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A combined reduction in activity of starch synthases II and III of potato has novel effects on the starch of tubers
Author(s) -
Edwards Anne,
Fulton Daniel C..,
Hylton Christopher M..,
Jobling Stephen A..,
Gidley Michael,
Rössner Ute,
Martin Cathie,
Smith Alison M..
Publication year - 1999
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 - 10.1046/j.1365-313x.1999.00371.x
Subject(s) - amylopectin , starch , starch synthase , amylose , solanum tuberosum , biochemistry , chemistry , granule (geology) , potato starch , food science , biology , botany , paleontology
Summary A chimeric antisense construct has been used to generate transgenic potatoes (Solanum tuberosumL.) in which activities of both of the main starch synthases responsible for amylopectin synthesis in the tuber (SSII and SSIII) are reduced. The properties of starch from tubers of these plants have been compared with those of starches from transgenic plants in which activity of either SSII or SSIII has been reduced. Starches from the three types of transgenic plant are qualitatively different from each other and from the starch of control plants with unaltered starch synthase activities, with respect to granule morphology, the branch lengths of amylopectin, and the gelatinisation behaviour analysed by viscometry. The effects of reducing SSII and SSIII together cannot be predicted from consideration of the effects of reducing these two isoforms individually. These results indicate that different isoforms of starch synthase make distinct contributions to the synthesis of amylopectin, and that they act in a synergistic manner, rather than independently, during amylopectin synthesis.