Premium
The phenotype of soluble starch synthase IV defective mutants of Arabidopsis thaliana suggests a novel function of elongation enzymes in the control of starch granule formation
Author(s) -
Roldán Isaac,
Wattebled Fabrice,
Mercedes Lucas M.,
Delvallé David,
Planchot Veronique,
Jiménez Sebastian,
Pérez Ricardo,
Ball Steven,
D'Hulst Christophe,
Mérida Ángel
Publication year - 2007
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2006.02968.x
Subject(s) - starch synthase , mutant , starch , biochemistry , elongation , granule (geology) , enzyme , plastid , biology , atp synthase , arabidopsis , chemistry , gene , amylopectin , chloroplast , paleontology , materials science , amylose , ultimate tensile strength , metallurgy
Summary All plants and green algae synthesize starch through the action of the same five classes of elongation enzymes: the starch synthases. Arabidopsis mutants defective for the synthesis of the soluble starch synthase IV (SSIV) type of elongation enzyme have now been characterized. The mutant plants displayed a severe growth defect but nonetheless accumulated near to normal levels of polysaccharide storage. Detailed structural analysis has failed to yield any change in starch granule structure. However, the number of granules per plastid has dramatically decreased leading to a large increase in their size. These results, which distinguish the SSIV mutants from all other mutants reported to date, suggest a specific function of this enzyme class in the control of granule numbers. We speculate therefore that SSIV could be selectively involved in the priming of starch granule formation.