201
|
Drummond RSM, Janssen BJ, Luo Z, Oplaat C, Ledger SE, Wohlers MW, Snowden KC. Environmental control of branching in petunia. PLANT PHYSIOLOGY 2015; 168:735-51. [PMID: 25911529 PMCID: PMC4453797 DOI: 10.1104/pp.15.00486] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 04/22/2015] [Indexed: 05/20/2023]
Abstract
Plants alter their development in response to changes in their environment. This responsiveness has proven to be a successful evolutionary trait. Here, we tested the hypothesis that two key environmental factors, light and nutrition, are integrated within the axillary bud to promote or suppress the growth of the bud into a branch. Using petunia (Petunia hybrida) as a model for vegetative branching, we manipulated both light quality (as crowding and the red-to-far-red light ratio) and phosphate availability, such that the axillary bud at node 7 varied from deeply dormant to rapidly growing. In conjunction with the phenotypic characterization, we also monitored the state of the strigolactone (SL) pathway by quantifying SL-related gene transcripts. Mutants in the SL pathway inhibit but do not abolish the branching response to these environmental signals, and neither signal is dominant over the other, suggesting that the regulation of branching in response to the environment is complex. We have isolated three new putatively SL-related TCP (for Teosinte branched1, Cycloidia, and Proliferating cell factor) genes from petunia, and have identified that these TCP-type transcription factors may have roles in the SL signaling pathway both before and after the reception of the SL signal at the bud. We show that the abundance of the receptor transcript is regulated by light quality, such that axillary buds growing in added far-red light have greatly increased receptor transcript abundance. This suggests a mechanism whereby the impact of any SL signal reaching an axillary bud is modulated by the responsiveness of these cells to the signal.
Collapse
Affiliation(s)
- Revel S M Drummond
- New Zealand Institute for Plant and Food Research, Limited, Sandringham, Auckland 1025, New Zealand
| | - Bart J Janssen
- New Zealand Institute for Plant and Food Research, Limited, Sandringham, Auckland 1025, New Zealand
| | - Zhiwei Luo
- New Zealand Institute for Plant and Food Research, Limited, Sandringham, Auckland 1025, New Zealand
| | - Carla Oplaat
- New Zealand Institute for Plant and Food Research, Limited, Sandringham, Auckland 1025, New Zealand
| | - Susan E Ledger
- New Zealand Institute for Plant and Food Research, Limited, Sandringham, Auckland 1025, New Zealand
| | - Mark W Wohlers
- New Zealand Institute for Plant and Food Research, Limited, Sandringham, Auckland 1025, New Zealand
| | - Kimberley C Snowden
- New Zealand Institute for Plant and Food Research, Limited, Sandringham, Auckland 1025, New Zealand
| |
Collapse
|
202
|
Affiliation(s)
- Harsh P Bais
- Delaware Biotechnology Institute, Newark, DE, 19711, USA; Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19716, USA
| |
Collapse
|
203
|
Martínez-García JF, Gallemí M, Molina-Contreras MJ, Llorente B, Bevilaqua MRR, Quail PH. The shade avoidance syndrome in Arabidopsis: the antagonistic role of phytochrome a and B differentiates vegetation proximity and canopy shade. PLoS One 2014; 9:e109275. [PMID: 25333270 PMCID: PMC4204825 DOI: 10.1371/journal.pone.0109275] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/02/2014] [Indexed: 11/18/2022] Open
Abstract
Light limitation caused by dense vegetation is one of the greatest threats to plant survival in natural environments. Plants detect such neighboring vegetation as a reduction in the red to far-red ratio (R:FR) of the incoming light. The low R:FR signal, perceived by phytochromes, initiates a set of responses collectively known as the shade avoidance syndrome, intended to reduce the degree of current or future shade from neighbors by overtopping such competitors or inducing flowering to ensure seed production. At the seedling stage these responses include increased hypocotyl elongation. We have systematically analyzed the Arabidopsis seedling response and the contribution of phyA and phyB to perception of decreased R:FR, at three different levels of photosynthetically active radiation. Our results show that the shade avoidance syndrome, induced by phyB deactivation, is gradually antagonized by phyA, operating through the so-called FR-High Irradiance Response, in response to high FR levels in a range that simulates plant canopy shade. The data indicate that the R:FR signal distinguishes between the presence of proximal, but non-shading, neighbors and direct foliar shade, via a intrafamily photosensory attenuation mechanism that acts to suppress excessive reversion toward skotomorphogenic development under prolonged direct vegetation shade.
Collapse
Affiliation(s)
- Jaime F. Martínez-García
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
- Centre for Research in Agricultural Genomics (CRAG), Consortium CSIC-IRTA-UAB-UB, Barcelona, Spain
- * E-mail:
| | - Marçal Gallemí
- Centre for Research in Agricultural Genomics (CRAG), Consortium CSIC-IRTA-UAB-UB, Barcelona, Spain
| | | | - Briardo Llorente
- Centre for Research in Agricultural Genomics (CRAG), Consortium CSIC-IRTA-UAB-UB, Barcelona, Spain
| | - Maycon R. R. Bevilaqua
- Centre for Research in Agricultural Genomics (CRAG), Consortium CSIC-IRTA-UAB-UB, Barcelona, Spain
- CAPES foundation, Ministry of Education of Brazil, Brasilia - DF, Brazil
| | - Peter H. Quail
- Department of Plant and Microbial Biology, University of California, Berkeley, California, United States of America
- US Department of Agriculture/Agriculture Research Service, Plant Gene Expression Center, Albany, California, United States of America
| |
Collapse
|
204
|
Cargnel MD, Demkura PV, Ballaré CL. Linking phytochrome to plant immunity: low red : far-red ratios increase Arabidopsis susceptibility to Botrytis cinerea by reducing the biosynthesis of indolic glucosinolates and camalexin. THE NEW PHYTOLOGIST 2014; 204:342-54. [PMID: 25236170 DOI: 10.1111/nph.13032] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 08/01/2014] [Indexed: 05/21/2023]
Abstract
Shade-intolerant plants respond to low red : far-red (R : FR) ratios, which signal the proximity of potential competitors, by down-regulating immune responses. Here we investigated the mechanisms underlying this immune suppression in Arabidopsis. We used genetic, transcriptomic and metabolomic approaches to examine the functional connections between R : FR ratio and Arabidopsis resistance to the fungus Botrytis cinerea. Low R : FR ratios reduced the concentration of indol-3-ylmethyl glucosinolate (I3M) (an indolic glucosinolate, iGS) and camalexin in plants inoculated with B. cinerea, and attenuated the I3M response triggered by jasmonate elicitation. These effects on metabolite abundance correlated with reduced expression of iGS and camalexin biosynthetic genes. Furthermore, the effect of low R : FR increasing Arabidopsis susceptibility to B. cinerea was not present in mutants deficient in the biosynthesis of camalexin (pad3) or metabolism of iGS (pen2). Finally, in a mutant deficient in the JASMONATE ZIM DOMAIN-10 (JAZ10) protein, which does not respond to low R : FR with increased susceptibility to B. cinerea, supplemental FR failed to down-regulate iGS production. These results indicate that suppression of Arabidopsis immunity against B. cinerea by low R : FR ratios is mediated by reduced levels of Trp-derived defenses, and provide further evidence for a functional role of JAZ10 in the link between phytochrome and jasmonate signaling.
