Agrobacterium -mediated transient transformation of Mexican prickly poppy ( Argemone mexicana L.)

Shoot apex, leaf primordia, leaf sections and roots from Mexican prickly poppy seedlings, were inoculated with Agrobacterium tumefaciens harboring the binary vector pCAMBIA2301, which contained the \u3b2-glucuronidase (uid A) gene. Histochemical \u3b2-glucuronidase (GUS) assay in infected explants showed transient gus gene expression between 3 and 12 days after inoculation. To our knowledge, this is the first report of A. mexicana susceptibility to A. tumefaciens-mediated genetic transformation

Endogenous GUS-like activity in Capsicum chinense Jacq.

The gene uidA, codes for \u3b2-glucuronidase, which is one of the reporters more frequently utilized in transgenic plants. However, this can only be use if the selected organism does not present endogenous GUS-like activity. In tissues of C. chinense we found a GUS-like activity showing different levels of intensity. Histochemical screening showed that endogenous GUS-like activity decreased, or reduced significantly, in almost all tissues with exception of stament, when phosphate buffer was adjusted to pH 8. Subsequently, C. chinense zygotic embryo explants were transient transformed with Agrobacterium tumefaciens LBA4404 (pCAMBIA2301) and plantlets regenerated were histochemically stained in phosphate buffer pH 8. Observations of incubated tissues of C. chinense regenerants showed blue staining, suggesting expression of uidA. Incubated tissues of non-transformed regenerants did not show blue staining in phosphate buffer pH 8. The results show that for transformation experiments of C. chinense with uidA gene, pH 8 is recommended for histochemical staining

Agrobacterium tumefaciens-transient genetic transformation of Habanero pepper (Capsicum chinense Jacq.) leaf explants

Most of the pepper species of the genus Capsicum have been recalcitrant to efficient Agrobacterium tumefaciens-mediated stable or transient, genetic transformation. In the present work, we optimized a protocol for transient transformation of the Habanero pepper (Capsicum chinense Jacq.) through the standardization of several experimental factors. These included the age of the plants, the temperature, the length of co-cultivation, the application of a negative (vacuum) and/or a positive (infiltration) pressure, along with micro injection, the use of acetosyringone during the bacterial culturing, and modification of the pH during the GUS assay to eliminate the endogenous \u3b2-glucuronidase activity. The standardized protocol, which yielded nearly 55% fully transformed leaf explants, was used to successfully mobilize two empty binary vectors (pCAMBIA2301 and pCAMex), as well as the C. chinense cDNAs encoding the pathogenesis-related protein 10 and esterase, respectively