Fig. 2

Diagrammatic representation to contrast somatic growths between basidiomycetes with a typical life cycle and the Termitomyces symbiont. a–f Various stages of hyphal growth in a typical basidiomycete, whose heterokaryons (usually dikaryons), unlike those of Termitomyces, have a clamp connection at hyphal septa and dikaryotic mycelia, two commonly used indicators for successful matings. a, b Uninucleate homokaryons carrying different markers (red and blue) from single uninucleate basidiospores. c Binucleate heterokaryon resulting from pairing of two homokaryons. d Mitosis giving rise to four nuclei. e Formation of clamp connection, through which a blue nucleus migrates back to the penultimate cell, while two new septa are formed in the clamp cell and hyphal tip. f The final stage of hyphal cell division. g–m Various stages of Termitomyces hyphal growth. Note that a growing hyphal cell of a homokaryon or heterokaryon is binucleate or trinucleate. Only binucleate tip cells are shown here. g, h Binucleate homokaryons carrying different markers (red and blue) from single uninucleate basidiospores. i Binucleate heterokaryon resulting from pairing of two homokaryons. Homokaryons and heterokaryons cannot be discerned by nuclear numbers, both having two or three nuclei in a growing hyphal cell. j Karyogamy. k Stage resembling Meiosis I. l Stage resembling Meiosis II. m Two cells separated by a newly formed septum as the final stage