Agrobacterium mediated transformation of almond: In vitro rooting through localized infection of A-rhizogenes WT

Satisfactory in vitro rooting (96.8%) was obtained in the almond cultivar Supernova through the infection of Agrobacterium rhizogenes w.t., strain 1855 NCPPB, at the base of the microcuttings. The rooting medium was that of Bourgin and Nitsch(1967) hormone-free; the addition of indolacetic acid inhibited rooting when the explants were infected (35.5%). No roots were formed by the controls not infected and not treated with indolacetic acid (0%). Southern blot analysis, made with two probes, confirmed the transgenic nature of the genomic DNA extracted from roots of the infected cuttings and excluded the contamination of bacterial DNA during the extraction. The plants were successfully transferred to soil, where the roots resumed a vigorous growth.