Collapse
Affiliation(s)
- Miriam D Cargnel
- IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, C1417DSE, Buenos Aires, Argentina
| | | | | |
Collapse
|
205
|
Leone M, Keller MM, Cerrudo I, Ballaré CL. To grow or defend? Low red : far-red ratios reduce jasmonate sensitivity in Arabidopsis seedlings by promoting DELLA degradation and increasing JAZ10 stability. THE NEW PHYTOLOGIST 2014; 204:355-67. [PMID: 25103816 DOI: 10.1111/nph.12971] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/02/2014] [Indexed: 05/19/2023]
Abstract
How plants balance resource allocation between growth and defense under conditions of competitive stress is a key question in plant biology. Low red : far-red (R : FR) ratios, which signal a high risk of competition in plant canopies, repress jasmonate-induced defense responses. The mechanism of this repression is not well understood. We addressed this problem in Arabidopsis by investigating the role of DELLA and JASMONATE ZIM domain (JAZ) proteins. We showed that a quintuple della mutant and a phyB mutant were insensitive to jasmonate for several physiological readouts. Inactivation of the photoreceptor phyB by low R : FR ratios rapidly reduced DELLA protein abundance, and the inhibitory effect of FR on jasmonate signaling was missing in the gai-1 mutant, which encodes a stable version of the GAI DELLA protein. We also demonstrated that low R : FR ratios and the phyB mutation stabilized the protein JAZ10. Furthermore, we demonstrated that JAZ10 was required for the inhibitory effect of low R : FR on jasmonate responses, and that the jaz10 mutation restored jasmonate sensitivity to the phyB mutant. We conclude that, under conditions of competition for light, plants redirect resource allocation from defense to rapid elongation by promoting DELLA degradation and enhancing JAZ10 stability.
Collapse
Affiliation(s)
- Melisa Leone
- IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, C1417DSE, Buenos Aires, Argentina
| | | | | | | |
Collapse
|
206
|
Zhang Z, Ji R, Li H, Zhao T, Liu J, Lin C, Liu B. CONSTANS-LIKE 7 (COL7) is involved in phytochrome B (phyB)-mediated light-quality regulation of auxin homeostasis. MOLECULAR PLANT 2014; 7:1429-1440. [PMID: 24908267 DOI: 10.1093/mp/ssu058] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Arabidopsis phytochrome B (phyB) is the major photoreceptor that senses the ratio of red to far-red light (R:FR) to regulate the shade-avoidance response (SAR). It has been hypothesized that altered homeostasis of phytohormones such as auxin and strigolactone is at least partially responsible for SAR, but the mechanism underlying phyB regulation of the hormonal change is not fully understood. Previously we reported that CONSTANS-LIKE 7 (COL7) enhances branching number under high R:FR but not under low R:FR, implying that COL7 may be involved in the phyB-mediated SAR. In this study, we provide evidence that COL7 reduces auxin levels in a high R:FR-dependent manner. We found that the phyB mutation suppresses the COL7-induced branching proliferation. Moreover, COL7 promotes mRNA expression of SUPERROOT 2 (SUR2), which encodes a suppressor of auxin biosynthesis, in high R:FR but not in low R:FR. Consistently with these results, deficiency of phyB suppresses the elevated transcription of SUR2 in COL7 overexpression plants grown in high R:FR. Taking these results together with data suggesting that photo-excited phyB is required for stabilization of the COL7 protein, we argue that COL7 is a critical factor linking light perception to changes in auxin level in Arabidopsis.
Collapse
Affiliation(s)
- Zenglin Zhang
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Ronghuan Ji
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Hongyu Li
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Tao Zhao
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jun Liu
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Chentao Lin
- Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Bin Liu
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| |
Collapse
|
207
|
Balcerowicz M, Ranjan A, Rupprecht L, Fiene G, Hoecker U. Auxin represses stomatal development in dark-grown seedlings via Aux/IAA proteins. Development 2014; 141:3165-76. [DOI: 10.1242/dev.109181] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Stomatal development is tightly regulated through internal and external factors that are integrated by a complex signalling network. Light represents an external factor that strongly promotes stomata formation. Here, we show that auxin-resistant aux/iaa mutants, e.g. axr3-1, exhibit a de-repression of stomata differentiation in dark-grown seedlings. The higher stomatal index in dark-grown axr3-1 mutants when compared with the wild type is due to increased cell division in the stomatal lineage. Excessive stomata in dark-grown seedlings were also observed in mutants defective in auxin biosynthesis or auxin perception and in seedlings treated with the polar auxin transport inhibitor NPA. Consistent with these findings, exogenous auxin repressed stomata formation in light-grown seedlings. Taken together, these results indicate that auxin is a negative regulator of stomatal development in dark-grown seedlings. Epistasis analysis revealed that axr3-1 acts genetically upstream of the bHLH transcription factors SPCH, MUTE and FAMA, as well as the YDA MAP kinase cascade, but in parallel with the repressor of photomorphogenesis COP1 and the receptor-like protein TMM. The effect of exogenous auxin required the ER family of leucine-rich repeat receptor-like kinases, suggesting that auxin acts at least in part through the ER family. Expression of axr3-1 in the stomatal lineage was insufficient to alter the stomatal index, implying that cell-cell communication is necessary to mediate the effect of auxin. In summary, our results show that auxin signalling contributes to the suppression of stomatal differentiation observed in dark-grown seedlings.
Collapse
Affiliation(s)
- Martin Balcerowicz
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, BioCenter, Zuelpicher Str. 47b, 50674 Cologne, Germany
| | - Aashish Ranjan
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, BioCenter, Zuelpicher Str. 47b, 50674 Cologne, Germany
| | - Laura Rupprecht
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, BioCenter, Zuelpicher Str. 47b, 50674 Cologne, Germany
| | - Gabriele Fiene
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, BioCenter, Zuelpicher Str. 47b, 50674 Cologne, Germany
| | - Ute Hoecker
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, BioCenter, Zuelpicher Str. 47b, 50674 Cologne, Germany
| |
Collapse
|
208
|
Phytochrome regulation of plant immunity in vegetation canopies. J Chem Ecol 2014; 40:848-57. [PMID: 25063023 DOI: 10.1007/s10886-014-0471-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 06/20/2014] [Accepted: 06/23/2014] [Indexed: 01/05/2023]
Abstract
Plant immunity against pathogens and herbivores is a central determinant of plant fitness in nature and crop yield in agroecosystems. Plant immune responses are orchestrated by two key hormones: jasmonic acid (JA) and salicylic acid (SA). Recent work has demonstrated that for plants of shade-intolerant species, which include the majority of those grown as grain crops, light is a major modulator of defense responses. Light signals that indicate proximity of competitors, such as a low red to far-red (R:FR) ratio, down-regulate the expression of JA- and SA-induced immune responses against pests and pathogens. This down-regulation of defense under low R:FR ratios, which is caused by the photoconversion of the photoreceptor phytochrome B (phyB) to an inactive state, is likely to help the plant to efficiently redirect resources to rapid growth when the competition threat posed by neighboring plants is high. This review is focused on the molecular mechanisms that link phyB with defense signaling. In particular, we discuss novel signaling players that are likely to play a role in the repression of defense responses under low R:FR ratios. A better understanding of the molecular connections between photoreceptors and the hormonal regulation of plant immunity will provide a functional framework to understand the mechanisms used by plants to deal with fundamental resource allocation trade-offs under dynamic conditions of biotic stress.
