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Characterization of cDNAs encoding two isoforms of granule‐bound starch synthase which show differential expression in developing storage organs of pea and potato
Author(s) -
Dry Ian,
Smith Alison,
Edwards Anne,
Bhattacharyya Madan,
Dunn Paul,
Martin Cathie
Publication year - 1992
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.1992.t01-42-00999.x
Subject(s) - gene isoform , biology , starch synthase , complementary dna , gene , biochemistry , isozyme , cdna library , microbiology and biotechnology , enzyme , starch , amylopectin , amylose
Summary We have isolated cDNA clones to two isoforms of granule‐bound starch synthase (GBSS) from pea embryos and potato tubers. The sequences of both isoforms are related to that of glycogen synthase from E. coli and one, GBSSI, is very similar to the waxy protein of maize and other species. In pea, GBSSII carries a novel 203‐amino‐acid domain at its N‐terminus. Genes encoding both proteins are expressed during pea embryo development, but GBSSII is most highly expressed earlier in development than GBSSI. Similarly, GBSSI and GBSSII are differentially expressed in developing potato tubers. Expression of both isoforms is much lower in other organs of pea than in embryos. GBSSII is expressed in every organ tested while GBSSI is not expressed in roots, stipules or flowers. The possible consequences of this differential use of GBSS isoforms are discussed.