Citrus Phloem Transcriptional Profiling Using a Citrus Tristeza Virus Vectored Translating Ribosome Affinity Purification System

A phloem-limited citrus tristeza virus (CTV) vector was developed for the expression of an immune-tagged ribosomal protein, hfRPL18. CTV expressed hfRPL18 was used to pull down phloem derived polysomes from infected Citrus macrophylla leaf tissues. Associated hfRPL18 mRNAs were subsequently isolated and sequenced. To remove background mRNAs, isolated mRNAs from leaf tissues infected with the empty CTV vector were similarly sequenced. In summary, the CTV-hfRPL18 vector provides a transgene-free means to examine translating mRNAs within citrus phloem tissues.