Collapse
|
209
|
Brouwer B, Gardeström P, Keech O. In response to partial plant shading, the lack of phytochrome A does not directly induce leaf senescence but alters the fine-tuning of chlorophyll biosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4037-49. [PMID: 24604733 PMCID: PMC4106438 DOI: 10.1093/jxb/eru060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Phytochrome is thought to control the induction of leaf senescence directly, however, the signalling and molecular mechanisms remain unclear. In the present study, an ecophysiological approach was used to establish a functional connection between phytochrome signalling and the physiological processes underlying the induction of leaf senescence in response to shade. With shade it is important to distinguish between complete and partial shading, during which either the whole or only a part of the plant is shaded, respectively. It is first shown here that, while PHYB is required to maintain chlorophyll content in a completely shaded plant, only PHYA is involved in maintaining the leaf chlorophyll content in response to partial plant shading. Second, it is shown that leaf yellowing associated with strong partial shading in phyA-mutant plants actually correlates to a decreased biosynthesis of chlorophyll rather than to an increase of its degradation. Third, it is shown that the physiological impact of this decreased biosynthesis of chlorophyll in strongly shaded phyA-mutant leaves is accompanied by a decreased capacity to adjust the Light Compensation Point. However, the increased leaf yellowing in phyA-mutant plants is not accompanied by an increase of senescence-specific molecular markers, which argues against a direct role of PHYA in inducing leaf senescence in response to partial shade. In conclusion, it is proposed that PHYA, but not PHYB, is essential for fine-tuning the chlorophyll biosynthetic pathway in response to partial shading. In turn, this mechanism allows the shaded leaf to adjust its photosynthetic machinery to very low irradiances, thus maintaining a positive carbon balance and repressing the induction of leaf senescence, which can occur under prolonged periods of shade.
Collapse
Affiliation(s)
- Bastiaan Brouwer
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, S-90187 Umeå, Sweden
| | - Per Gardeström
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, S-90187 Umeå, Sweden
| | - Olivier Keech
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, S-90187 Umeå, Sweden
| |
Collapse
|
210
|
Abstract
Plant immunity against pathogens and herbivores is a central determinant of plant fitness in nature and crop yield in agroecosystems. Plant immune responses are orchestrated by two key hormones: jasmonic acid (JA) and salicylic acid (SA). Recent work has demonstrated that for plants of shade-intolerant species, which include the majority of those grown as grain crops, light is a major modulator of defense responses. Light signals that indicate proximity of competitors, such as a low red to far-red (R:FR) ratio, down-regulate the expression of JA- and SA-induced immune responses against pests and pathogens. This down-regulation of defense under low R:FR ratios, which is caused by the photoconversion of the photoreceptor phytochrome B (phyB) to an inactive state, is likely to help the plant to efficiently redirect resources to rapid growth when the competition threat posed by neighboring plants is high. This review is focused on the molecular mechanisms that link phyB with defense signaling. In particular, we discuss novel signaling players that are likely to play a role in the repression of defense responses under low R:FR ratios. A better understanding of the molecular connections between photoreceptors and the hormonal regulation of plant immunity will provide a functional framework to understand the mechanisms used by plants to deal with fundamental resource allocation trade-offs under dynamic conditions of biotic stress.
Collapse
Affiliation(s)
- Javier E Moreno
- Instituto de Agrobiotecnología del Litoral, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional del Litoral, CC 242 Ciudad Universitaria, Santa Fe, Argentina,
| | | |
Collapse
|
211
|
Gong W, Qi P, Du J, Sun X, Wu X, Song C, Liu W, Wu Y, Yu X, Yong T, Wang X, Yang F, Yan Y, Yang W. Transcriptome analysis of shade-induced inhibition on leaf size in relay intercropped soybean. PLoS One 2014; 9:e98465. [PMID: 24886785 PMCID: PMC4041726 DOI: 10.1371/journal.pone.0098465] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 05/02/2014] [Indexed: 11/25/2022] Open
Abstract
Multi-species intercropping is a sustainable agricultural practice worldwide used to utilize resources more efficiently. In intercropping systems, short crops often grow under vegetative shade of tall crops. Soybean, one important legume, is often planted in intercropping. However, little is known about the mechanisms of shade inhibition effect on leaf size in soybean leaves at the transcriptome level. We analyzed the transcriptome of shaded soybean leaves via RNA-Seq technology. We found that transcription 1085 genes in mature leaves and 1847 genes in young leaves were significantly affected by shade. Gene ontology analyses showed that expression of genes enriched in polysaccharide metabolism was down-regulated, but genes enriched in auxin stimulus were up-regulated in mature leaves; and genes enriched in cell cycling, DNA-replication were down-regulated in young leaves. These results suggest that the inhibition of higher auxin content and shortage of sugar supply on cell division and cell expansion contribute to smaller and thinner leaf morphology, which highlights potential research targets such as auxin and sugar regulation on leaves for crop adaptation to shade in intercropping.
Collapse
Affiliation(s)
- Wanzhuo Gong
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Pengfei Qi
- Triticeae Research Institute of Sichuan Agricultural University, Chengdu, China
| | - Junbo Du
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Xin Sun
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Xiaoling Wu
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Chun Song
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
- College of Resource and Environment, Sichuan Agricultural University, Chengdu, China
| | - Weiguo Liu
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Yushan Wu
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Xiaobo Yu
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Taiwen Yong
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Xiaochun Wang
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Feng Yang
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| | - Yanhong Yan
- College of Animal Science and Technology, Sichuan Agricultural University, Ya'an, China
| | - Wenyu Yang
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Chengdu, China
| |
Collapse
|
212
|
Franklin KA, Toledo-Ortiz G, Pyott DE, Halliday KJ. Interaction of light and temperature signalling. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2859-71. [PMID: 24569036 DOI: 10.1093/jxb/eru059] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Light and temperature are arguably two of the most important signals regulating the growth and development of plants. In addition to their direct energetic effects on plant growth, light and temperature provide vital immediate and predictive cues for plants to ensure optimal development both spatially and temporally. While the majority of research to date has focused on the contribution of either light or temperature signals in isolation, it is becoming apparent that an understanding of how the two interact is essential to appreciate fully the complex and elegant ways in which plants utilize these environmental cues. This review will outline the diverse mechanisms by which light and temperature signals are integrated and will consider why such interconnected systems (as opposed to entirely separate light and temperature pathways) may be evolutionarily favourable.
