Metabolic Alternations of Amino Acids, γ-Aminobutyric Acid, and Salicylic Acid in Solanum lycopersicum (L.) Following Preplanting Seedling Spray with Salicylic Acid.

Preplanting foliar spray of salicylic acid (SA) (0.0, 5.0, and 10.0 µg/mL) to Solanum lycopersicum (L.) altered the metabolite profile of amino acids, γ-aminobutyric acid (GABA), and SA in leaf, root, and fruits. Free amino acid pools increased; bound amino acid pools reduced. In vegetative tissues, amino acid biosyntheses linked to osmo-compatibility (Pro, Leu, Val and GABA); N (Arg, Asn, Asp, Gln, and Glu); C (Pro, Ser, and Tyr); S (Cys) assimilation; stress tolerance (Ala, Gly, Hyp, His, Lys, Met, and Thr); and central metabolism (Phe, Trp, and Tyr) enhanced for 60-120 days. Concentrations of Ala, Arg, Gln, Gly, Leu, and Ser in leaf and of Asp, Cys, Glu, His, Hyp, Lys, Met, Pro, and Val in root predominated. In planta SA and GABA biosynthesis increased concurrently. SA affected GABA biosynthesis via Glu, Pro, and Arg metabolism. SA, GABA, Glu, and Pro were key canonical variables. This study first reported SA-induced metabolites promoting health (SA/GABA; Cys/Met) and palatability (Glu/Asp; Gln) in table tomato.

A liquid chromatography method for determination of selected amino acids, coenzymes, growth regulators, and vitamins from Cicer arietinum (L.) and Solanum lycopersicum (L.).

A bottleneck in crosstalk and QC research has been the quantification of diverse chemotypes in small amounts of tissue. An LC-UV method for estimating 28 selected metabolites of the regulatory network underlying growth, development, maintenance, vital functions, defense reactions, and food quality is reported. The method was based on binary gradient resolutions of the analytes in an RP C18 column. The mobile phase comprised solvent A [water+0.1% trifluoroacetic acid (TFA)] and B (acetonitrile + 0.085% TFA at a flow rate of 1 ml/min. Twenty-three metabolites (selected amino acids, coenzymes, growth regulators, phenolic antioxidant, and water-soluble vitamins) were detected at 254 nm, and four fat-soluble vitamins at 280 nm. Jasmonic acid was quantified at 210 nm. The RSDs of peak area and retention time for each metabolite were <5.8%. The calibration graphs were linear with R2 values ranging from 0.98 to 0.99. The LODs (microg/mL) were about 0.01-1.0 for 23 metabolites quantified at 254 nm, 0.1-0.2 for fat-soluble vitamins, and 0.1 for jasmonic acid. The recoveries ranged from 80 to 105%, with RSDs of 2.8 to 11.2%. The method has been satisfactorily applied for determination of 28 metabolites from Cicer arietinum (L.) and Solanum lycopersicum (L.). It could be an alternative and competitive method of choice that can cheaply and easily perform routine analysis for food quality and targeted metabolomics of chickpea and tomato in response to stressors.

A GC-ECD method for estimation of free and bound amino acids, gamma-aminobutyric acid, salicylic acid, and acetyl salicylic acid from Solanum lycopersicum (L.).

A gas chromatograph with electron capture detection method for estimation of selected metabolites--amino acids (free and bound), gamma-aminobutyric acid (GABA), salicylic acid (SA), and acetyl salicylic acid (ASA) from tomato--is reported. The method is based on nitrophenylation of the metabolites by 1-fluoro-2, 4-dinitrobenzene under aqueous alkaline conditions to form dinitophenyl derivatives. The derivatives were stable under the operating conditions of GC. Analysis of bound amino acids comprised perchloric acid precipitation of protein, alkylation (carboxymethylation) with iodoacetic acid, vapor-phase hydrolysis, and derivatization with 1-fluoro-2,4-dinitrobenzene in that order. The metabolites were resolved in 35 min, using a temperature-programmed run. The method is rapid, sensitive, and precise. It easily measured the typical amino acids (aspartate, asparagine, glutamate, glutamine, alanine, leucine, lysine, and phenylalanine) used for identification and quantification of a protein, resolved amino acids of the same mass (leucine and isoleucine), satisfactorily measured sulfur amino acid (methionine, cystine, and cysteine), and quantified GABA, SA, and ASA, as well. The developed method was validated for specificity, linearity, and precision. It has been applied and recommended for estimation of 25 metabolites from Solanum lycopersicum (L.).

