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Involvement of AtNAP1 in the regulation of chlorophyll degradation in Arabidopsis thaliana
| Title: | Involvement of AtNAP1 in the regulation of chlorophyll degradation in Arabidopsis thaliana |
| Authors: | Nagane, Tomohiro Browse this author | | Tanaka, Ayumi Browse this author | | Tanaka, Ryouichi Browse this author |
| Keywords: | Arabidopsis thaliana | | Chlorophyll metabolism | | Plastid |
| Issue Date: | Mar-2010 |
| Publisher: | Springer Berlin / Heidelberg |
| Journal Title: | Planta |
| Volume: | 231 |
| Issue: | 4 |
| Start Page: | 939 |
| End Page: | 949 |
| Publisher DOI: | 10.1007/s00425-010-1099-8 |
| PMID: | 20087600 |
| Abstract: | In plants, chlorophyll is actively synthesized from glutamate in the developmental phase and degraded into non-fluorescent chlorophyll catabolites during senescence. The chlorophyll metabolism must be strictly regulated because chlorophylls and their intermediate molecules generate reactive oxygen species. Many mechanisms have been proposed for the regulation of chlorophyll synthesis including gene expression, protein stability, and feedback inhibition. However, information on the regulation of chlorophyll degradation is limited. The conversion of chlorophyll b to chlorophyll a is the first step of chlorophyll degradation. In order to understand the regulatory mechanism of this reaction, we isolated a mutant which accumulates 7-hydroxymethyl chlorophyll a (HMChl), an intermediate molecule of chlorophyll b to chlorophyll a conversion, and designated the mutant hmc1. In addition to HMChl, hmc1 accumulated pheophorbide a, a chlorophyll degradation product, when chlorophyll degradation was induced by dark incubation. These results indicate that the activities of HMChl reductase (HAR) and pheophorbide a oxygenase (PaO) are simultaneously down-regulated in this mutant. We identified a mutation in the AtNAP1 gene, which encodes a subunit of the complex for iron-sulfur cluster formation. HAR and PaO use ferredoxin as a reducing power and PaO has an iron-sulfur center; however, there were no distinct differences in the protein levels of ferredoxin and PaO between wild type and hmc1. The concerted regulation of chlorophyll degradation is discussed in relation to the function of AtNAP1. |
| Rights: | The original publication is available at www.springerlink.com |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/44896 |
| Appears in Collections: | 低温科学研究所 (Institute of Low Temperature Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 田中 亮一
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