© 1997 Heron Publishing—Victoria, Canada
Influences of altered phytohormone use on endogenous ABA and mRNA populations during white spruce (Picea glauca) somatic embryo culture
Jin-Zhuo Dong, Cheryl A. Bock and David I. Dunstan
Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, Saskatchewan S7N 0W9,
Canada / Received November 9, 1995
Summary
We examined endogenous abscisic acid [(+)-ABA] amounts and mRNA populations in white spruce (Picea glauca (Moench) Voss) somatic embryos in liquid suspension culture during a pretreatment prior to induction of maturation with exogenous
(+)-ABA. The pretreatment consisted of removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from the multiplication medium for
7 days. The removal of 2,4-D resulted in a slight increase in endogenous ABA in pretreated tissues compared to nonpretreated
tissues at the end of the 7-day pretreatment period (42.4 versus 20.0 pg mg–1 lyophilized tissue). Altered gene expression patterns were observed as early as one day after the start of the pretreatment,
with more than 17 new polypeptides found in pretreated tissues. The influence of pretreatment continued to be observed after
tissues were transferred to ABA-containing maturation medium. By comparing mRNA populations in pretreated and nonpretreated
tissues cultured on either ABA-containing or ABA-free maturation medium, at least 12 mRNAs were observed to be induced by
ABA, among which three polypeptides were ABA inducible only in pretreated tissues.
Keywords:
abscisic acid, 2,4-dichlorophenoxyacetic acid, embryogenic cultures, gene expression.
