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Horta Araújo N, Nouwen N, Arrighi JF. Nodulating another way: what can we learn from lateral root base nodulation in legumes? JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3214-3219. [PMID: 38476021 PMCID: PMC11156805 DOI: 10.1093/jxb/erae101] [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: 01/29/2024] [Accepted: 03/06/2024] [Indexed: 03/14/2024]
Abstract
Certain legumes provide a special pathway for rhizobia to invade the root and develop nitrogen-fixing nodules, a process known as lateral root base (LRB) nodulation. This pathway involves intercellular infection at the junction of the lateral roots with the taproot, leading to nodule formation in the lateral root cortex. Remarkably, this LRB pathway serves as a backbone for various adaptative symbiotic processes. Here, we describe different aspects of LRB nodulation and highlight directions for future research to elucidate the mechanisms of this as yet little known but original pathway that will help in broadening our knowledge on the rhizobium-legume symbiosis.
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Affiliation(s)
- Natasha Horta Araújo
- PHIM Plant Health Institute, Univ Montpellier, IRD, INRAE, CIRAD, Institut Agro, TA-A82/J, Campus de Baillarguet, 34398 Montpellier, France
| | - Nico Nouwen
- PHIM Plant Health Institute, Univ Montpellier, IRD, INRAE, CIRAD, Institut Agro, TA-A82/J, Campus de Baillarguet, 34398 Montpellier, France
| | - Jean-François Arrighi
- PHIM Plant Health Institute, Univ Montpellier, IRD, INRAE, CIRAD, Institut Agro, TA-A82/J, Campus de Baillarguet, 34398 Montpellier, France
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2
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Thomas J, Frugoli J. Mutation of BAM2 rescues the sunn hypernodulation phenotype in Medicago truncatula, suggesting that a signaling pathway like CLV1/BAM in Arabidopsis affects nodule number. FRONTIERS IN PLANT SCIENCE 2024; 14:1334190. [PMID: 38273950 PMCID: PMC10808729 DOI: 10.3389/fpls.2023.1334190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 12/18/2023] [Indexed: 01/27/2024]
Abstract
The unique evolutionary adaptation of legumes for nitrogen-fixing symbiosis leading to nodulation is tightly regulated by the host plant. The autoregulation of nodulation (AON) pathway negatively regulates the number of nodules formed in response to the carbon/nitrogen metabolic status of the shoot and root by long-distance signaling to and from the shoot and root. Central to AON signaling in the shoots of Medicago truncatula is SUNN, a leucine-rich repeat receptor-like kinase with high sequence similarity with CLAVATA1 (CLV1), part of a class of receptors in Arabidopsis involved in regulating stem cell populations in the root and shoot. This class of receptors in Arabidopsis includes the BARELY ANY MERISTEM family, which, like CLV1, binds to CLE peptides and interacts with CLV1 to regulate meristem development. M. truncatula contains five members of the BAM family, but only MtBAM1 and MtBAM2 are highly expressed in the nodules 48 hours after inoculation. Plants carry mutations in individual MtBAMs, and several double BAM mutant combinations all displayed wild-type nodule number phenotypes. However, Mtbam2 suppressed the sunn-5 hypernodulation phenotype and partially rescued the short root length phenotype of sunn-5 when present in a sunn-5 background. Grafting determined that bam2 suppresses supernodulation from the roots, regardless of the SUNN status of the root. Overexpression of MtBAM2 in wild-type plants increases nodule numbers, while overexpression of MtBAM2 in some sunn mutants rescues the hypernodulation phenotype, but not the hypernodulation phenotypes of AON mutant rdn1-2 or crn. Relative expression measurements of the nodule transcription factor MtWOX5 downstream of the putative bam2 sunn-5 complex revealed disruption of meristem signaling; while both bam2 and bam2 sunn-5 influence MtWOX5 expression, the expression changes are in different directions. We propose a genetic model wherein the specific root interactions of BAM2/SUNN are critical for signaling in nodule meristem cell homeostasis in M. truncatula.
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Affiliation(s)
| | - Julia Frugoli
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, United States
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3
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Molla F, Kundu A, DasGupta M. Sucrose-induced auxin conjugate hydrolase restores symbiosis in a Medicago cytokinin perception mutant. PLANT PHYSIOLOGY 2023; 191:2447-2460. [PMID: 36722159 PMCID: PMC10069879 DOI: 10.1093/plphys/kiad045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 12/27/2022] [Indexed: 06/18/2023]
Abstract
Rhizobia-legume interactions recruit cytokinin for the induction of nodule primordia in the cortex. Cytokinin signaling regulates auxin transport and biosynthesis, causing local auxin accumulation, which triggers cortical cell division. Since sugar signaling can trigger auxin responses, we explored whether sugar treatments could rescue symbiosis in the Medicago truncatula cytokinin response 1 (cre1) mutant. Herein, we demonstrate that sucrose and its nonmetabolizable isomer turanose can trigger auxin response and recover functional symbiosis in cre1, indicating sucrose signaling to be necessary for the restoration of symbiosis. In both M. truncatula A17 (wild type) and cre1, sucrose signaling significantly upregulated IAA-Ala Resistant 3 (IAR33), encoding an auxin conjugate hydrolase, in rhizobia-infected as well as in uninfected roots. Knockdown of IAR33 (IAR33-KD) significantly reduced nodulation in A17, highlighting the importance of deconjugation-mediated auxin accumulation during nodule inception. In cre1, IAR33-KD restricted the sucrose-mediated restoration of functional symbiosis, suggesting that deconjugation-mediated auxin accumulation plays a key role in the absence of CRE1-mediated auxin biosynthesis and transport control. Overexpression of IAR33 also restored functional symbiosis in cre1, further suggesting that IAR33 mediates auxin accumulation in response to sucrose signaling. Since all the observed sucrose-mediated responses were common to A17 and cre1, deconjugation-mediated auxin response appeared to be independent of CRE1, which normally governs local auxin accumulation in the presence of rhizobia. We propose that sucrose-dependent restoration of symbiosis in cre1 occurs by the activation of IAR33-mediated auxin deconjugation.
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Affiliation(s)
- Firoz Molla
- Department of Biochemistry, University of Calcutta, Kolkata 700019, India
| | - Anindya Kundu
- Department of Biochemistry, University of Calcutta, Kolkata 700019, India
| | - Maitrayee DasGupta
- Department of Biochemistry, University of Calcutta, Kolkata 700019, India
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Xu Y, Wang H, Lu Z, Wen L, Gu Z, Zhang X, Yu G, Wang H, Zhou C, Han L. Developmental Analysis of the GATA Factor HANABA TARANU Mutants in Medicago truncatula Reveals Their Roles in Nodule Formation. FRONTIERS IN PLANT SCIENCE 2021; 12:616776. [PMID: 33995430 PMCID: PMC8118203 DOI: 10.3389/fpls.2021.616776] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
Formation of nodules on legume roots results from symbiosis with rhizobial bacteria. Here, we identified two GATA transcription factors, MtHAN1 and MtHAN2, in Medicago truncatula, which are the homologs of HANABA TARANU (HAN) and HANABA TARANU LIKE in Arabidopsis thaliana. Our analysis revealed that MtHAN1 and MtHAN2 are expressed in roots and shoots including the root tip and nodule apex. We further show that MtHAN1 and MtHAN2 localize to the nucleus where they interact and that single and double loss-of-function mutants of MtHAN1 and MtHAN2 did not show any obvious phenotype in flower development, suggesting their role is different than their closest Arabidopsis homologues. Investigation of their symbiotic phenotypes revealed that the mthan1 mthan2 double mutant develop twice as many nodules as wild type, revealing a novel biological role for GATA transcription factors. We found that HAN1/2 transcript levels respond to nitrate treatment like their Arabidopsis counterparts. Global gene transcriptional analysis by RNA sequencing revealed different expression genes enriched for several pathways important for nodule development including flavonoid biosynthesis and phytohormones. In addition, further studies suggest that MtHAN1 and MtHAN2 are required for the expression of several nodule-specific cysteine-rich genes, which they may activate directly, and many peptidase and peptidase inhibitor genes. This work expands our knowledge of the functions of MtHANs in plants by revealing an unexpected role in legume nodulation.
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Affiliation(s)
- Yiteng Xu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Hongfeng Wang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Zhichao Lu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Lizhu Wen
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Zhiqun Gu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Xue Zhang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Guangle Yu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, China
| | - Hailong Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, China
| | - Chuanen Zhou
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Lu Han
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
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Xiao A, Yu H, Fan Y, Kang H, Ren Y, Huang X, Gao X, Wang C, Zhang Z, Zhu H, Cao Y. Transcriptional regulation of NIN expression by IPN2 is required for root nodule symbiosis in Lotus japonicus. THE NEW PHYTOLOGIST 2020; 227:513-528. [PMID: 32187696 DOI: 10.1111/nph.16553] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/09/2020] [Indexed: 05/14/2023]
Abstract
Expression of Nodule Inception (NIN) is essential for initiation of legume-rhizobial symbiosis. An existing model regarding the regulation of NIN expression involves two GRAS transcription factors - NSP1 (Nodulation Signaling Pathway 1) and NSP2. NSP2 forms a complex with NSP1 to directly bind to NIN promoter. However, rhizobial treatment-induced NIN expression could still be detected in the nsp1 mutant plants, suggesting that other proteins must be involved in the regulation of NIN expression. A combination of molecular, biochemical and genetic analyses was used to investigate the molecular basis of IPN2 in regulating root development and NIN expression in Lotus japonicus. In this study, we identified that IPN2 is a close homolog of Arabidopsis APL (ALTERED PHLOEM DEVELOPMENT) with essential function in root development. However, Lotus IPN2 has a different expression pattern compared with the Arabidopsis APL gene. IPN2 binds to the IPN2-responsive cis element (IPN2-RE) of NIN promoter and activates NIN expression. IPN2, NSP1 and NSP2 form a protein complex to directly target NIN promoter and activate NIN expression in the legume-rhizobial symbiosis. Our data refine the regulatory model of NIN expression that NSP2 works together with NSP1 and IPN2 to activate the NIN gene allowing nodulation in L. japonicus.
