Related Experiment Video
Updated: Jun 28, 2026
13:03
Robust DNA Isolation and High-throughput Sequencing Library Construction for Herbarium Specimens
Published on: March 8, 2018
Phytoplasma: ecology and genomic diversity.
Phytopathology
|October 24, 2008
Summary
Molecular probes and phylogenetic analysis have advanced the detection and classification of phytoplasmas. Genomic diversity in these plant pathogens correlates with shared insect vectors and host plants.
Area of Science:
- Phytopathology
- Molecular Biology
- Microbial Phylogenetics
Background:
- Phytoplasmas, previously known as mycoplasma-like organisms, are uncultured plant pathogens.
- Advances in molecular probes (antibodies, DNA fragments, PCR primers) have improved phytoplasma detection.
- Phylogenetic studies using 16S ribosomal RNA (rRNA) sequences have clarified phytoplasma classification within the Mollicutes class.
Purpose of the Study:
- To review advances in phytoplasma detection and identification using molecular-based tools.
- To discuss the phylogenetic classification of phytoplasmas based on molecular data.
- To explore the genomic diversity and evolution of phytoplasmas in relation to their hosts and vectors.
Main Methods:
- Development and application of molecular probes, including antibodies and DNA fragments.
- Polymerase chain reaction (PCR) using phytoplasma-specific primers.
- Phylogenetic analysis of 16S rRNA and ribosomal protein gene sequences.
- Restriction fragment length polymorphism (RFLP) analysis of PCR-amplified 16S rRNA genes.
Main Results:
- Phytoplasmas are classified into 14 groups and 38 subgroups based on RFLP and phylogenetic analyses.
- Numerous phytoplasma strains associated with plants and insect vectors have been identified.
- Genomic diversity correlates with shared insect vectors and host plants.
- Vector-phytoplasma-plant interactions influence genetic exchange and the evolution of new phytoplasma strains.
Conclusions:
- Molecular tools have revolutionized phytoplasma detection and classification.
- Phytoplasma classification is well-supported by phylogenetic and RFLP data.
- Ecological interactions drive phytoplasma genomic diversity and evolution, potentially leading to new ecospecies.
Related Concept Videos
01:24Bacterial Phylum Tenericutes
The phylum Tenericutes, which includes the single class Mollicutes, comprises bacteria that lack cell walls. The term "Mollicutes" derives from the Latin word mollis, meaning "soft." These organisms are among the smallest known and are commonly referred to as mycoplasmas due to the prominence of the genus Mycoplasma, which includes well-known human pathogens. Despite their inability to stain gram-positively (a result of their lack of cell walls), mycoplasmas are phylogenetically related to the...
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...
01:28Plasmids
Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...
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...
01:27Diversity of Protists III
Rhizaria are a diverse group of unicellular protists characterized by their threadlike cytoplasmic extensions known as pseudopodia. These structures aid in both locomotion and feeding, giving Rhizaria an amoeboid appearance. Their amoeboid morphology once led to taxonomic confusion, but molecular phylogenetics has clarified their evolutionary placement and emphasized their shared use of pseudopodia despite divergent lineages.This clade comprises diverse lineages such as Chlorarachniophyta,...
01:27Diversity of Protists II
Alveolates are a group of organisms recognized by the presence of alveoli, which are cytoplasmic sacs located beneath the cell membrane. While their function remains uncertain, alveoli may help regulate water balance by controlling how much water enters and leaves the cell. In dinoflagellates, these structures may serve as armor plates. There are three major types of alveolates: ciliates, which move using cilia; dinoflagellates, which use flagella for movement; and apicomplexans, which are...