RT Journal Article
SR Electronic
T1 Population genomics supports clonal reproduction and multiple gains and losses of parasitic abilities in the most devastating nematode plant pest
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 362129
DO 10.1101/362129
A1 Georgios D. Koutsovoulos
A1 Eder Marques
A1 Marie-Jeanne Arguel
A1 Laurent Duret
A1 Andressa C.Z. Machado
A1 Regina M.D.G. Carneiro
A1 Djampa K. Kozlowski
A1 Marc Bailly-Bechet
A1 Philippe Castagnone-Sereno
A1 Erika V.S. Albuquerque
A1 Etienne G.J. Danchin
YR 2019
UL http://biorxiv.org/content/early/2019/07/09/362129.abstract
AB The most devastating nematodes to worldwide agriculture are the root-knot nematodes with Meloidogyne incognita being the most widely distributed and damaging species. This parasitic and ecological success seem surprising given its supposed obligatory clonal reproduction. Clonal reproduction has been suspected based on cytological observations but, so far, never confirmed by population genomics data. At the species level, M. incognita is highly polyphagous with thousands of host plants. However, the host range varies among different M. incognita isolates that may present distinct and more restricted host compatibilities. Historically, four ‘host races’ had been defined as a function of ranges of compatible and incompatible plants. We sequenced the genomes of 11 isolates across Brazil, covering these four distinct races to assess (i) how clonal reproduction is and (ii) how the level of genome variability associates with biological traits such as the host races, affected agronomic culture, and geographical distribution. By aligning the genomic reads of the isolates to the M. incognita reference genome assembly, we identified SNV and small-scale insertions/deletions. Analysis of linkage disequilibrium and 4-gametes test, showed no sign of recombination, confirming the clonal mode of reproduction of M. incognita. We showed that there are relatively few point variations between the different isolates, and these variations show no significant association with either the host races, the geographical origin of the samples or the host plant on which they have been collected. Due to the lack of phylogenetic signal underlying their existence, we recommend the discontinuation of the terminology ‘race’. Overall, these results suggest that multiple gains and losses of parasitic abilities and adaptations to different environmental conditions account for the broad host spectrum and wide geographic distribution of M. incognita. Hence, this nematode constitutes a model species to study adaptability without sexual recombination and overall low genomic variations in animals.