Agrobacterium tumefaciens-mediated Transformation of Jatropha curcas: Factors Affecting Transient Transformation Efficiency and Morphology Analysis of Transgenic Calli

An efficient system for Agrobacterium tumefaciensmediated transformation of Jatropha curcas was developed in this study. Several factors affecting the transformation efficiency were optimized, including the explant type, preculture and coculture periods, usage of acetosyringone and density of A. tumefaciens. Compared with other explants, 2-day precultured and cocultured hypocotyl explants showed a significant GUS transient expression efficiency (67.7%). Moreover, adding AS showed a remarkable increase in transformation efficiency. After infecting with A. tumefaciens, hypocotyl explants were subjected to expansion and proliferation on MS medium with 1.0 mg· l-1 IBA and 0.5 mg· l-1 BA. Transformants were demonstrated by the GUS assay and PCR analysis. Rate of hypocotyl explants forming resistant calli reached 67.08%. Furthermore, in the transformed calli development, morphologic changes (calli superficial development and internal structure) were observed by SEM and LM. The present study has provided a fundamental information and research approach for the future study of inducing new traits to J. curcas and genetic modification.