Early development of the root-knot nematode Meloidogyne incognita

Abstract

BackgroundDetailed descriptions of the early development of parasitic nematodes are seldom available. The embryonic development of the plant-parasitic nematode Meloidogyne incognita was studied, focusing on the early events.ResultsA fixed pattern of repeated cell cleavages was observed, resulting in the appearance of the six founder cells 3 days after the first cell division. Gastrulation, characterized by the translocation of cells from the ventral side to the center of the embryo, was seen 1 day later. Approximately 10 days after the first cell division a rapidly elongating two-fold stage was reached. The fully developed second stage juvenile hatched approximately 21 days after the first cell division.ConclusionsWhen compared to the development of the free-living nematode Caenorhabditis elegans, the development of M. incognita occurs approximately 35 times more slowly. Furthermore, M. incognita differs from C. elegans in the order of cell divisions, and the early cleavage patterns of the germ line cells. However, cytoplasmic ruffling and nuclear migration prior to the first cell division as well as the localization of microtubules are similar between C. elegans and M. incognita.Electronic supplementary materialThe online version of this article (doi:10.1186/s12861-016-0109-x) contains supplementary material, which is available to authorized users.

Embryogenesis in the parasitic nematode Heterodera glycines is independent of host-derived hatching stimulation

“…We, therefore, started most of our observations at the two-celled stage. We observed a similar sequence of pre-hatch developmental stages (2, 3, and 4-celled stages, gastrula, tadpole, J1, and J2) as recorded for other plant-parasitic nematodes [10, 14]. Furthermore, we traced the early cell lineage of some embryos.…”

“…The time in hours ( lower left corner ) was recorded for each of the cell divisions. Cell labels are based on Caenorhabditis elegans and inferred based on positional homology in other nematode species [10, 14, 25, 27]. Scale, 15 μm …”

“…Images were taken every 30 minutes using an upright compound microscope with a mechanized stage (Zeiss M2 AxioImager and Zen software). Cell divisions were labeled based on M. incognita and C. elegans [14, 25]. …”

“…However, a detailed description of the timing of early development in H. glycines is lacking and may be useful for understanding the hatching process. Recent work on the early embryonic development of the nematode M. incognita provides a comparative species within the primary plant-parasitic nematode clade to examine early cleavage events and a timeline from a single-celled embryo to hatching [14]. Here, we describe a similar detailed timeline of pre-hatch development for H. glycines .…”

Evaluation of root-knot nematode resistance in sweetpotato

“…Root-knot nematodes (RKNs) are a group of well-documented parasites of a wide variety of crops and are considered economically important plant-parasitic nematodes (Calderón-Urrea et al, 2016;Moens and Perry, 2009). Necrosis and galling values are the mean of five replications of five plants each.…”