1
|
Zhang CX, Li RJ, Baude L, Reinhardt D, Xie ZP, Staehelin C. CRISPR/Cas9-Mediated Generation of Mutant Lines in Medicago truncatula Indicates a Symbiotic Role of MtLYK10 during Nodule Formation. BIOLOGY 2024; 13:53. [PMID: 38275729 PMCID: PMC10812973 DOI: 10.3390/biology13010053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/27/2024]
Abstract
CRISPR/Cas9 systems are commonly used for plant genome editing; however, the generation of homozygous mutant lines in Medicago truncatula remains challenging. Here, we present a CRISPR/Cas9-based protocol that allows the efficient generation of M. truncatula mutants. Gene editing was performed for the LysM receptor kinase gene MtLYK10 and two major facilitator superfamily transporter genes. The functionality of CRISPR/Cas9 vectors was tested in Nicotiana benthamiana leaves by editing a co-transformed GUSPlus gene. Transformed M. truncatula leaf explants were regenerated to whole plants at high efficiency (80%). An editing efficiency (frequency of mutations at a given target site) of up to 70% was reached in the regenerated plants. Plants with MtLYK10 knockout mutations were propagated, and three independent homozygous mutant lines were further characterized. No off-target mutations were identified in these lyk10 mutants. Finally, the lyk10 mutants and wild-type plants were compared with respect to the formation of root nodules induced by nitrogen-fixing Sinorhizobium meliloti bacteria. Nodule formation was considerably delayed in the three lyk10 mutant lines. Surprisingly, the size of the rare nodules in mutant plants was higher than in wild-type plants. In conclusion, the symbiotic characterization of lyk10 mutants generated with the developed CRISPR/Cas9 protocol indicated a role of MtLYK10 in nodule formation.
Collapse
Affiliation(s)
- Chun-Xiao Zhang
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Ru-Jie Li
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Laura Baude
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Didier Reinhardt
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Zhi-Ping Xie
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Christian Staehelin
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| |
Collapse
|
2
|
Reyero-Saavedra R, Fuentes SI, Leija A, Jiménez-Nopala G, Peláez P, Ramírez M, Girard L, Porch TG, Hernández G. Identification and Characterization of Common Bean ( Phaseolus vulgaris) Non-Nodulating Mutants Altered in Rhizobial Infection. PLANTS (BASEL, SWITZERLAND) 2023; 12:1310. [PMID: 36986997 PMCID: PMC10059843 DOI: 10.3390/plants12061310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/07/2023] [Accepted: 03/12/2023] [Indexed: 06/19/2023]
Abstract
The symbiotic N2-fixation process in the legume-rhizobia interaction is relevant for sustainable agriculture. The characterization of symbiotic mutants, mainly in model legumes, has been instrumental for the discovery of symbiotic genes, but similar studies in crop legumes are scant. To isolate and characterize common bean (Phaseolus vulgaris) symbiotic mutants, an ethyl methanesulphonate-induced mutant population from the BAT 93 genotype was analyzed. Our initial screening of Rhizobium etli CE3-inoculated mutant plants revealed different alterations in nodulation. We proceeded with the characterization of three non-nodulating (nnod), apparently monogenic/recessive mutants: nnod(1895), nnod(2353) and nnod(2114). Their reduced growth in a symbiotic condition was restored when the nitrate was added. A similar nnod phenotype was observed upon inoculation with other efficient rhizobia species. A microscopic analysis revealed a different impairment for each mutant in an early symbiotic step. nnod(1895) formed decreased root hair curling but had increased non-effective root hair deformation and no rhizobia infection. nnod(2353) produced normal root hair curling and rhizobia entrapment to form infection chambers, but the development of the latter was blocked. nnod(2114) formed infection threads that did not elongate and thus did not reach the root cortex level; it occasionally formed non-infected pseudo-nodules. The current research is aimed at mapping the responsible mutated gene for a better understanding of SNF in this critical food crop.
Collapse
Affiliation(s)
- Rocío Reyero-Saavedra
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca 62210, Morelos, Mexico; (R.R.-S.); (S.I.F.); (A.L.); (G.J.-N.); (P.P.); (M.R.); (L.G.)
| | - Sara Isabel Fuentes
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca 62210, Morelos, Mexico; (R.R.-S.); (S.I.F.); (A.L.); (G.J.-N.); (P.P.); (M.R.); (L.G.)
| | - Alfonso Leija
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca 62210, Morelos, Mexico; (R.R.-S.); (S.I.F.); (A.L.); (G.J.-N.); (P.P.); (M.R.); (L.G.)
| | - Gladys Jiménez-Nopala
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca 62210, Morelos, Mexico; (R.R.-S.); (S.I.F.); (A.L.); (G.J.-N.); (P.P.); (M.R.); (L.G.)
| | - Pablo Peláez
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca 62210, Morelos, Mexico; (R.R.-S.); (S.I.F.); (A.L.); (G.J.-N.); (P.P.); (M.R.); (L.G.)
