Figure 9.

RBP50-Based RNP Complexes Move into the Cucumber Scion.

(A) Phloem sap collected from pumpkin stock (Pst), cucumber scion (Csc), and control (ungrafted) cucumber plants (Csp) was subjected to co-IP against RBP50 or purified preimmune serum. Proteins were visualized by GBS staining. Note the similarity between the protein profiles for co-IP performed with phloem sap collected from pumpkin stock and cucumber scions. The absence of proteins in the co-IP experiment performed with phloem sap collected from control cucumber plants indicates the specificity of the interaction between RBP50 and the purified anti-RBP50 antibody preparation. The asterisk indicates the presence of a 28-kD unknown cucumber phloem protein that copurified with the pumpkin RBP50-based RNP complexes.

(B) RT-PCR–based detection of phloem transcripts contained within the pumpkin stock (Pst), cucumber scion (Csc), and ungrafted cucumber stock (Csp) and RBP50 RNP complexes isolated from pumpkin stock or cucumber scion phloem sap. As controls, Cm NACP and Cs NACP transcripts were amplified using specific primer pairs. Results represent three independent RT-PCR experiments.