Al. Maddison et al., Expression of tandem invertase genes associated with sexual and vegetativegrowth cycles in potato, PLANT MOL B, 41(6), 1999, pp. 741-751
The organisation of two invertase genes (invGE and invGF) linked in direct
tandem repeat within the potato genome is detailed. The genes exhibit a sim
ilar intron/exon structure which differs from previously described plant in
vertase genes; while intron locations are conserved between the genes, mino
r differences in exon length are seen. Both genes encode enzymes with putat
ive extracellular location. Biochemical analysis of gene expression showed
expression in floral tissues for both genes, with expression of the upstrea
m gene (invGE) also detected in leaf tissue. Promoter sequences from both g
enes have been fused to the beta-glucuronidase (GUS) reporter gene (uidA) a
nd transformed into potato. One promoter-GUS reporter construct was also tr
ansformed into tobacco. Histochemical analysis of transgenic lines defined
specific expression from the downstream (invGF) promoter in potato and toba
cco pollen, with expression first detected in the late uninucleate stage of
tobacco microspore development. The invGE promoter determined expression i
n pollen and other floral tissues, but also at lateral nodes in stem, root
and tuber. An association of invertase expression with generative tissue, b
oth in vegetative and sexual modes of growth, is indicated.