Characterization of a Functional Role of the Bradyrhizobium japonicum Isocitrate Lyase in Desiccation Tolerance
Bradyrhizobium japonicum is a nitrogen-fixing symbiont of soybean. In previous studies, transcriptomic profiling of B. japonicum USDA110, grown under various environmental conditions, revealed the highly induced gene aceA, encoding isocitrate lyase (ICL). The ICL catalyzes the conversion of isocitr...
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MDPI AG
2015-07-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | http://www.mdpi.com/1422-0067/16/7/16695 |
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| author | Jeong-Min Jeon Hae-In Lee Michael J. Sadowsky Masayuki Sugawara Woo-Suk Chang |
| author_facet | Jeong-Min Jeon Hae-In Lee Michael J. Sadowsky Masayuki Sugawara Woo-Suk Chang |
| author_sort | Jeong-Min Jeon |
| collection | DOAJ |
| description | Bradyrhizobium japonicum is a nitrogen-fixing symbiont of soybean. In previous studies, transcriptomic profiling of B. japonicum USDA110, grown under various environmental conditions, revealed the highly induced gene aceA, encoding isocitrate lyase (ICL). The ICL catalyzes the conversion of isocitrate to succinate and glyoxylate in the glyoxylate bypass of the TCA cycle. Here, we evaluated the functional role of B. japonicum ICL under desiccation-induced stress conditions. We purified AceA (molecular mass = 65 kDa) from B. japonicum USDA110, using a His-tag and Ni-NTA column approach, and confirmed its ICL enzyme activity. The aceA mutant showed higher sensitivity to desiccation stress (27% relative humidity (RH)), compared to the wild type. ICL activity of the wild type strain increased approximately 2.5-fold upon exposure to 27% RH for 24 h. The aceA mutant also showed an increased susceptibility to salt stress. Gene expression analysis of aceA using qRT-PCR revealed a 148-fold induction by desiccation, while other genes involved in the glyoxylate pathway were not differentially expressed in this condition. Transcriptome analyses revealed that stress-related genes, such as chaperones, were upregulated in the wild-type under desiccating conditions, even though fold induction was not dramatic (ca. 1.5–2.5-fold). |
| first_indexed | 2024-04-13T02:11:03Z |
| format | Article |
| id | doaj.art-f9fcf90a0cd448c685368c634fd0caf0 |
| institution | Directory Open Access Journal |
| issn | 1422-0067 |
| language | English |
| last_indexed | 2024-04-13T02:11:03Z |
| publishDate | 2015-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-f9fcf90a0cd448c685368c634fd0caf02022-12-22T03:07:18ZengMDPI AGInternational Journal of Molecular Sciences1422-00672015-07-01167166951670910.3390/ijms160716695ijms160716695Characterization of a Functional Role of the Bradyrhizobium japonicum Isocitrate Lyase in Desiccation ToleranceJeong-Min Jeon0Hae-In Lee1Michael J. Sadowsky2Masayuki Sugawara3Woo-Suk Chang4Department of Biology, University of Texas, Arlington, TX 76019, USADepartment of Biology, University of Texas, Arlington, TX 76019, USADepartment of Soil, Water & Climate, and The BioTechnology Institute, University of Minnesota, St. Paul, MN 55108, USADepartment of Soil, Water & Climate, and The BioTechnology Institute, University of Minnesota, St. Paul, MN 55108, USADepartment of Biology, University of Texas, Arlington, TX 76019, USABradyrhizobium japonicum is a nitrogen-fixing symbiont of soybean. In previous studies, transcriptomic profiling of B. japonicum USDA110, grown under various environmental conditions, revealed the highly induced gene aceA, encoding isocitrate lyase (ICL). The ICL catalyzes the conversion of isocitrate to succinate and glyoxylate in the glyoxylate bypass of the TCA cycle. Here, we evaluated the functional role of B. japonicum ICL under desiccation-induced stress conditions. We purified AceA (molecular mass = 65 kDa) from B. japonicum USDA110, using a His-tag and Ni-NTA column approach, and confirmed its ICL enzyme activity. The aceA mutant showed higher sensitivity to desiccation stress (27% relative humidity (RH)), compared to the wild type. ICL activity of the wild type strain increased approximately 2.5-fold upon exposure to 27% RH for 24 h. The aceA mutant also showed an increased susceptibility to salt stress. Gene expression analysis of aceA using qRT-PCR revealed a 148-fold induction by desiccation, while other genes involved in the glyoxylate pathway were not differentially expressed in this condition. Transcriptome analyses revealed that stress-related genes, such as chaperones, were upregulated in the wild-type under desiccating conditions, even though fold induction was not dramatic (ca. 1.5–2.5-fold).http://www.mdpi.com/1422-0067/16/7/16695symbiotic nitrogen fixationBradyrhizobium japonicumisocitrate lyase (ICL)aceAdesiccation stress |
| spellingShingle | Jeong-Min Jeon Hae-In Lee Michael J. Sadowsky Masayuki Sugawara Woo-Suk Chang Characterization of a Functional Role of the Bradyrhizobium japonicum Isocitrate Lyase in Desiccation Tolerance International Journal of Molecular Sciences symbiotic nitrogen fixation Bradyrhizobium japonicum isocitrate lyase (ICL) aceA desiccation stress |
| title | Characterization of a Functional Role of the Bradyrhizobium japonicum Isocitrate Lyase in Desiccation Tolerance |
| title_full | Characterization of a Functional Role of the Bradyrhizobium japonicum Isocitrate Lyase in Desiccation Tolerance |
| title_fullStr | Characterization of a Functional Role of the Bradyrhizobium japonicum Isocitrate Lyase in Desiccation Tolerance |
| title_full_unstemmed | Characterization of a Functional Role of the Bradyrhizobium japonicum Isocitrate Lyase in Desiccation Tolerance |
| title_short | Characterization of a Functional Role of the Bradyrhizobium japonicum Isocitrate Lyase in Desiccation Tolerance |
| title_sort | characterization of a functional role of the bradyrhizobium japonicum isocitrate lyase in desiccation tolerance |
| topic | symbiotic nitrogen fixation Bradyrhizobium japonicum isocitrate lyase (ICL) aceA desiccation stress |
| url | http://www.mdpi.com/1422-0067/16/7/16695 |
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