The increase in unsaturation of fatty acids of phosphatidylglycerol in thylakoid membrane enhanced salt tolerance in tomato

Abstract

Overexpression of chloroplastic glycerol-3-phosphate acyltransferase gene (LeGPAT) in tomato increased cisunsaturated fatty acid content in phosphatidylglycerol (PG) of thylakoid membrane. By contrast, suppressing the expression of LeGPAT decreased the content of cis-unsaturated fatty acid in PG. Under salt stress, sense transgenic plants exhibited higher activities of chloroplastic antioxidant enzymes, lower content of reactive oxygen species (ROS) and less ion leakage compared with the wild type (WT) plants. The net photosynthetic rate (P N ) and the maximal photochemical efficiency (F v /F m ) of photosystem II (PSII) decreased more slightly in sense lines but more markedly in the antisense ones, compared to WT. D1 protein, located in the reactive center of the PSII, is the primary target of photodamage and has the highest turnover rate in the chloroplast. Under salt stress, compared with WT, the content of D1 protein decreased slightly in sense lines and significantly in the antisense ones. In the presence of streptomycin (SM), the net degradation of the damaged D1 protein was faster in sense lines than in other plants. These results suggested that, under salt-stress conditions, increasing cis-unsaturated fatty acids in PG by overexpression of LeGPAT can alleviate PSII photoinhibition by accelerating the repair of D1 protein and improving the activity of antioxidant enzymes in chloroplasts.

Research on the adaptive mechanism of photosynthetic apparatus under salt stress: New directions to increase crop yield in saline soils

“…It has been widely demonstrated that the absorption, transmission, and transformation of light energy by photosynthetic apparatus are carried out on pigmented protein complexes with a certain molecular arrangement and spatial conformation (Ai, Bie, Yuan, Liu, & Bo, ), and the process includes four high‐abundance multisubunit membrane integrin complexes, namely PSI (Photosystem I), PSII (Photosystem II), Cyt b6f (cytochrome b6f complex) and ATPase (ATP synthase), which contain 70 proteins in total (Dekker & Boekema, ; Peng, ; Y. L. Sun et al, ; Wijk, ). In general, ROS are produced in PSI under stress, but it affects both PSI and PSII, leading to damage to the structure and function of thylakoid membrane proteins (Hideg, Spetea, & Vass, ; Rochaix, ; Tjus, Scheller, Andersson, & Møller, ).…”

Therapeutic targeting of cellular stress responses in cancer

“…Reactive oxygen species (ROS), such as superoxide anion radicals, hydroxyl radicals, and hydrogen peroxide, are natural by‐products of aerobic metabolism . In cells, mitochondria are the primary source of endogenous intracellular reactive species.…”

“…Reactive oxygen species (ROS), such as superoxide anion radicals, hydroxyl radicals, and hydrogen peroxide, are natural by-products of aerobic metabolism. [51][52][53][54][55][56][57] In cells, mitochondria are the primary source of endogenous intracellular reactive species. These metabolic intermediates play important roles in physiological functions and signaling pathways, both as effectors and as signaling molecules.…”

Molecular mechanisms underlying stress response and adaptation

“…In rice, the casein kinase LTRPK1 plays a key role in cold tolerance by regulating cytoskeletal rearrangements that favor cold adaptation . Recent studies have shown that the light signaling gene phyB also participates in a pathway that promotes resistance to chilling . PhyB negatively regulates chloroplast structural stability by lowering levels of unsaturated fatty acids present in membrane lipids .…”

“…[132][133][134] Recent studies have shown that the light signaling gene phyB also participates in a pathway that promotes resistance to chilling. [135][136][137] PhyB negatively regulates chloroplast structural stability by lowering levels of unsaturated fatty acids present in membrane lipids. [138][139][140] PhyB deficiency positively regulates OsPIL16 and OsDREB1, 141 thereby alleviating chilling-induced photoinhibition and enhancing chilling tolerance.…”