Neurospora mutants beginning with S

Serine (ser)
Spore killer (Sk)
Semi-colonial (smco)
Sorbose resistant (sor)
Spreading colonial (spco)
Supersuppressors (ssu)
Suppressors (to su-trp)
Suppressors (from su-trp)

s
Originally used for arg-12s. See arg-12.

sar-1: surfactant resistant-1
I. Near mating type (21).

Resistant to surface-active agents dequalinium chloride, cetyltrimethyl ammonium bromide, and benzalkonium chloride. Resistant growth follows an adaptive lag phase. Em A (FGSC 627) and related A laboratory wild types carry a mating-type-linked sar gene that may be sar-1. Another, phenotypically distinct, mutation close to mt is designated sar-3, but evidence for nonallelism is not given (21).

sar-2: surfactant resistant-2
Unmapped. Independent of sar-1 (21).

sar-3: surfactant resistant-3
I. Near mating type (21).

Differs from sar-1 and sar-2 mutants in growth responses and resistance specificities (21). See sar-1.

sat: satellite
VL. Linked to lys-1 (35%) (60); left of T(OY321) and NO (D.D. Perkins, N.B. Raju, and E.G. Barry, in preparation).

Microscopically visible terminal satellite, distal to the nucleolus organizer in chromosome 2. Seen at pachytene as a tiny dot on the surface of the nucleolus (656). N. crassa laboratory strains differ in the presence (sat+) or absence (sat-) of the satellite. No satellite has been found in N. intermedia or other Neurospora species. Best scored during pachytene, using orcein. Photographs (60, 817). Translocations T(AR190), T(ALS182), and T(ALS176) involve the terminal satellite region (817).

sc: scumbo
IIIR. Between the centromere and ser-1 (504). Linked to thi-4 (1/280) and spg (0 + + /179); right of acr-2 (3 to 6%) (498, 814).

Irregular flat spreading growth with knobby protrusions but no conidia. Mycelium usually appears yellowish rather than orange. Female fertile. Homozygous sc x sc crosses give nonlinear asci (827, 828, 1011). Cell wall analysis (132). Reduced amount of cell wall peptides (1165). Allele R2503 called col-14; allele R2386 called smco-2 (382). For modifier, see mod(sc).

scon: sulfur control
Probably VR, right of his-6 (R.L. Metzenberg, personal communication). But presence of a translocation (and, therefore, pseudolinkage) cannot be ruled out because white spores are prevalent in sconc crosses. Difficult to map because of infertility (R. L. Metzenberg, personal communication).

Regulates a group of enzymes of sulfur metabolism, including arylsulfatase and choline sulfatase. Allele sconc is constitutive for these enzymes, but its effect in a heterokaryon is restricted to its own nucleus (123). Hypostatic to regulatory gene cys-3 (284). Review of regulation (642). Ascospores and conidia germinate poorly (123, 930).

scot: spreading colonial-temperature sensitive
VR. Between al-3 (7%) and his-6 (11%) (810).

Spreading colonial growth with delayed, reduced conidiation on solid media and pelleted growth in liquid medium, above 34°C. Not distinguishable from scot+ strains at 25°C. Best scored on glycerol complete medium at 39 C. Present in Beadle-Tatum and Rockefeller-Lindegren wild types and numerous derivatives (810). Probably the same gene was discovered independently by Fincham and by Emerson (322), studied by Pao (780), and called t, thermophobic. Strains containing t showed start-stop growth in growth tubes, with growth distance depending on carbon source (sucrose versus lactose or galactose) and concentration (J.R.S. Fincham, personal communication). scot could be responsible for temperature effects on moe mutants of reference 382.

scr: scruffy
IIR. Linked to arg-12 (2%); probably to the left (PB). (828)

Semicolonial growth, few aerial hyphae, dichotomization of hyphal tips, reduced conidiation. Heat sensitive, growing poorly with no conidia at 39 C and more like the wild type at 25°C. Asci abnormal in homozygous scr x scr crosses, with altered arrangement of ascospores. Occasional asci have fewer than eight ascospores, and these include large spores. Not all asci are nonlinear. Recessive. (827, 828)

sdh-1: succinate dehydrogenase-1
I. Linked to mating type (0/13) (307).

Succinate dehydrogenase activity 18% that of the wild type. Succinate oxidase activity low. Selected by failure to reduce nitrotetrazolium blue in the presence of succinate and phenazine methosulfate in overlays after inositol death enrichment on acetate. (307) Deficient in the high potential iron protein iron-sulfur center of the succinate dehydrogenase complex (306).

ser-1: serine-1
IIIR. Between sc (4%) and pro-1 (9%) (504).