Collapse
Affiliation(s)
- Keara A Franklin
- School of Biological Sciences, University of Bristol, Bristol BS8 1UG, UK
| | - Gabriela Toledo-Ortiz
- SynthSys, University of Edinburgh, C.H. Waddington Building, King's Buildings, Edinburgh EH9 3JD, UK
| | - Douglas E Pyott
- SynthSys, University of Edinburgh, C.H. Waddington Building, King's Buildings, Edinburgh EH9 3JD, UK
| | - Karen J Halliday
- SynthSys, University of Edinburgh, C.H. Waddington Building, King's Buildings, Edinburgh EH9 3JD, UK
| |
Collapse
|
213
|
Pierik R, de Wit M. Shade avoidance: phytochrome signalling and other aboveground neighbour detection cues. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2815-24. [PMID: 24323503 DOI: 10.1093/jxb/ert389] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants compete with neighbouring vegetation for limited resources. In competition for light, plants adjust their architecture to bring the leaves higher in the vegetation where more light is available than in the lower strata. These architectural responses include accelerated elongation of the hypocotyl, internodes and petioles, upward leaf movement (hyponasty), and reduced shoot branching and are collectively referred to as the shade avoidance syndrome. This review discusses various cues that plants use to detect the presence and proximity of neighbouring competitors and respond to with the shade avoidance syndrome. These cues include light quality and quantity signals, mechanical stimulation, and plant-emitted volatile chemicals. We will outline current knowledge about each of these signals individually and discuss their possible interactions. In conclusion, we will make a case for a whole-plant, ecophysiology approach to identify the relative importance of the various neighbour detection cues and their possible interactions in determining plant performance during competition.
Collapse
Affiliation(s)
- Ronald Pierik
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Mieke de Wit
- Centre for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland
| |
Collapse
|
214
|
Bou-Torrent J, Galstyan A, Gallemí M, Cifuentes-Esquivel N, Molina-Contreras MJ, Salla-Martret M, Jikumaru Y, Yamaguchi S, Kamiya Y, Martínez-García JF. Plant proximity perception dynamically modulates hormone levels and sensitivity in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2937-47. [PMID: 24609653 PMCID: PMC4056540 DOI: 10.1093/jxb/eru083] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The shade avoidance syndrome (SAS) refers to a set of plant responses initiated after perception by the phytochromes of light enriched in far-red colour reflected from or filtered by neighbouring plants. These varied responses are aimed at anticipating eventual shading from potential competitor vegetation. In Arabidopsis thaliana, the most obvious SAS response at the seedling stage is the increase in hypocotyl elongation. Here, we describe how plant proximity perception rapidly and temporally alters the levels of not only auxins but also active brassinosteroids and gibberellins. At the same time, shade alters the seedling sensitivity to hormones. Plant proximity perception also involves dramatic changes in gene expression that rapidly result in a new balance between positive and negative factors in a network of interacting basic helix-loop-helix proteins, such as HFR1, PAR1, and BIM and BEE factors. Here, it was shown that several of these factors act as auxin- and BR-responsiveness modulators, which ultimately control the intensity or degree of hypocotyl elongation. It was deduced that, as a consequence of the plant proximity-dependent new, dynamic, and local balance between hormone synthesis and sensitivity (mechanistically resulting from a restructured network of SAS regulators), SAS responses are unleashed and hypocotyls elongate.
Collapse
Affiliation(s)
- Jordi Bou-Torrent
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Bellaterra, 08193-Barcelona, Spain
| | - Anahit Galstyan
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Bellaterra, 08193-Barcelona, Spain
| | - Marçal Gallemí
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Bellaterra, 08193-Barcelona, Spain
| | - Nicolás Cifuentes-Esquivel
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Bellaterra, 08193-Barcelona, Spain
| | | | - Mercè Salla-Martret
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Bellaterra, 08193-Barcelona, Spain
| | - Yusuke Jikumaru
- RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan
| | | | - Yuji Kamiya
- RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan
| | - Jaime F Martínez-García
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Bellaterra, 08193-Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats, 08010-Barcelona, Spain
| |
Collapse
|
215
|
de Wit M, Lorrain S, Fankhauser C. Auxin-mediated plant architectural changes in response to shade and high temperature. PHYSIOLOGIA PLANTARUM 2014; 151:13-24. [PMID: 24011166 DOI: 10.1111/ppl.12099] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/06/2013] [Accepted: 08/15/2013] [Indexed: 05/24/2023]
Abstract
The remarkable plasticity of their architecture allows plants to adjust growth to the environment and to overcome adverse conditions. Two examples of environmental stresses that drastically affect shoot development are imminent shade and high temperature. Plants in crowded environments and plants in elevated ambient temperature display very similar phenotypic adaptations of elongated hypocotyls in seedlings and elevated and elongated leaves at later developmental stages. The comparable growth responses to shade and high temperature are partly regulated through shared signaling pathways, of which the phytohormone auxin and the phytochrome interacting factors (PIFs) are important components. During both shade- and temperature-induced elongation growth auxin biosynthesis and signaling are upregulated in a PIF-dependent manner. In this review we will discuss recent progress in our understanding of how auxin mediates architectural adaptations to shade and high temperature.
Collapse
Affiliation(s)
- Mieke de Wit
- Center for Integrative Genomics, University of Lausanne, Lausanne, CH-1015, Switzerland
| | | | | |
Collapse
|
216
|
Sasidharan R, Keuskamp DH, Kooke R, Voesenek LACJ, Pierik R. Interactions between auxin, microtubules and XTHs mediate green shade- induced petiole elongation in arabidopsis. PLoS One 2014; 9:e90587. [PMID: 24594664 PMCID: PMC3942468 DOI: 10.1371/journal.pone.0090587] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 02/03/2014] [Indexed: 01/06/2023] Open
Abstract
Plants are highly attuned to translating environmental changes to appropriate modifications in growth. Such phenotypic plasticity is observed in dense vegetations, where shading by neighboring plants, triggers rapid unidirectional shoot growth (shade avoidance), such as petiole elongation, which is partly under the control of auxin. This growth is fuelled by cellular expansion requiring cell-wall modification by proteins such as xyloglucan endotransglucosylase/hydrolases (XTHs). Cortical microtubules (cMTs) are highly dynamic cytoskeletal structures that are also implicated in growth regulation. The objective of this study was to investigate the tripartite interaction between auxin, cMTs and XTHs in shade avoidance. Our results indicate a role for cMTs to control rapid petiole elongation in Arabidopsis during shade avoidance. Genetic and pharmacological perturbation of cMTs obliterated shade-induced growth and led to a reduction in XTH activity as well. Furthermore, the cMT disruption repressed the shade-induced expression of a specific set of XTHs. These XTHs were also regulated by the hormone auxin, an important regulator of plant developmental plasticity and also of several shade avoidance responses. Accordingly, the effect of cMT disruption on the shade enhanced XTH expression could be rescued by auxin application. Based on the results we hypothesize that cMTs can mediate petiole elongation during shade avoidance by regulating the expression of cell wall modifying proteins via control of auxin distribution.
