dickinsonia. Evol Dev 2015; 17:315-24. [DOI: 10.1111/ede.12168] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- David A. Gold
- Department of EarthAtmosphericand Planetary SciencesMassachusetts Institute of Technology77 Massachusetts AvenueCambridgeMA 02139USA
| | - Bruce Runnegar
- Department of EarthPlanetaryand Space SciencesUniversity of CaliforniaLos AngelesCA 90095‐1567USA
| | - James G. Gehling
- South Australia Museum and the Sprigg Geobiology CentreUniversity of Adelaide, North TerraceAdelaideSouth Australia 5000Australia
| | - David K. Jacobs
- Department of EarthPlanetaryand Space SciencesUniversity of CaliforniaLos AngelesCA 90095‐1567USA
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaLos AngelesCA 90095USA
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56
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Wu MF, Yamaguchi N, Xiao J, Bargmann B, Estelle M, Sang Y, Wagner D. Auxin-regulated chromatin switch directs acquisition of flower primordium founder fate. eLife 2015; 4:e09269. [PMID: 26460543 PMCID: PMC4600763 DOI: 10.7554/elife.09269] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 09/14/2015] [Indexed: 12/16/2022] Open
Abstract
Reprogramming of cell identities during development frequently requires changes in the chromatin state that need to be restricted to the correct cell populations. Here we identify an auxin hormone-regulated chromatin state switch that directs reprogramming from transit amplifying to primordium founder cell fate in Arabidopsis inflorescences. Upon auxin sensing, the MONOPTEROS transcription factor recruits SWI/SNF chromatin remodeling ATPases to increase accessibility of the DNA for induction of key regulators of flower primordium initiation. In the absence of the hormonal cue, auxin sensitive Aux/IAA proteins bound to MONOPTEROS block recruitment of the SWI/SNF chromatin remodeling ATPases in addition to recruiting a co-repressor/histone deacetylase complex. This simple and elegant hormone-mediated chromatin state switch is ideally suited for iterative flower primordium initiation and orchestrates additional auxin-regulated cell fate transitions. Our findings establish a new paradigm for nuclear response to auxin. They also provide an explanation for how this small molecule can direct diverse plant responses.
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Affiliation(s)
- Miin-Feng Wu
- Department of Biology, University of Pennsylvania, Philadelphia, United States
| | - Nobutoshi Yamaguchi
- Department of Biology, University of Pennsylvania, Philadelphia, United States
| | - Jun Xiao
- Department of Biology, University of Pennsylvania, Philadelphia, United States
| | - Bastiaan Bargmann
- Section of Cell and Developmental Biology, Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States
| | - Mark Estelle
- Section of Cell and Developmental Biology, Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States
| | - Yi Sang
- Department of Biology, University of Pennsylvania, Philadelphia, United States
| | - Doris Wagner
- Department of Biology, University of Pennsylvania, Philadelphia, United States
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57
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Hrtyan M, Šliková E, Hejátko J, Růžička K. RNA processing in auxin and cytokinin pathways. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4897-912. [PMID: 25922481 DOI: 10.1093/jxb/erv189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Auxin and cytokinin belong to the 'magnificent seven' plant hormones, having tightly interconnected pathways leading to common as well as opposing effects on plant morphogenesis. Tremendous progress in the past years has yielded a broad understanding of their signalling, metabolism, regulatory pathways, transcriptional networks, and signalling cross-talk. One of the rapidly expanding areas of auxin and cytokinin research concerns their RNA regulatory networks. This review summarizes current knowledge about post-transcriptional gene silencing, the role of non-coding RNAs, the regulation of translation, and alternative splicing of auxin- and cytokinin-related genes. In addition, the role of tRNA-bound cytokinins is also discussed. We highlight the most recent publications dealing with this topic and underline the role of RNA processing in auxin- and cytokinin-mediated growth and development.
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Affiliation(s)
- Mónika Hrtyan
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
| | - Eva Šliková
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
| | - Jan Hejátko
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
| | - Kamil Růžička
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
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58
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Bennett T. PIN proteins and the evolution of plant development. TRENDS IN PLANT SCIENCE 2015; 20:498-507. [PMID: 26051227 DOI: 10.1016/j.tplants.2015.05.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/04/2015] [Accepted: 05/13/2015] [Indexed: 05/05/2023]
Abstract
Many aspects of development in the model plant Arabidopsis thaliana involve regulated distribution of the hormone auxin by the PIN-FORMED (PIN) family of auxin efflux carriers. The role of PIN-mediated auxin transport in other plants is not well understood, but studies in a wider range of species have begun to illuminate developmental mechanisms across land plants. In this review, I discuss recent progress in understanding the evolution of PIN-mediated auxin transport, and its role in development across the green plant lineage. I also discuss the idea that changes in auxin biology led to morphological novelty in plant development: currently available evidence suggests major innovations in auxin transport are rare and not associated with the evolution of new developmental mechanisms.
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Affiliation(s)
- Tom Bennett
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK.
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59
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Interaction and signalling between a cosmopolitan phytoplankton and associated bacteria. Nature 2015; 522:98-101. [PMID: 26017307 DOI: 10.1038/nature14488] [Citation(s) in RCA: 590] [Impact Index Per Article: 65.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 04/23/2015] [Indexed: 11/09/2022]
Abstract
Interactions between primary producers and bacteria impact the physiology of both partners, alter the chemistry of their environment, and shape ecosystem diversity. In marine ecosystems, these interactions are difficult to study partly because the major photosynthetic organisms are microscopic, unicellular phytoplankton. Coastal phytoplankton communities are dominated by diatoms, which generate approximately 40% of marine primary production and form the base of many marine food webs. Diatoms co-occur with specific bacterial taxa, but the mechanisms of potential interactions are mostly unknown. Here we tease apart a bacterial consortium associated with a globally distributed diatom and find that a Sulfitobacter species promotes diatom cell division via secretion of the hormone indole-3-acetic acid, synthesized by the bacterium using both diatom-secreted and endogenous tryptophan. Indole-3-acetic acid and tryptophan serve as signalling molecules that are part of a complex exchange of nutrients, including diatom-excreted organosulfur molecules and bacterial-excreted ammonia. The potential prevalence of this mode of signalling in the oceans is corroborated by metabolite and metatranscriptome analyses that show widespread indole-3-acetic acid production by Sulfitobacter-related bacteria, particularly in coastal environments. Our study expands on the emerging recognition that marine microbial communities are part of tightly connected networks by providing evidence that these interactions are mediated through production and exchange of infochemicals.
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60
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Flores-Sandoval E, Eklund DM, Bowman JL. A Simple Auxin Transcriptional Response System Regulates Multiple Morphogenetic Processes in the Liverwort Marchantia polymorpha. PLoS Genet 2015; 11:e1005207. [PMID: 26020649 PMCID: PMC4447368 DOI: 10.1371/journal.pgen.1005207] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 04/13/2015] [Indexed: 02/06/2023] Open
Abstract
In land plants comparative genomics has revealed that members of basal lineages share a common set of transcription factors with the derived flowering plants, despite sharing few homologous structures. The plant hormone auxin has been implicated in many facets of development in both basal and derived lineages of land plants. We functionally characterized the auxin transcriptional response machinery in the liverwort Marchantia polymorpha, a member of the basal lineage of extant land plants. All components known from flowering plant systems are present in M. polymorpha, but they exist as single orthologs: a single MpTOPLESS (TPL) corepressor, a single MpTRANSPORT inhibitor response 1 auxin receptor, single orthologs of each class of auxin response factor (ARF; MpARF1, MpARF2, MpARF3), and a single negative regulator auxin/indole-3-acetic acid (MpIAA). Phylogenetic analyses suggest this simple system is the ancestral condition for land plants. We experimentally demonstrate that these genes act in an auxin response pathway--chimeric fusions of the MpTPL corepressor with heterodimerization domains of MpARF1, MpARF2, or their negative regulator, MpIAA, generate auxin insensitive plants that lack the capacity to pattern and transition into mature stages of development. Our results indicate auxin mediated transcriptional regulation acts as a facilitator of branching, differentiation and growth, rather than acting to determine or specify tissues during the haploid stage of the M. polymorpha life cycle. We hypothesize that the ancestral role of auxin is to modulate a balance of differentiated and pluri- or totipotent cell states, whose fates are determined by interactions with combinations of unrelated transcription factors.
