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Velandia K, Correa-Lozano A, McGuiness PM, Reid JB, Foo E. Cell-layer specific roles for gibberellins in nodulation and root development. THE NEW PHYTOLOGIST 2024; 242:626-640. [PMID: 38396236 DOI: 10.1111/nph.19623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 02/01/2024] [Indexed: 02/25/2024]
Abstract
Gibberellins (GA) have a profound influence on the formation of lateral root organs. However, the precise role this hormone plays in the cell-specific events during lateral root formation, rhizobial infection and nodule organogenesis, including interactions with auxin and cytokinin (CK), is not clear. We performed epidermal- and endodermal-specific complementation of the severely GA-deficient na pea (Pisum sativum) mutant with Agrobacterium rhizogenes. Gibberellin mutants were used to examine the spatial expression pattern of CK (TCSn)- and auxin (DR5)-responsive promoters and hormone levels. We found that GA produced in the endodermis promote lateral root and nodule organogenesis and can induce a mobile signal(s) that suppresses rhizobial infection. By contrast, epidermal-derived GA suppress infection but have little influence on root or nodule development. GA suppress the CK-responsive TCSn promoter in the cortex and are required for normal auxin activation during nodule primordia formation. Our findings indicate that GA regulate the checkpoints between infection thread (IT) penetration of the cortex and invasion of nodule primordial cells and promote the subsequent progression of nodule development. It appears that GA limit the progression and branching of IT in the cortex by restricting CK response and activate auxin response to promote nodule primordia development.
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Affiliation(s)
- Karen Velandia
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Alejandro Correa-Lozano
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Peter M McGuiness
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - James B Reid
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Eloise Foo
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
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Velandia K, Reid JB, Foo E. Right time, right place: The dynamic role of hormones in rhizobial infection and nodulation of legumes. PLANT COMMUNICATIONS 2022; 3:100327. [PMID: 35605199 PMCID: PMC9482984 DOI: 10.1016/j.xplc.2022.100327] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 03/24/2022] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
Many legume plants form beneficial associations with rhizobial bacteria that are hosted in new plant root organs, nodules, in which atmospheric nitrogen is fixed. This association requires the precise coordination of two separate programs, infection in the epidermis and nodule organogenesis in the cortex. There is extensive literature indicating key roles for plant hormones during nodulation, but a detailed analysis of the spatial and temporal roles of plant hormones during the different stages of nodulation is required. This review analyses the current literature on hormone regulation of infection and organogenesis to reveal the differential roles and interactions of auxin, cytokinin, brassinosteroids, ethylene, and gibberellins during epidermal infection and cortical nodule initiation, development, and function. With the exception of auxin, all of these hormones suppress infection events. By contrast, there is evidence that all of these hormones promote nodule organogenesis, except ethylene, which suppresses nodule initiation. This differential role for many of the hormones between the epidermal and cortical programs is striking. Future work is required to fully examine hormone interactions and create a robust model that integrates this knowledge into our understanding of nodulation pathways.
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Affiliation(s)
- Karen Velandia
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia
| | - James B Reid
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia
| | - Eloise Foo
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia.
