Bistability and hysteresis of the 'Secteur' differentiation are controlled by a two-gene locus in Nectria haematococca

Table 4 Nectria haematococca strains used

		Characteristics^b
Strain	Origin^a	Mycelium	Fertility	Differentiation	Source
Wild type	CBS225/58	Gray	FFF	AS
s*₇₈₉	NG	Red	F	As*	Daboussi-Bareyre et al. 1979
s*₂₇	UV	Red	F	As*	This study
s*₄	UV	Red	F	As*	This study
s*₁₁	UV	Red	F	As*	This study
s*₁₈	UV	Red	F	As*	This study
s*₈₄	sp	Red	F	As*	Parisot et al. 1981
s₁	NG	Gray	FFF	As	This study
s₂	IM	Gray	FF	As	This study
61	UV	Gray	F	AS with a high frequency of Secteur	Daboussi 1985
a₁	Sp	Gray	FFF	aS	Daboussi-Bareyre et al. 1979
a*₅₈	NG	Red	F	a*S	Daboussi-Bareyre et al. 1979
arg₁₅₄	NG	Beige, Smooth arginine-auxotroph	F	AS	Daboussi-Bareyre 1980
lys₂₅₅	NG	Beige, Smooth lysine-auxotroph	F	AS	Daboussi-Bareyre 1980
I₄mod	cross	Gray	St, white and empty perithecia	AS	Babai-Ahary et al. 1982

^aCB: Centraal Bureau voor Schimmelcultures, Baarn, The Netherlands. sp, spontaneous mutation; NG, UV and IM recovered after N-methyl-N'-nitro-N-nitrosoguanidine, ultraviolet irradiadiation (254 nm) or insertional mutagenesis, respectively. cross: constructed by crossing. ^bMain phenotypic characteristics. FFF, very fertile; F, fertile; St, sterile. AS differentiates both Anneaux and Secteurs and synthesizes α and σ only in the respective modified areas. As* differentiates Anneaux but not Secteurs, though they have the σ determinant throughout the mycelium; As differentiates Anneaux but not Secteurs and never contain the σ determinant; a*S differentiates Secteurs but not Anneaux, though they have the α determinant throughout the mycelium; aS differentiate Secteurs but not the Anneaux and never contain the α determinant.