Active O-acetylserine-(thiol) lyase A and B confer improved selenium resistance and degradel-Cys andl-SeCys in Arabidopsis

Abstract

The roles of cytosolic O-acetylserine-(thiol)-lyase A (OASTLA), chloroplast-localized OASTLB and mitochondrion OASTLC in plant selenate resistance were studied in Arabidopsis. Impairment in OASTLA and OASTLB resulted in reduced biomass, chlorophyll and soluble protein levels compared with selenate treated impaired OASTLC and Wild-Type plants. The general lower total selenium (Se), protein-Se, organic-sulfur and protein-sulfur (S) in oastlA and oastlB levels compared to Wild-Type and oastlC leaves indicate that Se accumulation levels are not the main cause for the stress symptoms in these mutants. Notably, the application of selenate positively induced the S-starvation transcript markers: low-sulfur-induced1 (LSU1), LSU2 and ChaC like protein. Additionally, the activity of S-starvation enzymes markers, the adenosine-5′-phosphosulfate reductase and the OASTLs was increased followed by increased sulfite reductase and sulfite oxidase activities, as well as increased sulfite and sulfide levels. Taken together, the results indicate a futile anabolic S-starvation response that resulted in lower glutathione and increased oxidative stress symptoms in leaves of oastlA and oastlB mutants. Employing in-gel assays of L-cysteine and L-seleno-cysteine desulfhydrase activities revealed that two of the three OASTLs activity bands in each of the oastls single mutants were enhanced in response to selenate, whereas the impaired proteins exhibited a missing activity band in stressed and unstressed plants. The absence of differently migrated activity band in each of the three oastls indicates that these OASTLs are major components in Arabidopsis desulfhydrase activity, degrading not only L-cysteine but also L-Seleno-cysteine.

Hydrogen sulfide attenuates intracellular oxidative stress via repressing glycolate oxidase activities in Arabidopsis thaliana

“…Alternatively, this could raise another possibility that other and/or unidentified factors/pathways promoting 2 S generation may compensate for the loss of function of DES1 if they have redundant roles in the regulation of oxidative stress. Indeed, several candidate genes, encoding the cysteine desulfhydrase, have been implicated in enhancing resistance to many stresses such as heavy metal stress, salt, drought and cold stress, pathogen attack, and preventing ROS accumulation [44][45][46][47][48]. For instance, cytosolic O-acetylserine-(thiol) lyase A (OASTLA) and chloroplastic OASTLB have substantially higher LCD activities than the cytosolic DES1, and likely act as major cysteine desulfhydrases in Arabidopsis [44].…”

“…Indeed, several candidate genes, encoding the cysteine desulfhydrase, have been implicated in enhancing resistance to many stresses such as heavy metal stress, salt, drought and cold stress, pathogen attack, and preventing ROS accumulation [44][45][46][47][48]. For instance, cytosolic O-acetylserine-(thiol) lyase A (OASTLA) and chloroplastic OASTLB have substantially higher LCD activities than the cytosolic DES1, and likely act as major cysteine desulfhydrases in Arabidopsis [44].…”

Response of Sunflower to Biofertilization and Diatoms Under Saline Condition.

“…Consentino et al, (2022) stated that the soluble proteins are increased with better nitrogen supply and favorable growth condition. Kurmanbayeva et al,. (2022).…”

Gene Identification, Expression Analysis, and Molecular Docking of SAT/OASTL Reveal the Molecular Mechanisms of Selenocysteine Synthesis in Cardamine hupingshanensis

“…The different isoenzymes of OASTL are located in different organelles and play various important functions. Members of the OASTL family are involved in the synthesis and degradation of L-Cys and L-Sec, regulating the concentration of intracellular Cys and Sec homeostasis in plants [33]. Among the nine OASTL family members in A. thaliana, the main members of OASTL include cytoplasmic OASTLA1, chloroplast OASTLB, and mitochondrial OASTLC, which are involved in cysteine synthesis [34].…”