TR4-triggered recruitment of suppressive rhizomicrobiome enhances Fusarium wilt resistance in banana.

Fusarium wilt of banana threatens banana production world-wide. Although beneficial rhizomicrobiomes are linked to disease resistance, whether resistant cultivars systemically recruit disease-suppressive rhizomicrobiomes after pathogen challenge remains unclear. Using a split-root system combined with rhizomicrobiome transfer, we tested whether systemically recruited rhizomicrobiomes from different cultivars after pathogen challenge could alter disease development in a susceptible cultivar. Rhizosphere soil suspension from the pathogen-challenged highly resistant cultivar GCTCV119 was the only donor treatment that significantly reduced the disease index in the susceptible recipient cultivar Guijiao No. 1. This effect was associated with pathogen-induced enrichment of absolute bacterial abundance and absolute Bacillus abundance in the rhizosphere of GCTCV119, whereas such enrichment was not observed in the other donor cultivars. A syncom of seven Bacillus strains from the GCTCV119 rhizosphere most effectively reduced (by 90.20%) the disease index by the induction of plant resistance. Soil incubation showed that pathogen-induced D-sorbitol accumulation in GCTCV119 significantly increased total bacterial abundance and Bacillus abundance, and reduced the disease index. This study highlights pathogen-triggered rhizomicrobiome reshaping, higher absolute bacterial abundance, and the suppressive role of Bacillus as key features linked to disease resistance in banana, providing insights into microbiome-mediated disease suppression.