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Affiliation(s)
- Aifang Xiao
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Haixiang Yu
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuqian Fan
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Heng Kang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yaping Ren
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiaoqin Huang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiumei Gao
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Chao Wang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhongming Zhang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hui Zhu
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yangrong Cao
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
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Pankievicz VCS, Irving TB, Maia LGS, Ané JM. Are we there yet? The long walk towards the development of efficient symbiotic associations between nitrogen-fixing bacteria and non-leguminous crops. BMC Biol 2019; 17:99. [PMID: 31796086 PMCID: PMC6889567 DOI: 10.1186/s12915-019-0710-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 10/18/2019] [Indexed: 01/09/2023] Open
Abstract
Nitrogen is an essential element of life, and nitrogen availability often limits crop yields. Since the Green Revolution, massive amounts of synthetic nitrogen fertilizers have been produced from atmospheric nitrogen and natural gas, threatening the sustainability of global food production and degrading the environment. There is a need for alternative means of bringing nitrogen to crops, and taking greater advantage of biological nitrogen fixation seems a logical option. Legumes are used in most cropping systems around the world because of the nitrogen-fixing symbiosis with rhizobia. However, the world's three major cereal crops-rice, wheat, and maize-do not associate with rhizobia. In this review, we will survey how genetic approaches in rhizobia and their legume hosts allowed tremendous progress in understanding the molecular mechanisms controlling root nodule symbioses, and how this knowledge paves the way for engineering such associations in non-legume crops. We will also discuss challenges in bringing these systems into the field and how they can be surmounted by interdisciplinary collaborations between synthetic biologists, microbiologists, plant biologists, breeders, agronomists, and policymakers.
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Affiliation(s)
| | - Thomas B Irving
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Lucas G S Maia
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Jean-Michel Ané
- Department of Agronomy, University of Wisconsin, Madison, WI, USA.
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA.
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7
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Roy Choudhury S, Johns SM, Pandey S. A convenient, soil-free method for the production of root nodules in soybean to study the effects of exogenous additives. PLANT DIRECT 2019; 3:e00135. [PMID: 31245773 PMCID: PMC6589526 DOI: 10.1002/pld3.135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 03/25/2019] [Accepted: 03/27/2019] [Indexed: 05/16/2023]
Abstract
Legumes develop root nodules that harbor endosymbiotic bacteria, rhizobia. These rhizobia convert nitrogen to ammonia by biological nitrogen fixation. A thorough understanding of the biological nitrogen fixation in legumes and its regulation is key to develop sustainable agriculture. It is well known that plant hormones affect nodule formation; however, most studies are limited to model legumes due to their suitability for in vitro, plate-based assays. Specifically, it is almost impossible to measure the effects of exogenous hormones or other additives during nodule development in crop legumes such as soybean as they have huge root system in soil. To circumvent this issue, the present research develops suitable media and growth conditions for efficient nodule development under in vitro, soil-free conditions in an important legume crop, soybean. Moreover, we also evaluate the effects of all major phytohormones on soybean nodule development under identical growing conditions. Phytohormones such as abscisic acid (ABA) and jasmonic acid (JA) had an overall inhibitory effect and those such as gibberellic acid (GA) or brassinosteroids (BRs) had an overall positive effect on nodule formation. This versatile, inexpensive, scalable, and simple protocol provides several advantages over previously established methods. It is extremely time- and resource-efficient, does not require special training or equipment, and produces highly reproducible results. The approach is expandable to other large legumes as well as for other exogenous additives.
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Affiliation(s)
| | | | - Sona Pandey
- Donald Danforth Plant Science CenterSt. LouisMissouri
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8
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Gauthier-Coles C, White RG, Mathesius U. Nodulating Legumes Are Distinguished by a Sensitivity to Cytokinin in the Root Cortex Leading to Pseudonodule Development. FRONTIERS IN PLANT SCIENCE 2019; 9:1901. [PMID: 30671068 PMCID: PMC6331541 DOI: 10.3389/fpls.2018.01901] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 12/07/2018] [Indexed: 05/11/2023]
Abstract
Root nodule symbiosis (RNS) is a feature confined to a single clade of plants, the Fabids. Among Fabids capable of RNS, legumes form root cortex-based nodules in symbioses with rhizobia, while actinorhizal species form lateral root-based nodules with actinomycetes. Cytokinin has previously been shown to be sufficient for "pseudonodule" initiation in model legumes. Here, we tested whether this response correlates with the ability to nodulate across a range of plant species. We analyzed the formation of pseudonodules in 17 nodulating and non-nodulating legume species, and 11 non-legumes, including nodulating actinorhizal species, using light and fluorescence microscopy. Cytokinin-induced pseudonodules arising from cortical cell divisions occurred in all nodulating legume species, but not in any of the other species, including non-nodulating legumes. Pseudonodule formation was dependent on the CRE1 cytokinin receptor in Medicago truncatula. Inhibition of root growth by cytokinin occurred across plant groups, indicating that pseudonodule development is the result of a specific cortical cytokinin response unique to nodulating legumes. Lack of a cortical cytokinin response from the Arabidopsis thaliana cytokinin reporter TCSn::GFP supported this hypothesis. Our results suggest that the ability to form cortical cell-derived nodules was gained in nodulating legumes, and likely lost in non-nodulating legumes, due to a specific root cortical response to cytokinin.
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Affiliation(s)
- Christopher Gauthier-Coles
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | | | - Ulrike Mathesius
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT, Australia
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9
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Kundu A, DasGupta M. Silencing of Putative Cytokinin Receptor Histidine Kinase1 Inhibits Both Inception and Differentiation of Root Nodules in Arachis hypogaea. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:187-199. [PMID: 28876173 DOI: 10.1094/mpmi-06-17-0144-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Rhizobia-legume interaction activates the SYM pathway that recruits cytokinin signaling for induction of nodule primordia in the cortex. In Arachis hypogaea, bradyrhizobia invade through natural cracks developed in the lateral root base and are directly endocytosed in the cortical cells to generate the nodule primordia. To unravel the role of cytokinin signaling in A. hypogaea, RNA-interference (RNAi) of cytokinin receptor histidine-kinase1 (AhHK1) was done. AhHK1-RNAi downregulated the expression of type-A response regulators such as AhRR5 and AhRR3 along with several symbiotic genes, indicating that both cytokinin signaling and the SYM pathway were affected. Accordingly, there was a drastic downregulation of nodulation in AhHK1-RNAi roots and the nodules that developed were ineffective. These nodules were densely packed, with infected cells having a higher nucleo-cytoplasmic ratio and distinctively high mitotic index, where the rod-shaped rhizobia failed to differentiate into bacteroids within spherical symbiosomes. In accordance with the proliferating state, expression of a mitotic-cyclin AhCycB2.1 was higher in AhHK1-RNAi nodules, whereas expression of a retinoblastoma-related (AhRBR) nodule that restrains proliferation was lower. Also, higher expression of the meristem maintenance factor WUSCHEL-RELATED HOMEOBOX5 correlated with the undifferentiated state of AhHK1-RNAi nodules. Our results suggest that AhHK1-mediated cytokinin signaling is important for both inception and differentiation during nodule development in A. hypogaea.
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Affiliation(s)
- Anindya Kundu
- Department of Biochemistry, University of Calcutta, Kolkata 700019, India
| | - Maitrayee DasGupta
- Department of Biochemistry, University of Calcutta, Kolkata 700019, India
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Cox CE, Brandl MT, de Moraes MH, Gunasekera S, Teplitski M. Production of the Plant Hormone Auxin by Salmonella and Its Role in the Interactions with Plants and Animals. Front Microbiol 2018; 8:2668. [PMID: 29375530 PMCID: PMC5770404 DOI: 10.3389/fmicb.2017.02668] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/21/2017] [Indexed: 11/30/2022] Open
Abstract
The ability of human enteric pathogens to colonize plants and use them as alternate hosts is now well established. Salmonella, similarly to phytobacteria, appears to be capable of producing the plant hormone auxin via an indole-3-pyruvate decarboxylase (IpdC), a key enzyme of the IPyA pathway. A deletion of the Salmonella ipdC significantly reduced auxin synthesis in laboratory culture. The Salmonella ipdC gene was expressed on root surfaces of Medicago truncatula. M. truncatula auxin-responsive GH3::GUS reporter was activated by the wild type Salmonella, and not but the ipdC mutant, implying that the bacterially produced IAA (Indole Acetic Acid) was detected by the seedlings. Seedling infections with the wild type Salmonella caused an increase in secondary root formation, which was not observed in the ipdC mutant. The wild type Salmonella cells were detected as aggregates at the sites of lateral root emergence, whereas the ipdC mutant cells were evenly distributed in the rhizosphere. However, both strains appeared to colonize seedlings well in growth pouch experiments. The ipdC mutant was also less virulent in a murine model of infection. When mice were infected by oral gavage, the ipdC mutant was as proficient as the wild type strain in colonization of the intestine, but it was defective in the ability to cross the intestinal barrier. Fewer cells of the ipdC mutant, compared with the wild type strain, were detected in Peyer's patches, spleen and in the liver. Orthologs of ipdC are found in all Salmonella genomes and are distributed among many animal pathogens and plant-associated bacteria of the Enterobacteriaceae, suggesting a broad ecological role of the IpdC-catalyzed pathway.
