A group from State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China, etc. has reported that foliar pathogen infection recruits beneficial bacteria through root exudates.
It was found that foliar infection of Panax notoginseng by Alternaria panax modified the rhizosphere soil microbial community and reversed the direction of the buildup of the soilborne pathogen Ilyonectria destructans and beneficial microbes, including Trichoderma, Bacillus, and Streptomyces, in rhizosphere soil. These beneficial microbes not only showed antagonistic ability against the pathogen I. destructans but also enhanced the resistance of plants to A. panax.
Foliar infection changes the metabolite profiles of root exudates determined by GC-MS analyses. Inoculated means foliar infection.
This is similar to the human immune response, in which cytokines and chemokines are secreted from the inflammatory site, and immune cells such as leukocytes are attracted to the inflammatory site. Changes in the secretion from the root correspond to the secretion of cytokines and chemokines, and beneficial bacteria are immune cells derived from bone marrow cells.