FIG. 3.

Serinol, dihydrorhizobitoxine, and rhizobitoxine production by B. elkanii USDA94Δrtx::Ω1 complemented with pRTF1 cosmid derivatives created by insertion of a kanamycin cassette. (A) Large-deletion mutant USDA94Δrtx::Ω1, which lacks a 9.8-kb region (nodQP, rtxA, rtxC, ORF2, and truncated ORF3) of B. elkanii USDA94. Δ, 9.8-kb deleted SacII fragment. (B) The insertion point of each kanamycin cassette is indicated by the arrowheads. The N and C domains of rtxA show the regions where their deduced amino acid sequences are homologous to aminotransferase and O-acetylhomoserine sulfhydrylase, respectively (see the text). P, putative promoter (according to the sequence). For serinol production, +, ++, and +++ indicate 0 to 50, 50 to 100, and >100 μM, respectively; for dihydrorhizobitoxine production, +, ++, +++, and ++++ indicate 0 to 2, 2 to 5, 5 to 10, and >10 μM, respectively; for rhizobitoxine production, +, ++, +++, and ++++ indicate 0 to 0.5, 0.5 to 1.0, 1.0 to 10, and >10 μM, respectively. ND, not detected.