LaCl 3 treatment improves Agrobacterium -mediated immature embryo genetic transformation frequency of maize

Key message We report an optimized transformation system that uses a LaCl 3 pretreatment (a Ca 2+ channel blocker) for enhancing Agrobacterium -mediated infection of immature embryos and improving the genetic transformation frequency of maize. Abstract Agrobacterium -mediated genetic transformation of immature embryos is important for gene-function studies and molecular breeding of maize. However, the relatively low genetic transformation frequency remains a bottleneck for applicability of this method, especially on commercial scale. We report that pretreatment of immature embryos with LaCl 3 (a Ca 2+ channel blocker) improves the infection frequency of Agrobacterium tumefaciens , increases the proportion of positive callus, yields more positive regenerated plantlets, and increases the transformation frequency from 8.40 to 17.60% for maize. This optimization is a novel method for improving the frequency of plant genetic transformations mediated by Agrobacterium tumefaciens .