Transgenic Tobacco Accumulating a High Level Polymer

Transgenic plants may be an economical means of producing novel feedstocks, such as biodegradable polymers, if limitations to product accumulation and expression of unwanted traits can be minimized. Plants producing polymers with important industrial, agricultural and medical applications, such as polyhydroxybutyrate and polyaminoacids, have been developed. Expressions of these polymers though were accompanied by limited fitness.

Scientists from University of Rostock and Humboldt University in Germany have developed transgenic tobacco producing cyanophycin, an amino acid polymer that is the only known non-protein nitrogen storage polymer in cyanobacteria. The researchers targeted the expression of a bacterial cyanophycin synthase gene in the chloroplast, to minimize the unwanted effects of polymer accumulation. The transgenic plants produced as much as 6.8 percent (dry weight) of cyanophycin, with minor or no stress symptoms. This is more than five-fold higher than the previously published value. Although all lines tested were fertile, the transgenic lines produced fewer seeds compared to control plants.

The paper published by the Plant Biotechnology Journal is available at http://www.blackwell-synergy.com/doi/abs/10.1111/j.1467-7652.2007.00320.x