Pathogenic interaction and molecular characterization of Meloidogyne enterolobii infecting Lantana camara: A new host association from India

Abstract

Lantana camara L., a widely distributed perennial shrub in India, is often recognized for its invasive potential and reported nematicidal properties. Paradoxically, during a survey in guava orchards of Karnataka, India, extensive root galling was observed on L. camara plants growing as hedge borders. This study was undertaken to investigate the causal organism and assess its pathogenic potential. Nematodes isolated from the infected roots were purified and identified as Meloidogyne enterolobii based on detailed morphological and morphometric characteristics of second-stage juveniles, males, females, and perineal patterns. Molecular confirmation was achieved through PCR amplification of the ITS rDNA and COX1 regions, along with species-specific SCAR primers, which yielded a 520 bp product specific to M. enterolobii; no amplification occurred with M. incognita-specific primers. BLASTn analysis of ITS and COX1 sequences showed 100 percent identity with reference M. enterolobii sequences, and phylogenetic analysis clustered the isolates within the M. enterolobii clade. Pathogenicity was confirmed via pot experiments, wherein L. camara plants inoculated with two isolates (ChMe1 Bengaluru and ChMe2 Kolar) developed characteristic galls and egg masses: ChMe1 produced 79.8 ± 7.16 galls and 71.2 ± 6.72 egg masses, while ChMe2 yielded 99.6 ± 12.60 galls and 86.0 ± 8.94 egg masses (mean ± SD, n = 5). The nematode completed its life cycle in 30–35 days, and its identity was reconfirmed from re-isolated specimens, fulfilling Koch's postulates. This study provides the first report of M. enterolobii infecting L. camara from India, a plant previously regarded as nematode-suppressive. The results underscore the potential of invasive perennial weeds like L. camara to act as alternate or reservoir hosts for aggressive nematodes, complicating nematode management in adjoining crops such as guava. The study highlights the importance of including such weeds in integrated nematode management strategies to limit inoculum buildup and pathogen persistence in agroecosystems.