Chlorophyll breakdown in Chlorella protothecoides: characterization of degreening and cloning of degreening-related genes

Hörtensteiner, Stefan; Chinner, Joanne; Matile, Philippe; Thomas, Howard; Donnison, Iain S. (2000). Chlorophyll breakdown in Chlorella protothecoides: characterization of degreening and cloning of degreening-related genes. Plant molecular biology, 42(3), pp. 439-450. Springer 10.1023/A:1006380125438

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Chlorella protothecoides cultures grown in a nitrogen-free bleaching medium (BM−N) in the dark rapidly degraded chlorophyll (Chl) to red catabolites. This degreening process was investigated under different growth conditions. Supply of nitrogen to the culture medium (BM+N) inhibited bleaching and the synthesis of catabolites as did the addition to BM−N of cycloheximide or a chelator, 2,2′-bipyridyl. In contrast, chloramphenicol or the protease inhibitor E64 had no effect. During bleaching, Chl breakdown was accompanied by the degradation of cellular proteins such as light-harvesting complex II, cytochrome f and protochlorophyllide oxido-reductase. During growth in BM–N, protease activity increased and proteins immunologically detectable with an antibody against a senescence-enhanced cysteine protease accumulated. cDNAs from BM−N and BM+N cells were used for differential and subtractive screening to isolate cDNAs representing genes with degreening-enhanced expression (dee) in C. protothecoides. Several different dees were identified with different patterns of expression during Chlorella growth but which were all expressed at higher levels during bleaching. Among these, dee4 was most abundant and its expression was exclusive in BM–N cultures. Analysis of the dee sequences showed that they encode different proteins including a novel amino acid carrier (dee4), ferritin, ATP-dependent citrate lyase, a Ca2+-binding protein, MO25, ubiquinone-cytochrome c-reductase and several new proteins.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS) > Plant nutrition (discontinued)
08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS)

UniBE Contributor:

Hörtensteiner, Stefan

Subjects:

500 Science > 580 Plants (Botany)

ISSN:

0167-4412

Publisher:

Springer

Language:

English

Submitter:

Peter Alfred von Ballmoos-Haas

Date Deposited:

16 Nov 2016 13:29

Last Modified:

05 Jul 2017 09:46

Publisher DOI:

10.1023/A:1006380125438

BORIS DOI:

10.7892/boris.90350

URI:

https://boris.unibe.ch/id/eprint/90350

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