Integrative taxonomy of Meloidogye ottersoni (Thorne, 1969) Franklin, 1971 (Nematoda: Meloidogynidae) parasitizing flooded rice in Brazil

International audience; A root-knot nematode (RKN) parasitizing rice (Oryza sativaL.) and causing damage in Santa Catarina (SC), Rio Grande do Sul (RS) and Parana (PR) states (Brazil) was identified asMeloidogyne ottersoni(Thorne1969) Franklin1971. The species is redescribed from the Brazilian population from Meleiro (SC) and compared with the description ofM. ottersonifrom Wind Lake (Wisconsin, USA) with additional morphological, biochemical and molecular characterization. The female and male bear smaller stylets: 10-12 mu m, 14-16 mu m, respectively, when compared withM. graminicola: 12-14 mu m, 16-18 mu m, andM. oryzae: 14-16 mu m, 18-20 mu m.Meloidogyne ottersonipresents perineal patterns located on the contour of a slight protuberance. Striae are mostly continuous, never raised by transverse irregular striae, as frequently observed inM. graminicolaandM. oryzae.Meloidogyne ottersonibelongs to the RKN group 11 described by Jepson (1987); the reproduction is by meiotic parthenogenesis and the somatic chromosome number is 18. The tail of second-stage juveniles is very long and thin, and tapers to a long, narrow, irregular hyaline terminus (M. ottersoni, 20.5 mu mvs M. graminicola,17.9 mu m andM. oryzae, 22.0 mu m, respectively). The ability of the BrazilianM. ottersonipopulation to parasitize canary grass,Phalaris arundinaceaL. (type host), and barnyard grass,Echinocloa crus-galli,was confirmed. Biochemically, the esterase profile ofM. ottersonilacks any band (Est Ot0, Rm=0), which differentiates it fromM. graminicolaandM. oryzae(Est VS1, Rm=0.70 and Est O1,Rm=1.02, respectively). In Maximum Likelihood analysis of ITS, D2D3 and COXII-16S rRNA sequences, populations ofM. ottersonifrom different states of Brazil clustered together and were separated from otherMeloidogynespp., thus confirming that all four populations are very similar and conspecific.