Induction of resistance to Meloidogyne graminicola in rice

Abstract

Root-knot nematodes are responsible for substantial losses in rice production. These parasites are difficult to control, particularly in flooded fields, which require carefully designed strategies to avoid contamination of water bodies. This study investigated whether biotic and abiotic elicitors can induce resistance to the root-knot nematode Meloidogyne graminicola in rice plants. An initial screening test was performed to determine the elicitors with the greatest potential to control nematodes. Then, a second experiment was conducted under net house conditions to assess the effects of a mannanoligosaccharide-based fertilizer (MOS), acibenzolar-S-methyl (ASM), and silicate clay on nematode reproduction, penetration, and activation of plant defence-related enzymes. Elicitor treatment reduced nematode reproduction by 57.4 to 75.6% at 60 days after inoculation (DAI). Two factors that may have contributed to this result include reduced nematode penetration and delayed development, as observed in the screening test. All elicitors increased phenylalanine ammonia-lyase activity at 10 DAI. MOS and silicate clay also increased catalase, peroxidase, and glucanase activity at 8 DAI. Elicitor treatment activates defence responses in rice plants and may be an environmentally friendly strategy for controlling M. graminicola in an integrated management system.