Uses serine or glycine (504). Slightly deficient in serine hydroxymethyltransferase: raised levels of 10-formyltetrahydrofolate synthetase. Lacks ability to incorporate C1 units from glycine. Extracts lack detectable methylfolates. Negligibly deficient in 5,10-methylene tetrahydrofolate reductase. (209). Ascospores from ser-1 x ser-1 crosses do not blacken or do so only after a long delay (816). Morphologically normal; abnormal morphology at elevated temperatures that was reported in reference 816 was not due to ser-1 but to scot (810).

ser-2: serine-2
VR. Between met-3 (4%) (438) and cot-2 (5 to 8%) (156, 158). (812)

Uses serine (290) but not glycine (D.D. Perkins, unpublished data). Does not grow on hydrolyzed casein (290). Inhibited by thienylserine (R.W. Barratt, personal communication).

ser-3: serine-3
IL. Right of cys-5 (<1%). Left of un-3 (<1%) and In(NM176) (8I6, 1093, PB).

Uses serine and grows less well on formate. Also grows fairly well on a combination of adenine, methionine, tryptophan, and lysine. Does not grow on casein hydrolysate (290). No or little response to glycine (D.D. Perkins, unpublished data). Deficient in phosphoserine phosphatase activity (70). Inhibited by leucine. Scorability good, but vigor and leakiness vary markedly in different isolates. Homozygous crosses give mostly white ascospores (816; D.D. Perkins, unpublished data). Alleles, 47903 and JBM5.

ser-4: serine-4
IVR. Right of arg-2 (<1%) (652). (651)

Uses serine or glycine. Incompletely blocked. Not deficient for any of the enzymes involved in serine synthesis from 3-phosphoglyceric acid or glyceric acid. Intracellular pool deficient in serine, glycine, and alanine and accumulates threonine and homoserine (651). Produces abundant L-amino acid oxidase but no tyrosinase while growing slowly on minimal medium (651, 1099). Allele DW110 called P110 in reference 651.

ser-5: serine-5
IIIR. Linked to trp-1 (1%) and ser-1 (12%) (653).

Uses serine or glycine. Incompletely blocked (653).

ser-6: serine-6
VIL. Between nit-6 (10%) and ad-8 (16%) (PB). (544)

Responds to serine. Slight response to glycine. Extremely leaky. Scorable by slow, sparse conidiation on minimal slants or auxoanographically (D.D. Perkins, unpublished data). Can be crossed on minimal crossing medium without supplement. Allele DK42 obtained as putative leucine regulatory mutation (544), but a regulatory role is dubious (S.R. Gross, personal communication). Called DK42 (544). Probably allelic with T(VL;VIL)OY325 ser, which has a breakpoint left of lys-5 (11%) in VIL, and shows 0/28 recombination with DK42, which it resembles in leakiness. The mutant OY325 grows more profusely than the mutant DK42 on minimal slants (PB).

sf: slow-fine
I. Linked to mt (3%) and cy, (3% in regular perithecia) (689, PB).

Growth from ascospores or conidial inoculum on minimal or complete medium is initially slow. Morphology not distinguishable in mass culture after it is grown up. Originally detected microscopically. Irregular ascus types reported for some perithecia. (689) First hyphae grow clockwise on surface. Scorable by slow initial growth on slants 3 or 4 days after ascospore germination, 25°C (PB).

sfo: sulfonamide dependent
Linked to the centromere (<1%) (318), between thi-3 (6%) (874) and hlp-1 (1 to 9%) (458).

Requires sulfonamide at 35°C and is stimulated by sulfonamide at lower temperatures (319). Overproduces p-aminobenzoic acid; hence, growth is inhibited by exogenous p-aminobenzoic acid (1179). For sfo;pab-1 double mutant on minimal medium plus sulfonamide, p-amino-benzoic acid is stimulatory at very low concentrations but inhibitory at higher (319). For sfo;met-1 double mutant on minimal medium plus sulfonamide, methionine is stimulatory at very low concentrations but inhibitory at higher (1180). Best tested on solid minimal medium growth tubes at 35°C. Suppressor mutations occur frequently (318).

sg: spontaneous germination
Unmapped.

Ascospores germinate without heat shock. Usually associated with a very poor vegetative growth habit. A component of the multiply mutant combination resulting in the cell-wall-less "slime" phenotype. Possibly more complex than a single gene (321). See slime.

sh: shallow
VR. Between ilv (4 to 7%) and md (3%) (296). (812)

Spreading morphology. Hyphae do not penetrate deeply into agar (812). Fanlike array of hyphae. Photographs (296, 382).

shg:shaggy
IIIR. Linked to trp-1 (7%) and acr-6 (0/368). Recombines with vel and col-13. (499, PB).

