Catalyzes the transfer of a farnesyl moiety from farnesyl diphosphate to a cysteine at the fourth position from the C-terminus of several proteins having the C-terminal sequence Cys-aliphatic-aliphatic-X (CaaX) (PubMed:20565889). The beta subunit is responsible for peptide-binding (PubMed:20565889). Acts as an abscisic acid (ABA) negative regulator by mediating ASG2 farnesylation and consequently monitoring its subcellular localization (PubMed:26147561). Involved in responses to salt (NaCl) and osmotic (e.g. in response to mannitol and PEG) stresses (PubMed:26147561). (2E,6E)-farnesyl diphosphate + L-cysteinyl-[protein] = diphosphate + S-(2E,6E)-farnesyl-L-cysteinyl-[protein] Binds 1 zinc ion per subunit. kcat is 49.1 h(-1), 28.8 h(-1), 12.8 h(-1) and 3.7 h(-1) for CVIQ, CVIM, CVII and CVIL substrates, respectively. Heterodimer of FTA and FTB (farnesyltransferase). Heterodimer of an alpha and a beta subunit. Plants show an increase in floral organ number, particularly in the sepals and petals, correlating with an increase in the width of young floral meristems (PubMed:10840062). Increased sensitivity to abscisic acid (ABA) as well as salt (NaCl) and osmotic (e.g. in response to mannitol and PEG) stresses in term of seed germination and roots elongation (PubMed:26147561). Belongs to the protein prenyltransferase subunit beta family. Truncated N-terminus.