abstract
Iron (Fe) deficiency is an important agricultural concern that leads to lower yields and crop quality. A better understanding Of the condition at the metabolome level could contribute to the design of strategies to ameliorate Fe-deficiency problems. Fe-sufficient and Fe-deficient soybean leaf extracts and whole leaves were analyzed by liquid H-1 nuclear magnetic resonance (NMR) and high-resolution magic-angle spinning NMR spectroscopy, respectively. Overall, 30 compounds were measurable and identifiable (comprising amino and organic acids, fatty acids, carbohydrates, alcohols, polyphenols, and others), along with 22 additional spin systems (still unassigned). Thus, metabolite differences between treatment conditions could be evaluated for different compound families simultaneously. Statistically relevant metabolite changes upon Fe deficiency included higher levels of alanine, asparagine/aspartate, threonine, valine, GABA, acetate, choline, ethanolamine, hypoxanthine, trigonelline, and polyphenols and lower levels of citrate, malate, ethanol, methanol, chlorogenate, and 3-methyl-2-oxovalerate. The data indicate that the main metabolic impacts of Fe deficiency in soybean include enhanced tricarboxylic acid cycle activity, enhanced activation of oxidative stress protection mechanisms and enhanced amino acid accumulation. Metabolites showing accumulation differences in Fe-starved but visually asymptomatic leaves could serve as biomarkers for early detection of Fe-deficiency stress.
keywords
FIELD-GROWN PEAR; GLYCINE BETAINE; SECONDARY METABOLITES; CHLOROPHYLL METER; NMR METABOLOMICS; ACID-METABOLISM; FE-DEFICIENCY; XYLEM SAP; PLANTS; ARABIDOPSIS
subject category
Biochemistry & Molecular Biology
authors
Lima, MRM; Diaz, SO; Lamego, I; Grusak, MA; Vasconcelos, MW; Gil, AM
our authors
Ana Maria Pissarra Coelho Gil
Associate Professor with Aggregation
Inês Dias Lamego
PhD Student
Sílvia de Oliveira Diaz
PhD Studentacknowledgements
The Foundation for Science and Technology (FCT) (CICECO - FCOMP-01-0124-FEDER-037271) (Refa. FCT PEst-C/CTM/LA0011/2013, PTDC/AGR-GPL/102861/2008, PTDC/AGR-GPL/118772/2010, SFRH/BPD/69539/2010, SFRH/BD/64159/2009, and SFRH/BD/63916/2009), the European Regional Development Fund through the Competitive Factors Thematic Operational Programme, and the USDA Agricultural Research Service (cooperative agreement no. 58-6250-0-008) are acknowledged for funding. A.M.G. thanks the Portuguese National NMR Network (RNRMN), which is supported with FCT funds, M. Spraul, Bruker BioSpin, Germany (for providing access to spectral databases), and G. Graca (for assistance with statistical analysis). The contents of this publication do not necessarily reflect the views or policies of the U.S. Department of Agriculture, nor does the mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.