Molecular cloning and analysis of a pea cDNA that is expressed in darkness and very rapidly induced by gibberellic acid.
Using cDNA representational difference analysis (cDNA RDA), we isolated a cDNA named GDA-1 from a cDNA library constructed with mRNA from short-day (SD) grown G2 pea apical tissue. The amino acid sequence deduced from GDA-1 shares partial identity with the B2 protein which is expressed during embryogenesis of carrot cells. Northern analysis showed that GDA-1 mRNA is abundant in SD-grown G2 pea apical buds. In long-day (LD) conditions, there was almost no detectable GDA-1 mRNA. When LD-grown G2 peas were kept in continuous darkness for 24 h, the GDA-1 mRNA content reached a level equivalent to about 50% of that in the SD samples. On the other hand, when SD-grown peas were transferred into the light for 24 h, the amount of hybridizable GDA-1 mRNA dropped to the same as that of LD-grown plants. GDA-1 expression was found to be independent of flower initiation time. GA3 application in vitro resulted in rapid accumulation of GDA-1 mRNA in LD-grown G2 pea apical buds, which is compatible with its delaying effect on apical senescence. Time-course experiments revealed that GDA-1 is induced within 15 min of GA3 application. Exogenous GA3 did not influence the expression of GDA-1 in SD-grown G2 peas. Since both photoperiod and GA induce the expression of GDA-1, we speculate that they may activate similar signal transduction pathways in G2 peas. Our work also shows that photoperiod may change the efficiency of gibberellin perception by plants.
Li
H Y
HY
The National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing, People's Republic of China.
Guo
Z F
ZF
Zhu
Y X
YX
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D003624:Darkness; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000494:pharmacology*; D008969:Molecular Sequence Data; D018532:Pisum sativum / Q000235:genetics*; D010940:Plant Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; C115244:GDA-1 protein, Pisum sativum; D005875:Gibberellins; D010940:Plant Proteins; C007842:gibberellic acid