101
|
Efroni I, Mello A, Nawy T, Ip PL, Rahni R, DelRose N, Powers A, Satija R, Birnbaum KD. Root Regeneration Triggers an Embryo-like Sequence Guided by Hormonal Interactions. Cell 2016; 165:1721-1733. [PMID: 27212234 DOI: 10.1016/j.cell.2016.04.046] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/02/2016] [Accepted: 04/14/2016] [Indexed: 01/09/2023]
Abstract
Plant roots can regenerate after excision of their tip, including the stem cell niche. To determine which developmental program mediates such repair, we applied a combination of lineage tracing, single-cell RNA sequencing, and marker analysis to test different models of tissue reassembly. We show that multiple cell types can reconstitute stem cells, demonstrating the latent potential of untreated plant cells. The transcriptome of regenerating cells prior to stem cell activation resembles that of an embryonic root progenitor. Regeneration defects are more severe in embryonic than in adult root mutants. Furthermore, the signaling domains of the hormones auxin and cytokinin mirror their embryonic dynamics and manipulation of both hormones alters the position of new tissues and stem cell niche markers. Our findings suggest that plant root regeneration follows, on a larger scale, the developmental stages of embryonic patterning and is guided by spatial information provided by complementary hormone domains.
Collapse
Affiliation(s)
- Idan Efroni
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA
| | - Alison Mello
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA
| | - Tal Nawy
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA
| | - Pui-Leng Ip
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA
| | - Ramin Rahni
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA
| | - Nicholas DelRose
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA
| | | | - Rahul Satija
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA; New York Genome Center, New York, NY 10013, USA
| | - Kenneth D Birnbaum
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA.
| |
Collapse
|
102
|
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.
Collapse
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;
| |
Collapse
|
103
|
Cheng F, Liu YF, Lu GY, Zhang XK, Xie LL, Yuan CF, Xu BB. Graphene oxide modulates root growth of Brassica napus L. and regulates ABA and IAA concentration. JOURNAL OF PLANT PHYSIOLOGY 2016; 193:57-63. [PMID: 26945480 DOI: 10.1016/j.jplph.2016.02.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 01/28/2016] [Accepted: 02/05/2016] [Indexed: 06/05/2023]
Abstract
Researchers have proven that nanomaterials have a significant effect on plant growth and development. To better understand the effects of nanomaterials on plants, Zhongshuang 11 was treated with different concentrations of graphene oxide. The results indicated that 25-100mg/l graphene oxide treatment resulted in shorter seminal root length compared with the control samples. The fresh root weight decreased when treated with 50-100mg/l graphene oxide. The graphene oxide treatment had no significant effect on the Malondialdehyde (MDA) content. Treatment with 50mg/l graphene oxide increased the transcript abundance of genes involved in ABA biosynthesis (NCED, AAO, and ZEP) and some genes involved in IAA biosynthesis (ARF2, ARF8, IAA2, and IAA3), but inhibited the transcript levels of IAA4 and IAA7. The graphene oxide treatment also resulted in a higher ABA content, but a lower IAA content compared with the control samples. The results indicated that graphene oxide modulated the root growth of Brassica napus L. and affected ABA and IAA biosynthesis and concentration.
Collapse
Affiliation(s)
- Fan Cheng
- College of Life Science, Yangtze University, Jingzhou 434025, China
| | - Yu-Feng Liu
- College of Life Science, Yangtze University, Jingzhou 434025, China
| | - Guang-Yuan Lu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China
| | - Xue-Kun Zhang
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China
| | - Ling-Li Xie
- College of Life Science, Yangtze University, Jingzhou 434025, China
| | - Cheng-Fei Yuan
- College of Life Science, Yangtze University, Jingzhou 434025, China
| | - Ben-Bo Xu
- College of Life Science, Yangtze University, Jingzhou 434025, China.
| |
Collapse
|
104
|
Taylor-Teeples M, Lanctot A, Nemhauser JL. As above, so below: Auxin's role in lateral organ development. Dev Biol 2016; 419:156-164. [PMID: 26994944 DOI: 10.1016/j.ydbio.2016.03.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 02/02/2023]
Abstract
Organogenesis requires the coordination of many highly-regulated developmental processes, including cell fate determination, cell division and growth, and cell-cell communication. For tissue- and organ-scale coordination, a network of regulators enables molecular events in individual cells to translate into multicellular changes in structure and functional capacity. One recurrent theme in plant developmental networks is a central role for plant hormones, especially auxin. Here, we focus first on describing recent advances in understanding lateral root development, one of the best-studied examples of auxin-mediated organogenesis. We then use this framework to examine the parallel process of emergence of lateral organs in the shoot-a process called phyllotaxy. This comparison reveals a high degree of conservation, highlighting auxin's pivotal role determining overall plant architecture.
Collapse
Affiliation(s)
| | - Amy Lanctot
- Department of Biology, University of Washington, Seattle, WA 98195, USA.
| | | |
Collapse
|
105
|
Identification of genes regulated by histone acetylation during root development in Populus trichocarpa. BMC Genomics 2016; 17:96. [PMID: 26847576 PMCID: PMC4743431 DOI: 10.1186/s12864-016-2407-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 01/20/2016] [Indexed: 11/10/2022] Open
Abstract
Background Histone deacetylases (HDACs) are key enzymes catalyzing the removal of acetyl groups from histones. HDACs act in concert with histone acetyltransferases (HATs) to regulate histone acetylation status, which modifies chromatin structure, affecting gene transcription and thus regulating multiple biological processes such as plant growth and development. Over a decade, certain HDACs in herbaceous plants have been deeply studied. However, functions of HDACs in woody plants are not well understood. Results Histone deacetylase specific inhibitor trichostatin A (TSA) was used to investigate the role of HDACs in organogenesis of roots and root development in Populus trochocarpa. The adventitious roots were regenerated and grown on medium supplemented with 0, 1, and 2.5 μM TSA. TSA treatment delayed root regeneration and inhibited primary root growth. To examine the genes modified by TSA in the regenerated roots, tag-based digital gene expression (DGE) analysis was performed using Illumina HiSeqTM 2000. Approximately 4.5 million total clean tags were mapped per library. The distinct clean tags for the three libraries corresponding to 0, 1 and 2.5 μM TSA treatment were 166167, 143103 and 153507, from which 38.45 %, 31.84 % and 38.88 % were mapped unambiguously to the unigene database, respectively. Most of the tags were expressed at similar levels, showing a < 5-fold difference after 1 μM and 2.5 μM TSA treatments and the maximum fold-change of the tag copy number was around 20. The expression levels of many genes in roots were significantly altered by TSA. A total of 36 genes were up-regulated and 1368 genes were down-regulated after 1 μM TSA treatment, while 166 genes were up-regulated and 397 genes were down-regulated after 2.5 μM TSA treatment. Gene ontology (GO) and pathway analyses indicated that the differentially expressed genes were related to many kinds of molecular functions and biological processes. The genes encoding key enzymes catalyzing gibberellin biosynthesis were significantly down-regulated in the roots exposed to 2.5 μM TSA and their expression changes were validated by using real-time PCR. Conclusions HDACs were required for de novo organogenesis and normal growth of populus roots. DGE data provides the gene profiles in roots probably regulated by histone acetylation during root growth and development, which will lead to a better understanding of the mechanism controlling root development. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2407-x) contains supplementary material, which is available to authorized users.
Collapse
|
106
|
Zhang Y, Marcon C, Tai H, von Behrens I, Ludwig Y, Hey S, Berendzen KW, Hochholdinger F. Conserved and unique features of the homeologous maize Aux/IAA proteins ROOTLESS WITH UNDETECTABLE MERISTEM 1 and RUM1-like 1. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:1137-47. [PMID: 26672614 PMCID: PMC4753850 DOI: 10.1093/jxb/erv519] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The maize (Zea mays L.) Aux/IAA protein RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEM 1) is a key regulator of lateral and seminal root formation. An ancient maize genome duplication resulted in the emergence of its homeolog rum1-like1 (rul1), which displays 92% amino acid sequence identity with RUM1. Both, RUL1 and RUM1 exhibit the canonical four domain structure of Aux/IAA proteins. Moreover, both are localized to the nucleus, are instable and have similar short half-lives of ~23min. Moreover, RUL1 and RUM1 can be stabilized by specific mutations in the five amino acid degron sequence of domain II. In addition, proteins encoded by both genes interact in vivo with auxin response factors (ARFs) such as ZmARF25 and ZmARF34 in protoplasts. Although it was demonstrated that RUL1 and RUM1 can homo and heterodimerize in vivo, rul1 expression is independent of rum1. Moreover, on average rul1 expression is ~84-fold higher than rum1 in the 12 tested tissues and developmental stages, although the relative expression levels in different root tissues are very similar. While RUM1 and RUL1 display conserved biochemical properties, yeast-two-hybrid in combination with BiFC experiments identified a RUM1-associated protein 1 (RAP1) that specifically interacts with RUM1 but not with RUL1. This suggests that RUM1 and RUL1 are at least in part interwoven into different molecular networks.
