Promoters for molecular farming and/or early detection of transgenic plants

Abstract

Late embryogenesis abundant (Lea) proteins accumulate in maturing seeds after many of the storage compounds have been synthesized, and they are considered relevant to maturation. We report here the molecular organization and expression of BnLea3-1, a novel Group 3 Lea gene from Brassica napus. BnLea3-1 contains a coding region of 798 bp, sharing 84.4% homology at the amino acid level with Lea76 of B. napus. Two tandem 11-mer repeats are truncated from the coding region of BnLea3-1, compared to the 13 conserved 11-mer repeats of Lea76. Substitutions of consensus residues are found at various positions within the 11-mer repeats. A 1561 bp 5′ flanking promoter fragment of BnLea3-1 fused to E. coli β-glucurondiase (GUS) coding region conferred seed-specific GUS expression in stable transgenics of B. napus, tobacco and in transiently-transformed pea. A −137 bp minimal promoter preceding the first transcription start site, identified through progressive deletions from the upstream was sufficient for basal GUS expression in the seeds and in leaves treated with ABA. Deletion studies indicate the presence of enhancing elements located between −137 bp to −742 bp and suppressing elements located between −742 and −1561 bp. Bnlea3-1 expression in seeds precedes that of Lea76. Unlike other Group 3 Lea members including HVA1 and Dc3, BnLea3-1 is active in seeds and responsive weakly in vegetative tissues to ABA and methyl jasmonate (MeJA) but not to stress treatments. Possible functions of BnLea3-1 and another member of the Group 3 Lea family BnLea3-2 in embryo development is discussed.

We claim:  
     
         1 . An isolated DNA sequence or a DNA fragment or homologues thereof which selectively promotes gene expression in a plant seed, and under certain conditions in vegetative tissues for early detection of gene expression.  
     
     
         2 . An isolated DNA sequence as shown in FIG. 6 or a DNA fragment thereof or a DNA sequence substantially homologous thereto for expressing another DNA sequence in a seed.  
     
     
         3 . An isolated DNA sequence as shown in FIG. 6 or a DNA fragment thereof or a DNA sequence substantially homologous thereto for expressing another DNA sequence in vegetative tissue under certain conditions for early detection of the expressed DNA sequence.  
     
     
         4 . A plant, seed, vector, or expression cassette containing an isolated DNA sequence as shown in FIG. 6 or a DNA fragment thereof or a DNA sequence substantially homologous thereto.  
     
     
         5 . An isolated DNA sequence as shown in FIG. 11 or a DNA fragment thereof or a DNA sequence substantially homologous thereto for expressing another DNA sequence in a seed.  
     
     
         6 . An isolated DNA sequence as shown in FIG. 11 or a DNA fragment thereof or a DNA sequence substantially homologous thereto for expressing another DNA sequence in vegetative tissue under certain conditions for early detection of the expressed DNA sequence.  
     
     
         7 . A plant, seed, vector, or expression cassette containing an isolated DNA sequence as shown in FIG. 11 or a DNA fragment thereof or a DNA sequence substantially homologous thereto.