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Effect of a Shading Mesh on the Metabolic, Nutritional, and Defense Profiles of Harvested Greenhouse-Grown Organic Tomato Fruits and Leaves Revealed by NMR Metabolomics
journal contribution
posted on 2019-11-08, 22:30 authored by Ana Cristina Abreu, Patricia Marín, Luis Manuel Aguilera-Sáez, Ana Isabel Tristán, Araceli Peña, Isabel Oliveira, Manuel Simões, Diego Valera, Ignacio FernándezControlling the temperature inside
a greenhouse during the summer
is a problem of increasing importance in the Mediterranean countries,
especially in the Spanish southeast. The metabolic profile of greenhouse
tomatoes and leaves grown under conventional conditions and within
the presence of a shade mesh (∼50% reduction of sunlight radiation)
has been monitored. Tomatoes were weekly harvested from May to July
2017 and analyzed by NMR spectroscopy coupled to multivariate data
analysis techniques, together with oxygen radical absorbance capacity
(ORAC) assays (for antioxidant activity). Fatty acids and carotenoids
profiles were unraveled by GC-FID and HPLC-DAD, respectively. To verify
whether it would be possible to take advantage of different light
growing conditions to potentiate a plant’s defense system,
leaves of the corresponding plants were collected and their methanolic
extracts were analyzed by NMR toward deciphering new biomarkers, which
were used to assess their antibacterial and antibiofilm activities.
The presence of a shading mesh resulted in a reduction in tomato production
and in smaller fruits with lower contents of sugars (glucose and fructose)
and carotenoids (lycopene and β-carotene) and higher contents
of organic acids, amino acids, and polyunsaturated fatty acids (linoleic
and oleic acids) and of phenylpropanoids and flavonoids (which contributed
to an increased antioxidant activity). Methanolic extracts of leaves
of nonshaded plants showed a higher antibiofilm activity than that
from shaded plants. This activity was well-correlated with an increase
of phenolic compounds, together with some specific amino acids and
organic acids from tomato leaves.