Synthetic conversion of leaf chloroplasts into carotenoid-rich plastids reveals mechanistic basis of natural chromoplast development
Plastids, the defining organelles of plant cells, undergo physiological and morphological changes to fulfill distinct biological functions. In particular, the differentiation of chloroplasts into chromoplasts results in an enhanced storage capacity for carotenoids with industrial and nutritional value such as beta-carotene (provitamin A). Here, we show that synthetically inducing a burst in the production of phytoene, the first committed intermediate of the carotenoid pathway, elicits an artificial chloroplast-to-chromoplast differentiation in leaves. Phytoene overproduction initially interferes with photosynthesis, acting as a metabolic threshold switch mechanism that weakens chloroplast i…
Boolean computation in plants using post-translational genetic control and a visual output signal
[EN] Due to autotrophic growing capacity and extremely rich secondary metabolism, plants should be preferred targets of synthetic biology. However, developments in plants usually run below those in other taxonomic groups. In this work we engineered genetic circuits capable of logic YES, OR and AND Boolean computation in plant tissues with a visual output signal. The circuits, which are deployed by means of Agrobacterium tumefaciens, perform with the conditional activity of the MYB transcription factor Roseal from Antirrhinum majus inducing the accumulation of anthocyanins, plant endogenous pigments that are directly visible to the naked eye or accurately quantifiable by spectrophotometric a…
Model-based design of RNA hybridization networks implemented in living cells
[EN] Synthetic gene circuits allow the behavior of living cells to be reprogrammed, and non-coding small RNAs (sRNAs) are increasingly being used as programmable regulators of gene expression. However, sRNAs (natural or synthetic) are generally used to regulate single target genes, while complex dynamic behaviors would require networks of sRNAs regulating each other. Here, we report a strategy for implementing such networks that exploits hybridization reactions carried out exclusively by multifaceted sRNAs that are both targets of and triggers for other sRNAs. These networks are ultimately coupled to the control of gene expression. We relied on a thermo-dynamic model of the different stable…