Collapse
Affiliation(s)
- Rashmi Sasidharan
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands
| | - Diederik H Keuskamp
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands; Environmental Sciences, Wageningen University, Wageningen, The Netherlands
| | - Rik Kooke
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands; Laboratory of Plant Physiology, Wageningen University, Wageningen, The Netherlands
| | - Laurentius A C J Voesenek
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands
| | - Ronald Pierik
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands
| |
Collapse
|
217
|
Krishna Reddy S, Finlayson SA. Phytochrome B promotes branching in Arabidopsis by suppressing auxin signaling. PLANT PHYSIOLOGY 2014; 164:1542-50. [PMID: 24492336 PMCID: PMC3938639 DOI: 10.1104/pp.113.234021] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 01/31/2014] [Indexed: 05/18/2023]
Abstract
Many plants respond to competition signals generated by neighbors by evoking the shade avoidance syndrome, including increased main stem elongation and reduced branching. Vegetation-induced reduction in the red light:far-red light ratio provides a competition signal sensed by phytochromes. Plants deficient in phytochrome B (phyB) exhibit a constitutive shade avoidance syndrome including reduced branching. Because auxin in the polar auxin transport stream (PATS) inhibits axillary bud outgrowth, its role in regulating the phyB branching phenotype was tested. Removing the main shoot PATS auxin source by decapitation or chemically inhibiting the PATS strongly stimulated branching in Arabidopsis (Arabidopsis thaliana) deficient in phyB, but had a modest effect in the wild type. Whereas indole-3-acetic acid (IAA) levels were elevated in young phyB seedlings, there was less IAA in mature stems compared with the wild type. A split plate assay of bud outgrowth kinetics indicated that low auxin levels inhibited phyB buds more than the wild type. Because the auxin response could be a result of either the auxin signaling status or the bud's ability to export auxin into the main shoot PATS, both parameters were assessed. Main shoots of phyB had less absolute auxin transport capacity compared with the wild type, but equal or greater capacity when based on the relative amounts of native IAA in the stems. Thus, auxin transport capacity was unlikely to restrict branching. Both shoots of young phyB seedlings and mature stem segments showed elevated expression of auxin-responsive genes and expression was further increased by auxin treatment, suggesting that phyB suppresses auxin signaling to promote branching.
Collapse
|
218
|
Abstract
Precise allocation of limited resources between growth and defense is critical for plant survival. In shade-intolerant species, perception of competition signals by informational photoreceptors activates shade-avoidance responses and reduces the expression of defenses against pathogens and insects. The main mechanism underlying defense suppression is the simultaneous downregulation of jasmonate and salicylic acid signaling by low ratios of red:far-red radiation. Inactivation of phytochrome B by low red:far-red ratios appears to suppress jasmonate responses by altering the balance between DELLA and JASMONATE ZIM DOMAIN (JAZ) proteins in favor of the latter. Solar UVB radiation is a positive modulator of plant defense, signaling through jasmonate-dependent and jasmonate-independent pathways. Light, perceived by phytochrome B and presumably other photoreceptors, helps plants concentrate their defensive arsenals in photosynthetically valuable leaves. The discovery of connections between photoreceptors and defense signaling is revealing novel mechanisms that control key resource allocation decisions in plant canopies.
Collapse
Affiliation(s)
- Carlos L Ballaré
- IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, C1417DSE Buenos Aires, Argentina;
| |
Collapse
|
219
|
Reddy SK, Holalu SV, Casal JJ, Finlayson SA. The timing of low R:FR exposure profoundly affects Arabidopsis branching responses. PLANT SIGNALING & BEHAVIOR 2014; 9:e28668. [PMID: 24713589 PMCID: PMC4091421 DOI: 10.4161/psb.28668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The ratio of Red to Far Red light (R:FR) is sensed by phytochromes, including phytochrome B, and serves as a signal of potential competition. Low R:FR represses Arabidopsis thaliana branching by promoting the accumulation of abscisic acid in the young buds and by enhancing auxin signaling in the main shoot. While overall plant level branching is reduced by low R:FR, the growth of the uppermost branches tends to be promoted while the lower buds are suppressed. Buds at intermediate positions can show either growth promotion or growth suppression by low R:FR if they become exposed to low R:FR late or early, respectively. This pattern suggests that developmental stage specific programming occurs to modify the response of specific buds to branching regulators including auxin and ABA.
Collapse
Affiliation(s)
- Srirama Krishna Reddy
- Department of Soil and Crop Sciences; Texas A&M University and Texas A&M AgriLife Research; College Station, TX USA
- Faculty of Molecular and Environmental Plant Sciences; Texas A&M University; College Station, TX USA
| | - Srinidhi V Holalu
- Department of Soil and Crop Sciences; Texas A&M University and Texas A&M AgriLife Research; College Station, TX USA
- Faculty of Molecular and Environmental Plant Sciences; Texas A&M University; College Station, TX USA
| | - Jorge J Casal
- IFEVA-Facultad de Agronomía; Universidad de Buenos Aires; Consejo Nacional de Investigaciones Científicas y Técnicas; Buenos Aires, Argentina
- Fundación Instituto Leloir; Instituto de Investigaciones Bioquímicas de Buenos Aires–CONICET; Buenos Aires, Argentina
| | - Scott A Finlayson
- Department of Soil and Crop Sciences; Texas A&M University and Texas A&M AgriLife Research; College Station, TX USA
- Faculty of Molecular and Environmental Plant Sciences; Texas A&M University; College Station, TX USA
- Correspondence to: Scott A Finlayson,
| |
Collapse
|
220
|
Apo-bacteriophytochromes modulate bacterial photosynthesis in response to low light. Proc Natl Acad Sci U S A 2013; 111:E237-44. [PMID: 24379368 DOI: 10.1073/pnas.1322410111] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteriophytochromes (BphPs) are light-sensing regulatory proteins encoded by photosynthetic and nonphotosynthetic bacteria. This protein class has been characterized structurally, but its biological activities remain relatively unexplored. Two BphPs in the anoxygenic photosynthetic bacterium Rhodopseudomonas palustris, designated regulatory proteins RpBphP2 and RpBphP3, are configured as light-regulated histidine kinases, which initiate a signal transduction system that controls expression of genes for the low light harvesting 4 (LH4) antenna complex. In vitro, RpBphP2 and RpBphP3 respond to light quality by reversible photoconversion, a property that requires the light-absorbing chromophore biliverdin. In vivo, RpBphP2 and RpBphP3 are both required for the expression of the LH4 antenna complex under anaerobic conditions, but biliverdin requires oxygen for its synthesis by heme oxygenase. On further investigation, we found that the apo-bacteriophytochrome forms of RpBphP2 and RpBphP3 are necessary and sufficient to control LH4 expression in response to light intensity in conjunction with other signal transduction proteins. One possibility is that the system senses a reduced quinone pool generated when light energy is absorbed by bacteriochlorophyll. The biliverdin-bound forms of the BphPs have the additional property of being able to fine-tune LH4 expression in response to light quality. These observations support the concept that some bacteriophytochromes can function with or without a chromophore and may be involved in regulating physiological processes not directly related to light sensing.
