Correlation based clustering between hormones and metabolites in leaves and roots of P. pinnata under salt stress
Figure 5 shows the interaction between hormones and metabolites. In leaves, hormones including ABA, IBA, MeJA, zeatin and JA showed a positive correlation with MytA in leaves of 300 mM NaCl treated plants at 1DAS (Figure 5A). Hormones JA, MeJA and zeatin showed significant interaction with metabolites such as amino acids, carbohydrates, and organic acids in leaves of 300 mM NaCl treated plants at 4DAS (Figure 5B). In addition, JA and MeJA also showed strong association with carbohydrates and amino acids in leaves of 300 mM NaCl treated plants at 4DAS. At 8DAS, JA and ABA showed significant correlation with several metabolites MytA, Suc, Gal, Man and FA, while ABA and JA were showed significant interaction with metabolites pTag, organic acid group (NA, Pip, MA, 5Hpip, CAA), amino acids group (Hse, Asp, Asn), StA, and other metabolites (G3p, NAG, Grl-g) (Figure 5C). In leaves of 500 mM NaCl treated plants, we could observe more interaction between hormones and metabolites including MeJA:IBA:zeatin:JA:IAA::carbohydrates, JA:MeJA:IAA:zeatin::organic acids, ABA:IBA:IAA:zeatin::amino acids, JA:IBA:IAA:SA:zeatin::polyols and fatty acids at 1DAS (Figure 5D). Increased interactions were also observed between hormones and metabolites namely JA:MeJA:zeatin::carbohydrates and cell-wallcarbohydrates, JA:MeJA:IBA:zeatin::organic acids, MeJA:IBA:IAA::amino acids, JA:MeJA:zeatin::polyols at 4DAS (Figure 5E). We recorded a significant positive correlation between hormones and metabolites namely MeJA:JA:ABA:SA::carbohydrates and cell-wall carbohydrates, JA:ABA:MeJA:SA::organic acids, JA:ABA:MeJA:IBA:IAA::amino acids, JA:ABA::polyols, fatty acids and JA:ABA:MeJA:IBA:zeatin::fatty acids in leaves of 500 mM NaCl treated plants at 8DAS (Figure 5F).
In roots, significant associations between hormones and metabolites were including JA:SA:ABA:MeJA:IBA:zeatin::carbohydrates, JA:MeJA:SA:ABA:IAA:SA::organic acids and MeJA:IBA::fatty acids in 300 mM NaCl treated plants at 1DAS (Figure 5G). At 4DAS, more positive interactions were seen between hormones and metabolites namely JA:ABA:ABA:SA:IBA::cell-wall carbohydrates, MeJA:JA:zeatin::polyols and MeJA:zeatin::fatty acids (Figure 5H). At 8DAS, a strong interaction was noticed between hormones and metabolites (JA:MeJA:ABA:zeatin::organic acids, JA:IBA:zeatin::amino acidand JA:zeatin::polyols) (Figure 5I). As the salinity progressed from day 1 to day 8, the positive interactions decreased in roots of 500 mM NaCl treated plants (Figure 5J-L). In roots of 500 mM NaCl treated plants, significant interaction was between hormones and metabolites namely ABA:SA:IBA:zeatin::organic acids at 1DAS, JA:SA:IBA::cell-wall carbohydrates, ABA:SA:JA:MeJA::organic acids at 4DAS, and ABA:SA::cell-wall carbohydrates, ABA:MeJA::organic acid at 8DAS respectively.