MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis
Most legume plants can form nodules, specialized lateral organs that form on roots, and house nitrogen-fixing bacteria collectively called rhizobia. The uptake of the phytohormone auxin into cells is known to be crucial for development of lateral roots. To test the role of auxin influx in nodulation...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
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American Society of Plant Biologists
2017
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| Online Access: | https://eprints.nottingham.ac.uk/42910/ |
| _version_ | 1848796599660052480 |
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| author | Roy, Sonali Robson, Fran Lilley, Jodi Liu, Cheng-Wu Cheng, Xiaofei Wen, Jiangqi Walker, Simon Sun, Jongho Cousins, Donna Bone, Caitlin Bennett, Malcolm J. Downie, J. Allan Swarup, Ranjan Oldroyd, Giles Murray, Jeremy D. |
| author_facet | Roy, Sonali Robson, Fran Lilley, Jodi Liu, Cheng-Wu Cheng, Xiaofei Wen, Jiangqi Walker, Simon Sun, Jongho Cousins, Donna Bone, Caitlin Bennett, Malcolm J. Downie, J. Allan Swarup, Ranjan Oldroyd, Giles Murray, Jeremy D. |
| author_sort | Roy, Sonali |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Most legume plants can form nodules, specialized lateral organs that form on roots, and house nitrogen-fixing bacteria collectively called rhizobia. The uptake of the phytohormone auxin into cells is known to be crucial for development of lateral roots. To test the role of auxin influx in nodulation we used the auxin influx inhibitors 1-naphthoxyacetic acid (1-NOA) and 2-NOA, which we found reduced nodulation of Medicago truncatula. This suggested the possible involvement of the AUX/LAX family of auxin influx transporters in nodulation. Gene expression studies identified MtLAX2, a paralogue of Arabidopsis (Arabidopsis thaliana) AUX1, as being induced at early stages of nodule development. MtLAX2 is expressed in nodule primordia, the vasculature of developing nodules, and at the apex of mature nodules. The MtLAX2 promoter contains several auxin response elements, and treatment with indole-acetic acid strongly induces MtLAX2 expression in roots. mtlax2 mutants displayed root phenotypes similar to Arabidopsis aux1 mutants, including altered root gravitropism, fewer lateral roots, shorter root hairs, and auxin resistance. In addition, the activity of the synthetic DR5-GUS auxin reporter was strongly reduced in mtlax2 roots. Following inoculation with rhizobia, mtlax2 roots developed fewer nodules, had decreased DR5-GUS activity associated with infection sites, and had decreased expression of the early auxin responsive gene ARF16a. Our data indicate that MtLAX2 is a functional analog of Arabidopsis AUX1 and is required for the accumulation of auxin during nodule formation in tissues underlying sites of rhizobial infection. |
| first_indexed | 2025-11-14T19:50:33Z |
| format | Article |
| id | nottingham-42910 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:50:33Z |
| publishDate | 2017 |
| publisher | American Society of Plant Biologists |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-429102020-05-04T19:57:42Z https://eprints.nottingham.ac.uk/42910/ MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis Roy, Sonali Robson, Fran Lilley, Jodi Liu, Cheng-Wu Cheng, Xiaofei Wen, Jiangqi Walker, Simon Sun, Jongho Cousins, Donna Bone, Caitlin Bennett, Malcolm J. Downie, J. Allan Swarup, Ranjan Oldroyd, Giles Murray, Jeremy D. Most legume plants can form nodules, specialized lateral organs that form on roots, and house nitrogen-fixing bacteria collectively called rhizobia. The uptake of the phytohormone auxin into cells is known to be crucial for development of lateral roots. To test the role of auxin influx in nodulation we used the auxin influx inhibitors 1-naphthoxyacetic acid (1-NOA) and 2-NOA, which we found reduced nodulation of Medicago truncatula. This suggested the possible involvement of the AUX/LAX family of auxin influx transporters in nodulation. Gene expression studies identified MtLAX2, a paralogue of Arabidopsis (Arabidopsis thaliana) AUX1, as being induced at early stages of nodule development. MtLAX2 is expressed in nodule primordia, the vasculature of developing nodules, and at the apex of mature nodules. The MtLAX2 promoter contains several auxin response elements, and treatment with indole-acetic acid strongly induces MtLAX2 expression in roots. mtlax2 mutants displayed root phenotypes similar to Arabidopsis aux1 mutants, including altered root gravitropism, fewer lateral roots, shorter root hairs, and auxin resistance. In addition, the activity of the synthetic DR5-GUS auxin reporter was strongly reduced in mtlax2 roots. Following inoculation with rhizobia, mtlax2 roots developed fewer nodules, had decreased DR5-GUS activity associated with infection sites, and had decreased expression of the early auxin responsive gene ARF16a. Our data indicate that MtLAX2 is a functional analog of Arabidopsis AUX1 and is required for the accumulation of auxin during nodule formation in tissues underlying sites of rhizobial infection. American Society of Plant Biologists 2017-05 Article PeerReviewed Roy, Sonali, Robson, Fran, Lilley, Jodi, Liu, Cheng-Wu, Cheng, Xiaofei, Wen, Jiangqi, Walker, Simon, Sun, Jongho, Cousins, Donna, Bone, Caitlin, Bennett, Malcolm J., Downie, J. Allan, Swarup, Ranjan, Oldroyd, Giles and Murray, Jeremy D. (2017) MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis. Plant Physiology, 174 (1). pp. 326-338. ISSN 1532-2548 http://www.plantphysiol.org/content/174/1/326 doi:10.1104/pp.16.01473 doi:10.1104/pp.16.01473 |
| spellingShingle | Roy, Sonali Robson, Fran Lilley, Jodi Liu, Cheng-Wu Cheng, Xiaofei Wen, Jiangqi Walker, Simon Sun, Jongho Cousins, Donna Bone, Caitlin Bennett, Malcolm J. Downie, J. Allan Swarup, Ranjan Oldroyd, Giles Murray, Jeremy D. MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis |
| title | MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis |
| title_full | MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis |
| title_fullStr | MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis |
| title_full_unstemmed | MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis |
| title_short | MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis |
| title_sort | mtlax2, a functional homologue of the arabidopsis auxin influx transporter aux1, is required for nodule organogenesis |
| url | https://eprints.nottingham.ac.uk/42910/ https://eprints.nottingham.ac.uk/42910/ https://eprints.nottingham.ac.uk/42910/ |