Collapse
Affiliation(s)
- Yanxiang Zhang
- Center for Molecular Cell and Systems Biology, College of Life Science, Fujian Agriculture & Forestry University, 350002 Fuzhou, China Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Caroline Marcon
- Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Huanhuan Tai
- Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Inga von Behrens
- ZMBP, Center for Plant Molecular Biology, General Genetics, University of Tuebingen, 72076 Tuebingen, Germany
| | - Yvonne Ludwig
- Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Stefan Hey
- Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Kenneth W Berendzen
- ZMBP, Center for Plant Molecular Biology, Central Facilities, University of Tuebingen, 72076 Tuebingen, Germany
| | - Frank Hochholdinger
- Crop Functional Genomics, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| |
Collapse
|
107
|
Wei Z, Li J. Brassinosteroids Regulate Root Growth, Development, and Symbiosis. MOLECULAR PLANT 2016; 9:86-100. [PMID: 26700030 DOI: 10.1016/j.molp.2015.12.003] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 10/29/2015] [Accepted: 12/07/2015] [Indexed: 05/19/2023]
Abstract
Brassinosteroids (BRs) are natural plant hormones critical for growth and development. BR deficient or signaling mutants show significantly shortened root phenotypes. However, for a long time, it was thought that these phenotypes were solely caused by reduced cell elongation in the mutant roots. Functions of BRs in regulating root development have been largely neglected. Nonetheless, recent detailed analyses, revealed that BRs are not only involved in root cell elongation but are also involved in many aspects of root development, such as maintenance of meristem size, root hair formation, lateral root initiation, gravitropic response, mycorrhiza formation, and nodulation in legume species. In this review, current findings on the functions of BRs in mediating root growth, development, and symbiosis are discussed.
Collapse
Affiliation(s)
- Zhuoyun Wei
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jia Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
| |
Collapse
|
108
|
Slovak R, Ogura T, Satbhai SB, Ristova D, Busch W. Genetic control of root growth: from genes to networks. ANNALS OF BOTANY 2016; 117:9-24. [PMID: 26558398 PMCID: PMC4701154 DOI: 10.1093/aob/mcv160] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/28/2015] [Indexed: 05/08/2023]
Abstract
BACKGROUND Roots are essential organs for higher plants. They provide the plant with nutrients and water, anchor the plant in the soil, and can serve as energy storage organs. One remarkable feature of roots is that they are able to adjust their growth to changing environments. This adjustment is possible through mechanisms that modulate a diverse set of root traits such as growth rate, diameter, growth direction and lateral root formation. The basis of these traits and their modulation are at the cellular level, where a multitude of genes and gene networks precisely regulate development in time and space and tune it to environmental conditions. SCOPE This review first describes the root system and then presents fundamental work that has shed light on the basic regulatory principles of root growth and development. It then considers emerging complexities and how they have been addressed using systems-biology approaches, and then describes and argues for a systems-genetics approach. For reasons of simplicity and conciseness, this review is mostly limited to work from the model plant Arabidopsis thaliana, in which much of the research in root growth regulation at the molecular level has been conducted. CONCLUSIONS While forward genetic approaches have identified key regulators and genetic pathways, systems-biology approaches have been successful in shedding light on complex biological processes, for instance molecular mechanisms involving the quantitative interaction of several molecular components, or the interaction of large numbers of genes. However, there are significant limitations in many of these methods for capturing dynamic processes, as well as relating these processes to genotypic and phenotypic variation. The emerging field of systems genetics promises to overcome some of these limitations by linking genotypes to complex phenotypic and molecular data using approaches from different fields, such as genetics, genomics, systems biology and phenomics.
Collapse
Affiliation(s)
- Radka Slovak
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Takehiko Ogura
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Santosh B Satbhai
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Daniela Ristova
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Wolfgang Busch
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| |
Collapse
|
109
|
Khan MA, Gemenet DC, Villordon A. Root System Architecture and Abiotic Stress Tolerance: Current Knowledge in Root and Tuber Crops. FRONTIERS IN PLANT SCIENCE 2016; 7:1584. [PMID: 27847508 PMCID: PMC5088196 DOI: 10.3389/fpls.2016.01584] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 10/07/2016] [Indexed: 05/19/2023]
Abstract
The challenge to produce more food for a rising global population on diminishing agricultural land is complicated by the effects of climate change on agricultural productivity. Although great progress has been made in crop improvement, so far most efforts have targeted above-ground traits. Roots are essential for plant adaptation and productivity, but are less studied due to the difficulty of observing them during the plant life cycle. Root system architecture (RSA), made up of structural features like root length, spread, number, and length of lateral roots, among others, exhibits great plasticity in response to environmental changes, and could be critical to developing crops with more efficient roots. Much of the research on root traits has thus far focused on the most common cereal crops and model plants. As cereal yields have reached their yield potential in some regions, understanding their root system may help overcome these plateaus. However, root and tuber crops (RTCs) such as potato, sweetpotato, cassava, and yam may hold more potential for providing food security in the future, and knowledge of their root system additionally focuses directly on the edible portion. Root-trait modeling for multiple stress scenarios, together with high-throughput phenotyping and genotyping techniques, robust databases, and data analytical pipelines, may provide a valuable base for a truly inclusive 'green revolution.' In the current review, we discuss RSA with special reference to RTCs, and how knowledge on genetics of RSA can be manipulated to improve their tolerance to abiotic stresses.
Collapse
Affiliation(s)
- M. A. Khan
- International Potato CenterLima, Peru
- *Correspondence: M. A. Khan,
| | | | | |
Collapse
|
110
|
Zhao H, Ma T, Wang X, Deng Y, Ma H, Zhang R, Zhao J. OsAUX1 controls lateral root initiation in rice (Oryza sativa L.). PLANT, CELL & ENVIRONMENT 2015; 38:2208-22. [PMID: 25311360 DOI: 10.1111/pce.12467] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 10/01/2014] [Indexed: 05/06/2023]
Abstract
Polar auxin transport, mediated by influx and efflux transporters, controls many aspects of plant growth and development. The auxin influx carriers in Arabidopsis have been shown to control lateral root development and gravitropism, but little is known about these proteins in rice. This paper reports on the functional characterization of OsAUX1. Three OsAUX1 T-DNA insertion mutants and RNAi knockdown transgenic plants reduced lateral root initiation compared with wild-type (WT) plants. OsAUX1 overexpression plants exhibited increased lateral root initiation and OsAUX1 was highly expressed in lateral roots and lateral root primordia. Similarly, the auxin reporter, DR5-GUS, was expressed at lower levels in osaux1 than in the WT plants, which indicated that the auxin levels in the mutant roots had decreased. Exogenous 1-naphthylacetic acid (NAA) treatment rescued the defective phenotype in osaux1-1 plants, whereas indole-3-acetic acid (IAA) and 2,4-D could not, which suggested that OsAUX1 was a putative auxin influx carrier. The transcript levels of several auxin signalling genes and cell cycle genes significantly declined in osaux1, hinting that the regulatory role of OsAUX1 may be mediated by auxin signalling and cell cycle genes. Overall, our results indicated that OsAUX1 was involved in polar auxin transport and functioned to control auxin-mediated lateral root initiation in rice.
Collapse
Affiliation(s)
- Heming Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Tengfei Ma
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xin Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yingtian Deng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Haoli Ma
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Rongsheng Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| |
Collapse
|
111
|
Yu C, Sun C, Shen C, Wang S, Liu F, Liu Y, Chen Y, Li C, Qian Q, Aryal B, Geisler M, Jiang DA, Qi Y. The auxin transporter, OsAUX1, is involved in primary root and root hair elongation and in Cd stress responses in rice (Oryza sativa L.). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 83:818-30. [PMID: 26140668 DOI: 10.1111/tpj.12929] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/17/2015] [Accepted: 06/26/2015] [Indexed: 05/22/2023]
Abstract
Auxin and cadmium (Cd) stress play critical roles during root development. There are only a few reports on the mechanisms by which Cd stress influences auxin homeostasis and affects primary root (PR) and lateral root (LR) development, and almost nothing is known about how auxin and Cd interfere with root hair (RH) development. Here, we characterize rice osaux1 mutants that have a longer PR and shorter RHs in hydroponic culture, and that are more sensitive to Cd stress compared to wild-type (Dongjin). OsAUX1 expression in root hair cells is different from that of its paralogous gene, AtAUX1, which is expressed in non-hair cells. However, OsAUX1, like AtAUX1, localizes at the plasma membrane and appears to function as an auxin tranporter. Decreased auxin distribution and contents in the osaux1 mutant result in reduction of OsCyCB1;1 expression and shortened PRs, LRs and RHs under Cd stress, but may be rescued by treatment with the membrane-permeable auxin 1-naphthalene acetic acid. Treatment with the auxin transport inhibitors 1-naphthoxyacetic acid and N-1-naphthylphthalamic acid increased the Cd sensitivity of WT rice. Cd contents in the osaux1 mutant were not altered, but reactive oxygen species-mediated damage was enhanced, further increasing the sensitivity of the osaux1 mutant to Cd stress. Taken together, our results indicate that OsAUX1 plays an important role in root development and in responses to Cd stress.
