First Report of the Emerging Root-Knot Nematode Meloidogyne enterolobii on Soybean in Roraima, Northern Brazil

Meloidogyne enterolobii Yang & Eisenback is an emerging root-knot nematode of increasing phytosanitary concern due to its wide host range, high virulence, and ability to overcome resistance genes effective against other Meloidogyne spp. (Rutter et al. 2026). In Brazil, M. enterolobii has been reported infecting soybean (Glycine max [L.] Merr.) in the Southeast, Central-West, South, and Northeast (Almeida et al. 2008; Diniz et al. 2026a), but there is no report of its occurrence in the state of Roraima, located in northern Brazil. In July 2025, patches of stunted soybean plants cv. ‘Brasmax Bônus IPRO’ showing chlorotic leaves and severe root galling, were observed in a 100-ha center-pivot-irrigated field in Alto Alegre, Roraima state, Brazil. Approximately 40% of the plants exhibited symptoms. Symptomatic roots were collected and sent to the University of Brasília, for nematode identification. Species identification was performed using biochemical and molecular approaches. For esterase phenotyping, 40 adult females of Meloidogyne at the milky stage were individually removed from infected roots. Esterase analysis was conducted according to Alfenas et al. (1991) using five females per well and eight replicate wells. Females exhibited the esterase phenotype M2 (Rm = 0.70, 0.75, 0.90, and 0.95), characteristic of M. enterolobii. For molecular analyses, eggs were extracted from infected roots after maceration in an industrial blender followed by sieving through 230- and 500-mesh sieves (Boneti and Ferraz 1981). Genomic DNA was extracted according to Diniz et al. (2026b). The species-specific PCR primer pair MK7-F and MK7-R (Tigano et al. 2010) amplified the expected 520-bp fragment expected for M. enterolobii. In addition, mitochondrial cytochrome oxidase subunit I and II (COXI and COXII) regions were amplified and sequenced (Bowles et al. 1992; Powers and Harris 1993). COXI and COXII sequences showed 100% identity with M. enterolobii sequences deposited in GenBank (PV659924 and PV658692). The Roraima population clustered with reference sequences of M. enterolobii in Bayesian phylogenetic analysis that used the partial sequences of two loci. Sequences generated in this study were deposited in GenBank under accession numbers PZ530300 and PZ535524. Pathogenicity assays were performed using nine soybean cultivars: ‘BMX Desafio’, ‘BMX Domínio’, ‘BMX Foco’, ‘BMX Guepardo’, ‘BMX Olimpo’, ‘CZ37B43’, ‘Monsoy 8349’, ‘Brasmax Bônus IPRO’ and ‘TMG 2833’. At the V1 stage, plants were inoculated with 1,000 eggs per plant and maintained in a greenhouse at 26 ± 2°C for 60 days. Four pots each containing a single plant were used per cultivar. All cultivars developed typical root galling and supported nematode reproduction. Nematodes were extracted according to Boneti and Ferraz (1981), and the final population (Fp) was used to calculate the reproduction factor (RF = Fp/Ip). All cultivars presented RF values greater than 7 in all cultivars, confirming pathogenicity and reproductive capacity on soybean. To our knowledge, this is the first report of M. enterolobii infecting soybean in Northern Brazil. The detection of this species in Roraima is concerning because of the rapid expansion of soybean cultivation in the Brazilian Amazon frontier and the ability of M. enterolobii to overcome resistance sources commonly used against other root-knot nematodes. This finding expands the known distribution of M. enterolobii in Brazil and provides important information for nematode diagnosis and management in emerging soybean-producing regions.