Mating-Type Analysis in Diaporthe Isolates from Soybean in Central Europe

Area of Science:

• Mycology
• Fungal Genetics
• Plant Pathology

Background:

• The genus Diaporthe, like other Ascomycetes, possesses a mating-type system with MAT1-1 and MAT1-2, crucial for sexual reproduction.
• Species can be heterothallic (requiring a partner) or homothallic (self-fertile), but sexual reproduction remains unobserved in several Diaporthe species.
• Understanding mating systems is vital for fungal population genetics and disease management strategies.

Purpose of the Study:

• To determine the mating types of four central European Diaporthe species: D. caulivora, D. eres, D. longicolla, and D. novem.
• To investigate the mating-type genes (MAT1-1-1 and MAT1-2-1) and their role in the reproductive biology of these species.
• To enhance phylogenetic resolution using mating-type gene sequence data.

Main Methods:

• Polymerase Chain Reaction (PCR) using primers specific to MAT1-1-1 and MAT1-2-1 genes.
• Partial sequencing of mating-type genes from 25 isolates.
• Genomic sequence analysis and re-sequencing of DNA and RNA to identify and characterize mating-type loci.

Main Results:

• Diaporthe longicolla isolates exhibited either MAT1-1-1 or MAT1-2-1, confirming it as heterothallic, contrary to previous assumptions of asexual reproduction.
• Diaporthe eres and D. novem were also identified as heterothallic species.
• The MAT1-1-1 gene and the full mating-type locus were identified in the homothallic species Diaporthe caulivora.

Conclusions:

• The study clarifies the mating systems of four key Diaporthe species, revealing heterothallism in D. longicolla, D. eres, and D. novem.
• The identification of the complete mating-type locus in D. caulivora provides insights into homothallic reproduction within the genus.
• Sequence data from mating-type genes significantly improved phylogenetic resolution, aiding in the classification and understanding of Diaporthe diversity.