TIME SCENARIOS OF INTERACTION IN “TOMATO SEEDLINGS - Alternaria - FUNGAL ENDOPHYTES”

Abstract

In biological control one of the most common approaches is selecting microorganisms with antagonistic traits. Yet, indirect mechanisms of plant growth promotion may give advantages in biotic stress by allowing plants to overcome the colonization of the pathogen. Rapid methods of combined antagonistic and plant growth promotion traits are scarce. Here we propose a method for screening potentially bioactive fungal endophytes in a tripartite interaction “endophytes - Alternaria - tomato seedlings”. Endophytes are known to interact with pathogens chemically inhibiting their growth or development by means of specific biologically active metabolites, mycoparasitism, or by competition for nutrients, or indirectly by inducing resistance mechanisms in the host. The proposed method here could substitute the conventional assays of antagonism in dual culture (i.e. fungus – fungus), having introduced from the beginning the central biological actor, the plant. Results indicate that the order of arrival of each actor determines if seedling colonization or enhancement of seedling growth occur as the antagonistic interaction between endophyte and pathogen may precede the latter beneficial interactions.