Drought treatment induces the accumulation of dcTLP, which is similar in structure to the thaumatin-like proteins (TLPs) found in the embryogenic calli, seedlings, and mature plants of carrot (Daucus carota). We isolated a full-length dcTLP cDNA clone from carrot and characterized the 5' upstream sequences. The coding region of dcTLP consisted of 645 nucleotides; the theoretical pI value was 4.9, and its molecular weight was approximately 22 kDa. The production of dcTLP transcripts in the seedlings increased dramatically with dehydration treatment but was not affected by abscisic acid (ABA), salicylic acid, or jasmonic acid. The expression patterns of dcTLP mRNA at different developmental stages and in response to a variety of signal molecules was analyzed using reverse transcriptase-PCR and promoter analysis with fused genes of 0.5-kb 5' upstream sequences in which beta-glucuronidase (GUS) reporter genes (gus) were established. The induction of dcTLP was found to be highly specific to drought stress in the embryogenic calli, seedlings, and mature plants. Our results suggest that this new isoform of TLP that has been isolated from carrot is a drought-specific, ABA-independent, non-organ-specific, and non-developmental-stage-specific protein.
Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species.
Lutein is a carotenoid with a purported role in protecting eyes from oxidative stress, particularly the high-energy photons of blue light. Statistical optimization was performed to growth media that supports a higher production of lutein by heterotrophically cultivated Chlorella vulgaris. The effect of media composition of C. vulgaris on lutein was examined using fractional factorial design (FFD) and central composite design (CCD). The results indicated that the presence of magnesium sulfate, EDTA-2Na, and trace metal solution significantly affected lutein production. The optimum concentrations for lutein production were found to be 0.34 g/L, 0.06 g/L, and 0.4 mL/L for MgSO4 ·7H2 O, EDTA-2Na, and trace metal solution, respectively. These values were validated using a 5-L jar fermenter. Lutein concentration was increased by almost 80% (139.64 ± 12.88 mg/L to 252.75 ± 12.92 mg/L) after 4 days. Moreover, the lutein concentration was not reduced as the cultivation was scaled up to 25,000 L (260.55 ± 3.23 mg/L) and 240,000 L (263.13 ± 2.72 mg/L). These observations suggest C. vulgaris as a potential lutein source.
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