Collapse
Affiliation(s)
- ChenLiang Yu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - ChenDong Sun
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Chenjia Shen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Suikang Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Fang Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yan Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - YunLong Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qian Qian
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, China
| | - Bibek Aryal
- Department of Biology - Plant Biology, University of Fribourg, Rue Albert Gockel 3, CH-1700, Fribourg, Switzerland
| | - Markus Geisler
- Department of Biology - Plant Biology, University of Fribourg, Rue Albert Gockel 3, CH-1700, Fribourg, Switzerland
| | - De An Jiang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - YanHua Qi
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| |
Collapse
|
112
|
Lee HW, Cho C, Kim J. Lateral Organ Boundaries Domain16 and 18 Act Downstream of the AUXIN1 and LIKE-AUXIN3 Auxin Influx Carriers to Control Lateral Root Development in Arabidopsis. PLANT PHYSIOLOGY 2015; 168:1792-806. [PMID: 26059335 PMCID: PMC4528759 DOI: 10.1104/pp.15.00578] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/08/2015] [Indexed: 05/22/2023]
Abstract
Several members of the Lateral Organ Boundaries Domain (LBD)/Asymmetric Leaves2-Like (ASL) gene family have been identified to play important roles in Arabidopsis (Arabidopsis thaliana) lateral root (LR) development during auxin response, but their functional relationship with auxin transporters has not been established yet. Here, we show that the AUXIN1 (AUX1) and LIKE-AUXIN3 (LAX3) auxin influx carriers are required for auxin signaling that activates LBD16/ASL18 and LBD18/ASL20 to control LR development. The lax3 mutant phenotype was not significantly enhanced when combined with lbd16 or lbd18. However, LBD18 overexpression could rescue the defects in LR emergence in lax3 with concomitant expression of the LBD18 target genes. Genetic and gene expression analyses indicated that LBD16 and LBD18 act with AUX1 to regulate LR initiation and LR primordium development, and that AUX1 and LAX3 are needed for auxin-responsive expression of LBD16 and LBD18. LBD18:SUPERMAN REPRESSIVE DOMAIN X in the lbd18 mutant inhibited LR initiation and LR primordium development in response to a gravitropic stimulus and suppressed promoter activities of the cell cycle genes Cyclin-Dependent Kinase A1;1 and CYCLINB1;1. Taken together, these results suggest that LBD16 and LBD18 are important regulators of LR initiation and development downstream of AUX1 and LAX3.
Collapse
Affiliation(s)
- Han Woo Lee
- Department of Bioenergy Science and Technology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 500-757, Korea
| | - Chuloh Cho
- Department of Bioenergy Science and Technology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 500-757, Korea
| | - Jungmook Kim
- Department of Bioenergy Science and Technology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 500-757, Korea
| |
Collapse
|
113
|
Chang L, Ramireddy E, Schmülling T. Cytokinin as a positional cue regulating lateral root spacing in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4759-68. [PMID: 26019251 PMCID: PMC4507779 DOI: 10.1093/jxb/erv252] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The root systems of plants have developed adaptive architectures to exploit soil resources. The formation of lateral roots (LRs) contributes to root system architecture. Roots of plants with a lower cytokinin status form LR primordia (LRP) in unusually close proximity, indicating a role for the hormone in regulating the positioning of LRs along the main root axis. Data obtained from cytokinin-synthesis mutants of Arabidopsis thaliana combined with gene expression analysis indicate that cytokinin synthesis by IPT5 and LOG4 occurring early during LRP initiation generates a local cytokinin signal abbreviating LRP formation in neighbouring pericycle cells. In addition, IPT3, IPT5, and IPT7 contribute to cytokinin synthesis in the vicinity of existing LRP, thus suppressing initiation of new LRs. Interestingly, mutation of CYP735A genes required for trans-zeatin biosynthesis caused strong defects in LR positioning, indicating an important role for this cytokinin metabolite in regulating LR spacing. Further it is shown that cytokinin and a known regulator of LR spacing, the receptor-like kinase ARABIDOPSIS CRINKLY4 (ACR4), operate in a non-hierarchical manner but might exert reciprocal control at the transcript level. Taken together, the results suggest that cytokinin acts as a paracrine hormonal signal in regulating root system architecture.
Collapse
Affiliation(s)
- Ling Chang
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Albrecht-Thaer-Weg 6, D- 14195 Berlin, Germany Present address: Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Science, Hubei University, Wuhan 430062, China
| | - Eswarayya Ramireddy
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Albrecht-Thaer-Weg 6, D- 14195 Berlin, Germany
| | - Thomas Schmülling
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Albrecht-Thaer-Weg 6, D- 14195 Berlin, Germany
| |
Collapse
|
114
|
Zhan A, Schneider H, Lynch JP. Reduced Lateral Root Branching Density Improves Drought Tolerance in Maize. PLANT PHYSIOLOGY 2015; 168:1603-15. [PMID: 26077764 PMCID: PMC4528736 DOI: 10.1104/pp.15.00187] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Accepted: 06/12/2015] [Indexed: 05/18/2023]
Abstract
An emerging paradigm is that root traits that reduce the metabolic costs of soil exploration improve the acquisition of limiting soil resources. Here, we test the hypothesis that reduced lateral root branching density will improve drought tolerance in maize (Zea mays) by reducing the metabolic costs of soil exploration, permitting greater axial root elongation, greater rooting depth, and thereby greater water acquisition from drying soil. Maize recombinant inbred lines with contrasting lateral root number and length (few but long [FL] and many but short [MS]) were grown under water stress in greenhouse mesocosms, in field rainout shelters, and in a second field environment with natural drought. Under water stress in mesocosms, lines with the FL phenotype had substantially less lateral root respiration per unit of axial root length, deeper rooting, greater leaf relative water content, greater stomatal conductance, and 50% greater shoot biomass than lines with the MS phenotype. Under water stress in the two field sites, lines with the FL phenotype had deeper rooting, much lighter stem water isotopic signature, signifying deeper water capture, 51% to 67% greater shoot biomass at flowering, and 144% greater yield than lines with the MS phenotype. These results entirely support the hypothesis that reduced lateral root branching density improves drought tolerance. The FL lateral root phenotype merits consideration as a selection target to improve the drought tolerance of maize and possibly other cereal crops.
Collapse
Affiliation(s)
- Ai Zhan
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China (A.Z.); andDepartment of Plant Science, Pennsylvania State University, University Park, Pennsylvania 16802 (A.Z., H.S., J.P.L.)
| | - Hannah Schneider
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China (A.Z.); andDepartment of Plant Science, Pennsylvania State University, University Park, Pennsylvania 16802 (A.Z., H.S., J.P.L.)
| | - Jonathan P Lynch
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China (A.Z.); andDepartment of Plant Science, Pennsylvania State University, University Park, Pennsylvania 16802 (A.Z., H.S., J.P.L.)
| |
Collapse
|
115
|
The circadian clock rephases during lateral root organ initiation in Arabidopsis thaliana. Nat Commun 2015; 6:7641. [PMID: 26144255 DOI: 10.1038/ncomms8641] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 05/27/2015] [Indexed: 01/05/2023] Open
Abstract
The endogenous circadian clock enables organisms to adapt their growth and development to environmental changes. Here we describe how the circadian clock is employed to coordinate responses to the key signal auxin during lateral root (LR) emergence. In the model plant, Arabidopsis thaliana, LRs originate from a group of stem cells deep within the root, necessitating that new organs emerge through overlying root tissues. We report that the circadian clock is rephased during LR development. Metabolite and transcript profiling revealed that the circadian clock controls the levels of auxin and auxin-related genes including the auxin response repressor IAA14 and auxin oxidase AtDAO2. Plants lacking or overexpressing core clock components exhibit LR emergence defects. We conclude that the circadian clock acts to gate auxin signalling during LR development to facilitate organ emergence.
Collapse
|
116
|
Chandler JW, Werr W. Cytokinin-auxin crosstalk in cell type specification. TRENDS IN PLANT SCIENCE 2015; 20:291-300. [PMID: 25805047 DOI: 10.1016/j.tplants.2015.02.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/13/2015] [Accepted: 02/24/2015] [Indexed: 05/24/2023]
Abstract
Auxin and cytokinin affect cell fate specification transcriptionally and non-transcriptionally, and their roles have been characterised in several founder cell specification and activation contexts. Similarly to auxin, local cytokinin synthesis and response gradients are instructive, and the roles of ARABIDOPSIS RESPONSE REGULATOR 7/15 (ARR7/15) and the negative cytokinin response regulator ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 6, as well as auxin signalling via MONOPTEROS/BODENLOS, are functionally conserved across different developmental processes. Auxin and cytokinin crosstalk is tissue- and context-specific, and may be synergistic in the shoot apical meristem (SAM) but antagonistic in the root. We review recent advances in understanding the interactions between auxin and cytokinin in pivotal developmental processes, and show that feedback complexity and the multistep nature of specification processes argue against a single morphogenetic signal.
Collapse
Affiliation(s)
- John William Chandler
- Institute of Developmental Biology, Cologne Biocenter, Zülpicher Strasse 47b, 50674 Cologne, Germany.
| | - Wolfgang Werr
- Institute of Developmental Biology, Cologne Biocenter, Zülpicher Strasse 47b, 50674 Cologne, Germany
| |
Collapse
|
117
|
Martínez-de la Cruz E, García-Ramírez E, Vázquez-Ramos JM, Reyes de la Cruz H, López-Bucio J. Auxins differentially regulate root system architecture and cell cycle protein levels in maize seedlings. JOURNAL OF PLANT PHYSIOLOGY 2015; 176:147-56. [PMID: 25615607 DOI: 10.1016/j.jplph.2014.11.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 11/20/2014] [Accepted: 11/21/2014] [Indexed: 05/26/2023]
Abstract
Maize (Zea mays) root system architecture has a complex organization, with adventitious and lateral roots determining its overall absorptive capacity. To generate basic information about the earlier stages of root development, we compared the post-embryonic growth of maize seedlings germinated in water-embedded cotton beds with that of plants obtained from embryonic axes cultivated in liquid medium. In addition, the effect of four different auxins, namely indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA) and 2,4-dichlorophenoxyacetic acid (2,4-D) on root architecture and levels of the heat shock protein HSP101 and the cell cycle proteins CKS1, CYCA1 and CDKA1 were analyzed. Our data show that during the first days after germination, maize seedlings develop several root types with a simultaneous and/or continuous growth. The post-embryonic root development started with the formation of the primary root (PR) and seminal scutellar roots (SSR) and then continued with the formation of adventitious crown roots (CR), brace roots (BR) and lateral roots (LR). Auxins affected root architecture in a dose-response fashion; whereas NAA and IBA mostly stimulated crown root formation, 2,4-D showed a strong repressing effect on growth. The levels of HSP101, CKS1, CYCA1 and CDKA in root and leaf tissues were differentially affected by auxins and interestingly, HSP101 registered an auxin-inducible and root specific expression pattern. Taken together, our results show the timing of early branching patterns of maize and indicate that auxins regulate root development likely through modulation of the HSP101 and cell cycle proteins.
