Broadly applicable mating type primers for morels: a case study on life cycle and genotyping integrity detection

Area of Science:

• Mycology
• Genetics
• Agricultural Science

Background:

• A thorough understanding of the morel (Morchella) life cycle is essential for improving genetic breeding and cultivation.
• The mating type gene structures within the Morchella genus require detailed investigation due to ongoing debates about their life cycle.

Purpose of the Study:

• To develop and validate primers for analyzing mating type genes (Mat1-1-1 and Mat1-2-1) in Morchella species.
• To investigate the mating type gene distribution and integrity in various morel strains and cultivated populations.

Main Methods:

• Development of primers (Con_Mat1F/R and Con_Mat2F/R) targeting conserved domains of Mat1-1-1 and Mat1-2-1 genes.
• Validation of primers across 12 Morchella strains from Rufobrunnea, Elata, and Esculenta clades.
• Genotyping of single-spore populations and cultivated tissues (stipe and pileus) from multiple Morchella species.

Main Results:

• Primers successfully enabled efficient genotyping of morel mating types.
• Each tested strain carried only one mating type gene, supporting heterothallism.
• Pileus tissues consistently showed both mating types, while stipe tissues sometimes had only one, indicating genotype imbalances.
• A significant percentage (47.34%) of mating type genes were found to be incomplete in cultivated and commercial strains.

Conclusions:

• The study confirms the heterothallic nature of the investigated Morchella species.
• Incomplete mating type genes (genotype loss) are identified as a potential cause for instability in cultivated heterothallic morels.
• Genotyping integrity screening is crucial before commercial production to ensure stable cultivation of Morchella species.