Trichoderma-secreted anthranilic acid promotes lateral root development via auxin signaling and RBOHF-induced endodermal cell wall remodeling

Trichoderma spp. have evolved the capacity to communicate with plants by producing various secondary metabolites (SMs). Nonhormonal SMs play important roles in plant root development, while specific SMs from rhizosphere microbes and their underlying mechanisms to control plant root branching are still largely unknown. In this study, a compound, anthranilic acid (2-AA), is identified from T. guizhouense NJAU4742 to promote lateral root development. Further studies demonstrate that 2-AA positively regulates auxin signaling and transport in the canonical auxin pathway. 2-AA also partly rescues the lateral root numbers of CASP1