Collapse
Affiliation(s)
- Enrique Martínez-de la Cruz
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio A-1', Ciudad Universitaria Morelia, Morelia 58030, Michoacán, Mexico
| | - Elpidio García-Ramírez
- Departamento de Bioquímica, Facultad de Química, UNAM, Ciudad Universitaria, México DF C.P. 04510, Mexico
| | - Jorge M Vázquez-Ramos
- Departamento de Bioquímica, Facultad de Química, UNAM, Ciudad Universitaria, México DF C.P. 04510, Mexico
| | - Homero Reyes de la Cruz
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio A-1', Ciudad Universitaria Morelia, Morelia 58030, Michoacán, Mexico.
| | - José López-Bucio
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio A-1', Ciudad Universitaria Morelia, Morelia 58030, Michoacán, Mexico.
| |
Collapse
|
118
|
Vermeer JEM, Geldner N. Lateral root initiation in Arabidopsis thaliana: a force awakens. F1000PRIME REPORTS 2015; 7:32. [PMID: 25926983 PMCID: PMC4371239 DOI: 10.12703/p7-32] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Osmotically driven turgor pressure of plant cells can be higher than that of a car tire. It puts tremendous forces onto cell walls and drives cell growth and changes in cell shape. This has given rise to unique mechanisms to control organ formation compared to metazoans. The fascinating interplay between forces and local cellular reorganization is still poorly understood. Growth of lateral roots is a prominent example of a developmental process in which mechanical forces between neighboring cells are generated and must be dealt with. Lateral roots initiate from a single cell layer that resides deep within the primary root. On their way out, lateral roots grow through the overlying endodermal, cortical, and epidermal cell layers. It was recently demonstrated that endodermal cells actively accommodate lateral root formation. Interfering genetically with these accommodating responses in the endodermis completely blocks cell proliferation in the pericycle. The lateral root system provides a unique opportunity to elucidate the molecular and cellular mechanisms whereby mechanical forces and intercellular communication regulate spatial accommodation during plant development.
Collapse
|
119
|
Satbhai SB, Ristova D, Busch W. Underground tuning: quantitative regulation of root growth. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1099-112. [PMID: 25628329 DOI: 10.1093/jxb/eru529] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Plants display a high degree of phenotypic plasticity that allows them to tune their form and function to changing environments. The plant root system has evolved mechanisms to anchor the plant and to efficiently explore soils to forage for soil resources. Key to this is an enormous capacity for plasticity of multiple traits that shape the distribution of roots in the soil. Such root system architecture-related traits are determined by root growth rates, root growth direction, and root branching. In this review, we describe how the root system is constituted, and which mechanisms, pathways, and genes mainly regulate plasticity of the root system in response to environmental variation.
Collapse
Affiliation(s)
- Santosh B Satbhai
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocentre (VBC), Dr Bohr-Gasse 3, 1030 Vienna, Austria
| | - Daniela Ristova
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocentre (VBC), Dr Bohr-Gasse 3, 1030 Vienna, Austria
| | - Wolfgang Busch
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocentre (VBC), Dr Bohr-Gasse 3, 1030 Vienna, Austria
| |
Collapse
|
120
|
Vilches-Barro A, Maizel A. Talking through walls: mechanisms of lateral root emergence in Arabidopsis thaliana. CURRENT OPINION IN PLANT BIOLOGY 2015; 23:31-8. [PMID: 25449724 DOI: 10.1016/j.pbi.2014.10.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 10/10/2014] [Accepted: 10/12/2014] [Indexed: 05/04/2023]
Abstract
Lateral roots are formed postembryonically and determine the final shape of the root system, a determinant of the plants ability to uptake nutrients and water. The lateral root primordia are initiated deep into the main root and to protrude out the primary root they have to grow through three cell layers. Recent findings have revealed that these layers are not merely a passive physical obstacle to the emergence of the lateral root but have an active role in its formation. Here, we review examples of communication between the lateral root primordium and the surrounding tissues, highlighting the importance of auxin-mediated growth coordination as well as cell and tissue mechanics for the morphogenesis of lateral roots.
Collapse
Affiliation(s)
- Amaya Vilches-Barro
- Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Alexis Maizel
- Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany.
| |
Collapse
|
121
|
Shen C, Yue R, Sun T, Zhang L, Yang Y, Wang H. OsARF16, a transcription factor regulating auxin redistribution, is required for iron deficiency response in rice (Oryza sativa L.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 231:148-58. [PMID: 25576000 DOI: 10.1016/j.plantsci.2014.12.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 11/24/2014] [Accepted: 12/01/2014] [Indexed: 05/18/2023]
Abstract
Plant response to iron deficiency is the most important feature for survival in Fe-limited soils. Several phytohormones, including auxin, are involved in iron uptake and homeostasis. However, the mechanisms behind how auxin participates in the iron deficiency response in rice are largely unknown. We found that OsARF16 was involved in the iron deficiency response and the induction of iron deficiency response genes. Most Fe-deficient symptoms could be partially restored in the osarf16 mutant, including dwarfism, photosynthesis decline, a reduction in iron content and root system architecture (RSA) regulation. OsARF16 expression was induced in the roots and shoots by Fe deprivation. Restoration of the phenotype could also be mimicked by 1-NOA, an auxin influx inhibitor. Furthermore, the qRT-PCR data indicated that the induction of Fe-deficiency response genes by iron deficiency was more compromised in the osarf16 mutant than in Nipponbare. In conclusion, osarf16, an auxin insensitive mutant, was involved in iron deficiency response in rice. Our results reveal a new biological function for OsARF16 and provide important information on how ARF-medicated auxin signaling affects iron signaling and the iron deficiency response. This work may help us to improve production or increased Fe nutrition of rice to iron deficiency by regulating auxin signaling.
Collapse
Affiliation(s)
- Chenjia Shen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China.
| | - Runqing Yue
- Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Tao Sun
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Lei Zhang
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA
| | - Yanjun Yang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Huizhong Wang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China.
| |
Collapse
|
122
|
Guseman JM, Hellmuth A, Lanctot A, Feldman TP, Moss BL, Klavins E, Calderón Villalobos LIA, Nemhauser JL. Auxin-induced degradation dynamics set the pace for lateral root development. Development 2015; 142:905-9. [PMID: 25633353 DOI: 10.1242/dev.117234] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Auxin elicits diverse cell behaviors through a simple nuclear signaling pathway initiated by degradation of Aux/IAA co-repressors. Our previous work revealed that members of the large Arabidopsis Aux/IAA family exhibit a range of degradation rates in synthetic contexts. However, it remained an unresolved issue whether differences in Aux/IAA turnover rates played a significant role in plant responses to auxin. Here, we use the well-established model of lateral root development to directly test the hypothesis that the rate of auxin-induced Aux/IAA turnover sets the pace for auxin-regulated developmental events. We did this by generating transgenic plants expressing degradation rate variants of IAA14, a crucial determinant of lateral root initiation. Progression through the well-established stages of lateral root development was strongly correlated with the engineered rates of IAA14 turnover, leading to the conclusion that Aux/IAAs are auxin-initiated timers that synchronize developmental transitions.
Collapse
Affiliation(s)
- Jessica M Guseman
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Antje Hellmuth
- Leibniz Institute of Plant Biochemistry, Halle (Saale) 06120, Germany
| | - Amy Lanctot
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Tamar P Feldman
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Britney L Moss
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Eric Klavins
- Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA
| | | | | |
Collapse
|
123
|
Salehin M, Bagchi R, Estelle M. SCFTIR1/AFB-based auxin perception: mechanism and role in plant growth and development. THE PLANT CELL 2015; 27:9-19. [PMID: 25604443 PMCID: PMC4330579 DOI: 10.1105/tpc.114.133744] [Citation(s) in RCA: 273] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/14/2014] [Accepted: 12/26/2014] [Indexed: 05/18/2023]
Abstract
Auxin regulates a vast array of growth and developmental processes throughout the life cycle of plants. Auxin responses are highly context dependent and can involve changes in cell division, cell expansion, and cell fate. The complexity of the auxin response is illustrated by the recent finding that the auxin-responsive gene set differs significantly between different cell types in the root. Auxin regulation of transcription involves a core pathway consisting of the TIR1/AFB F-box proteins, the Aux/IAA transcriptional repressors, and the ARF transcription factors. Auxin is perceived by a transient coreceptor complex consisting of a TIR1/AFB protein and an Aux/IAA protein. Auxin binding to the coreceptor results in degradation of the Aux/IAAs and derepression of ARF-based transcription. Although the basic outlines of this pathway are now well established, it remains unclear how specificity of the pathway is conferred. However, recent results, focusing on the ways that these three families of proteins interact, are starting to provide important clues.