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Affiliation(s)
- Clayton E Cox
- Department of Soil and Water Science, University of Florida, Gainesville, FL, United States
| | - Maria T Brandl
- Produce Safety and Microbiology Research Unit, United States Department of Agriculture, Agricultural Research Service, Albany, CA, United States
| | - Marcos H de Moraes
- Department of Soil and Water Science, University of Florida, Gainesville, FL, United States
| | | | - Max Teplitski
- Department of Soil and Water Science, University of Florida, Gainesville, FL, United States.,Smithsonian Marine Station, Ft. Pierce, FL, United States
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11
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In BPS1 Downregulated Roots, the BYPASS1 Signal Disrupts the Induction of Cortical Cell Divisions in Bean-Rhizobium Symbiosis. Genes (Basel) 2018; 9:genes9010011. [PMID: 29301366 PMCID: PMC5793164 DOI: 10.3390/genes9010011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/23/2017] [Accepted: 12/27/2017] [Indexed: 11/17/2022] Open
Abstract
BYPASS1 (BPS1), which is a well-conserved gene in plants, is required for normal root and shoot development. In the absence of BPS1 gene function, Arabidopsis overproduces a mobile signalling compound (the BPS1 signal) in roots, and this transmissible signal arrests shoot growth and causes abnormal root development. In addition to the shoot and root meristem activities, the legumes also possess transient meristematic activity in root cortical cells during Rhizobium symbiosis. We explored the role of Phaseolus vulgaris BPS1 during nodule primordium development using an RNA-interference (RNAi) silencing approach. Our results show that upon Rhizobium infection, the PvBPS1-RNAi transgenic roots failed to induce cortical cell divisions without affecting the rhizobia-induced root hair curling and infection thread formation. The transcript accumulation of early nodulin genes, cell cyclins, and cyclin-dependent kinase genes was affected in RNAi lines. Interestingly, the PvBPS1-RNAi root nodule phenotype was partially rescued by exogenous application of fluridone, a carotenoid biosynthesis inhibitor, which was used because the carotenoids are precursors of BPS1 signalling molecules. Furthermore, we show that the PvBPS1 promoter was active in the nodule primordia. Together, our data show that PvBPS1 plays a vital role in the induction of meristematic activity in root cortical cells and in the establishment of nodule primordia during Phaseolus-Rhizobium symbiosis.
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Ibáñez F, Wall L, Fabra A. Starting points in plant-bacteria nitrogen-fixing symbioses: intercellular invasion of the roots. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:1905-1918. [PMID: 27756807 DOI: 10.1093/jxb/erw387] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Agricultural practices contribute to climate change by releasing greenhouse gases such as nitrous oxide that are mainly derived from nitrogen fertilizers. Therefore, understanding biological nitrogen fixation in farming systems is beneficial to agriculture and environmental preservation. In this context, a better grasp of nitrogen-fixing systems and nitrogen-fixing bacteria-plant associations will contribute to the optimization of these biological processes. Legumes and actinorhizal plants can engage in a symbiotic interaction with nitrogen-fixing rhizobia or actinomycetes, resulting in the formation of specialized root nodules. The legume-rhizobia interaction is mediated by a complex molecular signal exchange, where recognition of different bacterial determinants activates the nodulation program in the plant. To invade plants roots, bacteria follow different routes, which are determined by the host plant. Entrance via root hairs is probably the best understood. Alternatively, entry via intercellular invasion has been observed in many legumes. Although there are common features shared by intercellular infection mechanisms, differences are observed in the site of root invasion and bacterial spread on the cortex reaching and infecting a susceptible cell to form a nodule. This review focuses on intercellular bacterial invasion of roots observed in the Fabaceae and considers, within an evolutionary context, the different variants, distribution and molecular determinants involved. Intercellular invasion of actinorhizal plants and Parasponia is also discussed.
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Affiliation(s)
- Fernando Ibáñez
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - Luis Wall
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Bernal, Buenos Aires, Argentina
| | - Adriana Fabra
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
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13
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Franssen HJ, Kulikova O, Willemsen V, Heidstra R. Cis-regulatory PLETHORA promoter elements directing root and nodule expression are conserved between Arabidopsis thaliana and Medicago truncatula. PLANT SIGNALING & BEHAVIOR 2017; 12:e1278102. [PMID: 28067580 PMCID: PMC5351727 DOI: 10.1080/15592324.2016.1278102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 12/20/2016] [Accepted: 12/27/2016] [Indexed: 05/31/2023]
Abstract
Nodules are unique organs formed on roots of legumes by soil-borne bacteria, collectively known as rhizobium. Recently, we have shown that orthologs of the AINTEGUMENTA-like (AIL) AP2 transcription factors PLETHORA (PLT) 1 to 4, that redundantly regulate Arabidopsis thaliana root development are involved in root and nodule growth in Medicago truncatula. Hence, it is conceivable that rhizobium has co-opted these genes for nodule development. Whether this co-option requires the presence of specific cis-elements in the promoters and/or specialization of PLT protein function is not clear. Here, we analyzed the qualitative expression patterns of the Arabidopsis PLT1 to 4 promoters in Medicago roots and nodules and compared these with the described expression patterns of the Medicago PLT genes. Our studies reveal that the expression patterns of the investigated promoters and their Medicago orthologs are very similar, indicating that at least all cis-elements regulating spatial PLT expression are conserved among the Arabidopsis and Medicago PLT1 to 4 promoters.
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Affiliation(s)
- Henk J. Franssen
- Department of Plant Sciences, Laboratory of Molecular Biology, Wageningen University, Wageningen, The Netherlands
| | - Olga Kulikova
- Department of Plant Sciences, Laboratory of Molecular Biology, Wageningen University, Wageningen, The Netherlands
| | - Viola Willemsen
- Department of Plant Sciences, Plant Developmental Biology, Wageningen University, Wageningen, The Netherlands
| | - Renze Heidstra
- Department of Plant Sciences, Plant Developmental Biology, Wageningen University, Wageningen, The Netherlands
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Ng JLP, Perrine-Walker F, Wasson AP, Mathesius U. The Control of Auxin Transport in Parasitic and Symbiotic Root-Microbe Interactions. PLANTS (BASEL, SWITZERLAND) 2015; 4:606-43. [PMID: 27135343 PMCID: PMC4844411 DOI: 10.3390/plants4030606] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/12/2015] [Accepted: 08/18/2015] [Indexed: 01/13/2023]
Abstract
Most field-grown plants are surrounded by microbes, especially from the soil. Some of these, including bacteria, fungi and nematodes, specifically manipulate the growth and development of their plant hosts, primarily for the formation of structures housing the microbes in roots. These developmental processes require the correct localization of the phytohormone auxin, which is involved in the control of cell division, cell enlargement, organ development and defense, and is thus a likely target for microbes that infect and invade plants. Some microbes have the ability to directly synthesize auxin. Others produce specific signals that indirectly alter the accumulation of auxin in the plant by altering auxin transport. This review highlights root-microbe interactions in which auxin transport is known to be targeted by symbionts and parasites to manipulate the development of their host root system. We include case studies for parasitic root-nematode interactions, mycorrhizal symbioses as well as nitrogen fixing symbioses in actinorhizal and legume hosts. The mechanisms to achieve auxin transport control that have been studied in model organisms include the induction of plant flavonoids that indirectly alter auxin transport and the direct targeting of auxin transporters by nematode effectors. In most cases, detailed mechanisms of auxin transport control remain unknown.
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Affiliation(s)
- Jason Liang Pin Ng
- Division of Plant Science, Research School of Biology, Australian National University, Linnaeus Way, Building 134, Canberra ACT 2601, Australia.
| | | | | | - Ulrike Mathesius
- Division of Plant Science, Research School of Biology, Australian National University, Linnaeus Way, Building 134, Canberra ACT 2601, Australia.
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15
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Abscisic Acid: Hidden Architect of Root System Structure. PLANTS 2015; 4:548-72. [PMID: 27135341 PMCID: PMC4844405 DOI: 10.3390/plants4030548] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 08/01/2015] [Accepted: 08/03/2015] [Indexed: 01/15/2023]
Abstract
Plants modulate root growth in response to changes in the local environment, guided by intrinsic developmental genetic programs. The hormone Abscisic Acid (ABA) mediates responses to different environmental factors, such as the presence of nitrate in the soil, water stress and salt, shaping the structure of the root system by regulating the production of lateral roots as well as controlling root elongation by modulating cell division and elongation. Curiously, ABA controls different aspects of root architecture in different plant species, perhaps providing some insight into the great diversity of root architecture in different plants, both from different taxa and from different environments. ABA is an ancient signaling pathway, acquired well before the diversification of land plants. Nonetheless, how this ancient signaling module is implemented or interacts within a larger signaling network appears to vary in different species. This review will examine the role of ABA in the control of root architecture, focusing on the regulation of lateral root formation in three plant species, Arabidopsis thaliana, Medicago truncatula and Oryza sativa. We will consider how the implementation of the ABA signaling module might be a target of natural selection, to help contribute to the diversity of root architecture in nature.
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16
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Djordjevic MA, Mohd-Radzman NA, Imin N. Small-peptide signals that control root nodule number, development, and symbiosis. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:5171-81. [PMID: 26249310 DOI: 10.1093/jxb/erv357] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Many legumes have the capacity to enter into a symbiotic association with soil bacteria generically called 'rhizobia' that results in the formation of new lateral organs on roots called nodules within which the rhizobia fix atmospheric nitrogen (N). Up to 200 million tonnes of N per annum is fixed by this association. Therefore, this symbiosis plays an integral role in the N cycle and is exploited in agriculture to support the sustainable fixation of N for cropping and animal production in developing and developed nations. Root nodulation is an expendable developmental process and competency for nodulation is coupled to low-N conditions. Both nodule initiation and development is suppressed under high-N conditions. Although root nodule formation enables sufficient N to be fixed for legumes to grow under N-deficient conditions, the carbon cost is high and nodule number is tightly regulated by local and systemic mechanisms. How legumes co-ordinate nodule formation with the other main organs of nutrient acquisition, lateral roots, is not fully understood. Independent mechanisms appear to regulate lateral roots and nodules under low- and high-N regimes. Recently, several signalling peptides have been implicated in the local and systemic regulation of nodule and lateral root formation. Other peptide classes control the symbiotic interaction of rhizobia with the host. This review focuses on the roles played by signalling peptides during the early stages of root nodule formation, in the control of nodule number, and in the establishment of symbiosis. Here, we highlight the latest findings and the gaps in our understanding of these processes.
