Assessment of pleiotropic effects of a gene substitution in pea by two-dimensional polyacrylamide gel electrophoresis

We examined, by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), near-isogenic lines of the r-gene in pea (Pisum sativum) which determines round (RR) vs. wrinkled (rr) seed. The study was undertaken to assess the number of protein changes resulting from a single gene substitution as a means of quantifying pleiotropic effects. A total of 636 to 770 resolvable polypeptides were identical in all respects between RR and rr for roots, shoots, leaflets, stipules, young ovaries, and young embryos. A single difference between the lines became evident about 21-23 days after anthesis in the embryos. Mature seeds of the two lines showed 62 spot differences in addition to differences in four clusters of spots, representing about 10% of the total number of spots visible on the gels. The protein differences are presumably involved in the many known physiological differences of the two seed types. 2-D PAGE analyses of near-isogenic lines are likely to be valuable in a number of quantitative and developmental genetic contexts.