Slow growth over agar surface, forming conidia on irregular aerial hyphae that are most abundant high in the slant. Mutants acr-4 and acr-6 originated in shg and are resistant to acriflavin only in combination with shg (499). Formerly called mo(KH160).

sit: siderophore transport
Unmapped.

Defective uptake of exogenous ferricrocin and coprogen. Several mutations are known that represent at least three loci. Selected in triple mutant aga;arg-5;ota (G.W. Charlang and N.P. Williams, personal communication), which is blocked in the known pathways to ornithine (240) and thus depleted of siderophores (1147; G.W. Charlang and N.P. Williams, personal communication).

sk: skin
VIIR. Right of nt (7 to 17%) (789).

Leathery, nonconidiating rapid surface growth (789). "Mucilaginous substrate hyphae" (1088). sk ascospores are slow to mature, but good allele ratios are obtained from crosses held for 3 weeks at 25°C. Female sterile. Allele R2466 called mo-3; alleles Y6821, R2408, and R2529 called moe-1 (382, PB).

Sk-1: Spore killer-1
Unmapped. Less than 1% second-division segregation.

Characteristics similar to those of Sk-2, q.v. Found in N. sitophila. Sensitive and killer genotypes are about equally frequent among strains from different localities. Not introgressed into N. crassa (857, 1092). To avoid confusion, the symbol Sk-1 should not be used for any other Sk occurrence.

Sk-2: Spore killer-2
III. Second-division segregation rare or absent. The killer allele Sk-2K recombines with his-7 (25%) but suppresses crossing over in the interval r(Sk-2)-1 to leu-1 (29% in controls). (1092). Sk-2K does not recombine with acr-7 (0/1800) or acr-2 (0/100,000) (B.C. Turner, personal communication).

Kills ascospores of sensitive genotype after meiosis in crosses heterozygous for the killer allele Sk-2K. In Sk-2K x Sk-2S crosses (Killer x Sensitive), each ascus contains four inviable clear ascospores and four viable black ascospores that are SkK. Ascospores are not killed in SkK x SkK crosses (1092). Meiosis and postmeiotic mitosis appear normal by light microscopy. Sensitive spores first appear abnormal after one nuclear division in the ascospore. Sk-2S nuclei survive if included in the same ascospore with Sk-2 (857). Originated in N. intermedia; introgressed into N. crassa. Most strains from nature are sensitive, but resistant strains of N. intermedia are common in some geographic areas, and two resistant strains of N. crassa have been found [see r(Sk-2)-1]. Strains resistant to Sk-2K are not necessarily resistant to Sk-3K. In Sk-2K x Sk-3K crosses, less than 1% of the ascospores are normal and viable (1092; B.C. Turner, personal communication). If Sk-2K and Sk-3K nuclei are included in the same ascospore, both nuclei survive and the spore is not killed (N.B. Raju, personal communication).

Sk-3: Spore killer-3
Near the centromere. The killer allele Sk-3K suppresses crossing over in the interval r(Sk-2)-1-leu-1 (29% in controls). Recombines with his-7 (11%) but not with leu-1 (0/72) or acr-7 (0/60,000) and only 3/19,000 with acr-2. (1092; B.C. Turner, personal communication)

Origin and characteristics resemble those of Sk-2, q.v. However, Sk-3K strains are sensitive to killing by Sk-2K and vice versa. The killer allele was found in N. intermedia, introgressed into N. crassa. Most wild-type strains of both species are sensitive, but resistant strains of N. intermedia have been found. Strains resistant to Sk-3K are not necessarily resistant to Sk-2K (857, 1092).

Sk(ad-3A)
See ad-3A.

slime
A multiple-mutant strain lacking cell wall and growing as protoplasts or plasmodium. The original strain contained at least two mutations (fz, fuzzy; sg, slow germination) in addition to the markers already present, arg-1, cr-1, aur, and os-1. Of these, fz, sg, and os-1 are required for a slime-like phenotype (321). Can be recovered with inserted markers in f1 of crosses if filtration enrichment is used (746). Cell wall-like material may be produced in small quantities in newly resolved stocks. Loses ability to form heterokaryons or to function as the fertilizing parent after continuous growth (973). Slime protoplasts can be induced to fuse (743). Stocks maintained in same-mating type (321) or mixed-mating type (746) heterokaryons or frozen at -70°C in situ on agar medium (968) or in dimethyl sulfoxide (221) or growth medium (961). Recovered from heterokaryons by filtration; see reference 746. Plasma membrane can be isolated and stored in large quantity (1037). Used for fatty acid analysis of plasma membrane (365), for study of vacuoles (922, 638), and for gentle extraction of enzymes (372). Used to show that polyadenylic acid polymerase and nuclease activities are largely located in the nucleus (962). For general methodology, see references 746 and 1161. For an alternative source of cell wall-free Neurospora, see references 970 and 971.

slo-1: slow-1
IR. Between mt (14%) and thi-1 (2 to 5%) (789).

