Metabolic profiling in the roots of coffee plants exposed to the coffee root-knot nematode, Meloidogyne exigua

Abstract

To understand the effect of nematode Meloidogyne exigua infestation on coffee plants, resistant and susceptible coffee seedlings were inoculated with second-stage juveniles of M. exigua, and root metabolites were studied for four time intervals at 0, 24, 48 and 96 h. During this important period for parasite establishment, the concentrations of phenols, carbohydrates, amino acids and alkaloids in the roots were measured, and hydrogen nuclear magnetic resonance spectra of the root extracts were used to identify and quantify other metabolites. One of the most striking changes was the concentration of fumaric acid on resistant plants, which varied from 59 μg g(of root) −1 to 138 μg g(of root) −1 during the first 24 h of the nematode inoculation. The same level of variation was observed much later (96 h) in susceptible plants. Similarly, formic and quinic acid concentrations increased more rapidly in the resistant plants compared to the susceptibles. Sucrose concentrations increased to 370 % in the first 48 h in the resistant plants but showed no significant variation in the susceptible plant. Besides, the concentration of alkaloids was much higher at 24 and 48 h in the susceptibles compared to the resistant plants. These results suggest that the higher production of sucrose as well as formic, fumaric and quinic acids, and the lower production of alkaloids by the resistant cultivar in the first 48 h after the nematode inoculation are associated with the resistance of coffee plants to M. exigua.

NMR-Based Metabolomic Screening for Metabolites Associated with Resistance to Meloidogyne javanica in Annona muricata Roots

“…21,22 Other important negative loadings on PC1 are in the region of d 6.66-7.30, characteristic of phenolic compounds, which are a widespread group of defensive substances with an important role in phytoparasitic defense. 2,8 A signal at d 7.92 was observed and could be assigned to xanthine. 23 Besides being related to the maturation process of this plant, these kinds of compounds are powerful natural allelochemicals that can repel and inhibit the phytoparasite development.…”

“…Since current nematode control methods present many disadvantages, such as difficulty of implementation in some areas and high cost, there is an increasing demand for new safe methods that prevent human and environmental contamination with toxic substances. 1,2 Several nematicidal substances have been isolated from plants and can be considered possible alternatives. 1 Secondary metabolites reported as potential phytonematode controlling agents may present unique and complex chemical structures belonging to different classes of natural products, such as alkaloids, terpenes, tannins, flavonoids glycosides, among others.…”

Quantitative analysis of trigonelline in some Annona species by proton NMR spectroscopy

“…Many analytical techniques were employed for the characterization and identification of trigonelline 3,9 . Machado et al 10 observed by NMR spectroscopy a content of 1.20 mg·g -1 of trigonelline in Coffea Arabica roots. NMR in particular, is a non-targeted analytical technique where there is no need for previous separations, derivates and even purification with processes being quick and efficient and capable to simultaneously detect a large amount of metabolites in only one analysis 11 .…”

Functional Metabolomics—A Useful Tool to Characterize Stress-Induced Metabolome Alterations Opening New Avenues towards Tailoring Food Crop Quality

“…Numerous studies already indicate that a complex network of secondary metabolites is influenced by biotic stress challenges. Next to phenylpropanoids, including flavonoids [34,50,51,71], alkaloids [72,73], terpenoids [33], and fatty acids [74] are also known to be up-regulated [25]. In addition, lipids act under pathogen or herbivore attack as mechanical barriers.…”