Correlation of metabolites within the whole RIL
population
Spearman correlation analysis was performed and a correlation matrix was
generated between all pairs of known metabolites across the whole RIL
population. The results revealed that some metabolites are highly
correlated with each other (Figure 6 ). Except a few exceptions,
all amino acids cluster together. They showed a high degree of
correlation of mostly greater than 0.5 with p -values of less than
0.001 (Table S7 ). Such a high positive significant correlation
could be an indication of a preserved metabolism of amino acids in
seeds. It has previously been reported that the metabolism of amino
acids in seeds might be regulated by post-transcriptional regulators in
order to regulate the distribution of nitrogen (Kazmi et al.2017; Toubiana et al. 2012). We also observed a high number of
significant correlations between amino acids and TCA cycle intermediates
such as citrate, malate, fumarate and succinate. Such a correlation
between amino acids as a nitrogen (N) source and TCA intermediates as
carbon (C) metabolites, indicates a maintained crosstalk between N and C
metabolism in the seeds (Figure 6, Table S7 ). A similar
crosstalk has been previously suggested for different species including
Arabidopsis and tomato (GutiƩrrez et al. 2007; Kazmi et
al. 2017; Nunes-Nesi, Fernie & Stitt 2010; Stitt & Fernie 2003).
We have also detected significant correlation between galactinol and
myo-inositol (R=0.53 and p -value=1.06E-6) (Figure 6,
Table S7 ). These metabolites are classified as sugar alcohols which
have been reported to be involved in responses of seeds to stressful
environments, such as low temperature (He et al. 2016).