Bacillus as a source of phytohormones for use in agriculture

Microbial plant biostimulants (MPBs) are capable of improving the productivity and quality of crops by activating plant physiological and molecular processes, representing an efficient tool in sustainable agriculture. Through phytohormone production, MPBs are capable of regulating plant physiological processes, increasing the productivity and quality of crops, in addition to being an efficient alternative in the industrial production of phytohormones. Bacillus is a bacterial genus with various species on the market being used as biopesticides, due to their ability to produce antimicrobial, nematicidal and insecticidal compounds. The capability of Bacillus species to protect plants against pests and/or pathogens also entails the triggering or increase of plant defense responses. Furthermore, a relevant number of species from the genus Bacillus provoke plant growth promotion by different mechanisms such as increasing the tolerance of their host plants under abiotic stress conditions or improving plant nutrition. In several cases, the plant response is mediated by the bacterial production of phytohormones. In the present work, all studies from recent decades where the production of phytohormones by Bacillus species are reported, highlighting their role in host plants and the mechanisms by which they are capable of increasing plant growth, promoting their development, and improving their response to different stresses.

Automated summary

Microbial plant biostimulants (MPBs) enhance crop productivity and quality by activating plant physiological and molecular processes through phytohormone production. Bacillus species, a bacterial genus used as biopesticides, protect plants from pests and pathogens while promoting plant growth through various mechanisms, including increasing tolerance to stress conditions and improving plant nutrition. The production of phytohormones by Bacillus species plays a key role in increasing plant growth, development, and stress response.