Slow growth from conidia or ascospores (789). Conidiation lags significantly behind that of the wild type. Morphology normal. Not tested for cytochrome deficiency or ability to reduce tetrazolium.

slo-2: slow-2
VII. Left of met-7 (2%) (816). (W.N. Strickland, cited in reference 8I6)

Slow growth from conidia or ascospores. Conidiation lags days behind that of the wild type (816, 1035). Not tested for cytochrome deficiency or ability to reduce tetrazolium.

smco: semicolonial
Symbol and name used by Garnjobst and Tatum (382) for mutants that begin growth on agar as small colonies and sooner or later produce a flare of wild-type-appearing hyphae (with or without conidia). Mutant genes of the series smco-1 to smco-8, described in reference 382, were sometimes named as new smco loci without having been tested for allelism with already named morphological mutations having similar map locations.

smco-1: semicolonial-1
I. Linked to mt (1%) and rg-1 (0/72) (382).

smco-2: semicolonial-2
Allelic with sc, q.v. Linkage in group I suggested in reference 382 was not confirmed (A.M. Srb, personal communication). Independent of ad-3. Linked to his-7 (15%). No recombination (0/19 asci) or complementation with sc (A.M. Srb, personal communication).

smco-3: semicolonial-3
I. Linked to mating type (10%) and al-2 (29%). Recombines with col-7 and smco-1 (382).

smco-4: semicolonial-4
IVR. Linked to pan-1 (8%) (382)

smco-5: semicolonial-5
I. Linked to mating type (2%). Recombines with rg and smco-1. Not fertile with smco-3. (382)

Semicolonial flat growth persists until 4 to 7 days after ascospore germination, when the wild-type mycelium develops. Mycelium is similar to that of the wild-type on transfer, but smco-5 ascospores repeat the cycle. (382)

smco-6: semicolonial-6
VR. Right of met-3 (14%). Linked to asn (6%), near pyr-6 (156, 698).

smco-7: semicolonial-7
VR. Right of ilv-1 (2%). Linked to rol-3 (0/154) (698).

Conidiates in a crescent at the top of slants. Morphology distinct from that of strains carrying rol-3, which complements smco-7 (382).

smco-8: semicolonial-8
IVR. Linked to pan-1 (1 to 7%) and smco-4 (30%). Complements cot-1 and col-8 (382).

Sometimes flares out at the top of slants (382). Unable to grow on galactose or grows as restricted colonies (861). Reduced amount of cell wall peptides (1165).

smco-9: semicolonial-9
IVR. Linked to pan-1 (5%), smco-4 (2%), and smco-8 (13%) (382).

Morphology partially normalized by isomaltose or starch. Altered inhibitor of branching enzyme alpha-1,4-glucan-6-glycosyltransferase (1). Reduced amount of cell wall peptides (1165). Homozygous smco-9 x smco-9 cross produces nonlinear asci (similar to those of pk strains) (1011). Strain originally used was complex, producing two types of colonial progeny, only one of which behaves as a recessive ascus mutant (1007).

sn: snowflake
I. Right of T(39311) and arg-3 (1 to 6%). Left of T(AR173) and his-2 (<1 to 12%) (174, 808). (687)

Spreading colonial growth with good conidiation. Linear growth is less than 1/10 that of the wild type (19). Detectable immediately after ascospore germination by hyphal patterns which suggested the name (688). Abnormal microfilaments (19). Contains actin-like protein (20). Said not to exhibit cytoplasmic streaming (18). Meiosis and ascospore formation are normal in homozygous sn x sn crosses (N.B. Raju, personal communication). Good female fertility. Morphology similar to that of sp, cum, and cot-4 mutants (at 25 C) (PB). Used to study development of crystalline inclusions (17). The cr sn double mutant grows as small, discrete, conidiating colonies suitable for velvet replication. The double mutant cr sn resembles the rg cr double mutant phenotypically and has the advantage of fertility in homozygous crosses (796); for example of application, see reference 180.

