Related Experiment Video

Updated: Sep 28, 2026

Understanding the Development of Compensatory Pathways in a Mutant Malaria Parasite Harbouring Hypomorphic Allele of Plant-Like Kinases
09:13

Understanding the Development of Compensatory Pathways in a Mutant Malaria Parasite Harbouring Hypomorphic Allele of Plant-Like Kinases

Published on: November 22, 2024

A plasmid from a non-insect-transmissible line of a phytoplasma lacks two open reading frames that exist in the

Hisashi Nishigawa1, Kenro Oshima, Shigeyuki Kakizawa

  • 1Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 202 Bioscience Building, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.

Gene
|November 12, 2002
PubMed

Insights

Two novel plasmids were identified in onion yellows phytoplasma. These plasmids are stably maintained and may play a role in host specificity, with some proteins not being essential for plant cell survival.

Area of Science:

  • Plant pathology
  • Molecular biology
  • Microbiology

Background:

  • Onion yellows (OY) phytoplasma is a plant and insect endocellular mollicute.
  • Phytoplasmas are plant pathogens lacking cell walls, often transmitted by insect vectors.
  • Rolling circle replication (RCR) plasmids are common in phytoplasmas and play roles in their biology.

Purpose of the Study:

  • To characterize novel RCR plasmids from different OY phytoplasma variants.
  • To investigate the genetic differences between plasmids from insect-transmissible and non-insect-transmissible strains.
  • To identify potential phytoplasma proteins involved in host specificity.

Main Methods:

  • Isolation and sequencing of RCR plasmids (pOYM and pOYNIM) from OY phytoplasma variants.
  • Homology analysis of RCR-initiator proteins (Rep) with known plasmids.
  • Analysis of open reading frames (ORFs) and protein-coding potential.

Main Results:

  • Two novel RCR plasmids, pOYM and pOYNIM, were identified and sequenced.
  • The Rep proteins of pOYM and pOYNIM showed high homology to pOYW, indicating stable maintenance.
  • pOYNIM lacked two ORFs found in pOYW and pOYM, encoding SSB and a putative membrane protein.

Conclusions:

  • The identified RCR plasmids are stably maintained in OY phytoplasma.
  • The absence of specific ORFs in pOYNIM suggests these proteins are not essential for phytoplasma survival in plants.
  • These proteins are potential candidates for mediating phytoplasma host specificity.

More Related Videos

Site-Directed φC31-Mediated Integration and Cassette Exchange in Anopheles Vectors of Malaria09:38

Site-Directed φC31-Mediated Integration and Cassette Exchange in Anopheles Vectors of Malaria

Published on: February 2, 2021

Related Concept Videos

Plasmids01:28

Plasmids

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...
Bacterial Phylum Tenericutes01:24

Bacterial 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...
DNA Bacteriophages01:26

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
DNA-only Transposons02:57

DNA-only Transposons

DNA-only transposons are called autonomous transposons since they code for the enzyme transposase that is required for the transposition mechanism. Insertion of transposons can alter gene functions in multiple ways. They can mutate the gene, alter gene expression by introducing a novel promoter or insulator sequence, introduce new splice sites, and change the mRNA transcripts produced, or remodel chromatin structure.
The donor site from where the transposon is excised is either degraded or...
Non-LTR Retrotransposons03:18

Non-LTR Retrotransposons

As the name suggests, non-LTR retrotransposons lack the long terminal repeats characteristic of the LTR retrotransposons. Additionally, both LTR and non-LTR retrotransposons use distinct mechanisms of mobilization. Non-LTR retrotransposons are further divided into two classes - Long interspersed nuclear elements (LINEs) and short interspersed nuclear elements (SINEs), both of which occur abundantly in most mammals, including humans. Some of the active non-LTR retrotransposons in humans are L1...
Diversity of Protists II01:27

Diversity 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...