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A male gametophyte‐specific monosaccharide transporter in Arabidopsis
Author(s) -
Truernit Elisabeth,
Stadler Ruth,
Baier Kerstin,
Sauer Norbert
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.1999.00372.x
Subject(s) - gametophyte , callose , pollen , biology , microspore , arabidopsis , arabidopsis thaliana , messenger rna , microbiology and biotechnology , monosaccharide , pollen tube , gene , biochemistry , stamen , botany , mutant , pollination
Summary TheAtSTP2gene (sugar transport protein 2) ofArabidopsis thalianaencodes a high affinity, low specificity monosaccharide carrier that can transport a number of hexoses and pentoses at similar rates. AtSTP2 has 12 putative transmembrane helices and a molecular mass of 55.0 kDa.AtSTP2expression was localized inAtSTP2promoter‐β‐glucuronidase (GUS)Arabidopsisplants showingAtSTP2‐driven GUS activity during pollen maturation and also in germinating pollen. Immunohistochemical studies with anti‐AtSTP2 antiserum as well as RNAin situhybridization analyses modified these results and showed thatAtSTP2expression is confined to the early stages of gametophyte development. BothAtSTP2mRNA and AtSTP2 protein are first seen at the time of beginning callose degradation and microspore release from the tetrades.AtSTP2mRNA and AtSTP2 protein are no longer detected after the mitotic divisions and the formation of the trinucleate gametophyte. NoAtSTP2mRNA or AtSTP2 protein is seen in fully developed or germinating pollen. The putative role of AtSTP2 in the uptake of glucose units resulting from callose degradation during pollen maturation is discussed.