An Agrobacterium mediated transformation system of guava (Psidium guajava L.) with endochitinase gene

Genetic transformation of guava (Psidium guajava L.) was developed for the first time using in vitro grown shoot tip explant cocultivated with Agrobacterium tumefaciens strain LBA4404 harbouring binary vector pIIHR-JBMch with endochitinase and nptII genes. The highest transformation efficiency was achieved by wounding explants with tungsten particles (0.5 µm) through particle acceleration system, followed by infection for 45 minutes with A. tumefaciens, grown overnight with 100 µM acetosyringone, corresponding to OD600=0.5 followed by co-cultivation for 72 hours under dark condition on co-cultivation medium (MS+100 µM acetosyringone+100 mg L-1 L-Cystein). Putative transformed explants regenerated shoots on selection medium stressed with 200 mg L-1 kanamycin for 12 weeks. Molecular analysis of putative transformants by PCR confirmed the integration of endochitinase and nptII gene in the plant nuclear genom