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ABSTRACT: An economical method for the conversion of lignocellulosic biomass is to use plants as bioreactors for cellulases production. Two bacterial thermostable cellulases (E2 and E3) and a E3-E2 fusion form were expressed in tobacco, driven by a double 35S promoter and 5' TEV-UTL. The enzymes were targeted to the apoplast and cytosol via 5' signal peptides and 3' retention signal peptides, respectively, and all showed functional activities. All transgenic plants exhibited normal growth compared to wild type. Transgenic plants that expressed apoplast-localized E2 had the highest average activity, about 1.5 and 3 times higher than those expressed ER-localized and cytosolic E2, respectively. Effect of subcellular compartment localization was due primarily to post-transcriptional modification, since mRNA abundances were similar despite the range of cellulase activities obtained. The recombinant cellulases exhibited good thermostability below 65 °C. After storing for 3 days at -20 and 28 °C, the enzymes lost nearly 20 and 80% of activity, respectively. The results suggested a potential application for heterologous expression of cellulases in plant for biomass conversion.
Biotechnology Letters 05/2011; 33(9):1797-803. · 1.68 Impact Factor
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ABSTRACT: A minimal linear gene cassette (35S-phytase gene-nos) with T-DNA borders was acquired by PCR and directly introduced into soybean through the pollen tube pathway. A total of 13% of T(1 )plants were positive for phyA by specific PCR. Southern blot analyses showed that phyA insertions were harbored stably in T(2) progeny. Phytase expression level increased 2.5-fold over a 6-week period; its highest activity was 150 U/mg protein, compared to 56 U/mg protein in untransformed controls. Activity of phytase increased to 125 FTU/kg in T(3) transgenic seeds as compared to 64 FTU/kg in wild-type plants.
Biotechnology Letters 12/2007; 29(11):1781-7. · 1.68 Impact Factor
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ABSTRACT: Salt tolerant cultivars of sweet potato (Ipomoea batatas L.) can be obtained from induced mutation. The objective of the present study was to induce mutation for salt tolerance using
ethylmethanesulphonate (EMS) in calli of sweet potato, followed by cell line selection and subsequent plant regeneration.
Calli initiated from leaf explants were treated with 0.5% EMS for 0, 1, 1.5, 2, 2.5 and 3h, followed by rinsing with sterile
distilled water for four times. Preliminary experiments showed that 200mM NaCl could be used as selection pressure. Salt
tolerant calli were sub-cultured on medium supplemented with 200mM NaCl for selection of mutant cell lines and this process
repeated 5times (20days each). The selected calli were transferred onto somatic embryo formation medium, which was Murashige
and Skoog (MS) medium supplemented with 4mgl−1 abscisic acid (ABA), 10mgl−1 gibberellic acid (GA). After 15days, somatic embryos were transferred onto MS medium supplemented with 0.05mgl−1 ABA, 0.2mgl−1 zeatin (ZT) for regeneration. Plants designated as ML1, ML2and ML3 were regenerated from the somatic embryos formed by calli
treated with 0.5% EMS for 2 and 2.5h. After propagation, salt tolerance of these mutants was investigated. Data suggested
the mutants were more salt tolerant than control plants.
Plant Cell Tissue and Organ Culture 12/2006; 88(1):77-81. · 3.09 Impact Factor
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ABSTRACT: cDNA encoding betaine aldehyde dehydrogenase (BADH) from the halophyte Suaeda liaotungensis has been cloned, sequenced and expressed in tobacco (Nictiana tabacum 89). The full-length cDNA is 1506 base pairs (bp) long and encodes a 502 amino-acid polypeptide. The cDNA fragment coding for the mature enzyme was cloned into vector pCAMBIA-1301 for expression in tobacco. Southern blotting analysis showed that that the Badh gene was integrated into the genome of tobacco. Tobacco expressing BADH survived on MS medium containing 200 mM NaCl, whereas the untransformed plants turned yellow after about 20 d and died.
Biotechnology Letters 10/2003; 25(17):1431-6. · 1.68 Impact Factor
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ABSTRACT: Based on part of a known cDNA sequence of Suaeda liaotungensis betaine aldehyde dehydrogenase, we successfully cloned the 3' cDNA end of S. lianotungensis betaine aldehyde dehydrogenase using one-step PCR with a gene-specific primer and universal primer. Compared with the typical 3' RACE, one-step PCR is rapid, simple and inexpensive. It is very rapid to amplify an unknown cDNA 3' end using this method.
Hereditas (Beijing) 04/2002; 24(2):179-81.