Collapse
|
221
|
Reddy SK, Holalu SV, Casal JJ, Finlayson SA. Abscisic acid regulates axillary bud outgrowth responses to the ratio of red to far-red light. PLANT PHYSIOLOGY 2013; 163:1047-58. [PMID: 23929720 PMCID: PMC3793024 DOI: 10.1104/pp.113.221895] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/05/2013] [Indexed: 05/18/2023]
Abstract
Low red light/far-red light ratio (R:FR) serves as an indicator of impending competition and has been demonstrated to suppress branch development. The regulation of Arabidopsis (Arabidopsis thaliana) rosette bud outgrowth by the R:FR and the associated mechanisms were investigated at several levels. Growth under low R:FR suppressed outgrowth of the third from topmost bud (bud n-2) but not that of the topmost bud. Subsequently increasing the R:FR near the time of anthesis promoted bud n-2 outgrowth and reduced topmost bud growth. Buds from specific rosette positions, exhibiting divergent fates to increased R:FR, were harvested 3 h after modifying the R:FR and were used to conduct ATH1 microarray-based transcriptome profiling. Differentially expressed genes showed enrichment of light signaling and hormone-related Gene Ontology terms and promoter motifs, most notably those associated with abscisic acid (ABA). Genes associated with ABA biosynthesis, including the key biosynthetic gene NINE-CIS-EPOXYCAROTENOID DIOXYGENASE3 (NCED3), and with ABA signaling were expressed at higher levels in the responsive bud n-2, and increasing the R:FR decreased their expression only in bud n-2. ABA abundance in responsive buds decreased within 12 h of increasing the R:FR, while indole-3-acetic acid levels did not change. A role for ABA in repressing bud outgrowth from lower positions under low R:FR was demonstrated using the nced3-2 and aba2-1 ABA biosynthesis mutants, which showed enhanced branching and a defective bud n-2 outgrowth response to low R:FR. The results provide evidence that ABA regulates bud outgrowth responses to the R:FR and thus extend the known hormonal pathways associated with the regulation of branching and shade avoidance.
Collapse
|
222
|
Cifuentes-Esquivel N, Bou-Torrent J, Galstyan A, Gallemí M, Sessa G, Salla Martret M, Roig-Villanova I, Ruberti I, Martínez-García JF. The bHLH proteins BEE and BIM positively modulate the shade avoidance syndrome in Arabidopsis seedlings. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:989-1002. [PMID: 23763263 DOI: 10.1111/tpj.12264] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 05/29/2013] [Accepted: 06/03/2013] [Indexed: 05/25/2023]
Abstract
The shade avoidance syndrome (SAS) refers to a set of plant responses initiated after perception by the phytochromes of light with a reduced red to far-red ratio, indicative of vegetation proximity or shade. These responses, including elongation growth, anticipate eventual shading from potential competitor vegetation by overgrowing neighboring plants or flowering to ensure production of viable seeds for the next generation. In Arabidopsis thaliana seedlings, the SAS includes dramatic changes in gene expression, such as induction of PHYTOCHROME RAPIDLY REGULATED 1 (PAR1), encoding an atypical basic helix-loop-helix (bHLH) protein that acts as a transcriptional co-factor to repress hypocotyl elongation. Indeed, PAR1 has been proposed to act fundamentally as a dominant negative antagonist of conventional bHLH transcription factors by forming heterodimers with them to prevent their binding to DNA or other transcription factors. Here we report the identification of PAR1-interacting factors, including the brassinosteroid signaling components BR-ENHANCED EXPRESSION (BEE) and BES1-INTERACTING MYC-LIKE (BIM), and characterize their role as networked positive regulators of SAS hypocotyl responses. We provide genetic evidence that these bHLH transcriptional regulators not only control plant growth and development under shade and non-shade conditions, but are also redundant in the control of plant viability. Our results suggest that SAS responses are initiated as a consequence of a new balance of transcriptional regulators within the pre-existing bHLH network triggered by plant proximity, eventually causing hypocotyls to elongate.
Collapse
Affiliation(s)
- Nicolás Cifuentes-Esquivel
- Centre for Research in Agricultural Genomics (CRAG), Consejo Superior de Investigaciones Científicas (CSIC) - Institut de Recerca i Tecnologia Agroalimentàries (IRTA) - Universitat Autòmona de Barcelona (UAB) - Universitat de Barcelona (UB), Campus UAB Bellaterra, Barcelona 08193, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
223
|
No time for candy: passionfruit (Passiflora edulis) plants down-regulate damage-induced extra floral nectar production in response to light signals of competition. Oecologia 2013; 173:213-21. [DOI: 10.1007/s00442-013-2721-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 06/21/2013] [Indexed: 02/06/2023]
|
224
|
Ferrández-Ayela A, Alonso-Peral MM, Sánchez-García AB, Micol-Ponce R, Pérez-Pérez JM, Micol JL, Ponce MR. Arabidopsis TRANSCURVATA1 encodes NUP58, a component of the nucleopore central channel. PLoS One 2013; 8:e67661. [PMID: 23840761 PMCID: PMC3695937 DOI: 10.1371/journal.pone.0067661] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 05/20/2013] [Indexed: 01/20/2023] Open
Abstract
The selective trafficking of proteins and RNAs through the nuclear envelope regulates nuclear-cytoplasmic segregation of macromolecules and is mediated by nucleopore complexes (NPCs), which consist of about 400 nucleoporins (Nups) of about 30 types. Extensive studies of nucleoporin function in yeast and vertebrates showed that Nups function in nucleocytoplasmic trafficking and other processes. However, limited studies of plant Nups have identified only a few mutations, which cause pleiotropic phenotypes including reduced growth and early flowering. Here, we describe loss-of-function alleles of Arabidopsis TRANSCURVATA1 (TCU1); these mutations cause increased hypocotyl and petiole length, reticulate and asymmetrically epinastic leaf laminae of reduced size, and early flowering. TCU1 is transcribed in all of the organs and tissues examined, and encodes the putative ortholog of yeast and vertebrate Nup58, a nucleoporin of the Nup62 subcomplex. Nup58 forms the central channel of the NPC and acts directly in translocation of proteins through the nuclear envelope in yeast and vertebrates. Yeast two-hybrid (Y2H) assays identified physical interactions between TCU1/NUP58 and 34 proteins, including nucleoporins, SCF (Skp1/Cul1/F-box) ubiquitin ligase complex components and other nucleoplasm proteins. Genetic interactions were also found between TCU1 and genes encoding nucleoporins, soluble nuclear transport receptors and components of the ubiquitin-proteasome and auxin signaling pathways. These genetic and physical interactions indicate that TCU1/NUP58 is a member of the Nup62 subcomplex of the Arabidopsis NPC. Our findings also suggest regulatory roles for TCU1/NUP58 beyond its function in nucleocytoplasmic trafficking, a hypothesis that is supported by the Y2H and genetic interactions that we observed.