Persistence and nematicidal efficacy of carbosulfan, cadusafos, phorate, and triazophos in soil and uptake by chickpea and tomato crops under tropical conditions.

The productivity of chickpea, Cicer arietinum (L.), and tomato, Solanum lycopersicum (L.), is adversely affected by root-knot nematode, Meloidogyne species. Nematode-resistant chickpea and tomato are lacking except for a few varieties and therefore grower demand is not met. The available nematicides, namely, carbosulfan, cadusafos, phorate, and triazophos, were, therefore evaluated for their efficacy and persistence in soil and crops to devise nematode management decisions. In alluvial soil, cadusafos was the most persistent nematicide followed by phorate, carbosulfan, and triazophos in that order. The percent dissipation of cadusafos was greater (P < 0.05) in chickpea than in tomato plots, which influenced its half-life in soil. Nematicide residues were differentially taken up by chickpea and tomato plant roots with active absorption continuing for up to 45 days. Cadusafos and triazophos were absorbed to greater extent (P < 0.05) in tomato than in chickpea. The translocation of residues to shoot was highest by day 15 for cadusafos and at day 45 for other nematicides, with carbosulfan residues translocated the most. Nematicide residue concentrations in shoots never exceeded those in roots, with residues in both roots and shoots persisting beyond 90 days. Nematicide residues in green seeds of chickpea and tomato fruits were all below the Codex/German MRLs of 0.02, including the Indian tolerances of 0.1 microg/g in fruits and vegetables. Cadusafos was found to be the most effective nematicide followed by triazophos against Meloidogyne incognita and reniform nematode, Rotylenchulus reniformis . Application of cadusafos (Rugby 10 G) or, alternatively, spray application of triazophos (Hostathion 40 EC) in planting furrows, both at 1.0 kg of active ingredient/ha, followed by light irrigation is recommended for the effective control of M. incognita and R. reniformis infestations on chickpea and tomato.

Virulence development and genetic polymorphism in Meloidogyne incognita (Kofoid & White) Chitwood after prolonged exposure to sublethal concentrations of nematicides and continuous growing of resistant tomato cultivars.

BACKGROUND: The root-knot nematode, Meloidogyne incognita (Kofoid & White) Chitwood, is an important plant pathogen damaging to tomato. Continuous use of resistant tomato cultivars and nematicides for its effective management might lead to resistance break-up or nematicide failure. Genetic variability and virulence in M. incognita on susceptible Pusa Ruby tomato were analysed by bioassay, esterase and DNA polymorphism after a 5 year weekly exposure to carbofuran, carbosulfan, cadusafos and triazophos at 0.0125, 0.0250 and 0.0500 microg g(-1). Virulence in M. incognita after a 5 year multiplication on resistant tomatoes was assessed. RESULTS: The nematicidal treatments resulted in the development of virulent M. incognita populations. Their invasion potential increased significantly after continuous exposure to low concentrations of the nematicides. Also, growing resistant tomato cultivars for ten successive seasons resulted in a 6.6% increase in the invasion potential. These virulent populations exhibited 1-3 additional esterase and DNA bands compared with untreated populations. CONCLUSION: A 5 year exposure of M. incognita to sublethal concentrations of nematicides or resistant tomato cultivars exerted enough selection pressure to cause genomic alterations for virulence development. Isozyme markers can be used for rapid and precise diagnostics of field populations by advisory services, enabling judicious remedial management decisions.