Chloroplasts are organelles in plant and eukaryotic algal cells that convert light energy into relatively stable chemical energy via photosynthetic processes. By doing so, they sustain life on Earth. Following the previous Research Topics on Structure and Function of Chloroplasts, (
Vol 1,
Vol 2), in this third volume, we aim to update the latest advances and share perspectives on the biogenesis, morphogenesis, maintenance, protection, senescence, communication, and metabolite biosynthesis and transport of chloroplasts.
Chloroplasts are enclosed by an envelope of two membranes which encompass a third complex membrane system, the thylakoids: an interconnected network composed of both grana and stroma lamellae. Alongside thylakoids, plastoglobules, stromules, eyespots, pyrenoids, are all important structures of chloroplasts. In land plants, as the leaf develops from the shoot apical meristem, proplastids and etioplastids differentiate into photosynthetically active chloroplasts, though the extent of photosynthetic function varies widely, especially for C4 photosynthesizers.
Having evolved from a free-living photosynthetic cyanobacterium engulfed by a eukaryotic cell, chloroplasts retain a minimal genome. This is because most of the chloroplast proteins are now encoded by nuclear genes and these nuclear gene products are transported into the chloroplast through complex import machinery. This coordination of nuclear and plastid genome expression establishes the framework of both anterograde and retrograde signaling pathways.
Chloroplasts generate a diverse suite of primary and secondary metabolites for plant cells, such as starch, fatty acids, membrane lipids, isoprenoids, tetrapyrroles, amino acids, and many other carbon-based central metabolites and hormones. Similarly, reactive oxygen species and other cellular signals originate from the chloroplast. As an important metabolic and signaling hub of the plant cell, the chloroplast has been found to be critical for a variety of abiotic and biotic stresses, such as drought, high light, cold, heat, oxidative stresses, phosphate deprivation, wounding and pathogen infections. Therefore, a better understanding of how chloroplasts respond to these stresses is part of understanding how the plant itself responds to stress.
The above-mentioned processes are fundamental for the biogenesis, three-dimensional dynamic structures, and regulation of the function of chloroplasts. Ultimately, this knowledge is necessary to engineer plants for both higher yield and/or greater resistance to common stresses.
Following the two previous volumes, we aim to cover in this new Research Topic the recent advances on understanding the biogenesis, structure, and functions of chloroplasts, including but not limited to:
• morphogenesis,
• lipid biosynthesis,
• membrane function,
• engineering chloroplasts for increased yields,
• chloroplast protein structure,
• biosynthesis and transport of metabolites,
• autophagy,
• signaling,
• and stress responses.
This Research Topic will therefore continue to serve the researchers in the field and welcomes a range of article types including Original Research, Review, Mini-Review, Methods, Opinion, and Perspectives.
Note: There is a related current Research Topic, "
Regulation of Light-Harvesting Systems During Acclimation of Photosynthetic Organisms". Manuscripts on light harvesting and its regulation are encouraged to be submitted to that topic.