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3
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Van Dingenen J. From the archives: Polar auxin transport in nodule development, DNA replication timing, and developmentally light-regulated genes. THE PLANT CELL 2022; 34:3151-3153. [PMID: 35770820 PMCID: PMC9421473 DOI: 10.1093/plcell/koac175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
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4
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Gao Z, Chen Z, Cui Y, Ke M, Xu H, Xu Q, Chen J, Li Y, Huang L, Zhao H, Huang D, Mai S, Xu T, Liu X, Li S, Guan Y, Yang W, Friml J, Petrášek J, Zhang J, Chen X. GmPIN-dependent polar auxin transport is involved in soybean nodule development. THE PLANT CELL 2021; 33:2981-3003. [PMID: 34240197 PMCID: PMC8462816 DOI: 10.1093/plcell/koab183] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 07/01/2021] [Indexed: 05/27/2023]
Abstract
To overcome nitrogen deficiency, legume roots establish symbiotic interactions with nitrogen-fixing rhizobia that are fostered in specialized organs (nodules). Similar to other organs, nodule formation is determined by a local maximum of the phytohormone auxin at the primordium site. However, how auxin regulates nodule development remains poorly understood. Here, we found that in soybean, (Glycine max), dynamic auxin transport driven by PIN-FORMED (PIN) transporter GmPIN1 is involved in nodule primordium formation. GmPIN1 was specifically expressed in nodule primordium cells and GmPIN1 was polarly localized in these cells. Two nodulation regulators, (iso)flavonoids trigger expanded distribution of GmPIN1b to root cortical cells, and cytokinin rearranges GmPIN1b polarity. Gmpin1abc triple mutants generated with CRISPR-Cas9 showed the impaired establishment of auxin maxima in nodule meristems and aberrant divisions in the nodule primordium cells. Moreover, overexpression of GmPIN1 suppressed nodule primordium initiation. GmPIN9d, an ortholog of Arabidopsis thaliana PIN2, acts together with GmPIN1 later in nodule development to acropetally transport auxin in vascular bundles, fine-tuning the auxin supply for nodule enlargement. Our findings reveal how PIN-dependent auxin transport modulates different aspects of soybean nodule development and suggest that the establishment of auxin gradient is a prerequisite for the proper interaction between legumes and rhizobia.
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Affiliation(s)
- Zhen Gao
- College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Zhiwei Chen
- College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Yuanyuan Cui
- College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Meiyu Ke
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Huifang Xu
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Qinzhen Xu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiaomei Chen
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Yang Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Laimei Huang
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Hong Zhao
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Dingquan Huang
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Siyuan Mai
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Tao Xu
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Xiao Liu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shujia Li
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuefeng Guan
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Wenqiang Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiří Friml
- Institute of Science and Technology Austria (IST Austria), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Jan Petrášek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 43 Prague 2, Czech Republic
- The Czech Academy of Sciences, Institute of Experimental Botany, Rozvojová 263, 165 02 Prague 6, Czech Republic
| | - Jing Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xu Chen
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
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Shrestha A, Zhong S, Therrien J, Huebert T, Sato S, Mun T, Andersen SU, Stougaard J, Lepage A, Niebel A, Ross L, Szczyglowski K. Lotus japonicus Nuclear Factor YA1, a nodule emergence stage-specific regulator of auxin signalling. THE NEW PHYTOLOGIST 2021; 229:1535-1552. [PMID: 32978812 PMCID: PMC7984406 DOI: 10.1111/nph.16950] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/05/2020] [Indexed: 05/07/2023]
Abstract
Organogenesis of legume root nodules begins with the nodulation factor-dependent stimulation of compatible root cells to initiate divisions, signifying an early nodule primordium formation event. This is followed by cellular differentiation, including cell expansion and vascular bundle formation, and we previously showed that Lotus japonicus NF-YA1 is essential for this process, presumably by regulating three members of the SHORT INTERNODES/STYLISH (STY) transcription factor gene family. In this study, we used combined genetics, genomics and cell biology approaches to characterize the role of STY genes during root nodule formation and to test a hypothesis that they mediate nodule development by stimulating auxin signalling. We show here that L. japonicus STYs are required for nodule emergence. This is attributed to the NF-YA1-dependent regulatory cascade, comprising STY genes and their downstream targets, YUCCA1 and YUCCA11, involved in a local auxin biosynthesis at the post-initial cell division stage. An analogous NF-YA1/STY regulatory module seems to operate in Medicago truncatula in association with the indeterminate nodule patterning. Our data define L. japonicus and M. truncatula NF-YA1 genes as important nodule emergence stage-specific regulators of auxin signalling while indicating that the inductive stage and subsequent formation of early nodule primordia are mediated through an independent mechanism(s).
