Optimization of a plant regeneration and genetic transformation protocol for Eucalyptus clonal genotypes

Background Agrobacterium mediated gene transfer technology offers the potential to introduce novel, high-value traits into selected, elite tree genotypes. Significant progress has been made in the regeneration and genetic transformation of Eucalyptus trees, but transformation efficiency has generally been low for eucalypts [1], especially for elite clonal genotypes. As a preliminary step towards the regeneration of explants derived from clonal material and the production of transgenic plants from commercially important Eucalyptus genotypes, there is a need to identify genotypes exhibiting high regeneration capacity. In this ongoing study, we are comparing eight Eucalyptus genotypes for callus induction and shoot regeneration potential. Browning of callus tissue and surrounding culture media is a common obstacle limiting regeneration of shoots in eucalypts. Hence, a second aim is to minimize the oxidation of phenolic compounds released from the wounded tissue and improve shoot regeneration rates.