A diminution in ascorbate oxidase activity affects carbon allocation and improves yield in tomato under water deficit.
The regulation of carbon allocation between photosynthetic source leaves and sink tissues in response to stress is an important factor controlling plant yield. Ascorbate oxidase is an apoplastic enzyme, which controls the redox state of the apoplastic ascorbate pool. RNA interference was used to decrease ascorbate oxidase activity in tomato (Solanum lycopersicum L.). Fruit yield was increased in these lines under three conditions where assimilate became limiting for wild-type plants: when fruit trusses were left unpruned, when leaves were removed or when water supply was limited. Several alterations in the transgenic lines could contribute to the improved yield and favour transport of assimilate from leaves to fruits in the ascorbate oxidase lines. Ascorbate oxidase plants showed increases in stomatal conductance and leaf and fruit sugar content, as well as an altered apoplastic hexose:sucrose ratio. Modifications in gene expression, enzyme activity and the fruit metabolome were coherent with the notion of the ascorbate oxidase RNAi lines showing altered sink strength. Ascorbate oxidase may therefore be a target for strategies aimed at improving water productivity in crop species.
INRA, UR1052, Génétique et amélioration des fruits et légumes, Domaine St Maurice BP94, Montfavet, France.
Cécile
C
Garchery
Noé
N
Gest
Phuc T
PT
Do
Moftah
M
Alhagdow
Pierre
P
Baldet
Guillaume
G
Menard
Christophe
C
Rothan
Capucine
C
Massot
Hélène
H
Gautier
Jawad
J
Aarrouf
Alisdair R
AR
Fernie
Rebecca
R
Stevens
D001204:Ascorbate Oxidase / Q000235:genetics / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D018533:Biomass; D050260:Carbohydrate Metabolism; D005638:Fruit / Q000254:growth & development* / Q000378:metabolism; D006601:Hexoses / Q000378:metabolism; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000254:growth & development; D055442:Metabolome; D010084:Oxidation-Reduction; D018515:Plant Leaves / Q000201:enzymology; D054046:Plant Stomata / Q000502:physiology; D034622:RNA Interference; D013395:Sucrose / Q000378:metabolism; D014867:Water / Q000502:physiology*
D006601:Hexoses; D014867:Water; D013395:Sucrose; D001204:Ascorbate Oxidase; D001205:Ascorbic Acid