This work suggests that the URA3+ cells derived from pPZ3TA transformants are a result of genuine retrotransposition events, and furthermore, they show that most, if not all, of these colonies have arisen independently.
Homogeneity in protein expression in the population of transformants is always a great challenge in the field of fungal biotechnology because of the low efficiency of targeted integration events (Aw and Polizzi 2013).
Furthermore, transformation protocol for generating a large number of transformants is limited to only a few cultivars, indicating that experimental parameters for rice transformation have not been fully optimized (Ozawa 2009).
This difference with respect to the PSAD RSP3-HA transformants is due to two factors: a much lower PSAD RSP3-HAf cells are flagellatransformantsC6:RSP3-HA transformants (12% vs 90%) and, of these, a lower percentage are swisming (Table 1).
Stable transformants were obtained using a plasmid containing a 382 nt promoter fragment from PITG_10185, or a version in which the DPEP was mutated, fused to the GUS reporter gene.
Ethidium bromide-resistant transformants were selected in a single step, but at a transformation frequency of 10−6 to 10−7, 10- to 20-fold lower than that for transformants transformed with a spectinomycin resistance cassette under the same conditions.
Transformants were selected by PCR#A and PCR#B (as shown in Figure 1), which amplify the 5' and 3' regions of HBG-LoxP-vps-45-LoxP, respectively.
A total of 117 independent transformants were generated over a period of two years.
A total of 1540 yeast transformants were selected on a synthetic defined (SD) medium lacking Leu and Trp with 40 μg/ml X-α-Gal and 70 ng/ml aureobasidin A (DDO/X/A).
Aliquots of supernatants prepared from cell-free homogenates of E. coli transformants were applied to a Sepharose 12 column connected to a FPLC system (Pharmacia, Uppsala, Sweden).