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Affiliation(s)
- Michael A Djordjevic
- Division of Plant Sciences, Research School of Biology, College of Medicine, Biology and the Environment, The Australian National University, Canberra ACT 2601, Australia
| | - Nadiatul A Mohd-Radzman
- Division of Plant Sciences, Research School of Biology, College of Medicine, Biology and the Environment, The Australian National University, Canberra ACT 2601, Australia
| | - Nijat Imin
- Division of Plant Sciences, Research School of Biology, College of Medicine, Biology and the Environment, The Australian National University, Canberra ACT 2601, Australia
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17
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Franssen HJ, Xiao TT, Kulikova O, Wan X, Bisseling T, Scheres B, Heidstra R. Root developmental programs shape the Medicago truncatula nodule meristem. Development 2015; 142:2941-50. [DOI: 10.1242/dev.120774] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 07/24/2015] [Indexed: 02/03/2023]
Abstract
Nodules on the roots of legume plants host nitrogen-fixing rhizobium bacteria. Several lines of evidence indicate that nodules are evolutionary related to roots. We determined whether developmental control of the Medicago truncatula nodule meristem bears resemblance to that in root meristems through analyses of root meristem expressed PLETHORA genes. In nodules, MtPLETHORA1 and 2 genes are preferentially expressed in cells positioned at the periphery of the meristem abutting nodule vascular bundles. Their expression overlaps with an auxin response maximum and MtWOX5 that is a marker for the root quiescent centre. Strikingly, the cells in the central part of the nodule meristem have a high level of cytokinin and display MtPLETHORA 3 and 4 gene expression. Nodule-specific knock-down of MtPLETHORA genes results in reduced number of nodules and/or in nodules in which meristem activity has ceased. Our nodule gene expression map indicates that the nodule meristem is composed of two distinct domains in which different MtPLETHORA gene subsets are expressed. Our mutant studies show that MtPLETHORA genes redundantly function in nodule meristem maintenance. This indicates that Rhizobium has recruited root developmental programs for nodule formation
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Affiliation(s)
- Henk J. Franssen
- Department of Plant Sciences, Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Ting Ting Xiao
- Department of Plant Sciences, Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Olga Kulikova
- Department of Plant Sciences, Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Xi Wan
- Department of Plant Sciences, Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- Present address: NOVOGENE Bioinformatics technology, 38 Xueqing Road, Haidian district, Beijing, China
| | - Ton Bisseling
- Department of Plant Sciences, Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- College of Science, King Saud University, Post Office Box 2455, Riyadh 11451, Saudi Arabia
| | - Ben Scheres
- Department of Plant Sciences, Plant Developmental Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands, telephone: +31-317483264
| | - Renze Heidstra
- Department of Plant Sciences, Plant Developmental Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands, telephone: +31-317483264
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18
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Haichar FEZ, Santaella C, Heulin T, Achouak W. Root exudates mediated interactions belowground. SOIL BIOLOGY AND BIOCHEMISTRY 2014; 77:69-80. [PMID: 0 DOI: 10.1016/j.soilbio.2014.06.017] [Citation(s) in RCA: 300] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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19
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Herrbach V, Remblière C, Gough C, Bensmihen S. Lateral root formation and patterning in Medicago truncatula. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:301-10. [PMID: 24148318 DOI: 10.1016/j.jplph.2013.09.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/06/2013] [Accepted: 09/06/2013] [Indexed: 05/08/2023]
Abstract
The plant root system is crucial for anchorage and nutrition, and has a major role in plant adaptation, as well as in interactions with soil micro-organisms. Despite the agronomical and ecological importance of legume plants, whose roots can interact symbiotically with soil bacteria called rhizobia that fix atmospheric dinitrogen, and the evidence that lateral root (LR) development programmes are intercepted and influenced by symbiotic organisms, very little is known concerning the cellular and molecular events governing LR development in legumes. To better understand the interconnections between LR formation and symbiotic processes triggered by rhizobia or symbiotic molecules such as lipo-chitooligosaccharides (LCOs), we first need a detailed description of LR development mechanisms in legumes. Using thin sections, we have described the cellular events leading to the formation of a new LR primordium (LRP) in Medicago truncatula, and divided them into seven stages prior to LR emergence. To monitor auxin accumulation we generated transgenic DR5:GUS and DR5:VENUS-N7 reporter lines of M. truncatula, and used them to analyze early stages of LR development. Interesting differences were observed for LR ontogeny compared to Arabidopsis thaliana. Notably, we observed endodermal and cortical contributions to LRP formation, and the associated DR5:GUS expression profile indicated that endodermal and cortical cell divisions were correlated with auxin accumulation. As described for A. thaliana, we observed a preferential zone for LR initiation at 4.45 mm from the root tip. Finally, we studied LR emergence and showed that a significant proportion of new LRP do not emerge straight away and could thus be an additional source of root plasticity. Our results shed new light on the patterning and early development of LRs in M. truncatula.
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Affiliation(s)
- Violaine Herrbach
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326 Castanet-Tolosan, France
| | - Céline Remblière
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326 Castanet-Tolosan, France
| | - Clare Gough
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326 Castanet-Tolosan, France
| | - Sandra Bensmihen
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326 Castanet-Tolosan, France.
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20
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Imin N, Mohd-Radzman NA, Ogilvie HA, Djordjevic MA. The peptide-encoding CEP1 gene modulates lateral root and nodule numbers in Medicago truncatula. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:5395-409. [PMID: 24259455 DOI: 10.1093/jxb/ert369] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The role of MtCEP1, a member of the CEP (C-terminally encoded peptide) signaling peptide family, was examined in Medicago truncatula root development. MtCEP1 was expressed in root tips, vascular tissue, and young lateral organs, and was up-regulated by low nitrogen levels and, independently, by elevated CO2. Overexpressing MtCEP1 or applying MtCEP1 peptide to roots elicited developmental phenotypes: inhibition of lateral root formation, enhancement of nodulation, and the induction of periodic circumferential root swellings, which arose from cortical, epidermal, and pericycle cell divisions and featured an additional cortical cell layer. MtCEP peptide addition to other legume species induced similar phenotypes. The enhancement of nodulation by MtCEP1 is partially tolerant to high nitrate, which normally strongly suppresses nodulation. These nodules develop faster, are larger, and fix more nitrogen in the absence and presence of inhibiting nitrate levels. At 25mM nitrate, nodules formed on pre-existing swelling sites induced by MtCEP1 overexpression. RNA interference-mediated silencing of several MtCEP genes revealed a negative correlation between transcript levels of MtCEP1 and MtCEP2 with the number of lateral roots. MtCEP1 peptide-dependent phenotypes were abolished or attenuated by altering or deleting key residues in its 15 amino acid domain. RNA-Seq analysis revealed that 89 and 116 genes were significantly up- and down-regulated, respectively, by MtCEP1 overexpression, including transcription factors WRKY, bZIP, ERF, and MYB, homologues of LOB29, SUPERROOT2, and BABY BOOM. Taken together, the data suggest that the MtCEP1 peptide modulates lateral root and nodule development in M. truncatula.
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MESH Headings
- Carbon Dioxide/metabolism
- Gene Expression Regulation, Plant
- Genes, Reporter
- Medicago truncatula/cytology
- Medicago truncatula/genetics
- Medicago truncatula/growth & development
- Medicago truncatula/physiology
- Nitrogen/metabolism
- Nitrogen Fixation
- Peptides/genetics
- Peptides/pharmacology
- Phenotype
- Plant Proteins/genetics
- Plant Proteins/metabolism
- Plant Root Nodulation
- Plant Roots/cytology
- Plant Roots/genetics
- Plant Roots/growth & development
- Plant Roots/physiology
- Plants, Genetically Modified
- Promoter Regions, Genetic/genetics
- RNA Interference
- RNA, Plant/chemistry
- RNA, Plant/genetics
- Root Nodules, Plant/cytology
- Root Nodules, Plant/genetics
- Root Nodules, Plant/growth & development
- Root Nodules, Plant/physiology
- Sequence Analysis, RNA
- Signal Transduction
- Sinorhizobium meliloti/physiology
- Symbiosis
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Affiliation(s)
- Nijat Imin
- Division of Plant Sciences, Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra ACT 0200, Australia
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21
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Takahara M, Magori S, Soyano T, Okamoto S, Yoshida C, Yano K, Sato S, Tabata S, Yamaguchi K, Shigenobu S, Takeda N, Suzaki T, Kawaguchi M. Too much love, a novel Kelch repeat-containing F-box protein, functions in the long-distance regulation of the legume-Rhizobium symbiosis. PLANT & CELL PHYSIOLOGY 2013; 54:433-47. [PMID: 23390201 DOI: 10.1093/pcp/pct022] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The interaction of legumes with N2-fixing bacteria collectively called rhizobia results in root nodule development. The number of nodules formed is tightly restricted through the systemic negative feedback control by the host called autoregulation of nodulation (AON). Here, we report the characterization and gene identification of TOO MUCH LOVE (TML), a root factor that acts during AON in a model legume Lotus japonicus. In our genetic analyses using another root-regulated hypernodulation mutant, plenty, the tml-1 plenty double mutant showed additive effects on the nodule number, whereas the tml-1 har1-7 double mutant did not, suggesting that TML and PLENTY act in different genetic pathways and that TML and HAR1 act in the same genetic pathway. The systemic suppression of nodule formation by CLE-RS1/RS2 overexpression was not observed in the tml mutant background, indicating that TML acts downstream of CLE-RS1/RS2. The tml-1 Snf2 double mutant developed an excessive number of spontaneous nodules, indicating that TML inhibits nodule organogenesis. Together with the determination of the deleted regions in tml-1/-2/-3, the fine mapping of tml-4 and the next-generation sequencing analysis, we identified a nonsense mutation in the Kelch repeat-containing F-box protein. As the gene knockdown of the candidate drastically increased the number of nodules, we concluded that it should be the causative gene. An expression analysis revealed that TML is a root-specific gene. In addition, the activity of ProTML-GUS was constitutively detected in the root tip and in the nodules/nodule primordia upon rhizobial infection. In conclusion, TML is a root factor acting at the final stage of AON.
