PMC

Visualisation of the trichotomy of the covariate space based on the credible subgroup pair (D,S) relative to the true benefiting subgroup (B), adapted from Schnell et.al. [].

The property of trichotomy

Glucosinolates and benzoxazinoids as examples of secondary metabolites that blurr the functional trichotomy of plant metabolism. Different functions of glucosinolates in Arabidopsis and benzoxazinoids in maize and wheat are depicted. Genes that are known to be involved in the different functions are indicated. Note that a direct role of benzoxazinoids and glucosinolates as plant primary metabolites (for instance, in the context of nitrogen/sulfur and/or energy storage) has not been clearly demonstrated so far. *MEDs and KFBs are likely regulated by aldoxime precursors of glucosinolates. For references, see the article.

Low molecular weight compounds in plants are functionally classified as primary metabolites, secondary metabolites, or hormones. Present work on plant secondary metabolites demonstrates that many of them also have regulatory roles, and some are demonstrated precursors of primary metabolites. Note that primary metabolites and hormones also show functional overlap with the other metabolite classes (not discussed here). These findings blur the functional trichotomy of plant metabolism and call for a reassessment of ecological and evolutionary frameworks that are based on this model.