Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2008
Publication Date: N/A
Technical Abstract: We have identified and characterized a novel rice Leucine Rich Repeat-Receptor Kinase (LRR-RK) gene promoter. The 2,272 bp upstream genomic sequence of the LRR-RK gene was PCR amplified and cloned. The cloned genomic fragment includes the putative promoter, the 5´ untranslated region containing a 5´ intron and the first 4 codons of the LRR-RK gene. This genomic sequence was translationally fused to a bifunctional '-glucuronidase-enhanced Green Fluorescent Protein (GUS-eGFP) reporter gene in pGPro1, a novel binary vector well suited for monocot promoter characterization. Using Agrobacterium-mediated transformation, more than 15 independent T0 transgenic rice plant lines expressing detectable levels of reporter gene expression have been generated. Promoter function has been characterized using both RNA transcript analyses and assays detecting the transgenic reporter protein. GUS-eGFP expression has been extensively examined in 5 representative transgenic lines in the T1 and T2 generations. The LRR-RK promoter drives high levels of expression in most of the aerial parts of the rice plant, with the exception of the reproductive tissues. Weak or no expression was detectable in plant roots or in undifferentiated rice callus grown in tissue culture. Transgene expression in etiolated seedlings was modest and dramatically enhanced by exposure to light. Data from further characterization of this promoter and other candidate organ-specific cereal crop promoters under investigation will be presented. Our research goal is to identify a battery of cereal crop promoters that will be useful for precisely controlling transgene expression in genetically engineered crops.