Removal of feedback inhibition of delta(1)-pyrroline-5-carboxylate synthetase results in increased proline accumulation and protection of plants from osmotic stress.

By Z. Hong, Karuna Lakkineni, Zhongming Zhang, D. Verma. Plant Physiology, 2000

866 citations recorded by the source corpus.

The Delta(1)-pyrroline-5-carboxylate synthetase (P5CS; EC not assigned) is the rate-limiting enzyme in proline (Pro) biosynthesis in plants and is subject to feedback inhibition by Pro. It has been suggested that the feedback regulation of P5CS is lost in plants under stress conditions. We compared Pro levels in transgenic tobacco (Nicotiana tabacum) plants expressing a wild-type form of Vigna aconitifolia P5CS and a mutated form of the enzyme (P5CSF129A) whose feedback inhibition by Pro was removed by site-directed mutagenesis. Transgenic plants expressing P5CSF129A accumulated about 2-fold more Pro than the plants expressing V. aconitifolia wild-type P5CS. This difference was further increased in plants treated with 200 mM NaCl. These results demonstrated that the feedback regulation of P5CS plays a role in controlling the level of Pro in plants under both normal and stress conditions. The elevated Pro also reduced free radical levels in response to osmotic stress, as measured by malondialdehyde production, and significantly improved the ability of the transgenic seedlings to grow in medium containing up to 200 mM NaCl. These findings shed new light on the regulation of Pro biosynthesis in plants and the role of Pro in reducing oxidative stress induced by osmotic stress, in addition to its accepted role as an osmolyte.

Subfields: Molecular Biology, Plant Science

View Paper: https://www.semanticscholar.org/paper/5b1a4d12f62177d87c488122edb566ab6e56ba2e

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Citations in the corpus

Over‐expression of the water and salt stress‐regulated Asr1 gene confers an increased salt tolerance (2004, background): “Proline-accumulating transgenic plants exhibited increased salt tolerance (Hong et al. 2000).”
Chickpea molecular breeding: New tools and concepts (2006, background): “Plants have also been transformed with the gene P5CSF-129A that increases proline accumulation and improves tolerance to osmotic stress (Hong et al., 2000).”
Sesuvium portulacastrum, a plant for drought, salt stress, sand fixation, food and phytoremediation. A review (2013, background): “It is possible that proline may be contributing to the active non-enzymatic antioxidant system for an efficient scavenging of ROS, as findings of proline as a reducing agent for oxidative stress induced by osmotic stress have been reported (Hong et al. 2000).”
The Arabidopsis LOS5/ABA3 Locus Encodes a Molybdenum Cofactor Sulfurase and Modulates Cold Stress– and Osmotic Stress–Responsive Gene Expression (2001, background): “P5CS catalyzes the ratelimiting step in the biosynthesis of proline, a major osmolyte important for plant tolerance to freezing, drought, and salt stresses (Xin and Browse, 1998; Roosens et al., 1999; Hong et al., 2000).”
Influence of Silver Nano-particles on the Salt Resistance of Tomato (Solanum lycopersicum) during Germination (2016, background): “and include delta-1-pyrroline-5-carboxylate synthetase (P5CS) (Hong et al., 2000) and abscisic acid and environmental stress-inducible protein (TAS14) (MuñozMayor et al.”
Drought and Salt Tolerance in Plants (2005, background): “A further hypothesis is that compatible solutes are also involved in scavenging reactive oxygen species ( Shen et al. , 1997a , b ; Hong et al.”
Osmotic adjustment in transgenic citrus rootstock Carrizo citrange (Citrus sinensis Osb. x Poncirus trifoliata L. Raf.) overproducing proline (2004, background): “Most of the studies involving genetic transformation with genes coding osmoprotectants have been made with model plants, such as tobacco and Arabidopsis thaliana [15,16].”
Parameters Symptomatic for Boron Toxicity in Leaves of Tomato Plants (2012, background): “Some authors hold that proline can detoxify reactive oxygen species (ROS) by forming a complex with them and by inhibiting lipid peroxidation [14].”
Duplicated P5CS genes of Arabidopsis play distinct roles in stress regulation and developmental control of proline biosynthesis. (2008, background): “Proline is proposed to protect plant cells from adverse effects of ROS as a singlet oxygen quencher (Alia et al., 2001), reducing free radical levels (Hong et al., 2000; Mehta and Gaur, 1999) and increasing reduced GSH content (Siripornadulsil et al., 2002).”