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Affiliation(s)
| | - D. Magnus Eklund
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - John L. Bowman
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
- Department of Plant Biology, University of California, Davis, Davis, California, United States of America
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61
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Coudert Y, Palubicki W, Ljung K, Novak O, Leyser O, Harrison CJ. Three ancient hormonal cues co-ordinate shoot branching in a moss. eLife 2015; 4. [PMID: 25806686 PMCID: PMC4391503 DOI: 10.7554/elife.06808] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 03/10/2015] [Indexed: 11/13/2022] Open
Abstract
Shoot branching is a primary contributor to plant architecture, evolving independently in flowering plant sporophytes and moss gametophytes. Mechanistic understanding of branching is largely limited to flowering plants such as Arabidopsis, which have a recent evolutionary origin. We show that in gametophytic shoots of Physcomitrella, lateral branches arise by re-specification of epidermal cells into branch initials. A simple model co-ordinating the activity of leafy shoot tips can account for branching patterns, and three known and ancient hormonal regulators of sporophytic branching interact to generate the branching pattern- auxin, cytokinin and strigolactone. The mode of auxin transport required in branch patterning is a key divergence point from known sporophytic pathways. Although PIN-mediated basipetal auxin transport regulates branching patterns in flowering plants, this is not so in Physcomitrella, where bi-directional transport is required to generate realistic branching patterns. Experiments with callose synthesis inhibitors suggest plasmodesmal connectivity as a potential mechanism for transport. DOI:http://dx.doi.org/10.7554/eLife.06808.001 Most land plants have shoots that form branches and plants can regulate when and where they grow these branches to best exploit their environment. Plants with flowers and the more ancient mosses both have branching shoots, but these two groups of plants evolved to grow in this way independently of each other. Most studies on shoot branching have focused on flowering plants and so it is less clear how branching works in mosses. Three plant hormones—called auxin, cytokinin and strigolactone—control shoot branching in flowering plants. Auxin moves down the main shoot of the plant to prevent new branches from forming. This movement is controlled by the PIN proteins and several other families of proteins. On the other hand, cytokinin promotes the growth of new branches; and strigolactone can either promote or inhibit shoot branching depending on how the auxin is travelling around the plant. Coudert, Palubicki et al. studied shoot branching in a species of moss called Physcomitrella patens. The experiments show that cells on the outer surface of the main shoot are essentially reprogrammed to become so-called ‘branch initials’, which will then develop into new branches. Next, Coudert, Palubicki et al. made a computational model that was able to simulate the pattern of shoot branching in the moss. Further experiments supported the predictions made by the model. Coudert, Palubicki et al. found that, as in flowering plants, auxin from the tip of the main shoot suppresses branching in the moss, and cytokinin promotes branching. The experiments also showed that strigolactone inhibits shoot branching, but its role is restricted to the base of the shoots. The model predicts that, unlike in flowering plants, auxin must flow in both directions in moss shoots to produce the observed patterns of shoot branching. Also, the experiments suggest that the PIN proteins and another group of proteins that control the movement of auxin do not regulate shoot branching in moss. Instead, it appears that auxin may move through microscopic channels that link one moss cell to the next. Coudert, Palubicki et al.'s findings suggest that both flowering plants and mosses have evolved to use the same three hormones to control shoot branching, but that these hormones interact in different ways. One key next step will be to find out how auxin is transported during shoot branching in moss by manipulating the opening of the channels between the cells. A further challenge will be to find out the precise details of how the hormones control the activity of the branch initial cells. DOI:http://dx.doi.org/10.7554/eLife.06808.002
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Affiliation(s)
- Yoan Coudert
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Wojtek Palubicki
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Karin Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Umeå University, Umeå, Sweden
| | - Ondrej Novak
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University and Institute of Experimental Botany ASCR, Olomouc, Czech Republic
| | - Ottoline Leyser
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - C Jill Harrison
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
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62
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Coudert Y, Palubicki W, Ljung K, Novak O, Leyser O, Harrison CJ. Three ancient hormonal cues co-ordinate shoot branching in a moss. eLife 2015; 4. [PMID: 25806686 DOI: 10.7554/elife.06808.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 03/10/2015] [Indexed: 05/18/2023] Open
Abstract
Shoot branching is a primary contributor to plant architecture, evolving independently in flowering plant sporophytes and moss gametophytes. Mechanistic understanding of branching is largely limited to flowering plants such as Arabidopsis, which have a recent evolutionary origin. We show that in gametophytic shoots of Physcomitrella, lateral branches arise by re-specification of epidermal cells into branch initials. A simple model co-ordinating the activity of leafy shoot tips can account for branching patterns, and three known and ancient hormonal regulators of sporophytic branching interact to generate the branching pattern- auxin, cytokinin and strigolactone. The mode of auxin transport required in branch patterning is a key divergence point from known sporophytic pathways. Although PIN-mediated basipetal auxin transport regulates branching patterns in flowering plants, this is not so in Physcomitrella, where bi-directional transport is required to generate realistic branching patterns. Experiments with callose synthesis inhibitors suggest plasmodesmal connectivity as a potential mechanism for transport.
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Affiliation(s)
- Yoan Coudert
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Wojtek Palubicki
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Karin Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Umeå University, Umeå, Sweden
| | - Ondrej Novak
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University and Institute of Experimental Botany ASCR, Olomouc, Czech Republic
| | - Ottoline Leyser
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - C Jill Harrison
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
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63
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Li G, Zhu C, Gan L, Ng D, Xia K. GA(3) enhances root responsiveness to exogenous IAA by modulating auxin transport and signalling in Arabidopsis. PLANT CELL REPORTS 2015; 34:483-94. [PMID: 25540118 DOI: 10.1007/s00299-014-1728-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/13/2014] [Accepted: 12/03/2014] [Indexed: 05/22/2023]
Abstract
We used auxin-signalling mutants, auxin transport mutants, and auxin-related marker lines to show that exogenously applied GA enhances auxin-induced root inhibition by affecting auxin signalling and transport. Variation in root elongation is valuable when studying the interactions of phytohormones. Auxins influence the biosynthesis and signalling of gibberellins (GAs), but the influence of GAs on auxins in root elongation is poorly understood. This study was conducted to investigate the effect of GA3 on Arabidopsis root elongation in the presence of auxin. Root elongation was inhibited in roots treated with both IAA and GA3, compared to IAA alone, and the effect was dose dependent. Further experiments showed that GA3 could modulate auxin signalling based on root elongation in auxin-signalling mutants and the expression of auxin-responsive reporters. The GA3-enhanced inhibition of root elongation observed in the wild type was not found in the auxin-signalling mutants tir1-1 and axr1-3. GA3 increased DR5::GUS expression in the root meristem and elongation zones, and IAA2::GUS in the columella. The DR5rev::GFP signal was enhanced in columella cells of the root caps and in the elongation zone in GA3-treated seedling roots. A reduction was observed in the stele of PAC-treated roots. We also examined the effect of GA3 on auxin transport. The enhanced responsiveness caused by GA3 was not observed in the auxin influx mutant aux1-7 or the efflux mutant eir1-1. Additional molecular data demonstrated that GA3 could promote auxin transport via AUX1 and PIN proteins. However, GA3-induced PIN gene expression did not fully explain GA-enhanced PIN protein accumulation. These results suggest that GA3 is involved in auxin-mediated primary root elongation by modulating auxin signalling and transport, and thus enhances root responsiveness to exogenous IAA.
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Affiliation(s)
- Guijun Li
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
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64
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Wang C, Liu Y, Li SS, Han GZ. Insights into the origin and evolution of the plant hormone signaling machinery. PLANT PHYSIOLOGY 2015; 167:872-86. [PMID: 25560880 PMCID: PMC4348752 DOI: 10.1104/pp.114.247403] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Plant hormones modulate plant growth, development, and defense. However, many aspects of the origin and evolution of plant hormone signaling pathways remain obscure. Here, we use a comparative genomic and phylogenetic approach to investigate the origin and evolution of nine major plant hormone (abscisic acid, auxin, brassinosteroid, cytokinin, ethylene, gibberellin, jasmonate, salicylic acid, and strigolactone) signaling pathways. Our multispecies genome-wide analysis reveals that: (1) auxin, cytokinin, and strigolactone signaling pathways originated in charophyte lineages; (2) abscisic acid, jasmonate, and salicylic acid signaling pathways arose in the last common ancestor of land plants; (3) gibberellin signaling evolved after the divergence of bryophytes from land plants; (4) the canonical brassinosteroid signaling originated before the emergence of angiosperms but likely after the split of gymnosperms and angiosperms; and (5) the origin of the canonical ethylene signaling pathway postdates shortly the emergence of angiosperms. Our findings might have important implications in understanding the molecular mechanisms underlying the emergence of land plants.
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Affiliation(s)
- Chunyang Wang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China (C.W., G.-Z.H.);State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, China (C.W., Y.L., S.-S.L.); andDepartment of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721 (G.-Z.H.)
| | - Yang Liu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China (C.W., G.-Z.H.);State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, China (C.W., Y.L., S.-S.L.); andDepartment of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721 (G.-Z.H.)
| | - Si-Shen Li
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China (C.W., G.-Z.H.);State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, China (C.W., Y.L., S.-S.L.); andDepartment of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721 (G.-Z.H.)
| | - Guan-Zhu Han
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China (C.W., G.-Z.H.);State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, China (C.W., Y.L., S.-S.L.); andDepartment of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721 (G.-Z.H.)
