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

• Published in: European journal of plant pathology Vol. 157; no. 4; pp. 943 - 959
• Main Authors: Leite, Raycenne Rosa, Mattos, Vanessa S., Gomes, Ana Cristina M. M., Py, Leandro Grimaldi, Souza, Daniela A., Castagnone-Sereno, Philippe, Cares, Juvenil E., Carneiro, Regina M. D. G.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-08-2020; Springer Nature B.V; Springer Verlag
• Subjects: Agriculture; Biodiversity; Biomedical and Life Sciences; Chromosome number; Chromosomes; Ecology; Esterase; Expressed sequence tags; Grasses; Life Sciences; Meiosis; Meloidogyne; Microbiology and Parasitology; Morphology; Nematodes; Parasitology; Parthenogenesis; Phytopathology and phytopharmacy; Plant Pathology; Plant Sciences; Populations; Rice; rRNA 16S; Systematics, Phylogenetics and taxonomy; Taxonomy; Vegetal Biology; Brazil; COXII; ITS; D2D3; morphology; root-knot nematode; esterase phenotyping; Oryza
• ISSN: 0929-1873; 1573-8469
• DOI: 10.1007/s10658-020-02049-y

A root-knot nematode (RKN) parasitizing rice (
Oryza sativa
L.) and causing damage in Santa Catarina (SC), Rio Grande do Sul (RS) and Paraná (PR) states (Brazil) was identified as
Meloidogyne ottersoni
(Thorne
1969
) Franklin
1971
. The species is redescribed from the Brazilian population from Meleiro (SC) and compared with the description of
M. ottersoni
from Wind Lake (Wisconsin, USA) with additional morphological, biochemical and molecular characterization. The female and male bear smaller stylets: 10-12 μm, 14-16 μm, respectively, when compared with
M. graminicola
: 12-14 μm, 16-18 μm, and
M. oryzae
: 14-16 μm, 18-20 μm.
Meloidogyne ottersoni
presents perineal patterns located on the contour of a slight protuberance. Striae are mostly continuous, never raised by transverse irregular striae, as frequently observed in
M. graminicola
and
M. oryzae
.
Meloidogyne ottersoni
belongs 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 μm
vs M. graminicola,
17.9 μm and
M. oryzae
, 22.0 μm, respectively). The ability of the Brazilian
M. ottersoni
population to parasitize canary grass,
Phalaris arundinacea
L. (type host), and barnyard grass,
Echinocloa crus-galli,
was confirmed. Biochemically, the esterase profile of
M. ottersoni
lacks any band (Est Ot0, Rm=0), which differentiates it from
M. graminicola
and
M. 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 of
M. ottersoni
from different states of Brazil clustered together and were separated from other
Meloidogyne
spp., thus confirming that all four populations are very similar and conspecific.