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Affiliation(s)
- Masahiro Takahara
- Department of Basic Biology in the School of Life Science of the Graduate University for Advanced Studies, Aichi, Japan
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22
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Chen Y, Yordanov YS, Ma C, Strauss S, Busov VB. DR5 as a reporter system to study auxin response in Populus. PLANT CELL REPORTS 2013; 32:453-63. [PMID: 23283559 DOI: 10.1007/s00299-012-1378-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 11/19/2012] [Accepted: 12/12/2012] [Indexed: 05/23/2023]
Abstract
KEY MESSAGE : Auxin responsive promoter DR5 reporter system is functional in Populus to monitor auxin response in tissues including leaves, roots, and stems. We described the behavior of the DR5::GUS reporter system in stably transformed Populus plants. We found several similarities with Arabidopsis, including sensitivity to native and synthetic auxins, rapid induction after treatment in a variety of tissues, and maximal responses in root tissues. There were also several important differences from Arabidopsis, including slower time to maximum response and lower induction amplitude. Young leaves and stem sections below the apex showed much higher DR5 activity than did older leaves and stems undergoing secondary growth. DR5 activity was highest in cortex, suggesting high levels of auxin concentration and/or sensitivity in this tissue. Our study shows that the DR5 reporter system is a sensitive and facile system for monitoring auxin responses and distribution at cellular resolution in poplar.
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Affiliation(s)
- Yiru Chen
- Michigan Technological University, School of Forest Research and Environmental Science, 1400 Townsend Drive, Houghton, MI 49931, USA
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23
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Osipova MA, Dolgikh EA, Lutova LA. Peculiarities of meristem-specific WOX5 gene expression during nodule organogenesis in legumes. Russ J Dev Biol 2011. [DOI: 10.1134/s1062360411010085] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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24
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D'haeseleer K, Den Herder G, Laffont C, Plet J, Mortier V, Lelandais-Brière C, De Bodt S, De Keyser A, Crespi M, Holsters M, Frugier F, Goormachtig S. Transcriptional and post-transcriptional regulation of a NAC1 transcription factor in Medicago truncatula roots. THE NEW PHYTOLOGIST 2011; 191:647-661. [PMID: 21770944 DOI: 10.1111/j.1469-8137.2011.03719.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
• Legume roots develop two types of lateral organs, lateral roots and nodules. Nodules develop as a result of a symbiotic interaction with rhizobia and provide a niche for the bacteria to fix atmospheric nitrogen for the plant. • The Arabidopsis NAC1 transcription factor is involved in lateral root formation, and is regulated post-transcriptionally by miRNA164 and by SINAT5-dependent ubiquitination. We analyzed in Medicago truncatula the role of the closest NAC1 homolog in lateral root formation and in nodulation. • MtNAC1 shows a different expression pattern in response to auxin than its Arabidopsis homolog and no changes in lateral root number or nodulation were observed in plants affected in MtNAC1 expression. In addition, no interaction was found with SINA E3 ligases, suggesting that post-translational regulation of MtNAC1 does not occur in M. truncatula. Similar to what was found in Arabidopsis, a conserved miR164 target site was retrieved in MtNAC1, which reduced protein accumulation of a GFP-miR164 sensor. Furthermore, miR164 and MtNAC1 show an overlapping expression pattern in symbiotic nodules, and overexpression of this miRNA led to a reduction in nodule number. • This work suggests that regulatory pathways controlling a conserved transcription factor are complex and divergent between M. truncatula and Arabidopsis.
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Affiliation(s)
- Katrien D'haeseleer
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium
| | - Griet Den Herder
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium
| | - Carole Laffont
- Institut des Sciences du Végétal (ISV), Centre National de la Recherche Scientifique (CNRS), 91198 Gif sur Yvette Cedex, France
| | - Julie Plet
- Institut des Sciences du Végétal (ISV), Centre National de la Recherche Scientifique (CNRS), 91198 Gif sur Yvette Cedex, France
| | - Virginie Mortier
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium
| | - Christine Lelandais-Brière
- Institut des Sciences du Végétal (ISV), Centre National de la Recherche Scientifique (CNRS), 91198 Gif sur Yvette Cedex, France
- Université Paris Diderot Paris 7, 75205 Paris Cedex 13, France
| | - Stefanie De Bodt
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium
| | - Annick De Keyser
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium
| | - Martin Crespi
- Institut des Sciences du Végétal (ISV), Centre National de la Recherche Scientifique (CNRS), 91198 Gif sur Yvette Cedex, France
| | - Marcelle Holsters
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium
| | - Florian Frugier
- Institut des Sciences du Végétal (ISV), Centre National de la Recherche Scientifique (CNRS), 91198 Gif sur Yvette Cedex, France
| | - Sofie Goormachtig
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, 9052 Gent, Belgium
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25
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Yendrek CR, Lee YC, Morris V, Liang Y, Pislariu CI, Burkart G, Meckfessel MH, Salehin M, Kessler H, Wessler H, Lloyd M, Lutton H, Teillet A, Sherrier DJ, Journet EP, Harris JM, Dickstein R. A putative transporter is essential for integrating nutrient and hormone signaling with lateral root growth and nodule development in Medicago truncatula. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 62:100-12. [PMID: 20088899 DOI: 10.1111/j.1365-313x.2010.04134.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Legume root architecture involves not only elaboration of the root system by the formation of lateral roots but also the formation of symbiotic root nodules in association with nitrogen-fixing soil rhizobia. The Medicago truncatula LATD/NIP gene plays an essential role in the development of both primary and lateral roots as well as nodule development. We have cloned the LATD/NIP gene and show that it encodes a member of the NRT1(PTR) transporter family. LATD/NIP is expressed throughout the plant. pLATD/NIP-GFP promoter-reporter fusions in transgenic roots establish the spatial expression of LATD/NIP in primary root, lateral root and nodule meristems and the surrounding cells. Expression of LATD/NIP is regulated by hormones, in particular by abscisic acid which has been previously shown to rescue the primary and lateral root meristem arrest of latd mutants. latd mutants respond normally to ammonium but have defects in responses of the root architecture to nitrate. Taken together, these results suggest that LATD/NIP may encode a nitrate transporter or transporter of another compound.
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Affiliation(s)
- Craig R Yendrek
- Department of Plant Biology, University of Vermont, Burlington, VT 05405-0086, USA
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26
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Buer CS, Imin N, Djordjevic MA. Flavonoids: new roles for old molecules. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:98-111. [PMID: 20074144 DOI: 10.1111/j.1744-7909.2010.00905.x] [Citation(s) in RCA: 364] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Flavonoids are ubiquitous in the plant kingdom and have many diverse functions including defense, UV protection, auxin transport inhibition, allelopathy, and flower coloring. Interestingly, these compounds also have considerable biological activity in plant, animal and bacterial systems - such broad activity is accomplished by few compounds. Yet, for all the research over the last three decades, many of the cellular targets of these secondary metabolites are unknown. The many mutants available in model plant species such as Arabidopsis thaliana and Medicago truncatula are enabling the intricacies of the physiology of these compounds to be deduced. In the present review, we cover recent advances in flavonoid research, discuss deficiencies in our understanding of the physiological processes, and suggest approaches to identify the cellular targets of flavonoids.
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Affiliation(s)
- Charles S Buer
- Genomic Interactions Group, ARC Centre of Excellence for Integrative Legume Research, Research School of Biology, College of Medicine, Biology, and Environment, The Australian National University, Canberra ACT 2601, Australia
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Kuppusamy KT, Ivashuta S, Bucciarelli B, Vance CP, Gantt JS, VandenBosch KA. Knockdown of CELL DIVISION CYCLE16 reveals an inverse relationship between lateral root and nodule numbers and a link to auxin in Medicago truncatula. PLANT PHYSIOLOGY 2009; 151:1155-66. [PMID: 19789288 PMCID: PMC2773094 DOI: 10.1104/pp.109.143024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 09/25/2009] [Indexed: 05/18/2023]
Abstract
The postembryonic development of lateral roots and nodules is a highly regulated process. Recent studies suggest the existence of cross talk and interdependency in the growth of these two organs. Although plant hormones, including auxin and cytokinin, appear to be key players in coordinating this cross talk, very few genes that cross-regulate root and nodule development have been uncovered so far. This study reports that a homolog of CELL DIVISION CYCLE16 (CDC16), a core component of the Anaphase Promoting Complex, is one of the key mediators in controlling the overall number of lateral roots and nodules. A partial suppression of this gene in Medicago truncatula leads to a decrease in number of lateral roots and a 4-fold increase in number of nodules. The roots showing lowered expression of MtCDC16 also show reduced sensitivity to phytohormone auxin, thus providing a potential function of CDC16 in auxin signaling.
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Affiliation(s)
| | | | | | | | | | - Kathryn A. VandenBosch
- Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (K.T.K., S.I., J.S.G., K.A.V.); and United States Department of Agriculture Agricultural Research Service, Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108 (B.B., C.P.V.)