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65
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Jusoh M, Loh SH, Chuah TS, Aziz A, Cha TS. Indole-3-acetic acid (IAA) induced changes in oil content, fatty acid profiles and expression of four fatty acid biosynthetic genes in Chlorella vulgaris at early stationary growth phase. PHYTOCHEMISTRY 2015; 111:65-71. [PMID: 25583439 DOI: 10.1016/j.phytochem.2014.12.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/01/2014] [Accepted: 12/16/2014] [Indexed: 05/03/2023]
Abstract
Microalgae lipids and oils are potential candidates for renewable biodiesel. Many microalgae species accumulate a substantial amount of lipids and oils under environmental stresses. However, low growth rate under these adverse conditions account for the decrease in overall biomass productivity which directly influence the oil yield. This study was undertaken to investigate the effect of exogenously added auxin (indole-3-acetic acid; IAA) on the oil content, fatty acid compositions, and the expression of fatty acid biosynthetic genes in Chlorella vulgaris (UMT-M1). Auxin has been shown to regulate growth and metabolite production of several microalgae. Results showed that oil accumulation was highest on days after treatment (DAT)-2 with enriched levels of palmitic (C16:0) and stearic (C18:0) acids, while the linoleic (C18:2) and α-linolenic (C18:3n3) acids levels were markedly reduced by IAA. The elevated levels of saturated fatty acids (C16:0 and C18:0) were consistent with high expression of the β-ketoacyl ACP synthase I (KAS I) gene, while low expression of omega-6 fatty acid desaturase (ω-6 FAD) gene was consistent with low production of C18:2. However, the increment of stearoyl-ACP desaturase (SAD) gene expression upon IAA induction did not coincide with oleic acid (C18:1) production. The expression of omega-3 fatty acid desaturase (ω-3 FAD) gene showed a positive correlation with the synthesis of PUFA and C18:3n3.
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Affiliation(s)
- Malinna Jusoh
- School of Fundamental Sciences, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia.
| | - Saw Hong Loh
- School of Marine Science and Environment, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia.
| | - Tse Seng Chuah
- School of Food Science and Technology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia.
| | - Ahmad Aziz
- School of Food Science and Technology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia.
| | - Thye San Cha
- School of Fundamental Sciences, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia; Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia.
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66
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Abstract
Plants use auxin to relay critical information that shapes their growth and development. Auxin perception and transcriptional activation are mediated by the degradation of Aux/IAA repressor proteins. Degradation of Aux/IAAs relieves repression on Auxin Response Factors (ARFs), which bind DNA sequences called Auxin Response Elements (AuxREs). In most higher plant genomes, multiple paralogs exist for each part of the auxin nuclear signaling pathway. This potential combinatorial diversity in signaling pathways likely contributes to the myriad of context-specific responses to auxin. Recent structures of several domains from ARF proteins have exposed new modes of ARF dimerization, new models for ARF-AuxRE specificity, and the strong likelihood of larger order complexes formed by ARF and Aux/IAA homo- and heteromultimerization. Preliminary experiments support a role for these novel interactions in planta, further increasing the potential architectural complexity of this seemingly simple pathway.
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67
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Cardona-Correa C, Ecker A, Graham LE. Direction of illumination controls gametophyte orientation in seedless plants and related algae. PLANT SIGNALING & BEHAVIOR 2015; 10:e1051277. [PMID: 26237278 PMCID: PMC4883941 DOI: 10.1080/15592324.2015.1051277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 06/04/2023]
Abstract
The environmental influences that determine dorsiventral or axial gametophyte orientation are unknown for most modern seedless plants. To fill this gap, an experimental laboratory system was employed to evaluate the relative effects of light direction and gravity on body orientation of the dorsiventral green alga Coleochaete orbicularis, and gametophytes of liverworts Blasia pusilla and Marchantia polymorpha, early-diverging moss Sphagnum compactum, and fern Ceratopteris richardii, the latter functioning as experimental control. Replicate clonal cultures were experimentally illuminated only from above, only from below, or from multiple directions, with the same near-saturation PAR level for periods brief enough to minimize nutrient limitation effects, and orientation of new growth was evaluated. For all species tested, direction of illumination exerted stronger control over gametophyte body orientation than gravity. When illuminated only from below: 1) axial Sphagnum gametophores that had initially grown into an overlying air space inverted growth by 180°, burrowing into the substrate; 2) new growth of dorsiventral Blasia, Marchantia, and Ceratopteris gametophytes-whose ventral rhizoids initially penetrated agar substrate and dorsal surfaces initially faced overlying airspace-twisted 180° so that ventral surfaces bearing rhizoids faced overlying air space and rhizoids extended into the air; and 3) Coleochaete lost typical dorsiventral organization and diagnostic dorsal hairs. Direction of illumination also exerted stronger control over orientation of liverwort new growth than surface contact did. These results indicate that early land plants likely inherited light-directed gametophyte body orientation from ancestral streptophyte algae and suggest a mechanism for reorientation of gametophyte-dominant land plants after spatial disturbance.
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Affiliation(s)
| | - Alice Ecker
- Department of Botany; University of Wisconsin-Madison; Madison, WI USA
| | - Linda E Graham
- Department of Botany; University of Wisconsin-Madison; Madison, WI USA
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68
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Guilfoyle TJ. The PB1 domain in auxin response factor and Aux/IAA proteins: a versatile protein interaction module in the auxin response. THE PLANT CELL 2015; 27:33-43. [PMID: 25604444 PMCID: PMC4330575 DOI: 10.1105/tpc.114.132753] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/06/2014] [Accepted: 12/27/2014] [Indexed: 05/18/2023]
Abstract
An integral part of auxin-regulated gene expression involves the interplay of two types of transcription factors, the DNA binding auxin response factor (ARF) activators and the interacting auxin/indole acetic acid (Aux/IAA) repressors. Insight into the mechanism of how these transcription factors interact with one another has recently been revealed from crystallographic information on ARF5 and ARF7 C-terminal domains (i.e., a protein-protein interaction domain referred to as domain III/IV that is related to domain III/IV in Aux/IAA proteins). Three-dimensional structures showed that this domain in ARF5 and ARF7 conforms to a well-known PB1 (Phox and Bem1) domain that confers protein-protein interactions with other PB1 domain proteins through electrostatic contacts. Experiments verifying the importance of charged amino acids in conferring ARF and Aux/IAA interactions have confirmed the PB1 domain structure. Some in planta experiments designed to test the validity of PB1 interactions in the auxin response have led to updated models for auxin-regulated gene expression and raised many questions that will require further investigation. In addition to the PB1 domain, a second protein interaction module that functions in ARF-ARF dimerization and facilitates DNA binding has recently been revealed from crystallography studies on the ARF1 and ARF5 DNA binding domains.
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Affiliation(s)
- Tom J Guilfoyle
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211
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69
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Viaene T, Landberg K, Thelander M, Medvecka E, Pederson E, Feraru E, Cooper E, Karimi M, Delwiche C, Ljung K, Geisler M, Sundberg E, Friml J. Directional Auxin Transport Mechanisms in Early Diverging Land Plants. Curr Biol 2014; 24:2786-91. [DOI: 10.1016/j.cub.2014.09.056] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/20/2014] [Accepted: 09/16/2014] [Indexed: 10/24/2022]
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70
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Yue J, Hu X, Huang J. Origin of plant auxin biosynthesis. TRENDS IN PLANT SCIENCE 2014; 19:764-70. [PMID: 25129418 DOI: 10.1016/j.tplants.2014.07.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 06/30/2014] [Accepted: 07/17/2014] [Indexed: 05/05/2023]
Abstract
The recent finding of the tryptophan aminotransferase (TAA)/flavin monooxygenase (YUC) pathway as the principal route of auxin production in plants provides an opportunity to revisit the origin of plant auxin biosynthesis. Phylogenetic analyses of the TAA and YUC gene families provide very little evidence for the production of indole-3-acetic acid (IAA) in algae. Instead, horizontal gene transfer of YUCs from bacteria to the ancestral land plant suggests that the TAA/YUC pathway is a land plant innovation. In this Opinion article we postulate that the origin of tryptophan-dependent IAA biosynthesis in land plants might have evolved in response to interactions with microbes, particularly bacteria, allowing plants to counteract bacterial activities and control their own auxin signaling.
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Affiliation(s)
- Jipei Yue
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China; Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Xiangyang Hu
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Jinling Huang
- Department of Biology, East Carolina University, Greenville, NC 27858, USA.
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71
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Wang C, Liu Y, Li SS, Han GZ. Origin of plant auxin biosynthesis in charophyte algae. TRENDS IN PLANT SCIENCE 2014; 19:741-3. [PMID: 25457112 DOI: 10.1016/j.tplants.2014.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 09/26/2014] [Accepted: 10/06/2014] [Indexed: 05/20/2023]
Affiliation(s)
- Chunyang Wang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China; State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Yang Liu
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Si-Shen Li
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, China.
| | - Guan-Zhu Han
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
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72
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Huang X, Chen J, Bao Y, Liu L, Jiang H, An X, Dai L, Wang B, Peng D. Transcript profiling reveals auxin and cytokinin signaling pathways and transcription regulation during in vitro organogenesis of Ramie (Boehmeria nivea L. Gaud). PLoS One 2014; 9:e113768. [PMID: 25415356 PMCID: PMC4240604 DOI: 10.1371/journal.pone.0113768] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/28/2014] [Indexed: 12/13/2022] Open
Abstract
In vitro organogenesis, one of the most common pathways leading to in vitro plant regeneration, is widely used in biotechnology and the fundamental study of plant biology. Although previous studies have constructed a complex regulatory network model for Arabidopsis in vitro organogenesis, no related study has been reported in ramie. To generate more complete observations of transcriptome content and dynamics during ramie in vitro organogenesis, we constructed a reference transcriptome library and ten digital gene expression (DGE) libraries for illumina sequencing. Approximately 111.34 million clean reads were obtained for transcriptome and the DGE libraries generated between 13.5 and 18.8 million clean reads. De novo assembly produced 43,222 unigenes and a total of 5,760 differentially expressed genes (DEGs) were filtered. Searching against the Kyoto Encyclopedia of Genes and Genomes Pathway database, 26 auxin related and 11 cytokinin related DEGs were selected for qRT-PCR validation of two ramie cultivars, which had high (Huazhu No. 5) or extremely low (Dazhuhuangbaima) shoot regeneration abilities. The results revealed differing regulation patterns of auxin and cytokinin in different genotypes. Here we report the first genome-wide gene expression profiling of in vitro organogenesis in ramie and provide an overview of transcription and phytohormone regulation during the process. Furthermore, the auxin and cytokinin related genes have distinct expression patterns in two ramie cultivars with high or extremely low shoot regeneration ability, which has given us a better understanding of the in vitro organogenesis mechanism. This result will provide a foundation for future phytohormone research and lead to improvements of the ramie regeneration system.
