Glucosinolates profile of Arabidopsis thaliana modified root colonization of Trichoderma species

Abstract

Trichoderma is a genus of filamentous fungi with highly beneficial species for use in agriculture due to its ability to combat disease, increase growth, tolerance to abiotic stresses and resistance to biotic stresses in plants. To do this, Trichoderma must effectively colonize the roots of the plant, being able to overcome the existing plant defenses. In this sense, glucosinolates (GSLs) are a group of secondary metabolites present in cruciferous dishes such as Arabidopsis thaliana with great antimicrobial capacity. In order to determine the effect of the A. thaliana-roots GSLs profile in Trichoderma colonization, we have used different A. thaliana mutants (cyp: absent in indolic GSLs; myb: absent in aliphatic GSLs; QKO: absent in indolic and aliphatic GSLs; and atr1D: which hyperacumulates indolic GSLs) and inoculated them with the species Trichoderma harzianum and T. parareesei. The results showed how in the roots of A. thaliana mutants absent from IGSLs an increase occurs in the levels of root colonization of Trichoderma, without observing differences in the rest of the mutants. This increased root colonization by Trichoderma results in an increase in the formation of siliques by A. thaliana and an increase in the systemic resistance against Botrytis cinerea mediated by jasmonic acid, being more significant with T. harzianum; in addition to an increase in tolerance to abiotic stresses such as salinity and drought, being more significant with T. parareesei. Therefore, the presence of IGSLs in the roots of cruciferous plants, such as A. thaliana, inhibits Trichoderma's ability to root colonization, reducing the fungus's ability to increase plant productivity, tolerance to abiotic stresses and resistance to biotic stresses.