Agrobacterium tumefaciens-mediated transformation of Jatropha curcas L. with a polyhydroxyalkanoate gene (phaC)

Polyhydroxybutyrate is a component of bioplastics that is synthesized under the control of enzymes encoded by pha multigenes. The genes are naturally present in Ralstonia eutropha. However, the production of bioplastics in bacteria is inefficient because the bacterial biomass is relatively small compared with plants or fungi. As such, engineering techniques have been developed that enable pha genes to be inserted into plant biomass, and then be expressed in the biomass of the plant to produce polyhydroxybutyrate. The objectives of this study were to transform the tissue of Jatropha curcas using the phaC gene (a pha gene), to regenerate the transformed plant, and to confirm the presence of the inserted genes with PCR. The genetic transformation of J. curcas was mediated by Agrobacterium tumefaciens strain GV3101 containing pARTC by dipping the cotyledon tissue of J. curcas in a suspension of the bacterium for 30 min, followed by cocultivation for 3 d on Murashige and Skoog (MS) medium. The tissue was then placed on a selection medium, i.e. MS medium containing 13.3 µM BAP and 0.05 µM IBA with the addition of 20 mg/L kanamycin. The results showed that 12.35% of the tissue survived and regenerated into a shoot after 1–2 months. Molecular analysis of the transformed tissue was performed using phaC and nptII primers, in order to detect the presence of the phaC and nptII genes. Specific bands were detected at 659 bp and 700 bp, corresponding to the nptII primer and phaC primer, respectively.

Degradation and conversion of toxic compounds into useful bioplastics by Cupriavidus sp. CY-1: relative expression of the PhaC gene under phenol and nitrogen stress

In this study different types of toxic compounds,i.e., alkylphenols, mono and poly-aromatic hydrocarbons were converted into polyhydroxybutyrate (PHB) using the isolated bacteriaCupriavidussp. CY-1.

Rapid Identification of Polyhydroxyalkanoate Accumulating Members of Bacillales Using Internal Primers for phaC Gene of Bacillus megaterium

Bacillus megaterium is gaining recognition as an experimental model and biotechnologically important microorganism. Recently, descriptions of new strains of B. megaterium and closely related species isolated from diverse habitats have increased. Therefore, its identification requires several tests in combination which is usually time consuming and difficult to do. We propose using the uniqueness of the polyhydroxyalkanoate synthase C gene of B. megaterium in designing primers that amplify the 0.9 kb region of the phaC for its identification. The PCR method was optimized to amplify 0.9 kb region of phaC gene. After optimization of the PCR reaction, two methods were investigated in detail. Method I gave an amplification of a single band of 0.9 kb only in B. megaterium and was demonstrated by several strains of B. megaterium isolated from different habitats. The use of Method I did not result in the amplification of the phaC gene with other members of Bacillales. The specificity for identification of B. megaterium was confirmed using sequencing of amplicon and RT-PCR. Method II showed multiple banding patterns of nonspecific amplicons among polyhydroxyalkanoate accumulating members of Bacillales unique to the respective species. These methods are rapid and specific for the identification of polyhydroxyalkanoate accumulating B. megaterium and members of Bacillales.

Cloning, Molecular Analysis, and Expression of the Polyhydroxyalkanoic Acid Synthase (phaC) Gene fromChromobacterium violaceum

ABSTRACT The polyhydroxyalkanoic acid synthase gene fromChromobacterium violaceum (phaC Cv) was cloned and characterized. A 6.3-kb BamHI fragment was found to contain both phaC Cv and the polyhydroxyalkanoic acid (PHA)-specific 3-ketothiolase (phaA Cv). Escherichia coli strains harboring this fragment produced significant levels of PHA synthase and 3-ketothiolase, as judged by their activities. While C. violaceum accumulated poly(3-hydroxybutyrate) or poly(3-hydroxybutyrate-co-3-hydroxyvalerate) when grown on a fatty acid carbon source, Klebsiella aerogenes andRalstonia eutropha (formerly Alcaligenes eutrophus), harboring phaC Cv, accumulated the above-mentioned polymers and, additionally, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) when even-chain-length fatty acids were utilized as the carbon source. This finding suggests that the metabolic environments of these organisms are sufficiently different to alter the product range of the C. violaceum PHA synthase. Neither recombinant E. colinor recombinant Pseudomonas putida harboringphaC Cv accumulated significant levels of PHA. Sequence analysis of the phaC Cv product shows homology with several PHA synthases, most notably a 48% identity with that of Alcaligenes latus (GenBank accession no. AAD10274).