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Gutjahr C, Casieri L, Paszkowski U. Glomus intraradices induces changes in root system architecture of rice independently of common symbiosis signaling. THE NEW PHYTOLOGIST 2009; 182:829-837. [PMID: 19383099 DOI: 10.1111/j.1469-8137.2009.02839.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Arbuscular mycorrhizal fungi colonize the roots of most monocotyledons and dicotyledons despite their different root architecture and cell patterning. Among the cereal hosts of arbuscular mycorrhizal fungi, Oryza sativa (rice) possesses a peculiar root system composed of three different types of roots: crown roots; large lateral roots; and fine lateral roots. Characteristic is the constitutive formation of aerenchyma in crown roots and large lateral roots and the absence of cortex from fine lateral roots. Here, we assessed the distribution of colonization by Glomus intraradices within this root system and determined its effect on root system architecture. Large lateral roots are preferentially colonized, and fine lateral roots are immune to arbuscular mycorrhizal colonization. Fungal preference for large lateral roots also occurred in sym mutants that block colonization of the root beyond rhizodermal penetration. Initiation of large lateral roots is significantly induced by G. intraradices colonization and does not require a functional common symbiosis signaling pathway from which some components are known to be needed for symbiosis-mediated lateral root induction in Medicago truncatula. Our results suggest variation of symbiotic properties among the different rice root-types and induction of the preferred tissue by arbuscular mycorrhizal fungi. Furthermore, signaling for arbuscular mycorrhizal-elicited alterations of the root system differs between rice and M. truncatula.
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Affiliation(s)
| | | | - Uta Paszkowski
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
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Markmann K, Parniske M. Evolution of root endosymbiosis with bacteria: How novel are nodules? TRENDS IN PLANT SCIENCE 2009; 14:77-86. [PMID: 19167260 DOI: 10.1016/j.tplants.2008.11.009] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 11/03/2008] [Accepted: 11/05/2008] [Indexed: 05/17/2023]
Abstract
Plants form diverse symbioses with nitrogen-fixing bacteria to gain access to ammonium, a product of the prokaryote-exclusive enzyme nitrogenase. Improving the symbiotic effectiveness of crop plants like maize, wheat or rice is a highly topical challenge and could help reduce the need for energy-intense nitrogen fertilizer in staple food production. Root nodule symbiosis (RNS) constitutes one of the most productive nitrogen-fixing systems, but it is restricted to a small group of related angiosperms. Here, we review the genetic regulation of RNS and its interconnections with other plant symbiosis or plant developmental programs. Since RNS uses genetic programs that are widely conserved in land plants, we evaluate the prospects for a transfer to plants that are currently non-nodulating.
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Affiliation(s)
- Katharina Markmann
- Genetics, Faculty of Biology, Ludwig Maximilians Universität, Munich, Germany.
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Buer CS, Djordjevic MA. Architectural phenotypes in the transparent testa mutants of Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:751-63. [PMID: 19129166 PMCID: PMC2652062 DOI: 10.1093/jxb/ern323] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 11/17/2008] [Accepted: 11/19/2008] [Indexed: 05/18/2023]
Abstract
Flavonoids are low molecular weight secondary plant metabolites with a myriad of functions. As flavonoids affect auxin transport (an important growth-controlling hormone) and are biologically active in eukaryotes, flavonoid mutants were expected to have undescribed architectural phenotypes. The Arabidopsis thaliana transparent testa (tt) mutants are compromised in the enzymatic steps or transcriptional regulators affecting flavonoid synthesis. tt mutant seedlings were grown on hard-slanted agar (a stress condition), under varying light conditions, and in soil to examine the resulting growth patterns. These tt mutants revealed a wide variety of architectural phenotypes in root and aerial tissues. Mutants with increased inflorescences, siliques, and lateral root density or reduced stature are traits that could affect plant yield or performance under certain environmental conditions. The regulatory genes affected in architectural traits may provide useful molecular targets for examination in other plants.
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Affiliation(s)
- Charles S Buer
- Australian Research Council Centre of Excellence for Integrative Legume Research, School of Science, College of Medicine, Biology, and Environment, The Australian National University, Canberra ACT 2601, Australia.
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Mathesius U. Auxin: at the root of nodule development? FUNCTIONAL PLANT BIOLOGY : FPB 2008; 35:651-668. [PMID: 32688821 DOI: 10.1071/fp08177] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 08/14/2008] [Indexed: 06/11/2023]
Abstract
Root nodules are formed as a result of an orchestrated exchange of chemical signals between symbiotic nitrogen fixing bacteria and certain plants. In plants that form nodules in symbiosis with actinorhizal bacteria, nodules are derived from lateral roots. In most legumes, nodules are formed de novo from pericycle and cortical cells that are re-stimulated for division and differentiation by rhizobia. The ability of plants to nodulate has only evolved recently and it has, therefore, been suggested that nodule development is likely to have co-opted existing mechanisms for development and differentiation from lateral root formation. Auxin is an important regulator of cell division and differentiation, and changes in auxin accumulation and transport are essential for lateral root development. There is growing evidence that rhizobia alter the root auxin balance as a prerequisite for nodule formation, and that nodule numbers are regulated by shoot-to-root auxin transport. Whereas auxin requirements appear to be similar for lateral root and nodule primordium activation and organ differentiation, the major difference between the two developmental programs lies in the specification of founder cells. It is suggested that differing ratios of auxin and cytokinin are likely to specify the precursors of the different root organs.
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Affiliation(s)
- Ulrike Mathesius
- School of Biochemistry and Molecular Biology, Australian National University and Australian Research Council Centre of Excellence for Integrative Legume Research, Linnaeus Way, Canberra, ACT 0200, Australia. Email
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Osborne B, Bergman B. Why Does Gunnera Do It and Other Angiosperms Don't? An Evolutionary Perspective on the Gunnera–Nostoc Symbiosis. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/7171_2007_116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Capoen W, Den Herder J, Rombauts S, De Gussem J, De Keyser A, Holsters M, Goormachtig S. Comparative transcriptome analysis reveals common and specific tags for root hair and crack-entry invasion in Sesbania rostrata. PLANT PHYSIOLOGY 2007; 144:1878-89. [PMID: 17600136 PMCID: PMC1949896 DOI: 10.1104/pp.107.102178] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The tropical legume Sesbania rostrata provides its microsymbiont Azorhizobium caulinodans with versatile invasion strategies to allow nodule formation in temporarily flooded habitats. In aerated soils, the bacteria enter via the root hair curling mechanism. Submergence prevents this epidermal invasion by accumulation of inhibiting concentrations of ethylene and, under these conditions, the bacterial colonization occurs via intercellular cortical infection at lateral root bases. The transcriptome of both invasion ways was compared by cDNA-amplified fragment length polymorphism analysis. Clusters of gene tags were identified that were specific for either epidermal or cortical invasion or were shared by both. The data provide insight into mechanisms that control infection and illustrate that entry via the epidermis adds a layer of complexity to rhizobial invasion.
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Affiliation(s)
- Ward Capoen
- Department of Plant Systems Biology, Flanders Institute for Biotechnology, Ghent University, B-9052 Ghent, Belgium
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Péret B, Swarup R, Jansen L, Devos G, Auguy F, Collin M, Santi C, Hocher V, Franche C, Bogusz D, Bennett M, Laplaze L. Auxin influx activity is associated with Frankia infection during actinorhizal nodule formation in Casuarina glauca. PLANT PHYSIOLOGY 2007; 144:1852-62. [PMID: 17556507 PMCID: PMC1949887 DOI: 10.1104/pp.107.101337] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Plants from the Casuarinaceae family enter symbiosis with the actinomycete Frankia leading to the formation of nitrogen-fixing root nodules. We observed that application of the auxin influx inhibitor 1-naphtoxyacetic acid perturbs actinorhizal nodule formation. This suggests a potential role for auxin influx carriers in the infection process. We therefore isolated and characterized homologs of the auxin influx carrier (AUX1-LAX) genes in Casuarina glauca. Two members of this family were found to share high levels of deduced protein sequence identity with Arabidopsis (Arabidopsis thaliana) AUX-LAX proteins. Complementation of the Arabidopsis aux1 mutant revealed that one of them is functionally equivalent to AUX1 and was named CgAUX1. The spatial and temporal expression pattern of CgAUX1 promoter:beta-glucuronidase reporter was analyzed in Casuarinaceae. We observed that CgAUX1 was expressed in plant cells infected by Frankia throughout the course of actinorhizal nodule formation. Our data suggest that auxin plays an important role during plant cell infection in actinorhizal symbioses.
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Affiliation(s)
- Benjamin Péret
- Unité Mixte de Recherche Diversité et Adaptation des Plantes Cultivées , Equipe Rhizogenèse, 34394 Montpellier cedex 5, France
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Nontachaiyapoom S, Scott PT, Men AE, Kinkema M, Schenk PM, Gresshoff PM. Promoters of orthologous Glycine max and Lotus japonicus nodulation autoregulation genes interchangeably drive phloem-specific expression in transgenic plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:769-80. [PMID: 17601165 DOI: 10.1094/mpmi-20-7-0769] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The nodule autoregulation receptor kinase (GmNARK) of soybean (Glycine max) is essential for the systemic autoregulation of nodulation. Based on quantitative reverse-transcriptase polymerase chain reaction, GmNARK is ex-pressed to varying levels throughout the plant; the transcript was detected at high levels in mature leaves and roots but to a lesser extent in young leaves, shoot tips, and nodules. The transcript level was not significantly affected by Bradyrhizobium japonicum during the first week following inoculation. In addition, the activities of the promoters of GmNARK and Lotus japonicus HARI, driving a beta-glucuronidase (GUSPlus) reporter gene, were examined in stably transformed L. japonicus and transgenic hairy roots of soybean. Histochemical GUS activity in L. japonicus plants carrying either a 1.7-kb GmNARKpr::GUS or 2.0-kb LjHAR1pr::GUS construct was clearly localized to living cells within vascular bundles, especially phloem cells in leaves, stems, roots, and nodules. Phloem-specific expression also was detected in soybean hairy roots carrying these constructs. Our study suggests that regulatory elements required for the transcription of these orthologous genes are conserved. Moreover, rapid amplification of 5' cDNA ends (5' rapid amplification of cDNA ends) revealed two major transcripts of GmNARK potentially originating from two TATA boxes. Further analysis of the GmNARK promoter has confirmed that these two TATA boxes are functional. Deletion analysis also located a region controlling phloem-specific expression to a DNA sequence between 908 bp and 1.7 kb upstream of the translation start site of GmNARK.