Collapse
Affiliation(s)
- Mohammad Salehin
- Howard Hughes Medical Institute and Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093
| | - Rammyani Bagchi
- Howard Hughes Medical Institute and Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093
| | - Mark Estelle
- Howard Hughes Medical Institute and Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093
| |
Collapse
|
124
|
Breakspear A, Liu C, Roy S, Stacey N, Rogers C, Trick M, Morieri G, Mysore KS, Wen J, Oldroyd GED, Downie JA, Murray JD. The root hair "infectome" of Medicago truncatula uncovers changes in cell cycle genes and reveals a requirement for Auxin signaling in rhizobial infection. THE PLANT CELL 2014; 26:4680-701. [PMID: 25527707 PMCID: PMC4311213 DOI: 10.1105/tpc.114.133496] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 10/23/2014] [Accepted: 12/03/2014] [Indexed: 05/18/2023]
Abstract
Nitrogen-fixing rhizobia colonize legume roots via plant-made intracellular infection threads. Genetics has identified some genes involved but has not provided sufficient detail to understand requirements for infection thread development. Therefore, we transcriptionally profiled Medicago truncatula root hairs prior to and during the initial stages of infection. This revealed changes in the responses to plant hormones, most notably auxin, strigolactone, gibberellic acid, and brassinosteroids. Several auxin responsive genes, including the ortholog of Arabidopsis thaliana Auxin Response Factor 16, were induced at infection sites and in nodule primordia, and mutation of ARF16a reduced rhizobial infection. Associated with the induction of auxin signaling genes, there was increased expression of cell cycle genes including an A-type cyclin and a subunit of the anaphase promoting complex. There was also induction of several chalcone O-methyltransferases involved in the synthesis of an inducer of Sinorhizobium meliloti nod genes, as well as a gene associated with Nod factor degradation, suggesting both positive and negative feedback loops that control Nod factor levels during rhizobial infection. We conclude that the onset of infection is associated with reactivation of the cell cycle as well as increased expression of genes required for hormone and flavonoid biosynthesis and that the regulation of auxin signaling is necessary for initiation of rhizobial infection threads.
Collapse
Affiliation(s)
- Andrew Breakspear
- Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Chengwu Liu
- Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Sonali Roy
- Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Nicola Stacey
- Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Christian Rogers
- Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Martin Trick
- Computational and Systems Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Giulia Morieri
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Kirankumar S Mysore
- Division of Plant Biology, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Jiangqi Wen
- Division of Plant Biology, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Giles E D Oldroyd
- Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - J Allan Downie
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Jeremy D Murray
- Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| |
Collapse
|
125
|
Shen C, Yue R, Yang Y, Zhang L, Sun T, Tie S, Wang H. OsARF16 is involved in cytokinin-mediated inhibition of phosphate transport and phosphate signaling in rice (Oryza sativa L.). PLoS One 2014; 9:e112906. [PMID: 25386911 PMCID: PMC4227850 DOI: 10.1371/journal.pone.0112906] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/16/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Plant responses to phytohormone stimuli are the most important biological features for plants to survive in a complex environment. Cytokinin regulates growth and nutrient homeostasis, such as the phosphate (Pi) starvation response and Pi uptake in plants. However, the mechanisms underlying how cytokinin participates in Pi uptake and Pi signaling are largely unknown. In this study, we found that OsARF16 is required for the cytokinin response and is involved in the negative regulation of Pi uptake and Pi signaling by cytokinin. PRINCIPAL FINDINGS The mutant osarf16 showed an obvious resistance to exogenous cytokinin treatment and the expression level of the OsARF16 gene was considerably up-regulated by cytokinin. Cytokinin (6-BA) application suppressed Pi uptake and the Pi starvation response in wild-type Nipponbare (NIP) and all these responses were compromised in the osarf16 mutant. Our data showed that cytokinin inhibits the transport of Pi from the roots to the shoots and that OsARF16 is involved in this process. The Pi content in the osarf16 mutant was much higher than in NIP under 6-BA treatment. The expressions of PHOSPHATE TRANSPORTER1 (PHT1) genes, phosphate (Pi) starvation-induced (PSI) genes and purple PAPase genes were higher in the osarf16 mutant than in NIP under cytokinin treatment. CONCLUSION Our results revealed a new biological function for OsARF16 in the cytokinin-mediated inhibition of Pi uptake and Pi signaling in rice.
Collapse
Affiliation(s)
- Chenjia Shen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
- * E-mail: (CS); (ST); (HW)
| | - Runqing Yue
- Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Yanjun Yang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Lei Zhang
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, United States of America
| | - Tao Sun
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Shuanggui Tie
- Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- * E-mail: (CS); (ST); (HW)
| | - Huizhong Wang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
- * E-mail: (CS); (ST); (HW)
| |
Collapse
|
126
|
Ckurshumova W, Smirnova T, Marcos D, Zayed Y, Berleth T. Irrepressible MONOPTEROS/ARF5 promotes de novo shoot formation. THE NEW PHYTOLOGIST 2014; 204:556-566. [PMID: 25274430 DOI: 10.1111/nph.13014] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 07/09/2014] [Indexed: 05/29/2023]
Abstract
In vitro regeneration of complete organisms from diverse cell types is a spectacular property of plant cells. Despite the great importance of plant regeneration for plant breeding and biotechnology, its molecular basis is still largely unclear and many important crop plants have remained recalcitrant to regeneration. Hormone-exposure protocols to trigger the de novo formation of either roots or shoots from callus tissue demonstrate the importance of auxin and cytokinin signaling pathways, and genetic differences in these pathways may contribute to the highly divergent responsiveness of plant species to regeneration protocols. In this study, we show that signaling through MONOPTEROS (MP)/AUXIN RESPONSE FACTOR 5 is necessary for the formation of shoots from Arabidopsis calli. Most strikingly, an irrepressible variant of MP, MPΔ, is sufficient for promoting de novo shoot formation through pathways involving the genetically downstream functions of SHOOT MERISTEMLESS (STM) and CYTOKININ RESPONSE FACTOR2 (CRF2). We conclude that the MPΔ genotype can promote de novo shoot formation and can be used to probe corresponding signaling pathways.
Collapse
Affiliation(s)
- Wenzislava Ckurshumova
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Tatiana Smirnova
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Danielle Marcos
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Yara Zayed
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Thomas Berleth
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| |
Collapse
|
127
|
Atkinson JA, Rasmussen A, Traini R, Voß U, Sturrock C, Mooney SJ, Wells DM, Bennett MJ. Branching out in roots: uncovering form, function, and regulation. PLANT PHYSIOLOGY 2014; 166:538-50. [PMID: 25136060 PMCID: PMC4213086 DOI: 10.1104/pp.114.245423] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/12/2013] [Indexed: 05/18/2023]
Abstract
Root branching is critical for plants to secure anchorage and ensure the supply of water, minerals, and nutrients. To date, research on root branching has focused on lateral root development in young seedlings. However, many other programs of postembryonic root organogenesis exist in angiosperms. In cereal crops, the majority of the mature root system is composed of several classes of adventitious roots that include crown roots and brace roots. In this Update, we initially describe the diversity of postembryonic root forms. Next, we review recent advances in our understanding of the genes, signals, and mechanisms regulating lateral root and adventitious root branching in the plant models Arabidopsis (Arabidopsis thaliana), maize (Zea mays), and rice (Oryza sativa). While many common signals, regulatory components, and mechanisms have been identified that control the initiation, morphogenesis, and emergence of new lateral and adventitious root organs, much more remains to be done. We conclude by discussing the challenges and opportunities facing root branching research.
Collapse
Affiliation(s)
- Jonathan A Atkinson
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Amanda Rasmussen
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Richard Traini
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Ute Voß
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Craig Sturrock
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Sacha J Mooney
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Darren M Wells
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Malcolm J Bennett
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| |
Collapse
|
128
|
Talboys PJ, Healey JR, Withers PJA, Jones DL. Phosphate depletion modulates auxin transport in Triticum aestivum leading to altered root branching. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5023-32. [PMID: 25086590 PMCID: PMC4144783 DOI: 10.1093/jxb/eru284] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Understanding the mechanisms by which nutritional signals impact upon root system architecture is a key facet in the drive for greater nutrient application efficiency in agricultural systems. Cereal plants reduce their rate of lateral root emergence under inorganic phosphate (Pi) shortage; this study uses molecular and pharmacological techniques to dissect this Pi response in Triticum aestivum. Plants were grown in coarse sand washed in high- or low-Pi nutrient solution before being assessed for their root branching density and expression of AUX/IAA and PIN genes. Seedlings were also grown on media containing [(14)C]indole acetic acid to measure basipetal auxin transport. Seedlings grown in low-Pi environments displayed less capacity to transport auxin basipetally from the seminal root apex, a reduction in root expression of PIN auxin transporter genes, and perturbed expression of a range of AUX/IAA auxin response genes. Given the known importance of basipetally transported auxin in stimulating lateral root initiation, it is proposed here that, in T. aestivum, Pi availability directly influences lateral root production through modulation of PIN expression. Understanding such processes is important in the drive for greater efficiency in crop use of Pi fertilizers in agricultural settings.
Collapse
Affiliation(s)
- Peter J Talboys
- School of Environment, Natural Resources and Geography, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
| | - John R Healey
- School of Environment, Natural Resources and Geography, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
| | - Paul J A Withers
- School of Environment, Natural Resources and Geography, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
| | - Davey L Jones
- School of Environment, Natural Resources and Geography, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
| |
Collapse
|
129
|
Tian H, De Smet I, Ding Z. Shaping a root system: regulating lateral versus primary root growth. TRENDS IN PLANT SCIENCE 2014; 19:426-31. [PMID: 24513255 DOI: 10.1016/j.tplants.2014.01.007] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 01/04/2014] [Accepted: 01/14/2014] [Indexed: 05/22/2023]
Abstract
Primary and lateral roots comprise root systems, which are vital to the growth and survival of plants. Several molecular mechanisms associated with primary and lateral root growth have been described, including some common regulatory factors for their initiation and development. However, in this opinion article, we discuss the distinct growth behavior of lateral roots in response to environmental cues, such as salinity, gravity, and nutrient availability, which are mediated via specific regulators. We propose that differential growth dynamics between primary and lateral roots are crucial for plants to adapt to the ever-changing environmental conditions.
