Meropenem and moxalactam: Novel β-lactam antibiotics for efficient Agrobacterium-mediated transformation

We evaluated the usefulness of novel β-lactam antibiotics, meropenem (MEPM) and moxalactam (LMOX) for Agrobacterium-mediated transformation of tobacco, tomato and rice in comparison with commonly used β-lactams, carbenicillin (CBPC) and cefotaxime (CTX). Although antibacterial activities of β-lactams varied among transformation systems, MEPM at 25 mg l−1 completely suppressed overgrowth of Agrobacterium in all systems. In transformation of tobacco, tomato and rice, MEPM at 6.25–25 mg l−1 and LMOX at 6.25–50 mg l−1 led to a higher transformation efficiency than CBPC and CTX. We concluded that introduction of MEPM or LMOX at 25 mg l−1 for non-β-lactamase-producing strains and MEPM at 25 mg l−1 or LMOX at 50 mg l−1 for β-lactamase-producing strains, respectively, to Agrobacterium-mediated transformation may be a simple and efficient strategy to improve transformation efficiency of many plant species without modification of existing protocols.