title: Photosynthetic light reactions--an adjustable hub in basic production and plant immunity signaling.
abstract: Photosynthetic efficiency is a key trait that influences the sustainable utilization of plants for energy and nutrition. By now, extensive research on photosynthetic processes has underscored important structural and functional relationships among photosynthetic thylakoid membrane protein complexes, and their roles in determining the productivity and stress resistance of plants. Photosystem II photoinhibition-repair cycle, for example, has arisen vital in protecting also Photosystem I against light-induced damage. Availability of highly sophisticated genetic, biochemical and biophysical tools has greatly expanded the catalog of components that carry out photoprotective functions in plants. On thylakoid membranes, these components encompass a network of overlapping systems that allow delicate regulation of linear and cyclic electron transfer pathways, balancing of excitation energy distribution between the two photosystems and dissipation of excess light energy in the antenna system as heat. An increasing number of reports indicate that the above mentioned mechanisms also mediate important functions in the regulation of biotic stress responses in plants. Particularly the handling of excitation energy in the light harvesting II antenna complexes appears central to plant immunity signaling. Comprehensive understanding of the underlying mechanisms and regulatory cross-talk, however, still remain elusive. This review highlights the current understanding of components that regulate the function of photosynthetic light reactions and directly or indirectly also modulate disease resistance in higher plants.
authors.affiliation: Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Saijaliisa
authors.initials: S
authors.lastname: Kangasjärvi
authors.affiliation: Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Tikkanen
authors.affiliation: Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Guido
authors.initials: G
authors.lastname: Durian
authors.affiliation: Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland. Electronic address: evaaro@utu.fi.
authors.forename: Eva-Mari
authors.initials: EM
authors.lastname: Aro
mesh_terms: D002736:Chloroplasts / Q000378:metabolism; D004579:Electron Transport; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism; D057865:Plant Immunity; D010944:Plants / Q000276:immunology / Q000378:metabolism* / Q000528:radiation effects; D015398:Signal Transduction; D013312:Stress, Physiological; D020524:Thylakoids / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010100:Oxygen
keywords: Cyclic electron flow; Light stress; Linear electron flow; Photoprotection; Photosynthetic light reactions; Plant immunity