vectors for plant transformation and promoter analysis 34 methods enzymol 153 292 305 1987 transgenic plants transformed with the construct palf ifrl gus containing the longer 765 bp promoter fragment are referred to as 34 ifrl gus 34 plants similarly transgenic plants transformed with palf ifrs gus containing the shorter promoter fragment a 329 bp deletion to the ecori site within the longer promoter are referred to as 34 ifrs gus 34 plants both constructs are transcriptional fusions to the gus gene in which 80 nucleotides of the 92 nucleotide untranslated leader sequence of the ifr transcript were maintained intact these two constructs along with pbi121 camv 35s promoter gus for constitutive expression controls and pbi101 1 as a control for gus with no promoter were introduced into tobacco and alfalfa plants by agrobacterium mediated plant transformation regenerated plants were shown to be transformed by southern analysis using both a gus specific probe bamhi saci fragment of pbi101 1 and an ifr promoter specific probe the 845 bp spei fragment from pao4 1 border analysis indicated a range of 1 to 6 transgene copies in tobacco and 1 to 4 copies in alfalfa of eight ifrl gus independent tobacco transformants with the same qualitative gus staining pattern four plants t8 t9 t11 and t14 showed higher levels of staining with x gluc and were used in all studies all seven independent transgenic tobacco plants obtained by transformation with the short promoter construct showed the.