Expression of bacterial cellulase genes in transgenic alfalfa (Medicago sativa L.), potato (Solanum tuberosum L.) and tobacco (Nicotiana tabacum L.)

The genes encoding thermostable cellulases E2 and E3 of Thermomonospora fus ca were expressed in plants under the control of the constitutive, hybrid M ac promoter. For both E2 and E3, the genes were modified so as to remove th e sequence encoding the bacterial leader peptide. Western blot analysis ind icated that expression levels of recombinant cellulase in tobacco lines ran ged up to about 0.1% (E2) and 0.02% of soluble protein (E3). No phenotypic effect of cellulase expression was noted. Recombinant E2 expressed in eithe r tobacco or alfalfa was active and retained heat stability. These findings are an important first step in the development of crop plants as a product ion system for cellulases.