Bacillus is one of the most potential genus as a biocontrol agent of golden cyst nematode (Globodera rostochiensis)

The nematicidal ability of forty-five bacterial isolates from potato cultivation lands in Indonesia were examined. The isolates showing ≥50 cyst and egg mortality were identified based on morphological and molecular approach. DK-Sa-A1, SRJ-Sa-A1, KB-Se-A2, and SRJ-Se-A1 showed cyst mortality of 80, 63.3, 53.3, and 50, respectively. The ovicidal potential of SRJ-Se-A1, DK-Sa-A1, SRJ-Sa-A1, KB-Se-A2, KB-Sa-B3, KT-Se-A2, and PB-Sa-A2 were 98.7, 96.4, 95.2, 94.1, 76.4, 70.3, and 54.4 egg mortality, respectively. Five isolates representing each sampling location, DK-Sa-A1, KB-Se-A2, KT-Se-A2, PB-Sa-A2, and SRJ-Sa-A1 were selected for further analysis. These isolates showed significantly different protease and chitinase specific activity compared with the control and were identified as Bacillus flexus DK-Sa-A1, B. pumilus KB-Se-A2, B. cereus KT-Se-A2, B. megaterium PB-Sa-A2, and B. subtilis SRJ-Sa-A1. All identified isolates were not plant pathogenic and did not trigger a hypersensitive response. Therefore, they could be potential biocontrol agents for golden cyst nematode.