Intron polymorphism in small subunit rDNA of Nectria galligena

Area of Science:

• Molecular Biology
• Mycology
• Plant Pathology

Background:

• Nectria galligena is a significant plant pathogen.
• Accurate identification and differentiation of fungal isolates are crucial for effective disease management.
• Genetic markers can aid in understanding pathogen diversity and evolution.

Purpose of the Study:

• To investigate the genetic variability within Nectria galligena isolates using molecular techniques.
• To characterize the small subunit ribosomal DNA (SSU rDNA) gene, including intron presence and size.
• To develop a novel PCR-based method for rapid identification and categorization of N. galligena.

Main Methods:

• PCR amplification and RFLP analysis of the SSU rDNA gene from 40 N. galligena isolates.
• Nucleotide sequence analysis of SSU rDNA and identified introns.
• Development and testing of specific PCR primers for pathogen identification and categorization.

Main Results:

• Four length polymorphisms were detected in the SSU rDNA gene.
• PCR-RFLP and Southern-RFLP analyses yielded similar but not identical isolate categorizations.
• Introns of varying sizes (363 bp, 1185 bp, 1423 bp) were found in three SSU rDNA categories; the fourth category lacked an intron.
• The identified introns lacked typical group I intron characteristics but showed homology, suggesting a common origin.
• A new PCR assay successfully identified N. galligena and its SSU rDNA category.

Conclusions:

• The SSU rDNA gene exhibits variability in N. galligena, particularly regarding intron presence and size.
• The novel PCR assay provides a rapid and reliable tool for N. galligena identification and strain differentiation.
• This molecular approach can enhance disease surveillance and management strategies for Nectria galligena infections.