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Affiliation(s)
- Xing Huang
- College of Plant Science and Technology, Huazhong Agricultural University, #1 Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China
| | - Jie Chen
- College of Plant Science and Technology, Huazhong Agricultural University, #1 Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China
| | - Yaning Bao
- College of Plant Science and Technology, Huazhong Agricultural University, #1 Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China
| | - Lijun Liu
- College of Plant Science and Technology, Huazhong Agricultural University, #1 Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China
| | - Hui Jiang
- College of Plant Science and Technology, Huazhong Agricultural University, #1 Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China
| | - Xia An
- College of Plant Science and Technology, Huazhong Agricultural University, #1 Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China
| | - Lunjin Dai
- College of Plant Science and Technology, Huazhong Agricultural University, #1 Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China
| | - Bo Wang
- College of Plant Science and Technology, Huazhong Agricultural University, #1 Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China
| | - Dingxiang Peng
- College of Plant Science and Technology, Huazhong Agricultural University, #1 Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China
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73
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Domozych DS, Domozych CE. Multicellularity in green algae: upsizing in a walled complex. FRONTIERS IN PLANT SCIENCE 2014; 5:649. [PMID: 25477895 PMCID: PMC4235416 DOI: 10.3389/fpls.2014.00649] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 09/03/2014] [Indexed: 05/09/2023]
Abstract
Modern green algae constitute a large and diverse taxonomic assemblage that encompasses many multicellular phenotypes including colonial, filamentous, and parenchymatous forms. In all multicellular green algae, each cell is surrounded by an extracellular matrix (ECM), most often in the form of a cell wall. Volvocalean taxa like Volvox have an elaborate, gel-like, hydroxyproline rich glycoprotein covering that contains the cells of the colony. In "ulvophytes," uronic acid-rich and sulfated polysaccharides are the likely adhesion agents that maintain the multicellular habit. Charophytes also produce polysaccharide-rich cell walls and in late divergent taxa, pectin plays a critical role in cell adhesion in the multicellular complex. Cell walls are products of coordinated interaction of membrane trafficking, cytoskeletal dynamics and the cell's signal transduction machinery responding both to precise internal clocks and external environmental cues. Most often, these activities must be synchronized with the secretion, deposition and remodeling of the polymers of the ECM. Rapid advances in molecular genetics, cell biology and cell wall biochemistry of green algae will soon provide new insights into the evolution and subcellular processes leading to multicellularity.
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Affiliation(s)
- David S. Domozych
- Skidmore Microscopy Imaging Center, Department of Biology, Skidmore College, Saratoga SpringsNY, USA
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74
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Abstract
The green lineage of chlorophyte algae and streptophytes form a large and diverse clade with multiple independent transitions to produce multicellular and/or macroscopically complex organization. In this review, I focus on two of the best-studied multicellular groups of green algae: charophytes and volvocines. Charophyte algae are the closest relatives of land plants and encompass the transition from unicellularity to simple multicellularity. Many of the innovations present in land plants have their roots in the cell and developmental biology of charophyte algae. Volvocine algae evolved an independent route to multicellularity that is captured by a graded series of increasing cell-type specialization and developmental complexity. The study of volvocine algae has provided unprecedented insights into the innovations required to achieve multicellularity.
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Affiliation(s)
- James G Umen
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
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75
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Lu Y, Tarkowská D, Turečková V, Luo T, Xin Y, Li J, Wang Q, Jiao N, Strnad M, Xu J. Antagonistic roles of abscisic acid and cytokinin during response to nitrogen depletion in oleaginous microalga Nannochloropsis oceanica expand the evolutionary breadth of phytohormone function. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:52-68. [PMID: 25041627 DOI: 10.1111/tpj.12615] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 07/06/2014] [Accepted: 07/07/2014] [Indexed: 05/03/2023]
Abstract
The origin of phytohormones is poorly understood, and their physiological roles in microalgae remain elusive. Genome comparison of photosynthetic autotrophic eukaryotes has revealed that the biosynthetic pathways of abscisic acid (ABA) and cytokinins (CKs) emerged in unicellular algae. While ABA and CK degradation mechanisms emerged broadly in algal lineages, complete vascular plant-type conjugation pathways emerged prior to the rise of Streptophyta. In microalgae, a complete set of proteins from the canonical ABA and CK sensing and signaling pathways is not essential, but individual components are present, suggesting stepwise recruitment of phytohormone signaling components. In the oleaginous eustigmatophyte Nannochloropsis oceanica IMET1, UHPLC-MS/MS detected a wide array of plant hormones, despite a phytohormone profile that is very distinct from that of flowering plants. Time-series transcriptional analysis during nitrogen depletion revealed activation of the ABA biosynthetic pathway and antagonistic transcription of CK biosynthetic genes. Correspondingly, the ABA level increases while the dominant bioactive CK forms decrease. Moreover, exogenous CKs stimulate cell-cycle progression while exogenous ABA acts as both an algal growth repressor and a positive regulator in response to stresses. The presence of such functional flowering plant-like phytohormone signaling systems in Nannochloropsis sp. suggests a much earlier origin of phytohormone biosynthesis and degradation than previously believed, and supports the presence in microalgae of as yet unknown conjugation and sensing/signaling systems that may be exploited for microalgal feedstock development.
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Affiliation(s)
- Yandu Lu
- Single Cell Center, Chinese Academy of Sciences Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
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76
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Clouse RM, Carraro N. A novel phylogeny and morphological reconstruction of the PIN genes and first phylogeny of the ACC-oxidases (ACOs). FRONTIERS IN PLANT SCIENCE 2014; 5:296. [PMID: 25018760 PMCID: PMC4071234 DOI: 10.3389/fpls.2014.00296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 06/06/2014] [Indexed: 05/04/2023]
Abstract
The PIN and ACO gene families present interesting questions about the evolution of plant physiology, including testing hypotheses about the ecological drivers of their diversification and whether unrelated genes have been recruited for similar functions. The PIN-formed proteins contribute to the polar transport of auxin, a hormone which regulates plant growth and development. PIN loci are categorized into groups according to their protein length and structure, as well as subcellular localization. An interesting question with PIN genes is the nature of the ancestral form and location. ACOs are members of a superfamily of oxygenases and oxidases that catalyze the last step of ethylene synthesis, which regulates many aspects of the plant life cycle. We used publicly available PIN and ACO sequences to conduct phylogenetic analyses. Third codon positions of these genes in monocots have a high GC content, which could be historical but is more likely due to a mutational bias. Thus, we developed methods to extract phylogenetic information from nucleotide sequences while avoiding this convergent feature. One method consisted in using only A-T transformations, and another used only the first and second codon positions for serine, which can only take A or T and G or C, respectively. We also conducted tree-searches for both gene families using unaligned amino acid sequences and dynamic homology. PIN genes appear to have diversified earlier than ACOs, with monocot and dicot copies more mixed in the phylogeny. However, gymnosperm PINs appear to be derived and not closely related to those from primitive plants. We find strong support for a long PIN gene ancestor with short forms subsequently evolving one or more times. ACO genes appear to have diversified mostly since the dicot-monocot split, as most genes cluster into a small number of monocot and dicot clades when the tree is rooted by genes from mosses. Gymnosperm ACOs were recovered as closely related and derived.
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Affiliation(s)
- Ronald M. Clouse
- Department of Bioinformatics and Genomics, University of North Carolina at CharlotteCharlotte, NC, USA
| | - Nicola Carraro
- Department of Agronomy, Purdue UniversityWest Lafayette, IN, USA
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77
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Stirk WA, Bálint P, Tarkowská D, Novák O, Maróti G, Ljung K, Turečková V, Strnad M, Ordög V, van Staden J. Effect of light on growth and endogenous hormones in Chlorella minutissima (Trebouxiophyceae). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 79:66-76. [PMID: 24685518 DOI: 10.1016/j.plaphy.2014.03.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/04/2014] [Indexed: 05/28/2023]
Abstract
Plant growth regulators (PGRs) play an important role in mediating growth and stress responses in plants. Light influences PGRs concentrations in vascular plants. The effect of light on growth and endogenous PGR concentrations in microalgae was investigated in the present study. Chlorella minutissima MACC 360 was grown in 14:10 h light:dark (L:D), continuous dark (CD) and continuous dark with the addition of 5 g L(-1) glucose (CD + G) for 48 h. Cultures were synchronized in the L:D cultures, increasing in size during the light period and dividing during the dark period. C. minutissima cells did not increase in size or undergo cell division in CD cultures. In CD + G conditions, the cultures were no longer synchronized but did continue to increase in cell size and constantly underwent cell division although fewer cells divided than in the L:D cultures. Endogenous auxin and cytokinin concentrations increased and gibberellin concentrations decreased over time in the actively growing cultures (L:D and CD + G) but did not increase in the CD cultures. The largest increase in indole content was in the CD + G cultures while the L:D cultures had the largest cytokinin increase. Brassinosteroid concentrations decreased over time in all the cultures including those grown in CD conditions. Abscisic acid (ABA) concentrations were low and only increased in the CD cultures. These results show that endogenous PGRs were affected by the light regime and/or culture growth.
