THE PLANT CELL, Vol 2, Issue 3 185-194, Copyright © 1990 by American Society of Plant Biologists
Identification and Genetic Regulation of the Chalcone Synthase Multigene Family in Pea
C. L. Harker, THN. Ellis and E. S. Coen
John Innes Institute and AFRC Institute of Plant Science Research, Colney Lane, Norwich,NR4 7UH, United Kingdom
Chalcone synthase (CHS) is a key enzyme in the biosynthesis of diverse
flavonoids involved in disease resistance, nodulation, and pigmentation in
pea. We describe a multigene family encoding CHS and the effects of two
regulatory loci, a and a2, on the pattern of expression of three of its
member genes. Two of the genes, CHS1 and CHS3, are expressed in both petal
and root tissue, whereas expression of a third gene, CHS2, is detected only
in roots. The products encoded by the a and a2 loci are required for the
expression of the CHS1 gene and for wild-type levels of expression of the
CHS3 gene in petal tissue. In root tissue, all three CHS genes are
expressed and induced by CuCl2 regardless of the genotype at the a and a2
loci. These results show that the various members of the CHS multigene
family interact in diverse ways with multiple genetic signals in the plant,
providing a basis for the differential expression of these genes. Spatially
specific genetic regulation of distinct members of a multigene family has
been clearly demonstrated.
