Selection procedure for chimeric Hcr9 constructs that confer AVR9 recognition and position of the various specific primers. (A) CF1 and BR1 are Hcr9-specific primers (triangles) located at positions corresponding to the B-domain and LRR 17, respectively, of the encoded Hcr9 protein. Amplified fragments encoding LRRs 1–17 were inserted into a binary expression vector that contains the Cf-9 ORF lacking the fragment encoding LRRs 1–17. 35S, cauliflower mosaic virus 35S constitutive promoter; T, nos terminator; RB and LB, right and left borders of the T-DNA, respectively. For further details, see Materials and Methods. (B) Position of specific primers in and around Cf-9 and 9DC ORFs. Triangles indicate the annealing position and direction of primers relative to the ORF of Cf-9 and 9DC. For further details see Materials and Methods.