title: Sulfite Oxidase Activity Is Essential for Normal Sulfur, Nitrogen and Carbon Metabolism in Tomato Leaves.
abstract: Plant sulfite oxidase [SO; E.C.1.8.3.1] has been shown to be a key player in protecting plants against exogenous toxic sulfite. Recently we showed that SO activity is essential to cope with rising dark-induced endogenous sulfite levels in tomato plants (Lycopersicon esculentum/Solanum lycopersicum Mill. cv. Rheinlands Ruhm). Here we uncover the ramifications of SO impairment on carbon, nitrogen and sulfur (S) metabolites. Current analysis of the wild-type and SO-impaired plants revealed that under controlled conditions, the imbalanced sulfite level resulting from SO impairment conferred a metabolic shift towards elevated reduced S-compounds, namely sulfide, S-amino acids (S-AA), Co-A and acetyl-CoA, followed by non-S-AA, nitrogen and carbon metabolite enhancement, including polar lipids. Exposing plants to dark-induced carbon starvation resulted in a higher degradation of S-compounds, total AA, carbohydrates, polar lipids and total RNA in the mutant plants. Significantly, a failure to balance the carbon backbones was evident in the mutants, indicated by an increase in tricarboxylic acid cycle (TCA) cycle intermediates, whereas a decrease was shown in stressed wild-type plants. These results indicate that the role of SO is not limited to a rescue reaction under elevated sulfite, but SO is a key player in maintaining optimal carbon, nitrogen and sulfur metabolism in tomato plants.
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel. galina.brychkova@nuigalway.ie.
authors.forename: Galina
authors.initials: G
authors.lastname: Brychkova
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel. dmitry.yarmolinsky@ut.ee.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Yarmolinsky
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel. albert.batushansky@gmail.com.
authors.forename: Albert
authors.initials: A
authors.lastname: Batushansky
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel. grivvol@gmail.com.
authors.forename: Vladislav
authors.initials: V
authors.lastname: Grishkevich
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel. khozin@bgu.ac.il.
authors.forename: Inna
authors.initials: I
authors.lastname: Khozin-Goldberg
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel. fait@bgu.ac.il.
authors.forename: Aaron
authors.initials: A
authors.lastname: Fait
authors.affiliation: Migal-Galilee Technology Center, Southern Industrial Zone, POB831 Kiryat-Shmona 11016, Israel. rachel@migal.org.il.
authors.forename: Rachel
authors.initials: R
authors.lastname: Amir
authors.affiliation: Department of Plant Sciences, Weizmann Institute of Science, P.O.B. 26 Rehovot 76100, Israel. robert.fluhr@weizmann.ac.il.
authors.forename: Robert
authors.initials: R
authors.lastname: Fluhr
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel. gizi@bgu.ac.il.
authors.forename: Moshe
authors.initials: M
authors.lastname: Sagi
keywords: carbon metabolism; dark-induced senescence; lipid degradation; nitrogen; sulfite oxidase; sulfur