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Affiliation(s)
- Arina Shrestha
- Agriculture and Agri‐Food CanadaLondon Research and Development CentreLondonONN5V 4T3Canada
- Department of BiologyUniversity of Western OntarioLondonONN6A 5BFCanada
| | - Sihui Zhong
- Agriculture and Agri‐Food CanadaLondon Research and Development CentreLondonONN5V 4T3Canada
| | - Jasmine Therrien
- Agriculture and Agri‐Food CanadaLondon Research and Development CentreLondonONN5V 4T3Canada
- Department of BiologyUniversity of Western OntarioLondonONN6A 5BFCanada
| | - Terry Huebert
- Agriculture and Agri‐Food CanadaLondon Research and Development CentreLondonONN5V 4T3Canada
| | - Shusei Sato
- Graduate School of Life SciencesTohoku University2‐1‐1 KatahiraSendai980‐8577Japan
| | - Terry Mun
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDK‐8000Denmark
| | - Stig U. Andersen
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDK‐8000Denmark
| | - Jens Stougaard
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDK‐8000Denmark
| | - Agnes Lepage
- Laboratoire des Interactions Plantes‐Microorganismes (LIPM)Université de Toulouse, Institut National de la Recherche pour l’Agriculturel’Alimentation et l’Environnement (INRAE)Centre National de la Recherche Scientifique (CNRS)Castanet‐Tolosan31326France
| | - Andreas Niebel
- Laboratoire des Interactions Plantes‐Microorganismes (LIPM)Université de Toulouse, Institut National de la Recherche pour l’Agriculturel’Alimentation et l’Environnement (INRAE)Centre National de la Recherche Scientifique (CNRS)Castanet‐Tolosan31326France
| | - Loretta Ross
- Agriculture and Agri‐Food CanadaLondon Research and Development CentreLondonONN5V 4T3Canada
| | - Krzysztof Szczyglowski
- Agriculture and Agri‐Food CanadaLondon Research and Development CentreLondonONN5V 4T3Canada
- Department of BiologyUniversity of Western OntarioLondonONN6A 5BFCanada
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6
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Ng JLP, Welvaert A, Wen J, Chen R, Mathesius U. The Medicago truncatula PIN2 auxin transporter mediates basipetal auxin transport but is not necessary for nodulation. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1562-1573. [PMID: 31738415 DOI: 10.1093/jxb/erz510] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
The development of root nodules leads to an increased auxin response in early nodule primordia, which is mediated by changes in acropetal auxin transport in some legumes. Here, we investigated the role of root basipetal auxin transport during nodulation. Rhizobia inoculation significantly increased basipetal auxin transport in both Medicago truncatula and Lotus japonicus. In M. truncatula, this increase was dependent on functional Nod factor signalling through NFP, NIN, and NSP2, as well as ethylene signalling through SKL. To test whether increased basipetal auxin transport is required for nodulation, we examined a loss-of-function mutant of the M. truncatula PIN2 gene. The Mtpin2 mutant exhibited a reduction in basipetal auxin transport and an agravitropic phenotype. Inoculation of Mtpin2 roots with rhizobia still led to a moderate increase in basipetal auxin transport, but the mutant nodulated normally. No clear differences in auxin response were observed during nodule development. Interestingly, inoculation of wild-type roots increased lateral root numbers, whereas inoculation of Mtpin2 mutants resulted in reduced lateral root numbers compared with uninoculated roots. We conclude that the MtPIN2 auxin transporter is involved in basipetal auxin transport, that its function is not essential for nodulation, but that it plays an important role in the control of lateral root development.