Collapse
Affiliation(s)
| | | | | | - Rosa Micol-Ponce
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, Spain
| | | | - José Luis Micol
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, Spain
| | - María Rosa Ponce
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, Spain
- * E-mail:
| |
Collapse
|
225
|
Kasulin L, Agrofoglio Y, Botto JF. The receptor-like kinase ERECTA contributes to the shade-avoidance syndrome in a background-dependent manner. ANNALS OF BOTANY 2013; 111:811-9. [PMID: 23444123 PMCID: PMC3631326 DOI: 10.1093/aob/mct038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 01/10/2013] [Indexed: 05/19/2023]
Abstract
BACKGROUND AND AIMS Plants growing at high densities perceive a decrease in the red to far-red (R/FR) ratio of incoming light. These changes in light quality trigger a suite of responses collectively known as the shade-avoidance syndrome (SAS) including hypocotyl and stem elongation, inhibition of branching and acceleration of flowering. METHODS Quantitative trait loci (QTLs) were mapped for hypocotyl length to end-of-day far-red (EOD), a simulated shade-avoidance response, in recombinant inbred line (RIL) populations of Arabidopsis thaliana seedlings, derived from Landsberg erecta (Ler) and three accessions (Columbia, Col; Nossen, No-0; and Cape Verde Islands, Cvi-0). KEY RESULTS Five loci were identified as being responsible for the EOD response, with a positive contribution of Ler alleles on the phenotype independently of the RIL population. Quantitative complementation analysis and transgenic lines showed that PHYB is the candidate gene for EODRATIO5 in the Ler × Cvi-0 RIL population, but not for two co-localized QTLs, EODRATIO1 and EODRATIO2 mapped in the Ler × No-0 and Ler × Col RIL populations, respectively. The ERECTA gene was also implicated in the SAS in a background-dependent manner. For hypocotyl length EOD response, a positive contribution of erecta alleles was found in Col and Van-0, but not in Ler, Cvi-0, Hir-1 or Ws. Furthermore, pleiotropic effects of ERECTA in the EOD response were also detected for petiole and lamina elongation, hyponastic growth, and flowering time. CONCLUSIONS The results show that the analysis of multiple mapping populations leads to a better understanding of the SAS genetic architecture. Moreover, the background- and trait-dependent contribution of ERECTA in the SAS suggest that its function in shaded natural environments may be relevant for some populations in different phases of plant development. It is proposed that ERECTA is involved in canalization processes buffering the genetic variation of the SAS against environmental light fluctuations.
Collapse
Affiliation(s)
| | | | - Javier F. Botto
- IFEVA, Facultad de Agronomía, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas, C1417DSE, Ciudad de Buenos Aires, Argentina
| |
Collapse
|
226
|
González-Grandío E, Poza-Carrión C, Sorzano COS, Cubas P. BRANCHED1 promotes axillary bud dormancy in response to shade in Arabidopsis. THE PLANT CELL 2013; 25:834-50. [PMID: 23524661 PMCID: PMC3634692 DOI: 10.1105/tpc.112.108480] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 02/18/2013] [Accepted: 03/04/2013] [Indexed: 05/18/2023]
Abstract
Plants interpret a decrease in the red to far-red light ratio (R:FR) as a sign of impending shading by neighboring vegetation. This triggers a set of developmental responses known as shade avoidance syndrome. One of these responses is reduced branching through suppression of axillary bud outgrowth. The Arabidopsis thaliana gene BRANCHED1 (BRC1), expressed in axillary buds, is required for branch suppression in response to shade. Unlike wild-type plants, brc1 mutants develop several branches after a shade treatment. BRC1 transcription is positively regulated 4 h after exposure to low R:FR. Consistently, BRC1 is negatively regulated by phytochrome B. Transcriptional profiling of wild-type and brc1 buds of plants treated with simulated shade has revealed groups of genes whose mRNA levels are dependent on BRC1, among them a set of upregulated abscisic acid response genes and two networks of cell cycle- and ribosome-related downregulated genes. The downregulated genes have promoters enriched in TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) binding sites, suggesting that they could be transcriptionally regulated by TCP factors. Some of these genes respond to BRC1 in seedlings and buds, supporting their close relationship with BRC1 activity. This response may allow the rapid adaptation of plants to fluctuations in the ratio of R:FR light.
Collapse
Affiliation(s)
- Eduardo González-Grandío
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Cientificas, Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - César Poza-Carrión
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Cientificas, Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Carlos Oscar S. Sorzano
- Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Cientificas, Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Pilar Cubas
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Cientificas, Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
| |
Collapse
|
227
|
Gommers CMM, Visser EJW, St Onge KR, Voesenek LACJ, Pierik R. Shade tolerance: when growing tall is not an option. TRENDS IN PLANT SCIENCE 2013; 18:65-71. [PMID: 23084466 DOI: 10.1016/j.tplants.2012.09.008] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 09/04/2012] [Accepted: 09/21/2012] [Indexed: 05/18/2023]
Abstract
Two different plant strategies exist to deal with shade: shade avoidance and shade tolerance. All shade-exposed plants optimize photosynthesis to adapt to the decrease in light quality and quantity. When shaded, most species in open habitats express the shade-avoidance syndrome, a growth response to escape shade. Shade-tolerant species from forest understories cannot outgrow surrounding trees and adopt a tolerance response. Unlike shade avoidance, virtually nothing is known about regulation of shade tolerance. In this opinion article, we discuss potential modes of molecular regulation to adopt a shade-tolerance rather than a shade-avoidance strategy. We argue that molecular approaches using model and non-model species should help identify the molecular pathways that underpin shade tolerance, thus providing knowledge for further crop improvement.
Collapse
Affiliation(s)
- Charlotte M M Gommers
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | | | | | | | | |
Collapse
|
228
|
Wang H, Zhang Z, Li H, Zhao X, Liu X, Ortiz M, Lin C, Liu B. CONSTANS-LIKE 7 regulates branching and shade avoidance response in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:1017-24. [PMID: 23314820 PMCID: PMC3580813 DOI: 10.1093/jxb/ers376] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Branching is an important trait of plant development regulated by environmental signals. Phytochromes in Arabidopsis mediate branching in response to the changes in the red light:far-red light ratio (R:FR), the mechanisms of which are still elusive. Here it is shown that overexpression of CONSTANS-LIKE 7 (COL7) results in an abundant branching phenotype which could be efficiently suppressed by shade or a simulated shade environment (low R:FR). Moreover, col7 mutants develop shorter hypocotyls and COL7 overexpression lines develop longer hypocotyls in comparison with the wild type in low R:FR, indicating that COL7 acts as an enhancer of the shade avoidance response. In shade or transient low R:FR, transcriptional and post-transcriptional expression levels of COL7 are up-regulated and positively associated with rapid mRNA accumulation of PHYTOCHROME INTERACTING FACTOR 3-LIKE 1 (PIL1), a marker gene of shade avoidance syndrome (SAS). Taken together, the results suggest a dual role for COL7 which promotes branching in high R:FR conditions but enhances SAS in low R:FR conditions.
