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Sense transformation reveals a novel role for class I β‐1,3‐glucanase in tobacco seed germination
Author(s) -
LeubnerMetzger Gerhard,
Meins Frederick
Publication year - 2000
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.2000.00773.x
Subject(s) - endosperm , abscisic acid , germination , radicle , glucanase , biology , ripening , botany , gibberellin , seed dormancy , horticulture , dormancy , microbiology and biotechnology , enzyme , biochemistry , gene
Summary ‘Coat‐enhanced’ seed dormancy of many dicotyledonous species, including tobacco, is released during after‐ripening. Rupture of the endosperm, which is the limiting step in tobacco seed germination, is preceded by induction of class I β‐1,3‐glucanase (βGLU I) in the micropylar endosperm where the radicle will penetrate. Treating after‐ripened tobacco seeds with abscisic acid (ABA) delays endosperm rupture and inhibits βGLU I induction. Sense transformation with a chimeric ABA‐inducible βGLU I transgene resulted in over‐expression of βGLU I in seeds and promoted endosperm rupture of mature seeds and of ABA‐treated after‐ripened seeds. Taken together, these results provide direct evidence that βGLU I contributes to endosperm rupture. Over‐expression of βGLU I during germination also replaced the effects of after‐ripening on endosperm rupture. This suggests that regulation of βGLU I by ABA signalling pathways might have a key role in after‐ripening.