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Affiliation(s)
- Sureeporn Nontachaiyapoom
- Australian Research Council Centre of Excellence for Integrative Legume Research, University of Queensland, St. Lucia, QLD 4072, Australia
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Sprent JI, James EK. Legume evolution: where do nodules and mycorrhizas fit in? PLANT PHYSIOLOGY 2007; 144:575-81. [PMID: 17556520 PMCID: PMC1914177 DOI: 10.1104/pp.107.096156] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Accepted: 03/05/2007] [Indexed: 05/15/2023]
Affiliation(s)
- Janet I Sprent
- Division of Applied and Environmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom.
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Pii Y, Crimi M, Cremonese G, Spena A, Pandolfini T. Auxin and nitric oxide control indeterminate nodule formation. BMC PLANT BIOLOGY 2007; 7:21. [PMID: 17488509 PMCID: PMC1878477 DOI: 10.1186/1471-2229-7-21] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Accepted: 05/08/2007] [Indexed: 05/15/2023]
Abstract
BACKGROUND Rhizobia symbionts elicit root nodule formation in leguminous plants. Nodule development requires local accumulation of auxin. Both plants and rhizobia synthesise auxin. We have addressed the effects of bacterial auxin (IAA) on nodulation by using Sinorhizobium meliloti and Rhizobium leguminosarum bacteria genetically engineered for increased auxin synthesis. RESULTS IAA-overproducing S. meliloti increased nodulation in Medicago species, whilst the increased auxin synthesis of R. leguminosarum had no effect on nodulation in Phaseolus vulgaris, a legume bearing determinate nodules. Indeterminate legumes (Medicago species) bearing IAA-overproducing nodules showed an enhanced lateral root development, a process known to be regulated by both IAA and nitric oxide (NO). Higher NO levels were detected in indeterminate nodules of Medicago plants formed by the IAA-overproducing rhizobia. The specific NO scavenger cPTIO markedly reduced nodulation induced by wild type and IAA-overproducing strains. CONCLUSION The data hereby presented demonstrate that auxin synthesised by rhizobia and nitric oxide positively affect indeterminate nodule formation and, together with the observation of increased expression of an auxin efflux carrier in roots bearing nodules with higher IAA and NO content, support a model of nodule formation that involves auxin transport regulation and NO synthesis.
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Affiliation(s)
- Youry Pii
- Dipartimento Scientifico Tecnologico, University of Verona, Verona, Italy
| | - Massimo Crimi
- Dipartimento Scientifico Tecnologico, University of Verona, Verona, Italy
| | - Giorgia Cremonese
- Dipartimento Scientifico Tecnologico, University of Verona, Verona, Italy
| | - Angelo Spena
- Dipartimento Scientifico Tecnologico, University of Verona, Verona, Italy
| | - Tiziana Pandolfini
- Dipartimento Scientifico Tecnologico, University of Verona, Verona, Italy
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Affiliation(s)
- Bruce Osborne
- UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland (tel +35317162249; fax +35317161153; email )
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Sprent JI. Evolving ideas of legume evolution and diversity: a taxonomic perspective on the occurrence of nodulation. THE NEW PHYTOLOGIST 2007; 174:11-25. [PMID: 17335493 DOI: 10.1111/j.1469-8137.2007.02015.x] [Citation(s) in RCA: 218] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Legumes evolved about 60 million years ago (Ma), and nodulation 58 Ma. Nonnodulation remains common in Caesalpinioideae, with smaller numbers in Mimosoideae and Papilionoideae. The first type of infection by bacteria may have been at junctions where lateral roots emerged, followed by formation of infection threads to confine bacteria and convey them to some cells in the developing nodule, where they were generally released into symbiosomes. Infection threads were a prerequisite for root-hair infection, a process better controlled by the host, leading to a higher degree of specificity between symbionts. An alternative process, dating from the same time and persisting in about 25% of legumes, did not involve infection threads, bacteria entering a few host cells, surrounded by an undefined matrix. These cells divided repeatedly to give uniform infected tissue, with bacteria released into symbiosomes. Such legumes may have less stringent control of nodulation processes, and are found mainly in tropical and warm temperate areas. In each type of nodule, meristems may or may not be retained, leading to indeterminate or determinate forms. Nodule morphology and structure are host-determined, but the effectiveness of nitrogen fixation is largely controlled by the bacterial symbionts, which vary greatly in genotypic and phenotypic characters.
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Affiliation(s)
- Janet I Sprent
- Division of Applied and Environmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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Subramanian S, Stacey G, Yu O. Endogenous isoflavones are essential for the establishment of symbiosis between soybean and Bradyrhizobium japonicum. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 48:261-73. [PMID: 17018035 DOI: 10.1111/j.1365-313x.2006.02874.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Legume iso/flavonoids have been implicated in the nodulation process, but questions remain as to their specific role(s), and no unequivocal evidence exists showing that these compounds are essential for nodulation. Two hypotheses suggest that the primary role of iso/flavonoids is their ability to induce rhizobial nod gene expression and/or their ability to modulate internal root auxin concentrations. The present work provides direct, genetic evidence that isoflavones are essential for nodulation of soybean roots because of their ability to induce the nodulation genes of Bradyrhizobium japonicum. Expression of isoflavone synthase (IFS), a key enzyme in the biosynthesis of isoflavones, is specifically induced by B. japonicum. When IFS was silenced using RNA interference in soybean hairy root composite plants, these plants had severely reduced nodulation. Surprisingly, pre-treatment of B. japonicum or exogenous application to the root system of either of the major soybean isoflavones, daidzein or genistein, failed to restore normal nodulation. Silencing of chalcone reductase led to very low levels of daidzein and increased levels of genistein, but did not affect nodulation, suggesting that the endogenous production of genistein was sufficient to support nodulation. Consistent with a role for isoflavones as endogenous regulators of auxin transport in soybean roots, silencing of IFS resulted in altered auxin-inducible gene expression and auxin transport. However, use of a genistein-hypersensitive B. japonicum strain or purified B. japonicum Nod signals rescued normal nodulation in IFS-silenced roots, indicating that the ability of isoflavones to modulate auxin transport is not essential to nodulation.
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Kinkema M, Scott PT, Gresshoff PM. Legume nodulation: successful symbiosis through short- and long-distance signalling. FUNCTIONAL PLANT BIOLOGY : FPB 2006; 33:707-721. [PMID: 32689281 DOI: 10.1071/fp06056] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Accepted: 05/22/2006] [Indexed: 05/07/2023]
Abstract
Nodulation in legumes provides a major conduit of available nitrogen into the biosphere. The development of nitrogen-fixing nodules results from a symbiotic interaction between soil bacteria, commonly called rhizobia, and legume plants. Molecular genetic analysis in both model and agriculturally important legume species has resulted in the identification of a variety of genes that are essential for the establishment, maintenance and regulation of this symbiosis. Autoregulation of nodulation (AON) is a major internal process by which nodule numbers are controlled through prior nodulation events. Characterisation of AON-deficient mutants has revealed a novel systemic signal transduction pathway controlled by a receptor-like kinase. This review reports our present level of understanding on the short- and long-distance signalling networks controlling early nodulation events and AON.
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Affiliation(s)
- Mark Kinkema
- ARC Centre of Excellence for Integrative Legume Research, The University of Queensland, St Lucia, Brisbane, Qld 4072, Australia
| | - Paul T Scott
- ARC Centre of Excellence for Integrative Legume Research, The University of Queensland, St Lucia, Brisbane, Qld 4072, Australia
| | - Peter M Gresshoff
- ARC Centre of Excellence for Integrative Legume Research, The University of Queensland, St Lucia, Brisbane, Qld 4072, Australia
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Watt M, Silk WK, Passioura JB. Rates of root and organism growth, soil conditions, and temporal and spatial development of the rhizosphere. ANNALS OF BOTANY 2006; 97:839-55. [PMID: 16551700 PMCID: PMC2803425 DOI: 10.1093/aob/mcl028] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Revised: 10/05/2005] [Accepted: 01/05/2005] [Indexed: 05/07/2023]
Abstract
BACKGROUND Roots growing in soil encounter physical, chemical and biological environments that influence their rhizospheres and affect plant growth. Exudates from roots can stimulate or inhibit soil organisms that may release nutrients, infect the root, or modify plant growth via signals. These rhizosphere processes are poorly understood in field conditions. SCOPE AND AIMS We characterize roots and their rhizospheres and rates of growth in units of distance and time so that interactions with soil organisms can be better understood in field conditions. We review: (1) distances between components of the soil, including dead roots remnant from previous plants, and the distances between new roots, their rhizospheres and soil components; (2) characteristic times (distance(2)/diffusivity) for solutes to travel distances between roots and responsive soil organisms; (3) rates of movement and growth of soil organisms; (4) rates of extension of roots, and how these relate to the rates of anatomical and biochemical ageing of root tissues and the development of the rhizosphere within the soil profile; and (5) numbers of micro-organisms in the rhizosphere and the dependence on the site of attachment to the growing tip. We consider temporal and spatial variation within the rhizosphere to understand the distribution of bacteria and fungi on roots in hard, unploughed soil, and the activities of organisms in the overlapping rhizospheres of living and dead roots clustered in gaps in most field soils. CONCLUSIONS Rhizosphere distances, characteristic times for solute diffusion, and rates of root and organism growth must be considered to understand rhizosphere development. Many values used in our analysis were estimates. The paucity of reliable data underlines the rudimentary state of our knowledge of root-organism interactions in the field.
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Affiliation(s)
- Michelle Watt
- CSIRO Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia.
