Fig. 4

Results of the sPLS analysis between the concentration of the terpenes and the gene expression in M. alternifolia leaf samples. a Correlations between the first two principal components and each terpene proportion (orange text) or the gene expression (blue text) for variables selected with the sPLS analysis (see methods). Variables located in the same direction from the centre of the circle show a direct association. The further a variable is from the centre of the circle the stronger the correlations. b The correlation heatmap with a hierarchical cluster between the terpene matrix (x-axis) and the terpene synthase gene expression matrix (y-axis) using the first three principal components from the sPLS analysis. Blue cells indicate a negative correlation and red cells indicate a positive correlation with the intensity of the colour representing the strength of the correlation