Fig. 1.

Origin and evolution of B-function genes in Solanaceae. The four lineages, indicated in different colours, are present in tomato, Nicotiana and Petunia. Plausible relationships between these species are shown and their floral morphology is shown in the pictures. Below are a summary of yeast-two-hybrid studies by showing dimeric protein interactions. Most stringent are the interactions in tomato, followed by those in Petunia. Interactions showed least specificity in Nicotiana but N-terminally truncated constructs were used.