A New Mating Compatibility Locus in PHYSARUM POLYCEPHALUM

Area of Science:

• Cell Biology
• Genetics
• Mycology

Background:

• Plasmodium formation is crucial for the life cycle of Physarum polycephalum.
• Mating-type (mt) alleles regulate compatibility in amoebal fusions.
• Variability in mating efficiency has been observed but not fully explained.

Purpose of the Study:

• To investigate the factors influencing the rate and extent of plasmodium formation in Physarum polycephalum.
• To genetically analyze the variability observed in mating efficiency.
• To elucidate the genetic basis of mating specificity in this organism.

Main Methods:

• Mating tests were conducted using largely isogenic amoebal strains.
• Systematic observation and quantification of plasmodium formation.
• Genetic analysis to identify controlling loci.

Main Results:

• Significant variability in plasmodium formation was observed, ranging from rapid and extensive to slow and inefficient.
• Plasmodium formation was 10^3- to 10^4-fold more extensive in "rapid" crosses compared to "slow" crosses.
• A multiallelic compatibility locus (matB) was identified as a key determinant of mating efficiency.

Conclusions:

• The mating efficiency in Physarum polycephalum is governed by a tetrapolar mating specificity system.
• The identified compatibility locus (matB) and the mating type locus (matA) together define this system.
• Understanding this system is crucial for genetic studies and manipulation of Physarum polycephalum.