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Affiliation(s)
- Jason L P Ng
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, Australia
| | - Astrid Welvaert
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, Australia
| | - Jiangqi Wen
- Noble Research Institute LLC, Ardmore, OK, USA
| | - Rujin Chen
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Ulrike Mathesius
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, Australia
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7
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Roy S, Liu W, Nandety RS, Crook A, Mysore KS, Pislariu CI, Frugoli J, Dickstein R, Udvardi MK. Celebrating 20 Years of Genetic Discoveries in Legume Nodulation and Symbiotic Nitrogen Fixation. THE PLANT CELL 2020; 32:15-41. [PMID: 31649123 PMCID: PMC6961631 DOI: 10.1105/tpc.19.00279] [Citation(s) in RCA: 312] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 09/17/2019] [Accepted: 10/24/2019] [Indexed: 05/13/2023]
Abstract
Since 1999, various forward- and reverse-genetic approaches have uncovered nearly 200 genes required for symbiotic nitrogen fixation (SNF) in legumes. These discoveries advanced our understanding of the evolution of SNF in plants and its relationship to other beneficial endosymbioses, signaling between plants and microbes, the control of microbial infection of plant cells, the control of plant cell division leading to nodule development, autoregulation of nodulation, intracellular accommodation of bacteria, nodule oxygen homeostasis, the control of bacteroid differentiation, metabolism and transport supporting symbiosis, and the control of nodule senescence. This review catalogs and contextualizes all of the plant genes currently known to be required for SNF in two model legume species, Medicago truncatula and Lotus japonicus, and two crop species, Glycine max (soybean) and Phaseolus vulgaris (common bean). We also briefly consider the future of SNF genetics in the era of pan-genomics and genome editing.
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Affiliation(s)
- Sonali Roy
- Noble Research Institute, Ardmore, Oklahoma 73401
| | - Wei Liu
- Noble Research Institute, Ardmore, Oklahoma 73401
| | | | - Ashley Crook
- College of Science, Clemson University, Clemson, South Carolina 29634
| | | | | | - Julia Frugoli
- College of Science, Clemson University, Clemson, South Carolina 29634
| | - Rebecca Dickstein
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton Texas 76203
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Sańko-Sawczenko I, Dmitruk D, Łotocka B, Różańska E, Czarnocka W. Expression Analysis of PIN Genes in Root Tips and Nodules of Lotus japonicus. Int J Mol Sci 2019; 20:E235. [PMID: 30634426 PMCID: PMC6359356 DOI: 10.3390/ijms20020235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 12/31/2018] [Accepted: 01/04/2019] [Indexed: 02/02/2023] Open
Abstract
Auxins are postulated to be one of the pivotal factors in nodulation. However, their transporters in Lotus japonicus, the model species for the study of the development of determinate-type root nodules, have been scarcely described so far, and thus their role in nodulation has remained unknown. Our research is the first focusing on polar auxin transporters in L. japonicus. We analyzed and compared expression of PINs in 20 days post rhizobial inoculation (dpi) and 54 dpi root nodules of L. japonicus by real-time quantitative polymerase chain reaction (qPCR) along with the histochemical β-glucuronidase (GUS) reporter gene assay in transgenic hairy roots. The results indicate that LjPINs are essential during root nodule development since they are predominantly expressed in the primordia and young, developing nodules. However, along with differentiation, expression levels of several PINs decreased and occurred particularly in the nodule vascular bundles, especially in connection with the root's stele. Moreover, our study demonstrated the importance of both polar auxin transport and auxin intracellular homeostasis during L. japonicus root nodule development and differentiation.
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Affiliation(s)
- Izabela Sańko-Sawczenko
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland.
| | - Dominika Dmitruk
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland.
| | - Barbara Łotocka
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland.
| | - Elżbieta Różańska
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland.
| | - Weronika Czarnocka
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland.