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Affiliation(s)
- W A Stirk
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville 3209, South Africa.
| | - P Bálint
- Institute of Plant Biology, Faculty of Agricultural and Food Sciences, University of West Hungary, H-9200 Mosonmagyaróvár, Hungary
| | - D Tarkowská
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - O Novák
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic; Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
| | - G Maróti
- Hungarian Academy of Sciences, Biological Research Centre, Institute of Biochemistry, Temeszári krt. 62, H-6726 Szeged, Hungary
| | - K Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
| | - V Turečková
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - M Strnad
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - V Ordög
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville 3209, South Africa; Institute of Plant Biology, Faculty of Agricultural and Food Sciences, University of West Hungary, H-9200 Mosonmagyaróvár, Hungary
| | - J van Staden
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville 3209, South Africa
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78
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A Diverse Assemblage of Indole-3-Acetic Acid Producing Bacteria Associate with Unicellular Green Algae. Appl Biochem Biotechnol 2014; 173:1977-84. [DOI: 10.1007/s12010-014-0980-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 05/19/2014] [Indexed: 11/26/2022]
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79
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Ranocha P, Dima O, Nagy R, Felten J, Corratgé-Faillie C, Novák O, Morreel K, Lacombe B, Martinez Y, Pfrunder S, Jin X, Renou JP, Thibaud JB, Ljung K, Fischer U, Martinoia E, Boerjan W, Goffner D. Arabidopsis WAT1 is a vacuolar auxin transport facilitator required for auxin homoeostasis. Nat Commun 2014; 4:2625. [PMID: 24129639 PMCID: PMC3826630 DOI: 10.1038/ncomms3625] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 09/17/2013] [Indexed: 01/24/2023] Open
Abstract
The plant hormone auxin (indole-3-acetic acid, IAA) has a crucial role in plant development. Its spatiotemporal distribution is controlled by a combination of biosynthetic, metabolic and transport mechanisms. Four families of auxin transporters have been identified that mediate transport across the plasma or endoplasmic reticulum membrane. Here we report the discovery and the functional characterization of the first vacuolar auxin transporter. We demonstrate that WALLS ARE THIN1 (WAT1), a plant-specific protein that dictates secondary cell wall thickness of wood fibres, facilitates auxin export from isolated Arabidopsis vacuoles in yeast and in Xenopus oocytes. We unambiguously identify IAA and related metabolites in isolated Arabidopsis vacuoles, suggesting a key role for the vacuole in intracellular auxin homoeostasis. Moreover, local auxin application onto wat1 mutant stems restores fibre cell wall thickness. Our study provides new insight into the complexity of auxin transport in plants and a means to dissect auxin function during fibre differentiation.
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Affiliation(s)
- Philippe Ranocha
- 1] Université de Toulouse; UPS; UMR 5546, Laboratoire de Recherche en Sciences Végétales; BP 42617, F-31326, Castanet-Tolosan, France [2] Centre National de la Recherche Scientifique; CNRS; UMR5546; Laboratoire de Recherche en Sciences Végétales; BP 42617, F-31326, Castanet-Tolosan, France
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80
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Bennett T, Brockington SF, Rothfels C, Graham SW, Stevenson D, Kutchan T, Rolf M, Thomas P, Wong GKS, Leyser O, Glover BJ, Harrison CJ. Paralogous radiations of PIN proteins with multiple origins of noncanonical PIN structure. Mol Biol Evol 2014; 31:2042-60. [PMID: 24758777 PMCID: PMC4104312 DOI: 10.1093/molbev/msu147] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The plant hormone auxin is a conserved regulator of development which has been implicated in the generation of morphological novelty. PIN-FORMED1 (PIN) auxin efflux carriers are central to auxin function by regulating its distribution. PIN family members have divergent structures and cellular localizations, but the origin and evolutionary significance of this variation is unresolved. To characterize PIN family evolution, we have undertaken phylogenetic and structural analyses with a massive increase in taxon sampling over previous studies. Our phylogeny shows that following the divergence of the bryophyte and lycophyte lineages, two deep duplication events gave rise to three distinct lineages of PIN proteins in euphyllophytes. Subsequent independent radiations within each of these lineages were taxonomically asymmetric, giving rise to at least 21 clades of PIN proteins, of which 15 are revealed here for the first time. Although most PIN protein clades share a conserved canonical structure with a modular central loop domain, a small number of noncanonical clades dispersed across the phylogeny have highly divergent protein structure. We propose that PIN proteins underwent sub- and neofunctionalization with substantial modification to protein structure throughout plant evolution. Our results have important implications for plant evolution as they suggest that structurally divergent PIN proteins that arose in paralogous radiations contributed to the convergent evolution of organ systems in different land plant lineages.
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Affiliation(s)
- Tom Bennett
- Department of Plant Sciences, University of Cambridge, Cambridge, United KingdomSainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Samuel F Brockington
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Carl Rothfels
- Department of Zoology, University of British Columbia, Vancouver, British Colombia, Canada
| | - Sean W Graham
- UBC Botanical Garden Campbell Building, Vancouver, British Colombia, Canada
| | | | | | | | - Philip Thomas
- Royal Botanic Gardens Edinburgh, 20A Inverleith Row, Edinburgh, United Kingdom
| | - Gane Ka-Shu Wong
- Department of Medicine, University of Alberta, Edmonton, Alberta, CanadaDepartment of Biological Sciences, University of Alberta, Edmonton, Alberta, CanadaBGI-Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen, China
| | - Ottoline Leyser
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Beverley J Glover
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - C Jill Harrison
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
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81
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Civáň P, Foster PG, Embley MT, Séneca A, Cox CJ. Analyses of charophyte chloroplast genomes help characterize the ancestral chloroplast genome of land plants. Genome Biol Evol 2014; 6:897-911. [PMID: 24682153 PMCID: PMC4007539 DOI: 10.1093/gbe/evu061] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2014] [Indexed: 11/23/2022] Open
Abstract
Despite the significance of the relationships between embryophytes and their charophyte algal ancestors in deciphering the origin and evolutionary success of land plants, few chloroplast genomes of the charophyte algae have been reconstructed to date. Here, we present new data for three chloroplast genomes of the freshwater charophytes Klebsormidium flaccidum (Klebsormidiophyceae), Mesotaenium endlicherianum (Zygnematophyceae), and Roya anglica (Zygnematophyceae). The chloroplast genome of Klebsormidium has a quadripartite organization with exceptionally large inverted repeat (IR) regions and, uniquely among streptophytes, has lost the rrn5 and rrn4.5 genes from the ribosomal RNA (rRNA) gene cluster operon. The chloroplast genome of Roya differs from other zygnematophycean chloroplasts, including the newly sequenced Mesotaenium, by having a quadripartite structure that is typical of other streptophytes. On the basis of the improbability of the novel gain of IR regions, we infer that the quadripartite structure has likely been lost independently in at least three zygnematophycean lineages, although the absence of the usual rRNA operonic synteny in the IR regions of Roya may indicate their de novo origin. Significantly, all zygnematophycean chloroplast genomes have undergone substantial genomic rearrangement, which may be the result of ancient retroelement activity evidenced by the presence of integrase-like and reverse transcriptase-like elements in the Roya chloroplast genome. Our results corroborate the close phylogenetic relationship between Zygnematophyceae and land plants and identify 89 protein-coding genes and 22 introns present in the chloroplast genome at the time of the evolutionary transition of plants to land, all of which can be found in the chloroplast genomes of extant charophytes.
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Affiliation(s)
- Peter Civáň
- Centro de Ciências do Mar, Universidade do Algarve, Faro, Portugal
| | - Peter G. Foster
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Martin T. Embley
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Ana Séneca
- Department of Biology, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
- Department of Biology, Norges Teknisk-Naturvitenskapelige Universitet, Trondheim, Norway
| | - Cymon J. Cox
- Centro de Ciências do Mar, Universidade do Algarve, Faro, Portugal
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82
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Zhang S, van Duijn B. Cellular Auxin Transport in Algae. PLANTS 2014; 3:58-69. [PMID: 27135491 PMCID: PMC4844313 DOI: 10.3390/plants3010058] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 12/20/2013] [Accepted: 01/14/2014] [Indexed: 12/18/2022]
Abstract
The phytohormone auxin is one of the main directors of plant growth and development. In higher plants, auxin is generated in apical plant parts and transported from cell-to-cell in a polar fashion. Auxin is present in all plant phyla, and the existence of polar auxin transport (PAT) is well established in land plants. Algae are a group of relatively simple, autotrophic, photosynthetic organisms that share many features with land plants. In particular, Charophyceae (a taxon of green algae) are closest ancestors of land plants. In the study of auxin function, transport and its evolution, the algae form an interesting research target. Recently, proof for polar auxin transport in Chara species was published and auxin related research in algae gained more attention. In this review we discuss auxin transport in algae with respect to land plants and suggest directions for future studies.
