Host-induced silencing of the Minc09294 effector gene impairs Meloidogyne incognita and M. Enterolobii infection.
TL;DR
The root-knot nematode Meloidogyne incognita and its homolog ME_e1834_066g0351951 in M. enterolobii are required for successful parasitism and represent promising effector targets for durable, RNAi-based control of RKNs.
Abstract
The root-knot nematode (RKN) Meloidogyne incognita is one of the most important plant-parasitic nematodes (PPN) worldwide. M. incognita secretes a large number of effector proteins that play major roles in parasitism by modulating host susceptibility. In this study, we functionally characterized the M. incognita Minc3s00280g09294 (Minc09294) gene as a putative effector using a host-induced gene silencing (HIGS) approach in transgenic plants. Quantitative expression analyses showed that the Minc09294 gene is weakly expressed from eggs through the J4 stage, but is strongly induced in adult females during plant parasitism, indicating a role in the sedentary feeding phase. In silico domain prediction revealed that the encoded Minc09294 protein contains four galectin/galactose-binding lectin domains, an N-terminal signal peptide for extracellular secretion, a non-cytoplasmic region, and no predicted transmembrane domain, consistent with secretion into host tissues. Minc09294 silencing in host plants significantly decreased the number of galls (92.9%), egg masses (93.5%), eggs (79.0%), and the nematode reproduction factor (90.5%) in Minc09294-RNAi lines compared to wild-type plants. Histological analyses further revealed smaller galls and poorly developed giant cells in the Minc09294-RNAi lines. Since the homologous gene ME_e1834_066g0351951 in Meloidogyne enterolobii shares high sequence similarity with Minc09294, and consequently with the RNAi target sequence, we also challenged the Minc09294-RNAi lines with M. enterolobii. These Minc09294-RNAi lines exhibited a substantial reduction in the number of galls (up to 53.7%) and egg masses (up to 53.3%), whereas the effects on egg number and reproduction factor were less pronounced. Collectively, these data indicate that the Minc09294 in M. incognita and its homolog ME_e1834_066g0351951 in M. enterolobi are required for successful parasitism and represent promising effector targets for durable, RNAi-based control of RKNs. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.