An orange ripening mutant links plastid NAD(P)H dehydrogenase complex activity to central and specialized metabolism during tomato fruit maturation.
In higher plants, the plastidial NADH dehydrogenase (Ndh) complex supports nonphotochemical electron fluxes from stromal electron donors to plastoquinones. Ndh functions in chloroplasts are not clearly established; however, its activity was linked to the prevention of the overreduction of stroma, especially under stress conditions. Here, we show by the characterization of Orr(Ds), a dominant transposon-tagged tomato (Solanum lycopersicum) mutant deficient in the NDH-M subunit, that this complex is also essential for the fruit ripening process. Alteration to the NDH complex in fruit changed the climacteric, ripening-associated metabolites and transcripts as well as fruit shelf life. Metabolic processes in chromoplasts of ripening tomato fruit were affected in Orr(Ds), as mutant fruit were yellow-orange and accumulated substantially less total carotenoids, mainly beta-carotene and lutein. The changes in carotenoids were largely influenced by environmental conditions and accompanied by modifications in levels of other fruit antioxidants, namely, flavonoids and tocopherols. In contrast with the pigmentation phenotype in mature mutant fruit, Orr(Ds) leaves and green fruits did not display a visible phenotype but exhibited reduced Ndh complex quantity and activity. This study therefore paves the way for further studies on the role of electron transport and redox reactions in the regulation of fruit ripening and its associated metabolism.
Nashilevitz
Shai
S
Department of Plant Sciences, Weizman Institute of Science, Rehovot 76100, Israel.
Melamed-Bessudo
Cathy
C
Izkovich
Yinon
Y
Rogachev
Ilana
I
Osorio
Sonia
S
Itkin
Maxim
M
Adato
Avital
A
Pankratov
Ilya
I
Hirschberg
Joseph
J
Fernie
Alisdair R
AR
Wolf
Shmuel
S
Usadel
Björn
B
Levy
Avraham A
AA
Rumeau
Dominique
D
Aharoni
Asaph
A
D002338:Carotenoids / Q000378:metabolism; D004251:DNA Transposable Elements; D018744:DNA, Plant / Q000235:genetics; D005419:Flavonoids / Q000378:metabolism; D005638:Fruit / Q000201:enzymology* / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D018551:Solanum lycopersicum / Q000201:enzymology / Q000235:genetics*; D016254:Mutagenesis, Insertional; D009154:Mutation; D009245:NADH Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D024505:Tocopherols / Q000378:metabolism
D004251:DNA Transposable Elements; D018744:DNA, Plant; D005419:Flavonoids; D010940:Plant Proteins; D002338:Carotenoids; D009245:NADH Dehydrogenase; D024505:Tocopherols