Collapse
Affiliation(s)
- Honggui Wang
- College of Life Sciences, Hunan University, Changsha 410082, China
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Zenglin Zhang
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Hongyu Li
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xiaoying Zhao
- College of Life Sciences, Hunan University, Changsha 410082, China
| | - Xuanming Liu
- College of Life Sciences, Hunan University, Changsha 410082, China
- To whom correspondence should be addressed. E-mail: or
| | - Michael Ortiz
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Chentao Lin
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Bin Liu
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- To whom correspondence should be addressed. E-mail: or
| |
Collapse
|
229
|
Maloof JN, Nozue K, Mumbach MR, Palmer CM. LeafJ: an ImageJ plugin for semi-automated leaf shape measurement. J Vis Exp 2013:50028. [PMID: 23380664 DOI: 10.3791/50028] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
High throughput phenotyping (phenomics) is a powerful tool for linking genes to their functions (see review and recent examples). Leaves are the primary photosynthetic organ, and their size and shape vary developmentally and environmentally within a plant. For these reasons studies on leaf morphology require measurement of multiple parameters from numerous leaves, which is best done by semi-automated phenomics tools. Canopy shade is an important environmental cue that affects plant architecture and life history; the suite of responses is collectively called the shade avoidance syndrome (SAS). Among SAS responses, shade induced leaf petiole elongation and changes in blade area are particularly useful as indices. To date, leaf shape programs (e.g. SHAPE, LAMINA, LeafAnalyzer, LEAFPROCESSOR) can measure leaf outlines and categorize leaf shapes, but can not output petiole length. Lack of large-scale measurement systems of leaf petioles has inhibited phenomics approaches to SAS research. In this paper, we describe a newly developed ImageJ plugin, called LeafJ, which can rapidly measure petiole length and leaf blade parameters of the model plant Arabidopsis thaliana. For the occasional leaf that required manual correction of the petiole/leaf blade boundary we used a touch-screen tablet. Further, leaf cell shape and leaf cell numbers are important determinants of leaf size. Separate from LeafJ we also present a protocol for using a touch-screen tablet for measuring cell shape, area, and size. Our leaf trait measurement system is not limited to shade-avoidance research and will accelerate leaf phenotyping of many mutants and screening plants by leaf phenotyping.
Collapse
Affiliation(s)
- Julin N Maloof
- Department of Plant Biology, University of California Davis, USA.
| | | | | | | |
Collapse
|
230
|
Abstract
The dynamic light environment of vegetation canopies is perceived by phytochromes, cryptochromes, phototropins, and UV RESISTANCE LOCUS 8 (UVR8). These receptors control avoidance responses to preclude exposure to limiting or excessive light and acclimation responses to cope with conditions that cannot be avoided. The low red/far-red ratios of shade light reduce phytochrome B activity, which allows PHYTOCHROME INTERACTING FACTORS (PIFs) to directly activate the transcription of auxin-synthesis genes, leading to shade-avoidance responses. Direct PIF interaction with DELLA proteins links gibberellin and brassinosteroid signaling to shade avoidance. Shade avoidance also requires CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1), a target of cryptochromes, phytochromes, and UVR8. Multiple regulatory loops and the input of the circadian clock create a complex network able to respond even to subtle threats of competition with neighbors while still compensating for major environmental fluctuations such as the day-night cycles.
Collapse
Affiliation(s)
- Jorge J Casal
- IFEVA, Facultad de Agronomía, Universidad de Buenos Aires and CONICET, 1417 Buenos Aires, Argentina.
| |
Collapse
|
231
|
Rolauffs S, Fackendahl P, Sahm J, Fiene G, Hoecker U. Arabidopsis COP1 and SPA genes are essential for plant elongation but not for acceleration of flowering time in response to a low red light to far-red light ratio. PLANT PHYSIOLOGY 2012; 160:2015-27. [PMID: 23093358 PMCID: PMC3510128 DOI: 10.1104/pp.112.207233] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Plants sense vegetative shade as a reduction in the ratio of red light to far-red light (R:FR). Arabidopsis (Arabidopsis thaliana) responds to a reduced R:FR with increased elongation of the hypocotyl and the leaf petioles as well as with an acceleration of flowering time. The repressor of light signaling, CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1), has been shown previously to be essential for the shade-avoidance response in seedlings. Here, we have investigated the roles of COP1 and the COP1-interacting SUPPRESSOR OF PHYA-105 (SPA) proteins in seedling and adult facets of the shade-avoidance response. We show that COP1 and the four SPA genes are essential for hypocotyl and leaf petiole elongation in response to low R:FR, in a fashion that involves the COP1/SPA ubiquitination target LONG HYPOCOTYL IN FR LIGHT1 but not ELONGATED HYPOCOTYL5. In contrast, the acceleration of flowering in response to a low R:FR was normal in cop1 and spa mutants, thus demonstrating that the COP1/SPA complex is only required for elongation responses to vegetative shade and not for shade-induced early flowering. We further show that spa mutant seedlings fail to exhibit an increase in the transcript levels of the auxin biosynthesis genes YUCCA2 (YUC2), YUC8, and YUC9 in response to low R:FR, suggesting that an increase in auxin biosynthesis in vegetative shade requires SPA function. Consistent with this finding, expression of the auxin-response marker gene DR5::GUS did not increase in spa mutant seedlings exposed to low R:FR. We propose that COP1/SPA activity, via LONG HYPOCOTYL IN FR LIGHT1, is required for shade-induced modulation of the auxin biosynthesis pathway and thereby enhances cell elongation in low R:FR.
Collapse
|
232
|
Nomoto Y, Kubozono S, Yamashino T, Nakamichi N, Mizuno T. Circadian Clock- and PIF4-Controlled Plant Growth: A Coincidence Mechanism Directly Integrates a Hormone Signaling Network into the Photoperiodic Control of Plant Architectures in Arabidopsis thaliana. ACTA ACUST UNITED AC 2012; 53:1950-64. [DOI: 10.1093/pcp/pcs137] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
233
|
Cagnola JI, Ploschuk E, Benech-Arnold T, Finlayson SA, Casal JJ. Stem transcriptome reveals mechanisms to reduce the energetic cost of shade-avoidance responses in tomato. PLANT PHYSIOLOGY 2012; 160:1110-9. [PMID: 22872775 PMCID: PMC3461533 DOI: 10.1104/pp.112.201921] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
While the most conspicuous response to low red/far-red ratios (R:FR) of shade light perceived by phytochrome is the promotion of stem growth, additional, less obvious effects may be discovered by studying changes in the stem transcriptome. Here, we report rapid and reversible stem transcriptome responses to R:FR in tomato (Solanum lycopersicum). As expected, low R:FR promoted the expression of growth-related genes, including those involved in the metabolism of cell wall carbohydrates and in auxin responses. In addition, genes involved in flavonoid synthesis, isoprenoid metabolism, and photosynthesis (dark reactions) were overrepresented in clusters showing reduced expression in the stem of low R:FR-treated plants. Consistent with these responses, low R:FR decreased the levels of flavonoids (anthocyanin, quercetin, kaempferol) and selected isoprenoid derivatives (chlorophyll, carotenoids) in the stem and severely reduced the photosynthetic capacity of this organ. However, lignin contents were unaffected. Low R:FR reduced the stem levels of jasmonate, which is a known inducer of flavonoid synthesis. The rate of stem respiration was also reduced in low R:FR-treated plants, indicating that by downsizing the stem photosynthetic apparatus and the levels of photoprotective pigments under low R:FR, tomato plants reduce the energetic cost of shade-avoidance responses.
Collapse
|