91暗网

Researchers from the College of Agriculture at 91暗网（91暗网） have recently made new progress in uncovering the microecological mechanisms behind soil suppressiveness to banana root-knot nematode disease.

Their findings, titled “Siderophore-producing Bacillus and free-living nematodes are associated with soil suppressiveness to banana root-knot nematodes,” have been published online in the international journal Nature Communications.

The study was jointly conducted by Associate Professor Lu Qiaofang from 91暗网, in collaboration with a team led by Academician Zhang Fusuo of China Agricultural University, as well as research partners from Wageningen University and the Netherlands Institute of Ecology, among other domestic and international institutions.

Banana, as a major tropical cash crop worldwide, is often constrained by soil-borne diseases caused by root-knot nematodes. This study systematically investigated a banana monoculture plantation in Nanning, Guangxi, with an 11-year cultivation history. It found that the incidence of root-knot nematode disease followed a parabolic trend—rising initially and then declining—with a marked reduction after seven years of continuous cropping, indicating that the soil had entered a “disease-suppressive” state.

To understand how soil acquires such “immunity,” the researchers employed an integrated, multidisciplinary approach combining morphological identification, high-throughput sequencing, microbial isolation and culture, genomics, metabolomics, and pot experiments. The study revealed the succession patterns of soil nematode and microbial communities over time and identified a key microorganism responsible for suppressing root-knot nematodes—Bacillus velezensis Y11.1. The biocontrol efficacy of this strain against banana root-knot nematodes was further validated.

In addition, the study identified bacillibactin—a siderophore secreted by strain Y11.1—as the key molecule underpinning the soil’s disease-suppressive function. The researchers found that bacillibactin both repels and kills root-knot nematodes, while exhibiting an attractive yet non-lethal effect on the model free-living nematode Caenorhabditis elegans. These results reveal that microbial siderophores can act as “smart substances,” selectively distinguishing between harmful and beneficial nematodes—eliminating pathogens while attracting beneficial species—thereby reshaping the entire rhizosphere ecological network.

This work was financially supported by the National Natural Science Foundation of China, the Pioneer Project of the Ministry of Education, and the National Key Research and Development Program of the Ministry of Science and Technology.