| | - Mario Ramírez
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca 62210, Morelos, Mexico; (R.R.-S.); (S.I.F.); (A.L.); (G.J.-N.); (P.P.); (M.R.); (L.G.)
| | - Lourdes Girard
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca 62210, Morelos, Mexico; (R.R.-S.); (S.I.F.); (A.L.); (G.J.-N.); (P.P.); (M.R.); (L.G.)
| | - Timothy G. Porch
- USDA-ARS, Tropical Agriculture Research Station, 2200 P.A. Campos Avenue, Suite 201, Mayaguez 00680, Puerto Rico;
| | - Georgina Hernández
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca 62210, Morelos, Mexico; (R.R.-S.); (S.I.F.); (A.L.); (G.J.-N.); (P.P.); (M.R.); (L.G.)
| |
Collapse
|
3
|
Li X, Liu M, Cai M, Chiasson D, Groth M, Heckmann AB, Wang TL, Parniske M, Downie JA, Xie F. RPG interacts with E3-ligase CERBERUS to mediate rhizobial infection in Lotus japonicus. PLoS Genet 2023; 19:e1010621. [PMID: 36735729 PMCID: PMC9931111 DOI: 10.1371/journal.pgen.1010621] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 02/15/2023] [Accepted: 01/17/2023] [Indexed: 02/04/2023] Open
Abstract
Symbiotic interactions between rhizobia and legumes result in the formation of root nodules, which fix nitrogen that can be used for plant growth. Rhizobia usually invade legume roots through a plant-made tunnel-like structure called an infection thread (IT). RPG (Rhizobium-directed polar growth) encodes a coiled-coil protein that has been identified in Medicago truncatula as required for root nodule infection, but the function of RPG remains poorly understood. In this study, we identified and characterized RPG in Lotus japonicus and determined that it is required for IT formation. RPG was induced by Mesorhizobium loti or purified Nodulation factor and displayed an infection-specific expression pattern. Nodule inception (NIN) bound to the RPG promoter and induced its expression. We showed that RPG displayed punctate subcellular localization in L. japonicus root protoplasts and in root hairs infected by M. loti. The N-terminal predicted C2 lipid-binding domain of RPG was not required for this subcellular localization or for function. CERBERUS, a U-box E3 ligase which is also required for rhizobial infection, was found to be localized similarly in puncta. RPG co-localized and directly interacted with CERBERUS in the early endosome (TGN/EE) compartment and near the nuclei in root hairs after rhizobial inoculation. Our study sheds light on an RPG-CERBERUS protein complex that is involved in an exocytotic pathway mediating IT elongation.
Collapse
Affiliation(s)
- Xiaolin Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Miaoxia Liu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Min Cai
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - David Chiasson
- Faculty of Biology, University of Munich, Großhaderner Straße 2–4, Planegg-Martinsried, Germany
| | - Martin Groth
- Faculty of Biology, University of Munich, Großhaderner Straße 2–4, Planegg-Martinsried, Germany
| | - Anne B. Heckmann
- John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Trevor L. Wang
- John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Martin Parniske
- Faculty of Biology, University of Munich, Großhaderner Straße 2–4, Planegg-Martinsried, Germany
| | - J. Allan Downie
- John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Fang Xie
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|
4
|
Li RJ, Zhang CX, Fan SY, Wang YH, Wen J, Mysore KS, Xie ZP, Staehelin C. The Medicago truncatula hydrolase MtCHIT5b degrades Nod factors of Sinorhizobium meliloti and cooperates with MtNFH1 to regulate the nodule symbiosis. FRONTIERS IN PLANT SCIENCE 2022; 13:1034230. [PMID: 36466271 PMCID: PMC9712974 DOI: 10.3389/fpls.2022.1034230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
Nod factors secreted by nitrogen-fixing rhizobia are lipo-chitooligosaccharidic signals required for establishment of the nodule symbiosis with legumes. In Medicago truncatula, the Nod factor hydrolase 1 (MtNFH1) was found to cleave Nod factors of Sinorhizobium meliloti. Here, we report that the class V chitinase MtCHIT5b of M. truncatula expressed in Escherichia coli can release lipodisaccharides from Nod factors. Analysis of M. truncatula mutant plants indicated that MtCHIT5b, together with MtNFH1, degrades S. meliloti Nod factors in the rhizosphere. MtCHIT5b expression was induced by treatment of roots with purified Nod factors or inoculation with rhizobia. MtCHIT5b with a fluorescent tag was detected in the infection pocket of root hairs. Nodulation of a MtCHIT5b knockout mutant was not significantly altered whereas overexpression of MtCHIT5b resulted in fewer nodules. Reduced nodulation was observed when MtCHIT5b and MtNFH1 were simultaneously silenced in RNA interference experiments. Overall, this study shows that nodule formation of M. truncatula is regulated by a second Nod factor cleaving hydrolase in addition to MtNFH1.
Collapse
Affiliation(s)
- Ru-Jie Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Chun-Xiao Zhang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Sheng-Yao Fan
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yi-Han Wang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jiangqi Wen
- Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Kirankumar S. Mysore
- Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhi-Ping Xie
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Christian Staehelin
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| |
Collapse
|