Combined use of Trichoderma and beneficial bacteria (mainly Bacillus and Pseudomonas): Development of microbial synergistic bio-inoculants in sustainable agriculture

Agriculture nowadays is facing many challenges, with among the most important to be able to feed the increasing human population through more sustainable and environmentally friendly production. In this context, the use of microorganisms has been extensively studied, both with fungi such as Trichoderma spp. and with bacteria, such as Bacillus spp. or Pseudomonas spp. While inoculation with these microorganisms has a positive effect on crops, their combination offers even greater potential as plant growth promoters and as biocontrol agents, with diverse mechanisms that are thoroughly considered in this review. Synergies between Trichoderma and bacteria cause more benefits than the sum of their parts, and this makes them a promising alternative for managing crops and controlling diseases or pests in modern agriculture. However, more studies are needed to determine the specific mechanisms of this synergistic effect in certain lines of research, since there is extensive data about their use as plant growth promoters or biocontrol agents against diseases and certain pests, but little or no information is available about their use against diseases caused by viruses or the effect on plant tolerance to abiotic stresses.