Sc. Ilgoutz et al., TRANSCRIPTION OF GENES FOR CONGLUTIN-GAMMA AND A LEGINSULIN-LIKE PROTEIN IN NARROW-LEAFED LUPIN, Plant molecular biology, 34(4), 1997, pp. 613-627
The expression of genes encoding conglutin gamma and a leginsulin-like
protein has been examined in narrow-leafed lupin, Lupinus angustifoli
us L. Conglutin gamma is a homologue of basic 7S globulin (Bg), the in
sulin and leginsulin binding protein from soybean. Accumulation of con
glutin gamma mRNA, as assessed by northern assays and reverse-transcri
ption PCR, was tightly regulated both spatially and temporally in lupi
n plants and was detected almost exclusively in developing seeds. Simi
lar tissue and temporal specificity was demonstrated when 1.8 kb of th
e promoter region from the conglutin gamma gene was used to drive the
expression of a beta-glucuronidase reporter gene in transgenic plants.
In stably transformed tobacco the conglutin gamma promoter produced s
trong, temporally regulated and seed-specific expression of the report
er gene which was localised to the embryo tissues and to a layer of ce
lls adjacent to the seed coat. A truncated 0.29 kb promoter fragment p
roduced much reduced levels of expression and a loss of embryo specifi
city. Leginsulin-like mRNA was similarly detected in lupins only in de
veloping seeds. The leginsulin-like gene detected in L. angustifolius
showed 96% sequence identity to leginsulin from soybean within the 280
bp region amplified from lupin by PCR. The results demonstrate that b
oth components of a Bg-leginsulin putative signal transduction pathway
are present in the seeds of lupin.