Collapse
Affiliation(s)
- Huiyu Tian
- The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan, Shandong 250100, PR China
| | - Ive De Smet
- Department of Plant Systems Biology, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium; Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
| | - Zhaojun Ding
- The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan, Shandong 250100, PR China.
| |
Collapse
|
130
|
Abstract
Auxin influences nearly every aspect of plant biology through a simple signaling pathway; however, it remains unclear how much of the diversity in auxin effects is explained by variation in the core signaling components and which properties of these components may contribute to diversification in response dynamics. Here, we recapitulated the entire Arabidopsis thaliana forward nuclear auxin signal transduction pathway in Saccharomyces cerevisiae to test whether signaling module composition enables tuning of the dynamic response. Sensitivity analysis guided by a small mathematical model revealed the centrality of auxin/indole-3-acetic acid (Aux/IAA) transcriptional corepressors in controlling response dynamics and highlighted the strong influence of natural variation in Aux/IAA degradation rates on circuit performance. When the basic auxin response circuit was expanded to include multiple Aux/IAAs, we found that dominance relationships between coexpressed Aux/IAAs were sufficient to generate distinct response modules similar to those seen during plant development. Our work provides a new method for dissecting auxin signaling and demonstrates the key role of Aux/IAAs in tuning auxin response dynamics.
Collapse
|
131
|
Kajala K, Ramakrishna P, Fisher A, C. Bergmann D, De Smet I, Sozzani R, Weijers D, Brady SM. Omics and modelling approaches for understanding regulation of asymmetric cell divisions in arabidopsis and other angiosperm plants. ANNALS OF BOTANY 2014; 113:1083-1105. [PMID: 24825294 PMCID: PMC4030820 DOI: 10.1093/aob/mcu065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/06/2014] [Indexed: 05/23/2023]
Abstract
BACKGROUND Asymmetric cell divisions are formative divisions that generate daughter cells of distinct identity. These divisions are coordinated by either extrinsic ('niche-controlled') or intrinsic regulatory mechanisms and are fundamentally important in plant development. SCOPE This review describes how asymmetric cell divisions are regulated during development and in different cell types in both the root and the shoot of plants. It further highlights ways in which omics and modelling approaches have been used to elucidate these regulatory mechanisms. For example, the regulation of embryonic asymmetric divisions is described, including the first divisions of the zygote, formative vascular divisions and divisions that give rise to the root stem cell niche. Asymmetric divisions of the root cortex endodermis initial, pericycle cells that give rise to the lateral root primordium, procambium, cambium and stomatal cells are also discussed. Finally, a perspective is provided regarding the role of other hormones or regulatory molecules in asymmetric divisions, the presence of segregated determinants and the usefulness of modelling approaches in understanding network dynamics within these very special cells. CONCLUSIONS Asymmetric cell divisions define plant development. High-throughput genomic and modelling approaches can elucidate their regulation, which in turn could enable the engineering of plant traits such as stomatal density, lateral root development and wood formation.
Collapse
Affiliation(s)
- Kaisa Kajala
- Department of Plant Biology and Genome Center, UC Davis, Davis, CA 95616, USA
| | - Priya Ramakrishna
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
| | - Adam Fisher
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Dominique C. Bergmann
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Ive De Smet
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium
| | - Rosangela Sozzani
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703HA Wageningen, The Netherlands
| | - Siobhan M. Brady
- Department of Plant Biology and Genome Center, UC Davis, Davis, CA 95616, USA
| |
Collapse
|
132
|
Ohashi-Ito K, Fukuda H. Initiation of vascular development. PHYSIOLOGIA PLANTARUM 2014; 151:142-146. [PMID: 24111590 DOI: 10.1111/ppl.12111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 09/06/2013] [Accepted: 09/22/2013] [Indexed: 06/02/2023]
Abstract
The initiation of vascular development occurs during embryogenesis and the development of lateral organs, such as lateral roots and leaves. Understanding the mechanism underlying the initiation of vascular development has been an important goal of plant biologists. Auxin flow is a crucial factor involved in the initiation of vascular development. In addition, recent studies have identified key factors that regulate the establishment of vascular initial cells in embryos and roots. In this review, we summarize the recent findings in this field and discuss the initiation of vascular development.
Collapse
Affiliation(s)
- Kyoko Ohashi-Ito
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | | |
Collapse
|
133
|
Stauffer E, Maizel A. Post-transcriptional regulation in root development. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:679-96. [PMID: 24827552 DOI: 10.1002/wrna.1239] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 03/20/2014] [Accepted: 03/26/2014] [Indexed: 11/08/2022]
Abstract
Plants constantly adapt their root system to the changing environmental conditions. This developmental plasticity is underpinned by changes in the profile of the mRNA expressed. Here we review how post-transcriptional modulation of gene expression control root development and growth. In particular we focus on the role of small RNA-mediated post-transcriptional regulation processes. Small RNAs play an important role in fine tuning gene expression during root formation and patterning, development of lateral organs and symbiosis, nutrient homeostasis, and other stress-related responses. We also highlight the impact of alternative splicing on root development and the establishment of symbiotic structures as well as the emerging role of long noncoding RNAs in root physiology.
Collapse
Affiliation(s)
- Eva Stauffer
- Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | | |
Collapse
|
134
|
Tian H, Jia Y, Niu T, Yu Q, Ding Z. The key players of the primary root growth and development also function in lateral roots in Arabidopsis. PLANT CELL REPORTS 2014; 33:745-53. [PMID: 24504658 DOI: 10.1007/s00299-014-1575-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/25/2013] [Accepted: 01/20/2014] [Indexed: 05/04/2023]
Abstract
The core regulators which are required for primary root growth and development also function in lateral root development or lateral root stem cell niche maintenance. The primary root systems and the lateral root systems are the two important root systems which are vital to the survival of plants. Though the molecular mechanism of the growth and development of both the primary root systems and the lateral root systems have been extensively studied individually in Arabidopsis, there are not so much evidence to show that if both root systems share common regulatory mechanisms. AP2 family transcription factors such as PLT1 (PLETHORA1) and PLT2, GRAS family transcription factors such as SCR (SCARECROW) and SHR (SHORT ROOT) and WUSCHEL-RELATED HOMEOBOX transcription factor WOX5 have been extensively studied and found to be essential for primary root growth and development. In this study, through the expression pattern analysis and mutant examinations, we found that these core regulators also function in lateral root development or lateral root stem cell niche maintenance.
Collapse
Affiliation(s)
- Huiyu Tian
- The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan, People's Republic of China
| | | | | | | | | |
Collapse
|
135
|
Abstract
Auxin signaling through the SCF(TIR1)-Aux/IAA-ARF pathway is one of the best-studied plant hormone response pathways. Components of this pathway, from receptors through to transcription factors, have been identified and analyzed in detail. Although we understand elementary aspects of how the auxin signal is perceived and leads to a transcriptional response, many questions remain about the in vivo function of the pathway. Two crucial issues are the tissue specificity of the response, i.e. how distinct cell types can interpret the same auxin signal differently, and the response to a signaling gradient, i.e. how a graded distribution of auxin can elicit distinct expression patterns along its range. Here, we speculate on how signaling through the canonical SCF(TIR1)-Aux/IAA-ARF pathway may achieve divergent responses.
Collapse
|
136
|
Wang WS, Zhu J, Lu YT. Overexpression of AtbHLH112 suppresses lateral root emergence in Arabidopsis. FUNCTIONAL PLANT BIOLOGY : FPB 2014; 41:342-352. [PMID: 32480995 DOI: 10.1071/fp13253] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 10/14/2013] [Indexed: 06/11/2023]
Abstract
The basic/helix-loop-helix (bHLH) transcription factors are ubiquitous transcriptional regulators that control many different developmental and physiological processes in the eukaryotic kingdom. In this study, the function of AtbHLH112, an uncharacterised member of the bHLH family in Arabidopsis was investigated. Overexpression of AtbHLH112 suppressed lateral root (LR) development in Arabidopsis seedlings. Examination under the microscope revealed that abnormal lateral root primordia (LRP) with flat-head and more than four cell layers retained in the endodermal layer account for over 45% of the total number of LRP and LRs. This suggests that LRP emergence was prevented before LRP penetrated the cortical layer in the transgenic lines. Decreased auxin level within the LRP and parental root cells surrounding the LRP, as well as downregulated expression of cell-wall-remodelling (CWR) genes in the roots may contribute to the suppression of LR emergence in AtbHLH112-overexpressing lines. This finding was further supported by the observation that exogenous application of auxin recovered LR development and upregulated the expression of CWR genes in AtbHLH112-overexpressing lines.
