PROMOTERS FOR MOLECULAR FARMING AND/OR EARLY DETECTION OF TRANSGENIC PLANTS

摘要

Late embryogenesis abundant (Lea) proteins accumulate in maturing seedsafter many of the storage compounds have been synthesized, and they areconsideredrelevant to maturation. We report here the molecular organization andexpression ofBnLea3-1, a novel Group 3 Lea gene from Brassica napus. BnLea3-1 contains acoding region of 798 bp, sharing 84.4% homology at the amino acid level withLea76of B. napus. Two tandem 11-mer repeats are truncated from the coding region ofBnLea3-l, compared to the 13 conserved 11-mer repeats of Lea76. Substitutionsofconsensus residues are found at various positions within the 11-mer repeats. A1561by 5' flanking promoter fragment of BnLea3-1 fused to E. coli .beta.3-glucurondiase(GUS) coding region conferred seed-specific GUS expression in stabletransgenics ofB. napus, tobacco and in transiently-transformed pea. A -137 by minimalpromoterpreceding the first transcription start site, identified through progressivedeletionsfrom the upstream, was sufficient for basal GUS expression in the seeds aridin leavestreated with ABA. Deletion studies indicate the presence of enhancing elementslocated between -137 by to -742 by and suppressing elements located between -742and -1561 bp. Bnlea3-1 expression in seeds precedes that of Lea76. UnlikeotherGroup 3 Lea members including HVA1 and Dc3, BnLea3-1 is active in seeds andresponsive weakly in vegetative tissues to ABA and methyl jasmonate (MeJA) hutnotto stress treatments. Possible functions of BnLea3-1 and another member of theGroup3 Lea family BnLea3-2 in embryo development is discussed.