Exometabolites of bread wheat and tomato affecting the plant-microbe interactions in the rhizosphere

The composition of organic acids, carbohydrates, and amino acids released by the roots of wheat (Triticum aestivum L., cv. Obelisk) and tomato (Lycopersicon esculentum L., cv. Carmello) was examined. Tomato roots released threefold more organic acids, sevenfold more tyrosine, 3.8-fold more threonine, and 2.8-fold more arginine that wheat roots; in contrast, wheat roots released 4.1-fold more tryptophan than tomato roots. Differences in the ratio between organic acids and sugars and also in the intensity of L-tryptophan release could affect the interaction between tested plants and microorganisms in their rhizosphere.