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Affiliation(s)
- Suyun Zhang
- Plant Biodynamics Laboratory, Biology Institute Leiden, Leiden University, Sylviusweg 72, Leiden 2333, BE, The Netherlands.
| | - Bert van Duijn
- Plant Biodynamics Laboratory, Biology Institute Leiden, Leiden University, Sylviusweg 72, Leiden 2333, BE, The Netherlands.
- Fytagoras, Sylviusweg 72, Leiden 2333, BE, The Netherlands.
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83
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Motte H, Vereecke D, Geelen D, Werbrouck S. The molecular path to in vitro shoot regeneration. Biotechnol Adv 2014; 32:107-21. [DOI: 10.1016/j.biotechadv.2013.12.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 11/20/2013] [Accepted: 12/08/2013] [Indexed: 10/25/2022]
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84
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Kazan K. Auxin and the integration of environmental signals into plant root development. ANNALS OF BOTANY 2013; 112:1655-65. [PMID: 24136877 PMCID: PMC3838554 DOI: 10.1093/aob/mct229] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 08/12/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND Auxin is a versatile plant hormone with important roles in many essential physiological processes. In recent years, significant progress has been made towards understanding the roles of this hormone in plant growth and development. Recent evidence also points to a less well-known but equally important role for auxin as a mediator of environmental adaptation in plants. SCOPE This review briefly discusses recent findings on how plants utilize auxin signalling and transport to modify their root system architecture when responding to diverse biotic and abiotic rhizosphere signals, including macro- and micro-nutrient starvation, cold and water stress, soil acidity, pathogenic and beneficial microbes, nematodes and neighbouring plants. Stress-responsive transcription factors and microRNAs that modulate auxin- and environment-mediated root development are also briefly highlighted. CONCLUSIONS The auxin pathway constitutes an essential component of the plant's biotic and abiotic stress tolerance mechanisms. Further understanding of the specific roles that auxin plays in environmental adaptation can ultimately lead to the development of crops better adapted to stressful environments.
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Affiliation(s)
- Kemal Kazan
- Commonwealth Scientific and Industrial Organization (CSIRO) Plant Industry, Queensland Bioscience Precinct (QBP), Brisbane, Queensland 4067, Australia
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85
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Do Nascimento M, Dublan MDLA, Ortiz-Marquez JCF, Curatti L. High lipid productivity of an Ankistrodesmus-Rhizobium artificial consortium. BIORESOURCE TECHNOLOGY 2013; 146:400-407. [PMID: 23948276 DOI: 10.1016/j.biortech.2013.07.085] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/17/2013] [Accepted: 07/19/2013] [Indexed: 05/09/2023]
Abstract
Microalgae have great potential as alternative productive platforms for sustainable production of bioenergy, food, feed and other commodities. Process optimization to realize the claimed potential often comprises strains selection and improvement and also developing of more efficient cultivation, harvesting and downstream processing technology. In this work we show that inoculation with the bacterium Rhizobium strain 10II resulted in increments of up to 30% in chlorophyll, biomass and lipids accumulation of the oleaginous microalgae Ankistrodesmus sp. strain SP2-15. Inoculated cultures have reached a high lipid productivity of up to 112 mg L(-1) d(-1) after optimization. The resulting biomass presented significant levels of Ω3 fatty acids including stearidonic acid, suggesting potential as an alternative land-based source of essential fatty acids.
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Affiliation(s)
- Mauro Do Nascimento
- Instituto de Investigaciones en Biodiversidad y Biotecnología - Consejo Nacional de Investigaciones Científicas y Técnicas, Mar del Plata, Buenos Aires, Argentina
| | - Maria de Los Angeles Dublan
- Instituto de Investigaciones en Biodiversidad y Biotecnología - Consejo Nacional de Investigaciones Científicas y Técnicas, Mar del Plata, Buenos Aires, Argentina; Laboratorio Integrado de Microbiología Agrícola y de Alimentos, Facultad de Agronomía, Universidad Nacional del Centro de la Provincia de Buenos Aires, Argentina
| | - Juan Cesar Federico Ortiz-Marquez
- Instituto de Investigaciones en Biodiversidad y Biotecnología - Consejo Nacional de Investigaciones Científicas y Técnicas, Mar del Plata, Buenos Aires, Argentina
| | - Leonardo Curatti
- Instituto de Investigaciones en Biodiversidad y Biotecnología - Consejo Nacional de Investigaciones Científicas y Técnicas, Mar del Plata, Buenos Aires, Argentina.
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86
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Offringa R, Huang F. Phosphorylation-dependent trafficking of plasma membrane proteins in animal and plant cells. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:789-808. [PMID: 23945267 DOI: 10.1111/jipb.12096] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 08/02/2013] [Indexed: 05/27/2023]
Abstract
In both unicellular and multicellular organisms, transmembrane (TM) proteins are sorted to and retained at specific membrane domains by endomembrane trafficking mechanisms that recognize sorting signals in the these proteins. The trafficking and distribution of plasma membrane (PM)-localized TM proteins (PM proteins), especially of those PM proteins that show an asymmetric distribution over the PM, has received much attention, as their proper PM localization is crucial for elementary signaling and transport processes, and defects in their localization often lead to severe disease symptoms or developmental defects. The subcellular localization of PM proteins is dynamically regulated by post-translational modifications, such as phosphorylation and ubiquitination. These modificaitons mostly occur on sorting signals that are located in the larger cytosolic domains of the cargo proteins. Here we review the effects of phosphorylation of PM proteins on their trafficking, and present the key examples from the animal field that have been subject to studies for already several decades, such as that of aquaporin 2 and the epidermal growth factor receptor. Our knowledge on cargo trafficking in plants is largely based on studies of the family of PIN FORMED (PIN) carriers that mediate the efflux of the plant hormone auxin. We will review what is known on the subcellular distribution and trafficking of PIN proteins, with a focus on how this is modulated by phosphorylation, and identify and discuss analogies and differences in trafficking with the well-studied animal examples.
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Affiliation(s)
- Remko Offringa
- Molecular and Developmental Genetics, Institute Biology Leiden, Sylvius Laboratory, Sylviusweg 72, 2333 BE Leiden, Leiden University, The Netherlands
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87
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Shimasaki Y, Tsuyama M, Tasmin R, Qiu X, Shimizu M, Sato Y, Yamasaki Y, Kato-Unoki Y, Nukata A, Nakashima T, Ichinose H, Wariishi H, Honjo T, Oshima Y. Thiobencarb herbicide reduces growth, photosynthetic activity, and amount of Rieske iron-sulfur protein in the diatom Thalassiosira pseudonana. J Biochem Mol Toxicol 2013; 27:437-44. [PMID: 23801610 DOI: 10.1002/jbt.21505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 05/31/2013] [Indexed: 11/06/2022]
Abstract
We investigated the effects of the herbicide thiobencarb on the growth, photosynthetic activity, and expression profile of photosynthesis-related proteins in the marine diatom Thalassiosira pseudonana. Growth rate was suppressed by 50% at a thiobencarb concentration of 1.26 mg/L. Growth and photosystem II activity (Fv /Fm ratio) were drastically decreased at 5 mg/L, at which the expression levels of 13 proteins increased significantly and those of 11 proteins decreased significantly. Among these proteins, the level of the Rieske iron-sulfur protein was decreased to less than half of the control level. This protein is an essential component of the cytochrome b6 f complex in the photosynthetic electron transport chain. Although the mechanism by which thiobencarb decreased the Rieske iron-sulfur protein level is not clear, these results suggest that growth was inhibited by interruption of the photosynthetic electron transport chain by thiobencarb.
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Affiliation(s)
- Yohei Shimasaki
- Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka, 812-8581, Japan.
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88
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Stirk WA, Ördög V, Novák O, Rolčík J, Strnad M, Bálint P, van Staden J. Auxin and cytokinin relationships in 24 microalgal strains(1). JOURNAL OF PHYCOLOGY 2013; 49:459-67. [PMID: 27007035 DOI: 10.1111/jpy.12061] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 02/18/2013] [Indexed: 05/18/2023]
Abstract
Endogenous auxins and cytokinins were quantitated in 24 axenic microalgal strains from the Chlorophyceae, Trebouxiophyceae, Ulvophyceae, and Charophyceae. These strains were in an exponential growth phase, being harvested on day 4. Acutodesmus acuminatus Mosonmagyaróvár Algal Culture Collection-41 (MACC) produced the highest biomass and Chlorococcum ellipsoideum MACC-712 the lowest biomass. The auxins, indole-3-acetic acid (IAA) and indole-3-acetamide (IAM) were present in all microalgal strains. No other auxin conjugates were detected. IAA and IAM concentrations varied greatly, ranging from 0.50 to 71.49 nmol IAA · g(-1) DW and 0.18 to 99.83 nmol IAM · g(-1) DW, respectively. In 19 strains, IAA occurred in higher concentrations than IAM. Nineteen cytokinins were identified in the microalgal strains. Total cytokinin concentrations varied, ranging from 0.29 nmol · g(-1) DW in Klebsormidium flaccidum MACC-692 to 21.40 nmol · g(-1) DW in Stigeoclonium nanum MACC-790. The general trend was that cis-zeatin types were the predominant cytokinins; isopentenyladenine-type cytokinins were present in moderate concentrations, while low levels of trans-zeatin-type and very low levels of dihydrozeatin-type cytokinins were detected. Ribotides were generally the main cytokinin conjugate forms present with the cytokinin free bases and ribosides present in similar but moderate levels. The levels of O-glucosides were low. Only one N-glucoside was detected, being present in nine strains in very low concentrations. In 15 strains, the auxin content was 2- to 4-fold higher than the cytokinin content.
