Plant growth-promoting microorganisms from native plants: an untapped resource of biocontrol and biofertilizer agents

Microbial biocontrol agents (BCAs) constitute a promising alternative to agrochemicals for the mitigation of plant pathogens. However, most studies describing successful microbial BCAs have focused on microorganisms from agricultural or ornamental crops, thus overlooking the huge microbial diversity associated with native plants. This chapter highlights the potential of microorganisms associated with native plants as BCAs and biofertilizers. Microorganisms isolated from native forest trees have been described as sources of antifungal compounds that could be used against causal agents of tree diseases and phytopathogens of agricultural relevance. Native plants are also sources of bioactive compounds and are colonized by specific microorganisms; in this context, medicinal plants are potential sources of microorganisms with antimicrobial activity. Mechanisms underlying the antimicrobial properties displayed by microorganisms from native plants should be further investigated using novel chemical profiling or genome mining tools to gain a deeper understanding of their potential as BCAs. Recent studies have focused on crop wild relatives to isolate beneficial microbial strains that could be applied in agrosystems; however, their focus has been largely directed toward wild Solanaceae, which calls for the exploration of other crop wild relatives. Furthermore, native plants are often subjected to harsh environmental conditions, and their associated microbiota has developed a wide range of adaptations to overcome these limitations. This ability to adapt to extreme environmental conditions should be harnessed to fully exploit the potential of native plant microorganisms as plant growth promoters or BCAs. Finally, we call for future research to focus on fungal endophytes of native plants as potential BCAs, as their role in plant development and protection against biotic and abiotic stress has been largely ignored.