Collapse
Affiliation(s)
- Wen-Shu Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jiang Zhu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ying-Tang Lu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| |
Collapse
|
137
|
Cucinotta M, Colombo L, Roig-Villanova I. Ovule development, a new model for lateral organ formation. FRONTIERS IN PLANT SCIENCE 2014; 5:117. [PMID: 24723934 PMCID: PMC3973900 DOI: 10.3389/fpls.2014.00117] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 03/11/2014] [Indexed: 05/18/2023]
Abstract
In spermatophytes the ovules upon fertilization give rise to the seeds. It is essential to understand the mechanisms that control ovule number and development as they ultimately determine the final number of seeds and, thereby, the yield in crop plants. In Arabidopsis thaliana, ovules arise laterally from a meristematic tissue within the carpel referred to as placenta. For a correct determination of the number of ovules, a precise establishment of the positions where ovule primordia emerge is needed, and a tight definition of the boundaries between ovules is therefore also required. In the last decades, few factors have been identified to be involved in the determination of ovule number. Recently, plant hormones have also been revealed as fundamental players in the control of the initiation of ovule formation. In this review we summarize the current knowledge about both the molecular and hormonal mechanisms that control ovule formation in Arabidopsis thaliana.
Collapse
|
138
|
Fang T, Cao Z, Li J, Shen W, Huang L. Auxin-induced hydrogen sulfide generation is involved in lateral root formation in tomato. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 76:44-51. [PMID: 24463534 DOI: 10.1016/j.plaphy.2013.12.024] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 12/30/2013] [Indexed: 05/21/2023]
Abstract
Similar to auxin, hydrogen sulfide (H2S), mainly produced by l-cysteine desulfhydrase (DES; EC 4.4.1.1) in plants, could induce lateral root formation. The objective of this study was to test whether H2S is also involved in auxin-induced lateral root development in tomato (Solanum lycopersicum L.) seedlings. We observed that auxin depletion-induced down-regulation of transcripts of SlDES1, decreased DES activity and endogenous H2S contents, and the inhibition of lateral root formation were rescued by sodium hydrosulfide (NaHS, an H2S donor). However, No additive effects were observed when naphthalene acetic acid (NAA) was co-treated with NaHS (lower than 10 mM) in the induction of lateral root formation. Subsequent work revealed that a treatment with NAA or NaHS could simultaneously induce transcripts of SlDES1, DES activity and endogenous H2S contents, and thereafter the stimulation of lateral root formation. It was further confirmed that H2S or HS(-), not the other sulfur-containing components derived from NaHS, was attributed to the stimulative action. The inhibition of lateral root formation and decreased of H2S metabolism caused by an H2S scavenger hypotaurine (HT) were reversed by NaHS, but not NAA. Molecular evidence revealed that both NaHS- or NAA-induced modulation of some cell cycle regulatory genes, including the up-regulation of SlCDKA;1, SlCYCA2;1, together with simultaneous down-regulation of SlKRP2, were differentially reversed by HT pretreatment. To summarize, above results clearly suggested that H2S might, at least partially, act as a downstream component of auxin signaling to trigger lateral root formation.
Collapse
Affiliation(s)
- Tao Fang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Zeyu Cao
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Jiale Li
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Wenbiao Shen
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Liqin Huang
- College of Sciences, Nanjing Agricultural University, Nanjing 210095, China.
| |
Collapse
|
139
|
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]
|
140
|
Clark NM, de Luis Balaguer MA, Sozzani R. Experimental data and computational modeling link auxin gradient and development in the Arabidopsis root. FRONTIERS IN PLANT SCIENCE 2014; 5:328. [PMID: 25071810 PMCID: PMC4083358 DOI: 10.3389/fpls.2014.00328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/23/2014] [Indexed: 05/04/2023]
Abstract
The presence of an auxin gradient in the Arabidopsis root is crucial for proper root development and importantly, for stem cell niche (SCN) maintenance. Subsequently, developmental pathways in the root SCN regulate the formation of the auxin gradient. Combinations of experimental data and computational modeling enable the identification of pathways involved in establishing and maintaining the auxin gradient. We describe how the predictive power of these computational models is used to find how genes and their interactions tightly control the formation of an auxin maximum in the SCN. In addition, we highlight known connections between signaling pathways involving auxin and controlling patterning and development in Arabidopsis.
Collapse
Affiliation(s)
| | | | - Rosangela Sozzani
- *Correspondence: Rosangela Sozzani, Department of Plant and Microbial Biology, North Carolina State University, 2577 Thomas Hall, P. O. Box 7612, Raleigh, NC 27695, USA e-mail:
| |
Collapse
|
141
|
Perianez-Rodriguez J, Manzano C, Moreno-Risueno MA. Post-embryonic organogenesis and plant regeneration from tissues: two sides of the same coin? FRONTIERS IN PLANT SCIENCE 2014; 5:219. [PMID: 24904615 PMCID: PMC4033269 DOI: 10.3389/fpls.2014.00219] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 05/02/2014] [Indexed: 05/22/2023]
Abstract
Plants have extraordinary developmental plasticity as they continuously form organs during post-embryonic development. In addition they may regenerate organs upon in vitro hormonal induction. Advances in the field of plant regeneration show that the first steps of de novo organogenesis through in vitro culture in hormone containing media (via formation of a proliferating mass of cells or callus) require root post-embryonic developmental programs as well as regulators of auxin and cytokinin signaling pathways. We review how hormonal regulation is delivered during lateral root initiation and callus formation. Implications in reprograming, cell fate and pluripotency acquisition are discussed. Finally, we analyze the function of cell cycle regulators and connections with epigenetic regulation. Future work dissecting plant organogenesis driven by both endogenous and exogenous cues (upon hormonal induction) may reveal new paradigms of common regulation.
Collapse
Affiliation(s)
| | | | - Miguel A. Moreno-Risueno
- *Correspondence: Miguel A. Moreno-Risueno, Department of Biotechnology, Center for Plant Genomics and Biotechnology, Universidad Politecnica de Madrid, Parque Cientïfico y Tecnológico de la U.P.M., Campus de Montegancedo, C/M-40 km 38 s/n, 28223 Madrid, Spain e-mail:
| |
Collapse
|
142
|
Cho H, Ryu H, Rho S, Hill K, Smith S, Audenaert D, Park J, Han S, Beeckman T, Bennett MJ, Hwang D, De Smet I, Hwang I. A secreted peptide acts on BIN2-mediated phosphorylation of ARFs to potentiate auxin response during lateral root development. Nat Cell Biol 2013; 16:66-76. [DOI: 10.1038/ncb2893] [Citation(s) in RCA: 212] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 11/11/2013] [Indexed: 01/01/2023]
|
143
|
Van Norman JM, Xuan W, Beeckman T, Benfey PN. To branch or not to branch: the role of pre-patterning in lateral root formation. Development 2013; 140:4301-10. [PMID: 24130327 DOI: 10.1242/dev.090548] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The establishment of a pre-pattern or competence to form new organs is a key feature of the postembryonic plasticity of plant development, and the elaboration of such pre-patterns leads to remarkable heterogeneity in plant form. In root systems, many of the differences in architecture can be directly attributed to the outgrowth of lateral roots. In recent years, efforts have focused on understanding how the pattern of lateral roots is established. Here, we review recent findings that point to a periodic mechanism for establishing this pattern, as well as roles for plant hormones, particularly auxin, in the earliest steps leading up to lateral root primordium development. In addition, we compare the development of lateral root primordia with in vitro plant regeneration and discuss possible common molecular mechanisms.
Collapse
Affiliation(s)
- Jaimie M Van Norman
- Department of Biology, Duke Center for Systems Biology and Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA
| | | | | | | |
Collapse
|
144
|
Szymanowska-Pułka J. Form matters: morphological aspects of lateral root development. ANNALS OF BOTANY 2013; 112:1643-54. [PMID: 24190952 PMCID: PMC3838556 DOI: 10.1093/aob/mct231] [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] [Received: 06/09/2013] [Accepted: 08/13/2013] [Indexed: 05/06/2023]
Abstract
BACKGROUND The crucial role of roots in plant nutrition, and consequently in plant productivity, is a strong motivation to study the growth and functioning of various aspects of the root system. Numerous studies on lateral roots, as a major determinant of the root system architecture, mostly focus on the physiological and molecular bases of developmental processes. Unfortunately, little attention is paid either to the morphological changes accompanying the formation of a lateral root or to morphological defects occurring in lateral root primordia. The latter are observed in some mutants and occasionally in wild-type plants, but may also result from application of external factors. SCOPE AND CONCLUSIONS In this review various morphological aspects of lateral branching in roots are analysed. Morphological events occurring during the formation of a typical lateral root are described. This process involves dramatic changes in the geometry of the developing organ that at early stages are associated with oblique cell divisions, leading to breaking of the symmetry of the cell pattern. Several types of defects in the morphology of primordia are indicated and described. Computer simulations show that some of these defects may result from an unstable field of growth rates. Significant changes in both primary and lateral root morphology may also be a consequence of various mutations, some of which are auxin-related. Examples reported in the literature are considered. Finally, lateral root formation is discussed in terms of mechanics. In this approach the primordium is considered as a physical object undergoing deformation and is characterized by specific mechanical properties.
Collapse
|
145
|
Kyndt T, Vieira P, Gheysen G, de Almeida-Engler J. Nematode feeding sites: unique organs in plant roots. PLANTA 2013; 238:807-18. [PMID: 23824525 DOI: 10.1007/s00425-013-1923-z] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/13/2013] [Indexed: 05/19/2023]
Abstract
Although generally unnoticed, nearly all crop plants have one or more species of nematodes that feed on their roots, frequently causing tremendous yield losses. The group of sedentary nematodes, which are among the most damaging plant-parasitic nematodes, cause the formation of special organs called nematode feeding sites (NFS) in the root tissue. In this review we discuss key metabolic and cellular changes correlated with NFS development, and similarities and discrepancies between different types of NFS are highlighted.