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Affiliation(s)
- Wendy A Stirk
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville, 3209, South Africa
| | - Vince Ördög
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville, 3209, South Africa
- Institute of Plant Biology, Faculty of Agricultural and Food Science, University of West Hungary, Mosonmagyaróvár, H-9200, Hungary
| | - Ondřej Novák
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, Olomouc, CZ-783 71, Czech Republic
| | - Jakub Rolčík
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, Olomouc, CZ-783 71, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, Olomouc, CZ-783 71, Czech Republic
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, Olomouc, CZ-783 71, Czech Republic
| | - Péter Bálint
- Institute of Plant Biology, Faculty of Agricultural and Food Science, University of West Hungary, Mosonmagyaróvár, H-9200, Hungary
| | - Johannes van Staden
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville, 3209, South Africa
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89
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Recruitment and remodeling of an ancient gene regulatory network during land plant evolution. Proc Natl Acad Sci U S A 2013; 110:9571-6. [PMID: 23690618 DOI: 10.1073/pnas.1305457110] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The evolution of multicellular organisms was made possible by the evolution of underlying gene regulatory networks. In animals, the core of gene regulatory networks consists of kernels, stable subnetworks of transcription factors that are highly conserved in distantly related species. However, in plants it is not clear when and how kernels evolved. We show here that RSL (ROOT HAIR DEFECTIVE SIX-LIKE) transcription factors form an ancient land plant kernel controlling caulonema differentiation in the moss Physcomitrella patens and root hair development in the flowering plant Arabidopsis thaliana. Phylogenetic analyses suggest that RSL proteins evolved in aquatic charophyte algae or in early land plants, and have been conserved throughout land plant radiation. Genetic and transcriptional analyses in loss of function A. thaliana and P. patens mutants suggest that the transcriptional interactions in the RSL kernel were remodeled and became more hierarchical during the evolution of vascular plants. We predict that other gene regulatory networks that control development in derived groups of plants may have originated in the earliest land plants or in their ancestors, the Charophycean algae.
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90
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Willige BC, Ahlers S, Zourelidou M, Barbosa IC, Demarsy E, Trevisan M, Davis PA, Roelfsema MRG, Hangarter R, Fankhauser C, Schwechheimer C. D6PK AGCVIII kinases are required for auxin transport and phototropic hypocotyl bending in Arabidopsis. THE PLANT CELL 2013; 25:1674-88. [PMID: 23709629 PMCID: PMC3694699 DOI: 10.1105/tpc.113.111484] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 04/21/2013] [Accepted: 05/07/2013] [Indexed: 05/20/2023]
Abstract
Phototropic hypocotyl bending in response to blue light excitation is an important adaptive process that helps plants to optimize their exposure to light. In Arabidopsis thaliana, phototropic hypocotyl bending is initiated by the blue light receptors and protein kinases phototropin1 (phot1) and phot2. Phototropic responses also require auxin transport and were shown to be partially compromised in mutants of the PIN-FORMED (PIN) auxin efflux facilitators. We previously described the D6 PROTEIN KINASE (D6PK) subfamily of AGCVIII kinases, which we proposed to directly regulate PIN-mediated auxin transport. Here, we show that phototropic hypocotyl bending is strongly dependent on the activity of D6PKs and the PIN proteins PIN3, PIN4, and PIN7. While early blue light and phot-dependent signaling events are not affected by the loss of D6PKs, we detect a gradual loss of PIN3 phosphorylation in d6pk mutants of increasing complexity that is most severe in the d6pk d6pkl1 d6pkl2 d6pkl3 quadruple mutant. This is accompanied by a reduction of basipetal auxin transport in the hypocotyls of d6pk as well as in pin mutants. Based on our data, we propose that D6PK-dependent PIN regulation promotes auxin transport and that auxin transport in the hypocotyl is a prerequisite for phot1-dependent hypocotyl bending.
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Affiliation(s)
- Björn C. Willige
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising-Weihenstephan, Germany
| | - Siv Ahlers
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising-Weihenstephan, Germany
| | - Melina Zourelidou
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising-Weihenstephan, Germany
| | - Inês C.R. Barbosa
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising-Weihenstephan, Germany
| | - Emilie Demarsy
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Martine Trevisan
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Philip A. Davis
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - M. Rob G. Roelfsema
- Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Biosciences, Würzburg University, 97082 Wuerzburg, Germany
| | - Roger Hangarter
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Christian Fankhauser
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Claus Schwechheimer
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising-Weihenstephan, Germany
- Address correspondence to
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91
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Sanders HL, Langdale JA. Conserved transport mechanisms but distinct auxin responses govern shoot patterning in Selaginella kraussiana. THE NEW PHYTOLOGIST 2013; 198:419-428. [PMID: 23421619 DOI: 10.1111/nph.12183] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 01/02/2013] [Indexed: 05/18/2023]
Abstract
To provide a comparative framework to understand the evolution of auxin regulation in vascular plants, the effect of perturbed auxin homeostasis was examined in the lycophyte Selaginella kraussiana. Polar auxin transport was measured by tracing tritiated IAA in excised shoots. Shoots were cultured in the presence of auxin efflux inhibitors and exogenous auxin, and developmental abnormalities were documented. Auxin transport in Selaginella shoots is exclusively basipetal, as in angiosperms. Perturbed auxin transport results in the loss of meristem maintenance and abnormal shoot architecture. Dichotomous root branching in Selaginella appears to be regulated by an antagonistic relationship between auxin and cytokinin. The results suggest that basipetal polar auxin transport occurred in the common ancestor of lycophytes and euphyllophytes. Although the mechanisms of auxin transport appear to be conserved across all vascular plants, distinct auxin responses govern shoot growth and development in lycophytes and euphyllophytes.
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Affiliation(s)
- Heather L Sanders
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Jane A Langdale
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
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92
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Pandolfini T, Molesini B, Spena A. AUCSIA: an ancestral green plant miniprotein and the emergence of auxin transport. PLANT SIGNALING & BEHAVIOR 2013; 8:e22928. [PMID: 23299419 PMCID: PMC3656992 DOI: 10.4161/psb.22928] [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] [Received: 11/15/2012] [Accepted: 11/16/2012] [Indexed: 06/01/2023]
Abstract
Aucsia is a green plant gene family. In Angiosperms, Aucsia genes control several aspects of auxin biology, including polar auxin transport. AUCSIA miniproteins are produced via splicing of three exons. The first two exons span the conserved AUCSIA motif, while the third exon(s) encodes the more variable carboxyterminal end. AUCSIA presence in green algae indicates that the Aucsia gene family predated the emergence of land plants and the complex auxin biology of Angiosperms. In algae, however, AUCSIA might have been involved in a primitive auxin biology, when auxin was just a simple metabolite, probably noxious at high concentrations, and consequently pump out via the ancestral auxin exporters, i.e., ABCB1/19 homologs. This speculative scenario implies that in green algae AUCSIA is involved in controlling the ABCB-dependent efflux of noxious metabolites, including auxin. Such speculative hypothesis might be tested in living green algae.
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93
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Bowman JL. Walkabout on the long branches of plant evolution. CURRENT OPINION IN PLANT BIOLOGY 2013; 16:70-7. [PMID: 23140608 DOI: 10.1016/j.pbi.2012.10.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 10/15/2012] [Accepted: 10/15/2012] [Indexed: 05/09/2023]
Abstract
The closest living relatives of land plants, the Charophytes, and early diverging land plant lineages, the bryophytes, reside in a phylogenetic grade. Recent analyses have resolved relationships and demonstrated that some components of the land plant developmental genetic toolkit have their origin in algal ancestors. Phylogenetic grades of taxa imply long independent evolutionary histories, with extant species diversity potentially relictual and highly derived morphologically, making reconstruction of ancestral states problematic. Incorporating data on the genetic bases of character states may be phylogenetically informative in elucidating ancestral states in cases where morphology is highly divergent.
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Affiliation(s)
- John L Bowman
- School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia.
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94
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Abstract
Brown algae are an extremely interesting, but surprisingly poorly explored, group of organisms. They are one of only five eukaryotic lineages to have independently evolved complex multicellularity, which they express through a wide variety of morphologies ranging from uniseriate branched filaments to complex parenchymatous thalli with multiple cell types. Despite their very distinct evolutionary history, brown algae and land plants share a striking amount of developmental features. This has led to an interest in several aspects of brown algal development, including embryogenesis, polarity, cell cycle, asymmetric cell division and a putative role for plant hormone signalling. This review describes how investigations using brown algal models have helped to increase our understanding of the processes controlling early embryo development, in particular polarization, axis formation and asymmetric cell division. Additionally, the diversity of life cycles in the brown lineage and the emergence of Ectocarpus as a powerful model organism, are affording interesting insights on the molecular mechanisms underlying haploid-diploid life cycles. The use of these and other emerging brown algal models will undoubtedly add to our knowledge on the mechanisms that regulate development in multicellular photosynthetic organisms.
