Alternaria alternata JTF001 Metabolites Recruit Beneficial Microorganisms to Reduce the Parasitism of Orobanche aegyptiaca in Tomato

<i>Orobanche aegyptiaca</i> is a holoparasitic weed that extracts water, nutrients, and growth regulators from host plants, leading to significant yield and quality losses. Biocontrol microbial metabolites have been shown to enhance plant resistance against parasitic plants, yet the underlying microbial mechanisms remain poorly understood. In this study, we investigated the role of <i>Alternaria alternata</i> JTF001 (J1) microbial metabolites in recruiting beneficial microbes to the tomato rhizosphere and promoting the establishment of a disease-suppressive microbiome. Pot experiments revealed that J1 metabolite application significantly reduced <i>O. aegyptiaca</i> parasitism. High-throughput sequencing of full-length 16S rRNA genes and ITS regions, along with in vitro culture assays, demonstrated an increase in the abundance of plant-beneficial bacteria, particularly <i>Pseudomonas</i> spp. The three candidate beneficial strains (zOTU_388, zOTU_533, and zOTU_2335) showed an increase of 5.7-fold, 5.4-fold, and 4.7-fold, respectively. These results indicate that J1 metabolites induce the recruitment of a disease-suppressive microbiome in tomato seedlings, effectively inhibiting <i>O. aegyptiaca</i> parasitism. Our findings suggest that microbial metabolites represent a promising strategy for managing parasitic plant infestations through microbial community modulation, offering significant implications for sustainable agricultural practices.