Researchers at Berkeley Lab’s Joint BioEnergy Institute (JBEI) have invented a genetically modified plant cell or plant, comprising: (a) (i) one or more nucleic acids each encoding one or more transcription factors (or transcription activators) operatively linked to a first tissue-specific or inducible promoter, (ii) one or more nucleic acids each encoding one or more transcription repressors each operatively linked to a second tissue-specific or inducible promoter, or (iii) combinations thereof; and (b) one or more nucleic acids each encoding one or more independent genes of interest (GOI) each operatively linked to a promoter that is activated by the one or more transcription factors (or transcription activators), repressed by the one or more transcription repressors, or a combination of both.
One obstacle that has thwarted plant engineering efforts is the natural phenomenon of epigenetic silencing. Although poorly understood, plants have evolved robust defense mechanisms that may perceive multiple transgenes driven by the same promoter as a threat, resulting in gene silencing at the transcriptional (gene inactivation via DNA methylation) and post-transcriptional (RNA degradation) level. Thus, although many engineering efforts require the coordinated expression of multiple genes, it has long been observed that stacking the same promoter multiple times may also dramatically increase the chance of gene silencing. Hence, plant synthetic biology efforts will need to design promoters that circumvent silencing issues and facilitate the coordinated expression of multiple genes simultaneously in a tissue-specific manner. Taken all together, an ideal system would incorporate a library of synthetic promoters that would 1) control gene expression strength, 2) facilitate tissue-specific expression, and 3) decrease the likelihood of gene silencing mechanisms by avoiding the use of homologous promoter sequences.
Applications and Industries
- Bioenergy feedstock plants