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Affiliation(s)
- Kenny A Bogaert
- Phycology Research Group, Department of Biology, Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium
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95
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Viaene T, Delwiche CF, Rensing SA, Friml J. Origin and evolution of PIN auxin transporters in the green lineage. TRENDS IN PLANT SCIENCE 2013; 18:5-10. [PMID: 22981345 DOI: 10.1016/j.tplants.2012.08.009] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Revised: 08/09/2012] [Accepted: 08/22/2012] [Indexed: 05/04/2023]
Abstract
Polarized auxin transport is crucial for many developmental processes in flowering plants and requires the PIN-FORMED (PIN) family of auxin efflux carriers. However, the impact of polar auxin transport and PIN proteins on the development of non-seed plant species and green algal lineages is largely unknown. Using recently available sequence information from streptophyte algae and other non-seed plant species, we have constructed a preliminary phylogenetic framework and present several hypotheses for PIN protein evolution. We postulate that PIN proteins originated in streptophyte algae at the endoplasmic reticulum (ER) and that plasma membrane localization was acquired during land plant evolution. We also suggest that PIN proteins are evolutionarily distinct from another family of auxin transporters at the ER, the PIN-LIKES (PILS) proteins.
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Affiliation(s)
- Tom Viaene
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium.
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96
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Finet C, Berne-Dedieu A, Scutt CP, Marlétaz F. Evolution of the ARF gene family in land plants: old domains, new tricks. Mol Biol Evol 2012; 30:45-56. [PMID: 22977118 DOI: 10.1093/molbev/mss220] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Auxin response factors (ARF) are key players in plant development. They mediate the cellular response to the plant hormone auxin by activating or repressing the expression of downstream developmental genes. The pivotal activation function of ARF proteins is enabled by their four-domain architecture, which includes both DNA-binding and protein dimerization motifs. To determine the evolutionary origin of this characteristic architecture, we built a comprehensive data set of 224 ARF-related protein sequences that represents all major living divisions of land plants, except hornworts. We found that ARFs are split into three subfamilies that could be traced back to the origin of the land plants. We also show that repeated events of extensive gene duplication contributed to the expansion of those three original subfamilies. Further examination of our data set uncovered a broad diversity in the structure of ARF transcripts and allowed us to identify an additional conserved motif in ARF proteins. We found that additional structural diversity in ARF proteins is mainly generated by two mechanisms: genomic truncation and alternative splicing. We propose that the loss of domains from the canonical, four-domain ARF structure has promoted functional shifts within the ARF family by disrupting either dimerization or DNA-binding capabilities. For instance, the loss of dimerization domains in some ARFs from moss and spikemoss genomes leads to proteins that are reminiscent of Aux/IAA proteins, possibly providing a clue on the evolution of these modulators of ARF function. We also assessed the functional impact of alternative splicing in the case of ARF4, for which we have identified a novel isoform in Arabidopsis thaliana. Genetic analysis showed that these two transcripts exhibit markedly different developmental roles in A. thaliana. Gene duplications, domain rearrangement, and post-transcriptional regulation have thus enabled a subtle control of auxin signaling through ARF proteins that may have contributed to the critical importance of these regulators in plant development and evolution.
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Affiliation(s)
- Cédric Finet
- Université de Lyon, Laboratoire de Reproduction et Développement des Plantes, UMR 5667, CNRS, INRA, Université Claude Bernard Lyon I, Ecole Normale Supérieure de Lyon, Lyon, France.
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97
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Rosquete MR, Barbez E, Kleine-Vehn J. Cellular auxin homeostasis: gatekeeping is housekeeping. MOLECULAR PLANT 2012; 5:772-86. [PMID: 22199236 DOI: 10.1093/mp/ssr109] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The phytohormone auxin is essential for plant development and contributes to nearly every aspect of the plant life cycle. The spatio-temporal distribution of auxin depends on a complex interplay between auxin metabolism and cell-to-cell auxin transport. Auxin metabolism and transport are both crucial for plant development; however, it largely remains to be seen how these processes are integrated to ensure defined cellular auxin levels or even gradients within tissues or organs. In this review, we provide a glance at very diverse topics of auxin biology, such as biosynthesis, conjugation, oxidation, and transport of auxin. This broad, but certainly superficial, overview highlights the mutual importance of auxin metabolism and transport. Moreover, it allows pinpointing how auxin metabolism and transport get integrated to jointly regulate cellular auxin homeostasis. Even though these processes have been so far only separately studied, we assume that the phytohormonal crosstalk integrates and coordinates auxin metabolism and transport. Besides the integrative power of the global hormone signaling, we additionally introduce the hypothetical concept considering auxin transport components as gatekeepers for auxin responses.
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Affiliation(s)
- Michel Ruiz Rosquete
- Department of Applied Genetics and Cell Biology, University of Applied Life Sciences and Natural Resources (BOKU), 1190 Vienna, Austria
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98
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Finet C, Jaillais Y. Auxology: when auxin meets plant evo-devo. Dev Biol 2012; 369:19-31. [PMID: 22687750 DOI: 10.1016/j.ydbio.2012.05.039] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/09/2012] [Accepted: 05/31/2012] [Indexed: 11/27/2022]
Abstract
Auxin is implicated throughout plant growth and development. Although the effects of this plant hormone have been recognized for more than a century, it is only in the past two decades that light has been shed on the molecular mechanisms that regulate auxin homeostasis, signaling, transport, crosstalk with other hormonal pathways as well as its roles in plant development. These discoveries established a molecular framework to study the role of auxin in land plant evolution. Here, we review recent advances in auxin biology and their implications in both micro- and macro-evolution of plant morphology. By analogy to the term 'hoxology', which refers to the critical role of HOX genes in metazoan evolution, we propose to introduce the term 'auxology' to take into account the crucial role of auxin in plant evo-devo.
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Affiliation(s)
- Cédric Finet
- Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin, Madison, WI 53706, USA.
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99
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Boot KJM, Libbenga KR, Hille SC, Offringa R, van Duijn B. Polar auxin transport: an early invention. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:4213-8. [PMID: 22473986 PMCID: PMC3398450 DOI: 10.1093/jxb/ers106] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 03/14/2012] [Accepted: 03/19/2012] [Indexed: 05/20/2023]
Abstract
In higher plants, cell-to-cell polar auxin transport (PAT) of the phytohormone auxin, indole-3-acetic acid (IAA), generates maxima and minima that direct growth and development. Although IAA is present in all plant phyla, PAT has only been detected in land plants, the earliest being the Bryophytes. Charophyta, a group of freshwater green algae, are among the first multicellular algae with a land plant-like phenotype and are ancestors to land plants. IAA has been detected in members of Charophyta, but its developmental role and the occurrence of PAT are unknown. We show that naphthylphthalamic acid (NPA)-sensitive PAT occurs in internodal cells of Chara corallina. The relatively high velocity (at least 4-5 cm/h) of auxin transport through the giant (3-5 cm) Chara cells does not occur by simple diffusion and is not sensitive to a specific cytoplasmic streaming inhibitor. The results demonstrate that PAT evolved early in multicellular plant life. The giant Chara cells provide a unique new model system to study PAT, as Chara allows the combining of real-time measurements and mathematical modelling with molecular, developmental, cellular, and electrophysiological studies.
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Affiliation(s)
- Kees J. M. Boot
- Plant Biodynamics Laboratory, Institute Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Molecular and Developmental Genetics, Institute Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Kees R. Libbenga
- Plant Biodynamics Laboratory, Institute Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Sander C. Hille
- Plant Biodynamics Laboratory, Institute Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Mathematical Institute, Leiden University, Niels Bohrweg 1, 2333 CA Leiden, The Netherlands
| | - Remko Offringa
- Plant Biodynamics Laboratory, Institute Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Molecular and Developmental Genetics, Institute Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Bert van Duijn
- Plant Biodynamics Laboratory, Institute Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Fytagoras, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- To whom correspondence should be addressed. E-mail:
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100
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Hayashi KI. The interaction and integration of auxin signaling components. PLANT & CELL PHYSIOLOGY 2012; 53:965-75. [PMID: 22433459 DOI: 10.1093/pcp/pcs035] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
IAA, a naturally occurring auxin, is a simple signaling molecule that regulates many diverse steps of plant development. Auxin essentially coordinates plant development through transcriptional regulation. Auxin binds to TIR1/AFB nuclear receptors, which are F-box subunits of the SCF ubiquitin ligase complex. The auxin signal is then modulated by the quantitative and qualitative responses of the Aux/IAA repressors and the auxin response factor (ARF) transcription factors. The specificity of the auxin-regulated gene expression profile is defined by several factors, such as the expression of these regulatory proteins, their post-transcriptional regulation, their stability and the affinity between these regulatory proteins. Auxin-binding protein 1 (ABP1) is a candidate protein for an auxin receptor that is implicated in non-transcriptional auxin signaling. ABP1 also affects TIR1/AFB-mediated auxin-responsive gene expression, implying that both the ABP1 and TIR1/AFB signaling machineries coordinately control auxin-mediated physiological events. Systematic approaches using the comprehensive mapping of the expression and interaction of signaling modules and computational modeling would be valuable for integrating our knowledge of auxin signals and responses.
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Affiliation(s)
- Ken-ichiro Hayashi
- Department of Biochemistry, Okayama University of Science, Okayama, 700-0005 Japan.
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