A Pepper MSRB2 Gene Confers Drought Tolerance in Rice through the Protection of Chloroplast-Targeted Genes

Abstract

BackgroundThe perturbation of the steady state of reactive oxygen species (ROS) due to biotic and abiotic stresses in a plant could lead to protein denaturation through the modification of amino acid residues, including the oxidation of methionine residues. Methionine sulfoxide reductases (MSRs) catalyze the reduction of methionine sulfoxide back to the methionine residue. To assess the role of this enzyme, we generated transgenic rice using a pepper CaMSRB2 gene under the control of the rice Rab21 (responsive to ABA protein 21) promoter with/without a selection marker, the bar gene.ResultsA drought resistance test on transgenic plants showed that CaMSRB2 confers drought tolerance to rice, as evidenced by less oxidative stress symptoms and a strengthened PSII quantum yield under stress conditions, and increased survival rate and chlorophyll index after the re-watering. The results from immunoblotting using a methionine sulfoxide antibody and nano-LC-MS/MS spectrometry suggest that porphobilinogen deaminase (PBGD), which is involved in chlorophyll synthesis, is a putative target of CaMSRB2. The oxidized methionine content of PBGD expressed in E. coli increased in the presence of H2O2, and the Met-95 and Met-227 residues of PBGD were reduced by CaMSRB2 in the presence of dithiothreitol (DTT). An expression profiling analysis of the overexpression lines also suggested that photosystems are less severely affected by drought stress.ConclusionsOur results indicate that CaMSRB2 might play an important functional role in chloroplasts for conferring drought stress tolerance in rice.

Physiological Roles of Plant Methionine Sulfoxide Reductases in Redox Homeostasis and Signaling

“…The subcellular localization of some of them was proven experimentally, as reported for the three plastidial MSRA4, MSRB1, and MSRB2 isoforms [ 49 , 50 ], MSRB7 and MSRB8 in cytosol [ 51 ], and MSRB3 in endoplasmic reticulum [ 52 ]. Consistently, several MSRA and MSRB isoforms from other species (rice, tobacco, tomato, pepper, soybean, papaya, and banana) were found to localize in cytosol and plastids in Arabidopsis protoplasts using a bimolecular fluorescence complementation (BiFC) approach [ 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 ]. In other respects, data gained from BiFC experiments suggest that some cytosolic MSRA and MSRB isoforms from litchi and banana are present both in cytosol and in nucleus [ 61 , 62 ].…”

“…Thus, in rice, overexpression of plastidial MSRA4.1 is associated with improved tolerance to high salt (300 mM NaCl), as inferred from photosynthetic activity and oxidative damage measurements [ 55 ]. Furthermore, rice plants overexpressing pepper MSRB2 exhibit better tolerance to water deficit than WT upon shortage and higher survival rate following re-watering [ 57 , 114 ]. In these plants, microarray analysis indicated that genes coding for photosystem components are much less down-regulated in drought conditions than in WT [ 57 ].…”

“…Furthermore, rice plants overexpressing pepper MSRB2 exhibit better tolerance to water deficit than WT upon shortage and higher survival rate following re-watering [ 57 , 114 ]. In these plants, microarray analysis indicated that genes coding for photosystem components are much less down-regulated in drought conditions than in WT [ 57 ]. Regarding salt stress, few data are available regarding the protective effect of MSRs.…”

Multivariate analysis for the safety assessment of genetically modified rices in the anti‐nutrients and phenolic compounds

“…Agb0103 was a drought‐tolerant transgenic rice using a CaMSRB2 ( Capsicum annuum Methionine sulphoxide reductase B2) gene and bar (phosphinothricin acetyltransferase) gene with the Agrobacterium ‐mediated transformation (Kim et al ., ). The CaMSRB2 ‐overexpression transgenic rice has the tolerance to the drought treatment during vegetative stage.…”

“…CaMSRB2 gene was cloned into the pSB‐Rab21 without the potato protease inhibitor II terminator/35S promoter/bar, resulting in the plasmid MSRB2‐mini. Finally, the constructs were introduced into Agrobacterium tumefaciens LBA4404 by triparental mating (Kim et al ., ).…”