Genetic variability and evolutionary analysis of parietaria mottle virus: role of selection and genetic exchange

Area of Science:

• Plant Virology
• Molecular Evolution
• Genetics

Background:

• Parietaria mottle virus (PMoV) is an ilarvirus impacting plant health.
• Understanding PMoV genetic variability is crucial for disease management and control strategies.

Purpose of the Study:

• To investigate the genetic variability and evolutionary patterns of PMoV.
• To analyze the phylogenetic relationships of PMoV isolates based on 2b and CP gene sequences.

Main Methods:

• Phylogenetic analysis of nucleotide sequences of the 2b and CP genes from diverse PMoV isolates.
• Assessment of nucleotide sequence diversity and selective pressures (purifying and diversifying selection).
• Detection of genetic exchange events among isolates.

Main Results:

• PMoV isolates clustered into distinct phylogenetic clades, with geographical segregation observed (e.g., Italian vs. Spanish isolates).
• Low but notable nucleotide sequence diversity was found in both 2b and CP genes, exceeding that of other ilarviruses.
• Evidence suggests both purifying and diversifying selection acting on 2b and CP proteins, with detected genetic exchange among Spanish isolates.

Conclusions:

• PMoV exhibits significant genetic differentiation and evolutionary dynamics.
• The findings highlight the importance of ongoing genetic monitoring of PMoV populations.
• Purifying selection dominates, but diversifying selection at specific sites and genetic exchange contribute to PMoV evolution.