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Buer CS, Sukumar P, Muday GK. Ethylene modulates flavonoid accumulation and gravitropic responses in roots of Arabidopsis. PLANT PHYSIOLOGY 2006; 140:1384-96. [PMID: 16489132 PMCID: PMC1435817 DOI: 10.1104/pp.105.075671] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Plant organs change their growth direction in response to reorientation relative to the gravity vector. We explored the role of ethylene in Arabidopsis (Arabidopsis thaliana) root gravitropism. Treatment of wild-type Columbia seedlings with the ethylene precursor 1-aminocyclopropane carboxylic acid (ACC) reduced root elongation and gravitropic curvature. The ethylene-insensitive mutants ein2-5 and etr1-3 had wild-type root gravity responses, but lacked the growth and gravity inhibition by ACC found in the wild type. We examined the effect of ACC on tt4(2YY6) seedlings, which have a null mutation in the gene encoding chalcone synthase, the first enzyme in flavonoid synthesis. The tt4(2YY6) mutant makes no flavonoids, has elevated indole-3-acetic acid transport, and exhibits a delayed gravity response. Roots of tt4(2YY6), the backcrossed line tt4-2, and two other tt4 alleles had wild-type sensitivity to growth inhibition by ACC, whereas the root gravitropic curvature of these tt4 alleles was much less inhibited by ACC than wild-type roots, suggesting that ACC may reduce gravitropic curvature by altering flavonoid synthesis. ACC treatment induced flavonoid accumulation in root tips, as judged by a dye that becomes fluorescent upon binding flavonoids in wild type, but not in ein2-5 and etr1-3. ACC also prevented a transient peak in flavonoid synthesis in response to gravity. Together, these experiments suggest that elevated ethylene levels negatively regulate root gravitropism, using EIN2- and ETR1-dependent pathways, and that ACC inhibition of gravity response occurs through altering flavonoid synthesis.
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Affiliation(s)
- Charles S Buer
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina 27109, USA
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Perrine FM, Hocart CH, Hynes MF, Rolfe BG. Plasmid-associated genes in the model micro-symbiont Sinorhizobium meliloti 1021 affect the growth and development of young rice seedlings. Environ Microbiol 2005; 7:1826-38. [PMID: 16232297 DOI: 10.1111/j.1462-2920.2005.00927.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sinorhizobium meliloti strain 1021 and its closely related strain Rm2011 inhibit rice seedling (Oryza sativa L. cv. Pelde) growth and development under certain rice-growing conditions. Experiments showed that inoculation of seedlings with approximately less than 10 cells of 1021 was sufficient to cause this inhibition. By using a series of plasmid-cured and plasmid-deleted derivatives of Rm2011, it was found that interactions between genes encoded on pSymA, and possibly pSymB, of Rm2011, affected rice growth and development by affecting both/either the plant and/or the bacteria. Further studies found that genes potentially related to indole-3-acetic acid (IAA) synthesis and nitrate metabolism, encoded on pSymA, were involved in rice growth inhibition in Sm1021- and Sm2011-treated rice seedlings. We conclude that the rice growth inhibition by S. meliloti Sm1021 is pSymA-associated and is induced by environmental nitrate.
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Affiliation(s)
- Francine M Perrine
- Genomic Interactions Group, Research School of Biological Sciences, The Australian National University, GPO Box 475, Canberra, ACT 2601, Australia
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Liang Y, Harris JM. Response of root branching to abscisic acid is correlated with nodule formation both in legumes and nonlegumes. AMERICAN JOURNAL OF BOTANY 2005; 92:1675-83. [PMID: 21646084 DOI: 10.3732/ajb.92.10.1675] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Legumes are unique among higher plants in forming a symbiosis with Rhizobium. Phylogenetic studies indicate this symbiosis may have evolved as many as three times within the Fabaceae; alternatively, a predisposition for nodulation evolved early in the history of the legume lineage. We have identified a physiological trait-increased lateral root formation in response to abscisic acid (ABA)- that marks all nodulating and non-nodulating legume species in our study set with the exception of Chamaecrista fasciculata and Cercis occidentalis. In contrast, nonlegume species tested decrease lateral root formation in response to ABA. Cercis is not a descendant of any common ancestor hypothesized to have evolved Rhizobium nodulation and has an intermediate response to ABA, partway between that of nonlegumes and legumes. We suggest that acquisition of altered responsiveness of roots to ABA is coincident with the appearance of a predisposition for nodulation within the legumes, followed by a loss in Chamaecrista. In addition, we demonstrate that altered ABA responsiveness of lateral root formation characterizes roots of the actinorhizal nodulator, Casuarina glauca, but not the closely related, nonactinorhizal species, Betula papyrifera. Thus our data provide evidence for a physiological root trait associated with nodulation both in legumes and in an actinorhizal plant.
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Affiliation(s)
- Yan Liang
- Department of Botany, University of Vermont, Burlington, Vermont 05405-0086 USA
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Ferguson BJ, Reid JB. Cochleata: getting to the root of legume nodules. PLANT & CELL PHYSIOLOGY 2005; 46:1583-9. [PMID: 16043431 DOI: 10.1093/pcp/pci171] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The homeotic mutant of Pisum sativum, cochleata, has stipules replaced by alternative leaf components, abnormal flowers and reduced fertility. Although the root system dry weight, root lengths and nodule numbers of cochleata are similar to those of its wild type, the nodulation phenotype of the mutant is unique. The nodules typically dichotomously branch and multiple callus and root structures emerge from their meristems. These nodule-roots incorporate a peripheral vascular bundle of the nodule into their own central vascular cylinder. Both the nodules and roots of the hybrid structures appear functional. Roles for COCHLEATA in development are discussed.
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Affiliation(s)
- Brett J Ferguson
- School of Plant Science, University of Tasmania, Private Bag 55, Hobart, Tasmania, 7001, Australia
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Bright LJ, Liang Y, Mitchell DM, Harris JM. The LATD gene of Medicago truncatula is required for both nodule and root development. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:521-32. [PMID: 15986921 DOI: 10.1094/mpmi-18-0521] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The evolutionary origins of legume root nodules are largely unknown. We have identified a gene, LATD, of the model legume Medicago truncatula, that is required for both nodule and root development, suggesting that these two developmental processes may share a common evolutionary origin. The latd mutant plants initiate nodule formation but do not complete it, resulting in immature, non-nitrogen-fixing nodules. Similarly, lateral roots initiate, but remain short stumps. The primary root, which initially appears to be wild type, gradually ceases growth and forms an abnormal tip that resembles that of the mutant lateral roots. Infection by the rhizobial partner, Sinorhizobium meliloti, can occur, although infection is rarely completed. Once inside latd mutant nodules, S. meliloti fails to express rhizobial genes associated with the developmental transition from free-living bacterium to endosymbiont, such as bacA and nex38. The infecting rhizobia also fail to express nifH and fix nitrogen. Thus, both plant and bacterial development are blocked in latd mutant roots. Based on the latd mutant phenotype, we propose that the wild-type function of the LATD gene is to maintain root meristems. The strong requirement of both nodules and lateral roots for wild-type LATD gene function supports lateral roots as a possible evolutionary origin for legume nodules.
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Affiliation(s)
- Lydia J Bright
- Department of Botany and Agricultural Biochemistry, University of Vermont, Burlington 05405-0086, USA
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Ferraioli S, Tatè R, Rogato A, Chiurazzi M, Patriarca EJ. Development of ectopic roots from abortive nodule primordia. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2004; 17:1043-50. [PMID: 15497397 DOI: 10.1094/mpmi.2004.17.10.1043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The symbiotic phenotype of five Tn5-induced mutants of Rhizobium etli affected in different anabolic pathways (namely, gluconeogenesis and biosynthesis of lysine, purine, or pyrimidine) was analyzed. These mutants induced, on the root of Phaseolus vulgaris, a normal early sequence of morphogenetics events, including root hair deformation and development of nodule primordia. Later on, however, from the resulting root outgrowths, instead of nodules, one or more ectopic roots (spaced closely related and agravitropic) emerged. Therefore, this group of mutant was collectively called "root inducer" (RIND). It was observed that the RIND-induced infection threads aborted early inside the invaded root hair, and that the resulting abortive nodules lack induction of late nodulin genes. Moreover, experiments performed using a conditional mutant (a methionine-requiring invader) revealed that bacterial invasion plays a key role in the maintenance of the program of nodule development and, in particular, in the differentiation of the most specific symbiotic tissue of globose nodules, the central tissue. These data indicate that, in P. vulgaris, the nodule primordium is a root-specified pro-meristematic tissue.
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Affiliation(s)
- Simona Ferraioli
- Institute of Genetics and Biophysics A. Buzzati-Traverso, C.N.R., Via G. Marconi 10, 80125 Naples, Italy
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Brewin NJ. Plant Cell Wall Remodelling in the Rhizobium–Legume Symbiosis. CRITICAL REVIEWS IN PLANT SCIENCES 2004; 23:293-316. [PMID: 0 DOI: 10.1080/07352680490480734] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Abstract
All nutrients that plants absorb have to pass a region of intense interactions between roots, microorganisms and animals, termed the rhizosphere. Plants allocate a great portion of their photosynthetically fixed carbon to root-infecting symbionts, such asmycorrhizal fungi; another part is released as exudates fuelling mainly free-living rhizobacteria. Rhizobacteria are strongly top-down regulated by microfaunal grazers, particularly protozoa. Consequently, beneficial effects of protozoa on plant growth have been assigned to nutrients released from consumed bacterial biomass, that is, the 'microbial loop'. In recent years however, the recognition of bacterial communication networks, the common exchange of microbial signals with roots and the fact that these signals are used to enhance the efflux of carbon from roots have revolutionized our view of rhizosphere processes. Most importantly, effects of rhizobacteria on root architecture seem to be driven in large by protozoan grazers. Protozoan effects on plant root systems stand in sharp contrast to effects of mycorrhizal fungi. Because the regulation of root architecture is a key determinant of nutrient- and water-use efficiency in plants, protozoa provide a model system that may considerably advance our understanding of the mechanisms underlying plant growth and community composition.
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Affiliation(s)
- Michael Bonkowski
- Rhizosphere Ecology Group, Institut für Zoologie, Technische Universität Darmstadt, Schnittspahnstr. 3, D-64287 Darmstadt, Germany
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