Sophisticated crosstalk of tryptophan-derived metabolites in plant stress responses

Plants are continuously threatened by numerous stresses that cause detrimental damage to plant health and constrain crop productivity worldwide. Metabolic regulation, hence an important tool to regulate the stress tolerance of plants. Tryptophan, as a precursor of various plant natural products, including auxin, melatonin and glucosinolates, plays crucial roles in supporting plant health. To date, remarkable progress has been made in exploring the metabolism of tryptophan, particularly its involvement in enhancing plant stress tolerance. However, there is still a lack of systematic discussion on the crosstalk manipulation of tryptophan metabolites for protecting plants from stresses. Here, we attempt to dive into the tryptophan metabolism and its related crosstalk regulation under stresses. We provide an overview of the biosynthesis and biofunctions of tryptophan metabolites with a main focus on the crosstalk manipulation of tryptophan metabolites in plant stress resistance. The perspective applications of using tryptophan metabolism under stresses are also analyzed. This work endeavors to construct a fundamental framework regarding the regulatory role of tryptophan metabolites on plant health and related mechanisms in sustainable agriculture.