Collapse
Affiliation(s)
- Tina Kyndt
- Department Molecular Biotechnology, Ghent University (UGent), Coupure Links 653, 9000, Ghent, Belgium,
| | | | | | | |
Collapse
|
146
|
Chang L, Ramireddy E, Schmülling T. Lateral root formation and growth of Arabidopsis is redundantly regulated by cytokinin metabolism and signalling genes. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:5021-32. [PMID: 24023250 PMCID: PMC3830484 DOI: 10.1093/jxb/ert291] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The plant root system is important for the uptake of water and nutrients and the anchoring of plants in the soil. Lateral roots (LRs) contribute considerably to root system architecture. Their post-embryonic formation is regulated by hormones and environmental cues. The hormone cytokinin influences LR formation and growth in Arabidopsis thaliana on different levels by disturbing cell division activity and pattern formation. This includes inhibition of the first formative cell division of pericycle founder cells and inhibition of the outgrowth of young LR primordia. Mutant analysis revealed that the cytokinin biosynthesis genes IPT3 and IPT5 and all three cytokinin receptor genes (AHK2, AHK3, and CRE1/AHK4) act redundantly during LR initiation. Mutation of AHK2 and AHK3 caused increased auxin sensitivity of LR formation, corroborating the functional relevance of auxin-cytokinin interaction during LR formation. In contrast, LR development of cytokinin receptor mutants in response to other hormones was mostly similar to that of the wild type, which is consistent with separate response pathways. A noticeable exception was an increased sensitivity of LR elongation to brassinolide in ahk2 ahk3 mutants indicating antagonistic action of cytokinin and brassinosteroid. It is proposed that the multilevel redundancy of the cytokinin system in modulating LR formation reflects its role in mediating environmental cues.
Collapse
|
147
|
Lee HW, Kim J. EXPANSINA17 up-regulated by LBD18/ASL20 promotes lateral root formation during the auxin response. PLANT & CELL PHYSIOLOGY 2013; 54:1600-11. [PMID: 23872272 DOI: 10.1093/pcp/pct105] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Expansins are non-hydrolytic cell wall-loosening proteins involved in a variety of plant developmental processes during which cell wall modification occurs. Cell wall remodeling proteins including expansins have been suggested to be involved in cell separation to facilitate the emergence of lateral roots (LRs) through the overlaying tissues of the primary root. LBD18/ASL20 activates EXPANSINA14 (EXPA14) expression by directly binding to the EXPA14 promoter to enhance LR emergence in Arabidopsis thaliana. Here we show that EXPA17 is another target gene regulated by LBD18 to promote LR formation in Arabidopsis. We showed that nuclear translocation of the LBD18:GR fusion protein expressed under the Cauliflower mosaic virus (CaMV) 35S promoter or under the LBD18 promoter by dexamethasone treatment results in an increase in EXPA17 transcript levels. β-Glucuronidase (GUS) expression under the EXPA17 promoter, which is detected only in the roots of the wild type, was reduced in the LR primordium and overlaying tissues in an lbd18 mutant background. The number of emerged LRs of the EXPA17 RNAi (RNA interference) Arabidopsis lines was significantly lower than that of the wild type. Overexpression of EXPA17 in Arabidopsis increased the density of emerged LRs in the presence of auxin compared with the wild type. LR induction experiments with a gravitropic stimulus showed that LR emergence is delayed in the EXPA17 RNAi plants compared with the wild type. In addition, EXPA4 expression was also detected in overlaying tissues of the LR primordium and was inducible by LBD18. Taken together, these results support the notion that LBD18 up-regulates a subset of EXP genes to enhance cell separation to promote LR emergence in Arabidopsis.
Collapse
Affiliation(s)
- Han Woo Lee
- Department of Bioenergy Science and Technology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 500-757, Korea
| | | |
Collapse
|
148
|
Kim MH, Kim Y, Kim JW, Lee HS, Lee WS, Kim SK, Wang ZY, Kim SH. Identification of Arabidopsis BAK1-associating receptor-like kinase 1 (BARK1) and characterization of its gene expression and brassinosteroid-regulated root phenotypes. PLANT & CELL PHYSIOLOGY 2013; 54:1620-34. [PMID: 23921992 DOI: 10.1093/pcp/pct106] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Brassinosteroids (BRs) activate the BRI1 and BAK1/SERK3 membrane receptor complex, which leads to a wide range of changes in gene expression, plant growth and development. As an initial step to elucidate additional roles of BAK1, we cloned a BAK1-binding protein, BAK1-Associating Receptor-Like Kinase 1 (BARK1), and characterized its gene expression and root phenotypes. BARK1 is a putative membrane LRR-RLK (leucine-rich repeat receptor-like kinase) protein that specifically binds to BAK1 and its homologs. Careful examination of BARK1 expression using transgenic plants expressing a green fluorescent protein (GFP) reporter under the control of the native BARK1 promoter (BARK1p::GFP) revealed that this gene is ubiquitously expressed in most plant tissues, and shows especially strong expression in the xylem vasculature of primary and lateral roots as well as in mature pollen. Interestingly, the expression of the BARK1 gene was increased in the BR biosynthetic loss-of-function mutant, det2, and a loss-of-function mutant of BR signaling, bak1-3. In contrast, this gene was down-regulated in the bzr1-1D plant, which is a BR signal gain-of-function mutant. BARK1-overexpressing transgenic plants clearly enhanced primary root growth in a dose-dependent manner, and their roots were hypersensitive to BR-induced root growth inhibition. In addition, both the number and density of lateral roots were dramatically increased in the BARK1 transgenic plants in a dose-dependent manner. Together with observations that ARF (AUXIN RESPONSE FACTOR) genes are up-regulated in the BARK1 overexpressor, we suggest that the BARK1 overexpressor phenotype with more lateral roots is partly due to the increased expression of ARF genes in this genetic background. In conclusion, BAK1-interacting BARK1 protein may be involved in BR-mediated plant growth and development such as in lateral roots via auxin regulation.
Collapse
Affiliation(s)
- Min Hee Kim
- Division of Biological Science and Technology, Yonsei University, Wonju, 220-710, Korea
| | | | | | | | | | | | | | | |
Collapse
|
149
|
Lavenus J, Goh T, Roberts I, Guyomarc'h S, Lucas M, De Smet I, Fukaki H, Beeckman T, Bennett M, Laplaze L. Lateral root development in Arabidopsis: fifty shades of auxin. TRENDS IN PLANT SCIENCE 2013; 18:450-8. [PMID: 23701908 DOI: 10.1016/j.tplants.2013.04.006] [Citation(s) in RCA: 376] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 04/08/2013] [Accepted: 04/15/2013] [Indexed: 05/18/2023]
Abstract
The developmental plasticity of the root system represents a key adaptive trait enabling plants to cope with abiotic stresses such as drought and is therefore important in the current context of global changes. Root branching through lateral root formation is an important component of the adaptability of the root system to its environment. Our understanding of the mechanisms controlling lateral root development has progressed tremendously in recent years through research in the model plant Arabidopsis thaliana (Arabidopsis). These studies have revealed that the phytohormone auxin acts as a common integrator to many endogenous and environmental signals regulating lateral root formation. Here, we review what has been learnt about the myriad roles of auxin during lateral root formation in Arabidopsis.
Collapse
Affiliation(s)
- Julien Lavenus
- Institut de Recherche pour le Développement (IRD), UMR DIADE (IRD/UM2), 911 Avenue Agropolis, 34394 Montpellier cedex 5, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
150
|
Poupin MJ, Timmermann T, Vega A, Zuñiga A, González B. Effects of the plant growth-promoting bacterium Burkholderia phytofirmans PsJN throughout the life cycle of Arabidopsis thaliana. PLoS One 2013; 8:e69435. [PMID: 23869243 PMCID: PMC3711820 DOI: 10.1371/journal.pone.0069435] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Accepted: 06/07/2013] [Indexed: 12/31/2022] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) induce positive effects in plants, such as increased growth or reduced stress susceptibility. The mechanisms behind PGPR/plant interaction are poorly understood, as most studies have described short-term responses on plants and only a few studies have analyzed plant molecular responses under PGPR colonization. Here, we studied the effects of the PGPR bacterial model Burkholderiaphytofirmans PsJN on the whole life cycle of Arabidopsis thaliana plants. We reported that at different plant developmental points, strain PsJN can be found in the rhizosphere and also colonizing their internal tissues. In early ontogeny, strain PsJN increased several growth parameters and accelerated growth rate of the plants. Also, an Arabidopsis transcriptome analysis revealed that 408 genes showed differential expression in PsJN-inoculated plants; some of these genes are involved in stress response and hormone pathways. Specifically, genes implicated in auxin and gibberellin pathways were induced. Quantitative transcriptional analyses of selected genes in different developmental stages revealed that the beginning of these changes could be evidenced early in development, especially among the down-regulated genes. The inoculation with heat-killed bacteria provoked a more severe transcriptional response in plants, but was not able to induce plant growth-promotion. Later in ontogeny, the growth rates of inoculated plants decreased with respect to the non-inoculated group and, interestingly, the inoculation accelerated the flowering time and the appearance of senescence signs in plants; these modifications correlate with the early up-regulation of flowering control genes. Then, we show that a single inoculation with a PGPR could affect the whole life cycle of a plant, accelerating its growth rate and shortening its vegetative period, both effects relevant for most crops. Thus, these findings provide novel and interesting aspects of these relevant biological interactions.
Collapse
Affiliation(s)
- María Josefina Poupin
- Laboratorio de Bioingeniería, Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Santiago, Chile.
| | | | | | | | | |
Collapse
|