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Demina IV, Maity PJ, Nagchowdhury A, Ng JLP, van der Graaff E, Demchenko KN, Roitsch T, Mathesius U, Pawlowski K. Accumulation of and Response to Auxins in Roots and Nodules of the Actinorhizal Plant Datisca glomerata Compared to the Model Legume Medicago truncatula. FRONTIERS IN PLANT SCIENCE 2019; 10:1085. [PMID: 31608077 PMCID: PMC6773980 DOI: 10.3389/fpls.2019.01085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 08/09/2019] [Indexed: 05/13/2023]
Abstract
Actinorhizal nodules are structurally different from legume nodules and show a greater similarity to lateral roots. Because of the important role of auxins in lateral root and nodule formation, auxin profiles were examined in roots and nodules of the actinorhizal species Datisca glomerata and the model legume Medicago truncatula. The auxin response in roots and nodules of both species was analyzed in transgenic root systems expressing a beta-glucuronidase gene under control of the synthetic auxin-responsive promoter DR5. The effects of two different auxin on root development were compared for both species. The auxin present in nodules at the highest levels was phenylacetic acid (PAA). No differences were found between the concentrations of active auxins of roots vs. nodules, while levels of the auxin conjugate indole-3-acetic acid-alanine were increased in nodules compared to roots of both species. Because auxins typically act in concert with cytokinins, cytokinins were also quantified. Concentrations of cis-zeatin and some glycosylated cytokinins were dramatically increased in nodules compared to roots of D. glomerata, but not of M. truncatula. The ratio of active auxins to cytokinins remained similar in nodules compared to roots in both species. The auxin response, as shown by the activation of the DR5 promoter, seemed significantly reduced in nodules compared to roots of both species, suggesting the accumulation of auxins in cell types that do not express the signal transduction pathway leading to DR5 activation. Effects on root development were analyzed for the synthetic auxin naphthaleneacetic acid (NAA) and PAA, the dominant auxin in nodules. Both auxins had similar effects, except that the sensitivity of roots to PAA was lower than to NAA. However, while the effects of both auxins on primary root growth were similar for both species, effects on root branching were different: both auxins had the classical positive effect on root branching in M. truncatula, but a negative effect in D. glomerata. Such a negative effect of exogenous auxin on root branching has previously been found for a cucurbit that forms lateral root primordia in the meristem of the parental root; however, root branching in D. glomerata does not follow that pattern.
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Affiliation(s)
- Irina V. Demina
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Pooja Jha Maity
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Anurupa Nagchowdhury
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Jason L. P. Ng
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Eric van der Graaff
- Department of Plant Physiology, Karl-Franzens-Universität Graz, Graz, Austria
| | - Kirill N. Demchenko
- Laboratory of Cellular and Molecular Mechanisms of Plant Development, Komarov Botanical Institute, Russian Academy of Sciences, Saint-Petersburg, Russia
- Laboratory of Molecular and Cellular Biology, All-Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, Russia
| | - Thomas Roitsch
- Department of Plant Physiology, Karl-Franzens-Universität Graz, Graz, Austria
| | - Ulrike Mathesius
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Katharina Pawlowski
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- *Correspondence: Katharina Pawlowski,
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Buhian WP, Bensmihen S. Mini-Review: Nod Factor Regulation of Phytohormone Signaling and Homeostasis During Rhizobia-Legume Symbiosis. FRONTIERS IN PLANT SCIENCE 2018; 9:1247. [PMID: 30319665 PMCID: PMC6166096 DOI: 10.3389/fpls.2018.01247] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/06/2018] [Indexed: 05/22/2023]
Abstract
The rhizobia-legume symbiosis is a mutualistic association in which bacteria provide plants with nitrogen compounds and the plant provides bacteria with carbon sources. A successful symbiotic interaction relies on a molecular dialog between the plant and the bacteria, and generally involves rhizobial lipo-chitooligosaccharide signals called Nod factors (NFs). In most cases, specific NF perception is required for rhizobia to enter root cells through newly formed intracellular structures called infection threads (ITs). Concomitantly to IT formation in root hairs, root cortical cells start to divide to create a new root organ called the nodule, which will provide the bacteria with a specific micro-environment required for symbiotic nitrogen fixation. During all these steps of plant-bacteria interaction, new plant cellular compartments and developmental programs are activated. This interaction is costly for the plant that tightly controls symbiosis establishment and functioning. Phytohormones are key regulators of cellular and developmental plasticity in plants, and they are influential endogenous signals that rapidly control plant responses. Although early symbiotic responses were known for decades to be linked to phytohormone-related responses, new data reveal the molecular mechanisms involved and links between phytohormones and the control of early symbiotic events. Reciprocally, NF signaling also targets phytohormone signaling pathways. In this review, we will focus on the emerging notion of NF and phytohormone signaling crosstalk, and how it could contribute to the tight control of symbiosis establishment in legume host plants.
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