Expression of the entire polyhydroxybutyrate operon of Ralstonia eutropha in plants

Rita Mozes-Koch,Alexandra Brodezki,Edna Tanne,Ran Yehuda,Ilan Sela,Haim D Rabinowitch,Ofer Gover

doi:10.1186/s13036-017-0062-7

Rita Mozes-Koch, Alexandra Brodezki + Show 5 more

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https://doi.org/10.1186/s13036-017-0062-7

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Abstract

BackgroundPreviously we demonstrated that an entire bacterial operon (the PRN operon) is expressible in plants when driven by the Tomato -yellow-leaf-curl-virus (TYLCV) -derived universal vector IL-60.Petroleum-derived plastics are not degradable, and are therefore harmful to the environment. Fermentation of bacteria carrying operons for polyhydroxyalkanoates (PHAs) produces degradable bioplastics which are environmentally friendly. However, bacterial production of bioplastics is not cost-effective, and attention is turning to their production in plants. Such “green” plastics would be less expensive and environmentally friendly. Hence, attempts are being made to substitute petroleum-derived plastics with “green” plastics. However, transformation of plants with genes of operons producing bioplastics has deleterious effects. Transformation of plastids does not cause deleterious effects, however it is a complicated procedures.ResultsWe have developed another TYLCV-based vector (SE100) and show that yet another bacterial operon (the phaCAB operon) when driven by SE100 is also expressed in plants. We employed the combination of SE100 and the phaCAB operon to drive the operon to the plastids and produce in plants a biodegradable plastic [polyhydroxybutyrate (PHB)].Here we indicate that the bacterial operon (phaCAB), when driven by the newly developed universal plant vector SE100 is directed to chloroplasts and produces in plants PHB, a leading PHA. The PHB-producing plants circumvent the need for complicated technical procedures.ConclusionThe viral vector system SE100 facilitated the production of the bio-plastic poly-3-hydroxybutyrate. This was achieved by using the full pha-CAB operon indicating that TYLCV based system can transcribe and translate genes from bacterial operons controlled by a single cis element. Our data hints to the participation of the chloroplasts in these processes.

Highlights

We demonstrated that an entire bacterial operon is expressible in plants when driven by the Tomato -yellow-leaf-curl-virus (TYLCV) -derived universal vector IL-60
We previously reported the expression of an entire bacterial operon in plants [17] under the control of IL60, a universal vector for expression/silencing in plants [19]
The TYLCV-intergenic region (IR) may direct transcripts to chloroplasts Reporter genes fused to the IR, driven by TYLCVderived IL-60, can be expressed in plants [8]

Summary

Introduction

We demonstrated that an entire bacterial operon (the PRN operon) is expressible in plants when driven by the Tomato -yellow-leaf-curl-virus (TYLCV) -derived universal vector IL-60. Fermentation of bacteria carrying operons for polyhydroxyalkanoates (PHAs) produces degradable bioplastics which are environmentally friendly. Bacterial production of bioplastics is not cost-effective, and attention is turning to their production in plants. Such “green” plastics would be less expensive and environmentally friendly. Transformation of plants with genes of operons producing bioplastics has deleterious effects. Biodegradable plastics can be produced in microorganisms, but cannot yet compete with petroleum-derived plastics mainly due. Expression of bacterial operons in plants Prokaryotic genes are clustered in operons and their expression is driven by a common promoter. Metabolic pathways in plants are determined by gene clusters rather than operons [5], requiring the coordinated expression of various genes. Introducing these genes into plants to reconstruct an entire metabolic pathway is quite difficult and requires selection and backcrossing of plants that express operon’s genes

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