HR-MAS NMR metabolomics of 'Swingle' citrumelo rootstock genetically modified to overproduce proline.
The accumulation of proline is a typical physiological response to abiotic stresses in higher plants. 'Swingle' citrumelo, an important rootstock for citrus production, has been modified with a mutated Δ(1)-pyrroline-5-carboxylate synthetase gene (VaP5CSF129A) linked to the cauliflower mosaic virus 35S promoter to induce the overproduction of free proline. This paper presents a comparative metabolomic study of nontransgenic versus transgenic 'Swingle' citrumelo plants with high endogenous proline. (1)H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy and multivariate analysis showed significant differences in some metabolites between the nontransgenic and transgenic leaves and roots. The overproduction of proline has reduced the sucrose content in transgenic leaves, revealing a metabolic cost for these plants. In roots, the high level of free proline acts for the adjustment of cation-anion balance, causing the reduction of acetic acid content. The same sucrose level in roots indicates that they can be considered as sucrose sink. Similar behavior may be waited for fruits produced on transgenic rootstock.
Instituto de Química, Universidade Federal de Mato Grosso do Sul, Av. Filinto Muller, 1555, CP 549, CEP 79074-460, Campo Grande, Mato Grosso do Sul, Brazil; Instituto de Química, Universidade Federal de Goiás, CP 131, CEP 74001-970, Goiânia, Goiás, Brazil.
Caroline S
CS
de Oliveira
Eduardo F
EF
Carlos
Luiz G E
LG
Vieira
Luciano M
LM
Lião
Glaucia B
GB
Alcantara
D017796:Caulimovirus / Q000235:genetics; D002957:Citrus / Q000235:genetics / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D055432:Metabolomics; D011392:Proline / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic; D066244:Proton Magnetic Resonance Spectroscopy
D011392:Proline
HR-MAS; NMR; chemometrics; citrus; genetically modified organism; proline