AbstractIntercellular fluid (IF) extracted from the apoplastic leaf spaces ofPetuniacontained up to 6 new soluble proteins, called d proteins (d0to d5). Characterisation of the d proteins has shown that they can be divided into groups and show a genetic variability similar to the PR(b) proteins fromNicotiana.d protein patterns fromPetuniainterspecific hybrids clearly show that the determinant for the d proteins in sexually transmitted as is the case for b proteins inNicotiana.d‐protein induction in TMV‐SM1infectedPetunialeaves is discussed in relation to the resistance to infection shown by cultivars and hybrids ofPetu