| Autor: |
Delrue, B, Fontaine, T, Routier, F, Decq, A, Wieruszeski, J M, Van Den Koornhuyse, N, Maddelein, M L, Fournet, B, Ball, S |
| Zdroj: |
Journal of Bacteriology; June 1992, Vol. 174 Issue: 11 p3612-3620, 9p |
| Abstrakt: |
Amylose-defective mutants were selected after UV mutagenesis of Chlamydomonas reinhardtii cells. Two recessive nuclear alleles of the ST-2 gene led to the disappearance not only of amylose but also of a fraction of the amylopectin. Granule-bound starch synthase activities were markedly reduced in strains carrying either st-2-1 or st-2-2, as is the case for amylose-deficient (waxy) endosperm mutants of higher plants. The main 76-kDa protein associated with the starch granule was either missing or greatly diminished in both mutants, while st-2-1-carrying strains displayed a novel 56-kDa major protein. Methylation and nuclear magnetic resonance analysis of wild-type algal storage polysaccharide revealed a structure identical to that of higher-plant starch, while amylose-defective mutants retained a modified amylopectin fraction. We thus propose that the waxy gene product conditions not only the synthesis of amylose from endosperm storage tissue in higher-plant amyloplasts but also that of amylose and a fraction of amylopectin in all starch-accumulating plastids. The nature of the ST-2 (waxy) gene product with respect to the granule-bound starch synthase activities is discussed. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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