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García-Soto I, Andersen SU, Monroy-Morales E, Robledo-Gamboa M, Guadarrama J, Aviles-Baltazar NY, Serrano M, Stougaard J, Montiel J. A collection of novel Lotus japonicus LORE1 mutants perturbed in the nodulation program induced by the Agrobacterium pusense strain IRBG74. FRONTIERS IN PLANT SCIENCE 2024; 14:1326766. [PMID: 38250449 PMCID: PMC10796720 DOI: 10.3389/fpls.2023.1326766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/12/2023] [Indexed: 01/23/2024]
Abstract
The Lotus japonicus population carrying new Lotus retrotransposon 1 (LORE1) insertions represents a valuable biological resource for genetic research. New insertions were generated by activation of the endogenous retroelement LORE1a in the germline of the G329-3 plant line and arranged in a 2-D system for reverse genetics. LORE1 mutants identified in this collection contributes substantially to characterize candidate genes involved in symbiotic association of L. japonicus with its cognate symbiont, the nitrogen-fixing bacteria Mesorhizobium loti that infects root nodules intracellularly. In this study we aimed to identify novel players in the poorly explored intercellular infection induced by Agrobacterium pusense IRBG74 sp. For this purpose, a forward screen of > 200,000 LORE1 seedlings, obtained from bulk propagation of G329-3 plants, inoculated with IRBG74 was performed. Plants with perturbed nodulation were scored and the offspring were further tested on plates to confirm the symbiotic phenotype. A total of 110 Lotus mutants with impaired nodulation after inoculation with IRBG74 were obtained. A comparative analysis of nodulation kinetics in a subset of 20 mutants showed that most of the lines were predominantly affected in nodulation by IRBG74. Interestingly, additional defects in the main root growth were observed in some mutant lines. Sequencing of LORE1 flanking regions in 47 mutants revealed that 92 Lotus genes were disrupted by novel LORE1 insertions in these lines. In the IM-S34 mutant, one of the insertions was located in the 5´UTR of the LotjaGi5g1v0179800 gene, which encodes the AUTOPHAGY9 protein. Additional mutant alleles, named atg9-2 and atg9-3, were obtained in the reverse genetic collection. Nodule formation was significantly reduced in these mutant alleles after M. loti and IRBG74 inoculation, confirming the effectiveness of the mutant screening. This study describes an effective forward genetic approach to obtain novel mutants in Lotus with a phenotype of interest and to identify the causative gene(s).
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Affiliation(s)
- Ivette García-Soto
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Stig U. Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Elizabeth Monroy-Morales
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Mariana Robledo-Gamboa
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Jesús Guadarrama
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | | | - Mario Serrano
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Jens Stougaard
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Jesús Montiel
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
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Montiel J, García-Soto I, James EK, Reid D, Cárdenas L, Napsucialy-Mendivil S, Ferguson S, Dubrovsky JG, Stougaard J. Aromatic amino acid biosynthesis impacts root hair development and symbiotic associations in Lotus japonicus. PLANT PHYSIOLOGY 2023; 193:1508-1526. [PMID: 37427869 PMCID: PMC10517252 DOI: 10.1093/plphys/kiad398] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/07/2023] [Accepted: 06/12/2023] [Indexed: 07/11/2023]
Abstract
Legume roots can be symbiotically colonized by arbuscular mycorrhizal (AM) fungi and nitrogen-fixing bacteria. In Lotus japonicus, the latter occurs intracellularly by the cognate rhizobial partner Mesorhizobium loti or intercellularly with the Agrobacterium pusense strain IRBG74. Although these symbiotic programs show distinctive cellular and transcriptome signatures, some molecular components are shared. In this study, we demonstrate that 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase 1 (DAHPS1), the first enzyme in the biosynthetic pathway of aromatic amino acids (AAAs), plays a critical role in root hair development and for AM and rhizobial symbioses in Lotus. Two homozygous DAHPS1 mutants (dahps1-1 and dahps1-2) showed drastic alterations in root hair morphology, associated with alterations in cell wall dynamics and a progressive disruption of the actin cytoskeleton. The altered root hair structure was prevented by pharmacological and genetic complementation. dahps1-1 and dahps1-2 showed significant reductions in rhizobial infection (intracellular and intercellular) and nodule organogenesis and a delay in AM colonization. RNAseq analysis of dahps1-2 roots suggested that these phenotypes are associated with downregulation of several cell wall-related genes, and with an attenuated signaling response. Interestingly, the dahps1 mutants showed no detectable pleiotropic effects, suggesting a more selective recruitment of this gene in certain biological processes. This work provides robust evidence linking AAA metabolism to root hair development and successful symbiotic associations.
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Affiliation(s)
- Jesús Montiel
- Departamento de Genómica Funcional de Eucariotas. Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca 62210, Mexico
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus DK-8000, Denmark
| | - Ivette García-Soto
- Departamento de Genómica Funcional de Eucariotas. Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca 62210, Mexico
| | - Euan K James
- Ecological Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Dugald Reid
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus DK-8000, Denmark
- Department of Animal, Plant and Soil Sciences, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Luis Cárdenas
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca 62210, Mexico
| | - Selene Napsucialy-Mendivil
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca 62210, Mexico
| | - Shaun Ferguson
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus DK-8000, Denmark
| | - Joseph G Dubrovsky
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca 62210, Mexico
| | - Jens Stougaard
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus DK-8000, Denmark
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