Specific role of @entity3634 and functional overlaps with other thylakoid lipids in XXXX chloroplast biogenesis.

@entity62619 @entity958 @entity62618 @entity48735 @entity46502 @entity1391 @entity21934 @entity3634 @entity942 @entity10675
KEY MESSAGE: With @entity21934 , the role of @entity3634 is compensated by increased glycolipid content in thylakoid membrane biogenesis but not photosynthetic electron transport in @entity958 chloroplasts. In plants and cyanobacteria, anionic @entity3634 (PG) is the only major phospholipid in thylakoid membranes, where neutral galactolipids @entity10675 ( @entity46502 ) and @entity62618 ( @entity62619 ) are predominant. In addition to provide a lipid bilayer matrix, PG plays a specific role in photosynthetic electron transport. Non-phosphorous sulfoquinovosyldiacylglycerol (SQDG) is another anionic lipid in thylakoids; it substitutes for PG under @entity1391 (Pi) deficiency to maintain proper balance of anionic charge in thylakoid membranes. Although the crucial role of PG in photosynthesis has been deeply analyzed in cyanobacteria, its physiological function in seed plants other than photosynthesis remains unclear. To reveal specific roles of PG and functional overlaps with other thylakoid lipids, we characterized a @entity942 @entity958 mutant ( @entity48735 -2) under Pi-controlled conditions. Under Pi-sufficient conditions, the proportion of PG and other thylakoid lipids was decreased in @entity48735 -2, which led to severe disruption of thylakoid membrane biogenesis. Under Pi-deficient conditions, the proportion of all glycolipids in the mutant was greatly increased, with that of PG further decreased. In Pi-deficient @entity48735 -2, thylakoid membranes remarkably developed, which was accompanied by a change in nucleoid morphology and restored expression of nuclear- and plastid-encoded photosynthesis genes. Increase in glycolipid content with @entity942 may compensate for the loss of PG in terms of thylakoid membrane biogenesis. Although @entity942 increased chlorophyll and photosynthesis protein content in @entity48735 -2, it critically decreased photochemical activity in PSII. Further deprivation of PG in photosynthesis complexes may abolish the PSII activity in Pi-deficient @entity48735 -2, which suggests that glycolipids cannot replace PG in photosynthesis.
