Temporal metabolite profiling in leaves and roots ofPongamia pinnata under salt stress
The relative levels of metabolites in Pongamia under salt stress
conditions were quantified by using gas chromatography-mass spectrometry
(GC-MS) (Supplementary Figures 5 and 6). A total of 71 metabolites were
identified in both leaves (Supplementary Table 1) and roots
(Supplementary Table 2), which are related to 12 carbohydrate
metabolism, 22 organic acid metabolism, 15 amino acid metabolism, 6
cyclitol/ polyol metabolism,6 fatty acid metabolism and 10 other
miscellaneous metabolites.
In response to salinity stress, leaves accumulated a set of primary
metabolites related to various metabolic pathways such as amino acid
metabolism, carbohydrate metabolism, organic acid metabolism, polyol and
fatty acid metabolism (Supplementary Figure 5). Upon salt stress
exposure, leaves accumulated various metabolites, which includes Suc,
Fru, Man, pinitol, mannitol, myo-inositol, Phe, Val, butanoate,
coumarate and myristate showed significant increase in both 300 and 500
mM NaCl treated plants at 1, 4 and 8DAS. Importantly, mannitol levels
showed significant up-regulation by ~12 fold in leaves
of 300 and 500 mM NaCl treated plants at 1, 4 and 8DAS. With increasing
treatment time, Pongamia accumulated several metabolites related to cell
wall synthesis and TCA cycle, which include Gal, Xyl, pGlc, pFru, Leu,
fumarate, succinate and glutarate in leaves of 300 and 500 mM NaCl
treated plants at 8DAS. Additionally, several other metabolites were
increased marginally in related to glycerol pathway, organic acid
synthesis, amino acid metabolism and GABA shunt in leaves of treated
plants across all-time points.
In response to salt stress, roots accumulated a set of primary
metabolites related to various metabolic pathways such as amino acid
metabolism, carbohydrate metabolism, amino acid metabolism, polyol and
fatty acid metabolism (Supplementary Figure 6). Additionally, roots of
salt treated plants also accumulated various metabolites related to
cell-wall carbohydrates, carbohydrate alcohol, polyol, amino acid and
fatty acid metabolism, which includes Gal, mannitol, NAG, myristate,
laurate, palimitate, phytol and methyl-succinate showed significant
increase in 300 and 500 mM NaCl treated plants at 1, 4 and 8DAS.
Importantly, similar to leaves, mannitol levels showed significant
up-regulation by ~12 fold in roots of 300 and 500 mM
NaCl treated plants at 1, 4 and 8DAS. In addition, Pongamia leaves
accumulated several metabolites related to cell wall synthesis, polyols
and organic acids, which includeMan, Fru, pGlc, pTag, pinitol, Val, Leu,
glycerol, threonate and benzoate in roots of 300 and 500 mM NaCl treated
plants at 8DAS. Several other metabolites also increased marginally
relating to fatty acid, organic acid synthesis, amino acid metabolism
and GABA shunt in leaves of treated plants across all-time points.