Open AccessE m polypeptide and its messenger RNA levels are modulated by abscisic acid during embryogenesis in wheat
Author(s) -
WILLIAMSON John D.,
QUATRANO Ralph S.,
CUMING Andrew C.
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb09224.x
Subject(s) - northern blot , abscisic acid , complementary dna , biology , microbiology and biotechnology , messenger rna , western blot , cdna library , dot blot , embryo , rna , southern blot , protein biosynthesis , gene , biochemistry
The effect of abscisic acid (ABA) on the expression of the ‘early‐methionine‐labeled’ (E m ) polypeptide was examined in cultured, immature wheat ( Triticum aestivum , L.) embryos and in developing embryos and in developing embryos in planta . A complementary DNA (cDNA) library was constructed from poly(A)‐rich RNA from immature embryos cultured in the presence of ABA. ABA‐enhanced sequences were first identified by differential colony‐blot hybridization, and then verified using RNA slot‐blot analysis. Dot‐blot hybridization showed that one clone, p1015, was homologous to the previously isolated E m cDNA, pWG432. Electrophoretic analysis of the hybrid‐select translation product of p1015 confirmed its identity as an E m sequence. Comparison of the p1015 cDNA insert size and the E m message size, from northern blot analysis, showed that p1015 contained about 87% of the E m sequence. RNA slot‐blot analysis and protein electrophoresis showed that E m message, but not E m protein, accumulated at a low, basal level in immature embryos in the absence of ABA. Neither E m message nor E m protein was seen in three‐day germinated seedlings. Steady‐state levels of E m message and protein increased in immature embryos in the presence of ABA, both in culture and in planta . Regulation appeared to be primarily at the level of transcription or specific message stability. Regulation may also involve specific protein stability, since synthesis of E m protein continued in immature embryos in the absence of ABA, but E m protein did not accumulate in detectable amounts. We conclude that ABA specifically modulates E m message and protein levels in immature embryos, but is probably not responsible for the embryogenic specificity of E m expression.