About this Research Topic
One of the distinguishing features of plants is the presence of membrane-bound organelles called plastids. Starting from proplastids (undifferentiated plastids) they readily develop into specialised types adapted for functions ranging from photosynthesis to the synthesis of secondary metabolites. The central role of plastids in many aspects of plant cell biology means an in-depth understanding is key for a holistic view of plant physiology.
Plastids possess their own high-copy number genome known as the plastome. At maturity, they contain ~3,000 proteins, which are both plastid and nuclear encoded, the latter of which are imported from the cytosol, resulting in the evolution of a sophisticated signalling network between the plastids and the nucleus for proper organismal functioning and development. Despite the vast amount of research, the molecular details of many aspects of plastid biology remain unknown.
Transformation of chloroplasts – green plastids – has been developed as an alternative to conventional protein expression systems. A high-copy number of the plastome, site-specific integration of transgenes through homologous recombination, and high expression levels (>70% of total soluble proteins in some cases) have become the salient features of this technology. Additionally, plastids are inherited maternally, providing a natural gene containment system, and do not follow Mendelian laws of inheritance, allowing each individual member of the progeny of a transplastomic line to provide a similar expression level. Both algal and higher plant chloroplast transformation has been demonstrated, and with the ability to be propagated either in bioreactors or in the field, both systems are ideally suited for scale up of production.
The manipulation of chloroplast genes is essential for many approaches attempting to increase biomass accumulation or re-routing metabolic pathways for biofortification, food and fuel production. This includes metabolic engineering for lipid production, adapting the light harvesting apparatus to improve solar conversion efficiency and engineering means of suppressing photorespiration in crop species, which range from the introduction of artificial carbon concentrating mechanisms, or those pre-existing elsewhere in nature, to bypassing ribulose bisphosphate carboxylase/oxygenase entirely.
The purpose of this topic is to provide a vibrant platform for the scientific community engaged in researching various aspects of plastid biology including basic biology, biopharming, metabolic engineering, bio-fortification, stress physiology, and biofuel production.
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