Related Experiment Video
Updated: Jun 23, 2026
06:28
Screening Cotton Genotypes for Reniform Nematode Resistance
Published on: May 2, 2019
The genomes of root-knot nematodes
David McK Bird1, Valerie M Williamson, Pierre Abad
1Center for the Biology of Nematode Parasitism, North Carolina State University, Raleigh, North Carolina 27695, USA. david_bird@ncsu.edu
Annual Review of Phytopathology
|April 30, 2009
Summary
Comparative genomics reveals insights into plant-parasitic nematode success. Sequencing the genomes of two root-knot nematodes (Meloidogyne spp.) identified unique genes and adaptations contributing to their parasitic nature and asexual reproduction.
Area of Science:
- Genomics
- Nematology
- Plant Pathology
Background:
- Plant-parasitic nematodes are major global threats to agriculture, posing significant control challenges.
- Root-knot nematodes (Meloidogyne spp.) are particularly destructive pathogens.
- Understanding their genetic makeup is crucial for developing effective control strategies.
Purpose of the Study:
- To perform a comparative genomics analysis of two root-knot nematode species, Meloidogyne hapla and Meloidogyne incognita.
- To elucidate the genetic basis of their parasitic success and reproductive strategies.
- To identify potential targets for novel control methods.
Main Methods:
- Genome sequencing of Meloidogyne hapla and Meloidogyne incognita.
- Comparative genomic analysis with Caenorhabditis elegans.
- Identification and characterization of gene families and horizontally transferred genes.
Main Results:
- Meloidogyne hapla has a compact 54 Mbp genome with ~14,200 genes, the smallest metazoan genome sequenced to date.
- Meloidogyne incognita has a larger 86 Mbp genome with ~19,200 genes, exhibiting aneuploidy and high allelic divergence.
- Both species possess compacted gene families and unique enzyme suites, likely acquired via horizontal gene transfer, targeting host plants.
Conclusions:
- Comparative genomics provides a powerful approach to understanding nematode parasitism.
- Unique genetic adaptations, including horizontally transferred genes, underpin the success of root-knot nematodes.
- These findings offer new avenues for the development of targeted nematode control strategies.
Related Concept Videos
01:15Diversity of Protists I
Excavata is a diverse group of protists that includes both chemoorganotrophic and phototrophic species, with some thriving in anaerobic environments. Among the key groups within Excavata are diplomonads and parabasalids, which are flagellated protists that lack mitochondria and chloroplasts. These microorganisms typically inhabit anoxic environments, such as the intestines of animals, where they exist either symbiotically or as parasites, relying on fermentation for energy production. Some...
02:16Comparing Mitochondrial, Chloroplast, and Prokaryotic Genomes
The present-day mitochondrial and chloroplast genomes have retained some of the characteristics of their ancestral prokaryotes and also have acquired new attributes during their evolution within eukaryotic cells. Like prokaryotic genomes, mitochondrial and chloroplast genomes neither bind with histone-like proteins nor show complex packaging into chromosome-like structures, as observed in eukaryotes. Unlike mitotic cell divisions observed in eukaryotic cells, mitochondria and chloroplasts...
00:46Genomic DNA in Prokaryotes
The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the nucleoid. The chromosome is tightly wound, or supercoiled, for efficient storage. Prokaryotes also contain other circular pieces of DNA called plasmids. These plasmids are smaller than the chromosome and often carry genes that confer adaptive functions, such as antibiotic resistance.
Genomic Diversity in Bacteria
Although bacterial genomes are much...
Genomic Diversity in Bacteria
Although bacterial genomes are much...
01:08Evolution of Microbial Genome
Microbial genome evolution is a highly dynamic process shaped by continual gene gain and loss across species and strains. This genomic flexibility allows microorganisms to adapt rapidly to environmental pressures and interactions with other organisms. Central to understanding this diversity is the distinction between the core and pan genomes.The core genome comprises the genes shared by all sampled strains of a species, representing essential functions needed for fundamental cellular processes.
02:19Export of Mitochondrial and Chloroplast Genes
A eukaryotic cell can have up to three different types of genetic systems: nuclear, mitochondrial, and chloroplast. During evolution, organelles have exported many genes to the nucleus; this transfer is still ongoing in some plant species. Approximately 18% of the Arabidopsis thaliana nuclear genome is thought to be derived from the chloroplast’s cyanobacterial ancestor, and around 75% of the yeast genome derived from the mitochondria’s bacterial ancestor. This export has occurred irrespective...