Metabolites in normal type indicate their modulation shared
between the single (drought and heat) and combined stress
Figure 1. Scheme (A) and picture of the compartmented chambers
(B) and the sampling method used for the collection of the maize root
exudates (C).
Figure 2 . Compounds detected in the maize root exudate
collection solution: total phenols (a), total flavonols (b) total
flavonoids (c), aconitic acid (d), alanine (e), glycine (f), threonine
(g). Plants have been grown under following conditions: control (T1:
25°C, 80% soil field capacity); drought (T2: 25°C, 30% soil field
capacity); heat (T3: 32°C, 80% soil field capacity); combined stress
(T4: 32°C 30% soil field capacity). The exudates are collected to the
following root type-zone: seminal-apical (■), =, seminal-subapical (■),
primary-apical (■), primary-subapical (■). The values are reported as
means ± standard errors. Three way ANOVA with Tukey post hoc test:
*p =0.01-0.05, ** p=0.01-0.001; ***p <0.001.
Figure 3. Unsupervised hierarchical cluster analysis (Euclidean
distance; linkage rule: Ward) carried out from root exudates chemical
profiles. Metabolites were obtained by UHPLC-ESI/QTOF-MS untargeted
analysis, and their intensities used to build up the fold-change heatmap
here provided.
Figure 4. Score plot of Orthogonal projection to latent
structures discriminant analysis (OPLS-DA) supervised modelling carried
out from untargeted metabolomics profiles of root exudates (correlation
R2Y = 0.83), prediction ability Q2Y
= 0.48).
Figure 5 . Venn diagram summarizing the metabolites
differentially up-exuded (A) and down-exuded (B) that resulted from the
volcano analysis.