Biocontrol potential of Bacillus altitudinis AMCC1040 against root-knot nematode disease of ginger and its impact on rhizosphere microbial community

Root knot nematodes are one of the most destructive hemibiotrophic root pathogens that can cause ginger bark cracking disease in ginger planting areas around the world. There is an urgent need for sustainable alternatives methods, such as biological control. The nematicidal activity of Bacillus altitudinis AMCC1040 has been previously shown in vitro and in pot experiments. Here, field experiments were conducted to evaluate the biocontrol potential of Bacillus altitudinis AMCC1040 against ginger bark cracking disease, and to evaluate its ability to colonize the rhizosphere. In addition, we also evaluated its impact on the rhizosphere microbial communities. The results of biocontrol experiments demonstrated that the application of Bacillus altitudinis AMCC1040 can significantly inhibit nematode reproduction, inhibit root galling and reduce the severity of ginger bark cracking disease. In addition, Bacillus altitudinis AMCC1040 colonized steadily in ginger rhizosphere soil ranging from 5.08 to 5.49 Log10 CFU g−1 soils. Compared with fosthiazate (One of the most commonly used nematicides in China), Bacillus altitudinis AMCC1040 performed better in terms of bio-safety. Meanwhile, the taxa enriched in Bacillus altitudinis AMCC1040 treatment were found in Actinobacteria, Gemmatimonadetes and Firmicutes. This study demonstrated that Bacillus altitudinis AMCC1040 have a strong potential to control ginger bark cracking disease in the field. These results provide strong support for further exploration of the application of Bacillus spp. as biocontrol agents to control root knot nematodes in many crops. Furthermore, the occurrence of ginger bark cracking disease described in this study will be of great help to future prevention and control measures.