Expression Studies of Superoxide Dismutases in Nodules and Leaves of Transgenic Alfalfa Reveal Abundance of Iron-Containing Isozymes, Posttranslational Regulation, and Compensation of Isozyme Activities
The composition of antioxidant enzymes, especially superoxide dismutase (SOD), was studied in one nontransgenic and three transgenic lines of nodulated alfalfa plants. Transgenic lines overproduced MnSOD in the mitochondria of nodules and leaves (line 1–10), MnSOD in the chloroplasts (line 4–6), and...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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The American Phytopathological Society
2001-10-01
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| Series: | Molecular Plant-Microbe Interactions |
| Online Access: | https://apsjournals.apsnet.org/doi/10.1094/MPMI.2001.14.10.1178 |
| _version_ | 1811264526776008704 |
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| author | Maria C. Rubio Javier Ramos K. Judith Webb Frank R. Minchin Esther González Cesar Arrese-Igor Manuel Becana |
| author_facet | Maria C. Rubio Javier Ramos K. Judith Webb Frank R. Minchin Esther González Cesar Arrese-Igor Manuel Becana |
| author_sort | Maria C. Rubio |
| collection | DOAJ |
| description | The composition of antioxidant enzymes, especially superoxide dismutase (SOD), was studied in one nontransgenic and three transgenic lines of nodulated alfalfa plants. Transgenic lines overproduced MnSOD in the mitochondria of nodules and leaves (line 1–10), MnSOD in the chloroplasts (line 4–6), and FeSOD in the chloroplasts (line 10–7). In nodules of line 10–7, the absence of transgene-encoded FeSOD activity was due to a lack of mRNA, whereas in nodules of line 4-6 the absence of transgene-encoded MnSOD activity was due to enzyme inactivation or degradation. Transgenic alfalfa showed a novel compensatory effect in the activities of MnSOD (mitochondrial) and FeSOD (plastidic) in the leaves, which was not caused by changes in the mRNA levels. These findings imply that SOD activity in plant tissues and organelles is regulated, at least partially, at the posttranslational level. All four lines had low CuZnSOD activities and an abundant FeSOD isozyme, especially in nodules, indicating that FeSOD performs important antioxidant functions other than the scavenging of superoxide radicals generated in photosynthesis. This was confirmed by the detection of FeSOD cDNAs and proteins in nodules of other legumes such as cowpea, pea, and soybean. The cDNA encoding alfalfa nodule FeSOD was characterized and the deduced protein found to contain a plastid transit peptide. A comparison of sequences and other properties reveals that there are two types of FeSODs in nodules. |
| first_indexed | 2024-04-12T20:05:57Z |
| format | Article |
| id | doaj.art-96d3d37bc6174379aeea8453e1cef650 |
| institution | Directory Open Access Journal |
| issn | 0894-0282 1943-7706 |
| language | English |
| last_indexed | 2024-04-12T20:05:57Z |
| publishDate | 2001-10-01 |
| publisher | The American Phytopathological Society |
| record_format | Article |
| series | Molecular Plant-Microbe Interactions |
| spelling | doaj.art-96d3d37bc6174379aeea8453e1cef6502022-12-22T03:18:24ZengThe American Phytopathological SocietyMolecular Plant-Microbe Interactions0894-02821943-77062001-10-0114101178118810.1094/MPMI.2001.14.10.1178Expression Studies of Superoxide Dismutases in Nodules and Leaves of Transgenic Alfalfa Reveal Abundance of Iron-Containing Isozymes, Posttranslational Regulation, and Compensation of Isozyme ActivitiesMaria C. RubioJavier RamosK. Judith WebbFrank R. MinchinEsther GonzálezCesar Arrese-IgorManuel BecanaThe composition of antioxidant enzymes, especially superoxide dismutase (SOD), was studied in one nontransgenic and three transgenic lines of nodulated alfalfa plants. Transgenic lines overproduced MnSOD in the mitochondria of nodules and leaves (line 1–10), MnSOD in the chloroplasts (line 4–6), and FeSOD in the chloroplasts (line 10–7). In nodules of line 10–7, the absence of transgene-encoded FeSOD activity was due to a lack of mRNA, whereas in nodules of line 4-6 the absence of transgene-encoded MnSOD activity was due to enzyme inactivation or degradation. Transgenic alfalfa showed a novel compensatory effect in the activities of MnSOD (mitochondrial) and FeSOD (plastidic) in the leaves, which was not caused by changes in the mRNA levels. These findings imply that SOD activity in plant tissues and organelles is regulated, at least partially, at the posttranslational level. All four lines had low CuZnSOD activities and an abundant FeSOD isozyme, especially in nodules, indicating that FeSOD performs important antioxidant functions other than the scavenging of superoxide radicals generated in photosynthesis. This was confirmed by the detection of FeSOD cDNAs and proteins in nodules of other legumes such as cowpea, pea, and soybean. The cDNA encoding alfalfa nodule FeSOD was characterized and the deduced protein found to contain a plastid transit peptide. A comparison of sequences and other properties reveals that there are two types of FeSODs in nodules.https://apsjournals.apsnet.org/doi/10.1094/MPMI.2001.14.10.1178 |
| spellingShingle | Maria C. Rubio Javier Ramos K. Judith Webb Frank R. Minchin Esther González Cesar Arrese-Igor Manuel Becana Expression Studies of Superoxide Dismutases in Nodules and Leaves of Transgenic Alfalfa Reveal Abundance of Iron-Containing Isozymes, Posttranslational Regulation, and Compensation of Isozyme Activities Molecular Plant-Microbe Interactions |
| title | Expression Studies of Superoxide Dismutases in Nodules and Leaves of Transgenic Alfalfa Reveal Abundance of Iron-Containing Isozymes, Posttranslational Regulation, and Compensation of Isozyme Activities |
| title_full | Expression Studies of Superoxide Dismutases in Nodules and Leaves of Transgenic Alfalfa Reveal Abundance of Iron-Containing Isozymes, Posttranslational Regulation, and Compensation of Isozyme Activities |
| title_fullStr | Expression Studies of Superoxide Dismutases in Nodules and Leaves of Transgenic Alfalfa Reveal Abundance of Iron-Containing Isozymes, Posttranslational Regulation, and Compensation of Isozyme Activities |
| title_full_unstemmed | Expression Studies of Superoxide Dismutases in Nodules and Leaves of Transgenic Alfalfa Reveal Abundance of Iron-Containing Isozymes, Posttranslational Regulation, and Compensation of Isozyme Activities |
| title_short | Expression Studies of Superoxide Dismutases in Nodules and Leaves of Transgenic Alfalfa Reveal Abundance of Iron-Containing Isozymes, Posttranslational Regulation, and Compensation of Isozyme Activities |
| title_sort | expression studies of superoxide dismutases in nodules and leaves of transgenic alfalfa reveal abundance of iron containing isozymes posttranslational regulation and compensation of isozyme activities |
| url | https://apsjournals.apsnet.org/doi/10.1094/MPMI.2001.14.10.1178 |
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