Metabolomics of soybean green stem and foliar retention (GSFR) disease using mass spectrometry and molecular networking

Abstract

Rationale The nematode Aphelenchoides besseyi is the causal agent of green stem and foliar retention, a soybean disease recently described in Brazil. This condition can reduce soybean yield by up to 100%. However, little is known about chemical interactions between the plant and pathogen. Therefore, this work aimed to investigate metabolites from healthy soybean roots and from soybean roots that were inoculated with A. besseyi. Methods A. besseyi were multiplied in vitro with Fusarium sp. colonies in Petri dishes for 25 days, and were axenically inoculated into hydroponics healthy soybean plants. The metabolites were extracted from the roots of healthy and A. besseyi‐infected plants 16 days post‐inoculation. These extracts were analyzed using an untargeted metabolomic method with an ultra‐high‐performance liquid chromatography/electrospray ionization /tandem mass spectrometry (UHPLC/ESI‐MS/MS) and molecular networking approach. Results Roots from infected plants showed morphological alterations such as shrinkage, darkening, and arching. Similarly, they also showed an increased presence of flavonoids, compared with healthy roots. Compounds such as neobavaisoflavone, glycitin, genistin, and genistein were putatively identified and had greater intensity in inoculated roots. These compounds are linked to the defensive mechanisms in plants against nematodes. Moreover, coumaric acid, also exclusively putatively identified in inoculated roots, shows activity related to inhibition of root growth. Conclusions Liquid chromatography, mass spectrometry, and molecular networking approaches proved to be a powerful tool for the metabolomic study of GSFR. This study showed metabolomics differences of protective substances in the roots, evidencing a quick response of the plant to the attack of A. besseyi.

Metabolomics as a Tool to Study Underused Soy Parts: In Search of Bioactive Compounds

“…Moreover, the interaction between soy and microorganisms, nematodes, aphids, and other insects causes distinct metabolic responses, and metabolomics is a unique approach for understanding such changes, providing insights to improve soy's response against biotic factors [63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80]. Recent works used GNPS to identify metabolite variation in soy infected by the fungus Phakopsora pachyrhizi and the nematode Aphelenchoides besseyi [78][79][80]. Both pathogens resulted in a higher production of bioactive compounds such as flavonoids, isoflavonoids, and terpenoids.…”

“…In addition to the four main causes of change in soy metabolism mentioned above, both qualitative and quantitative metabolic variations among soy organs are expected. To present an overview of the metabolite profile of underused soy parts, we selected metabolomics and related works which used various approaches to analyze them [38,67,[78][79][80]93,94,[98][99][100][101][102][103][104][105][106][107][108]. Using Jchem (JChem for Excel 21.1.0.787, ChemAxon (https://www.chemaxon.com accessed on 8 April 2021)) [109] and ClassyFire [110], we organized and classified the metabolites identified in soy roots, leaves, branches, and pods, as presented in Supplementary Materials Table S1-S4, respectively.…”

Phytochelatin and coumarin enrichment in root exudates of arsenic‐treated white lupin

“…The nucleoside thymidine, a DNA constituent, has been shown to have exudate function as a growth substrate for rhizosphere microorganisms in Avena barbata (Zhalnina et al, 2018) and as a metabolite involved in response to P deficiency in Glycine max (Tawaraya et al, 2014). Enriched coumarins included four chromenone glycoside derivatives (Figure 5, Data S1), previously identified in root extracts from Glycine max (Zanzarin et al, 2020). The coumarin pathway was reported as up-regulated in response to Fe limitation in white lupin (Venuti et al, 2019) and some coumarins from Arabidopsis root exudates were shown to complex Fe (Schmid et al, 2014) but coumarins have not previously been associated to arsenic response, and their role in root exudates remain unclear.…”

Soybean Metabolomics Based in Mass Spectrometry: Decoding the Plant’s Signaling and Defense Responses under Biotic Stress

“…Cooling of plant samples is usually performed by freezing in liquid nitrogen and freezer storage at −80 °C . Several studies of untargeted metabolomics of crops, including soybean, have verified the same cultivation strategies, including collection, harvesting, and storage of samples, always looking for the integrity of the samples. ,,,− …”

“…LC–MS is an analytical system that offers robustness, sensitivity, and selectivity. The technique allows for the analysis of polar and nonpolar chemical compounds without derivatization steps, covering the primary and secondary metabolites involved in plant biotic stress, and it is frequently investigated in metabolomics studies. ,,,, …”