Construction of a Multifunctional Chloroplast Vector to Make Transgenic Plants Producing Biodegradable Biopolymer and Resistant to Salt, Drought and Cold Stresses

The objective of the present study was to design and construction of a specific chloroplast vector to produce biodegradable biopolymers and also induce abiotic tolerance in transgenic plants. To do this، three genes involved in Polyhidroxybutirate biosynthetic pathway were isolated. The genes isolation and functionality accuracy was proved using expression in recombinant E. coli. Then an inducible expression cassette was designed for this operon under control of groE promoter and Thr terminator and subsequently cloned adjacent of neo selectable marker gene integrated with large subunit of atpB under control of psbA promoter and terminator among loxP sequences. The resulting cassette was cloned in the center of a 4Kb fragment from chloroplast genome that makes possibility of transgene targeting into trnI/trnAintergenic region by homologous recombination. These recombinant plastid vectors were called pFNPi (+) and pFNPi (-). Moreover badh gene was added to the chloroplast vector. This gene coding a protein detoxifing Betaine could be used for resistance to salt، drought and cold stresses. After intron removing، codon optimization and remove of internal restriction enzyme recognition sites was placed under Prrn promoter and T7gene10 5’UTR. The final resulting vector called pFBNPi will be suitable for bacteria and plant transformation for production of biodegradable biopolymer and resistant transplastomic plant for salt، drought and cold stresses.