so: soft
IR. Between arg-13 (2 to 12%) and aro-8 (7 to 11%) (437, 816). (789)

Lawn of fuzzy short aerial hyphae and conidia formed more uniformly than by the wild type, and closer to surface of agar, similar to peach. Delicately pigmented, distinctive morphology (789). Recurrences arise frequently by mutation in strains of Oak Ridge background (538; E. Kafer, personal communication). Best scored early on short, obtuse slants. Phenotype more pronounced on sorbose-sucrose plates. Pleiotropic female sterility and short conidial life span. Maps at same site as age 1.3 and indistinguishable from age mutants; see age-1 (K.D. Munkres, personal communication). Aerial phenotype of allele B230 reverts (K.D. Munkres, personal communication).

sor: sorbose resistance
Sorbose is used to induce colonial growth in platings of Neurospora (109, 239). Resolution is improved if sorbose is used in conjunction with cot-1 (165). Numerous sor mutants have been obtained which show spreading growth on concentrations of sorbose that restrict the wild type (e.g., references 560, 561, and 898). With the exception of sor-4, scoring has been on minimal medium plus 0.025% filter-sterilized sorbose. Certain mutants selected in other ways may also be resistant to sorbose. For example, the mutant sor(T9), selected by ability to hydrolyze starch and defective in extracellular amylase, is simultaneously sorbose resistant and osmotic sensitive (710). Sorbose-resistant mutations at four loci act as dominance modifiers of the ascus effect of dominant Pk-2 alleles (898). Most sor mutants have probably not been examined for possible pleiotropic amylase or osmotic phenotypes.

sor-1: sorbose resistant-1
VIL. Left of ylo-1 (3%) (560).

Defective in sorbose uptake (561) and thereby resistant to growth restriction by sorbose (560). Recessive (562, 564). Symbol changed from sor-A (853).

sor-2: sorbose resistant-2
VII. Linked to nt (31%) (560).

Defective in sorbose uptake (561) and thereby resistant to growth restriction by sorbose (560). Recessive (562, 564). Symbol changed from sor-B (853).

sor-3: sorbose resistant-3
IIIR. Linked to ad-4 (7%) (560).

Resistant to growth restriction by sorbose (560). Recessive with respect to colony size. Partially recessive for percent conidial germination on sorbose test media (562, 564). In heterokaryons with sor-1 or sor-2, the phenotype is intermediate between the resistant single mutant phenotype and the sensitive wild type (562). Symbol changed from sor-C (853). Called sorr-17 (560).

sor-4: sorbose resistant-4
IL. Linked to phe-1 (<1%). Right of the In(H4250) breakpoint and of suc (1%). Left of arg-1 (<1 to 4%) (816). (1014)

Resistant to growth restriction by sorbose. Detected in the pat;pro-1 strain used to demonstrate circadian rhythm (1014). Modifies dominance of pk alleles (898). Scoring clear on minimal slants with 2% sucrose plus 3% sorbose after 1 and 2 days, 34°C (816). Called sor(DS) (816; see reference 853); called Pk-mod-D (898). sorr-15 and sor(T9) are possible alleles of sor-4 based on map position (560). It is not clear whether sor-4 is a locus separate from pat, q.v.

sor-5: sorbose resistant-5
V. Linked to his-1 (560).

Resistant to growth restriction by sorbose. Alleles designated sorr-14 and sorr-19 in reference 560.

sor-6: sorbose resistant-6
Probably III or VI (PB).

Resistant to growth restriction by sorbose (560). Recessive (561). Designated sorr-6 in reference 560.

sor(T9): sorbose resistant
IL. Between mt (6%) and the centromere (5%) (710).

Resistant to colonializing action of sorbose at 25°C but not at 35°C (712). Low glucoamylase activity. Extracellular amylase activity <0.5 that of the wild type. Slow growth; osmotic sensitivity comparable to that of os-1 mutants. High extracellular acid phosphatase activity (710). Enhances growth of gpi strains on glucose or sucrose; used to obtain mutants defective in glucosephosphate isomerase (711). Obtained by plating mutagenized conidia in medium containing starch and observing cleared zone around colonies. The glucoamylase, osmotic, and sorbose resistance properties cosegregated in 101 isolates (710). Formerly called T9 (710, 711), gla (glucoamylase) (50), and amy (325). Possibly allelic with sor-4 or sorr-15 or with both (560). Dissimilar in morphology to os-4 strains (PB). Linked to regulatory gene exo-1, which has not been tested for allelism but is stated to be on the other side of mt from sor(T9); see exo-1. (T in the allele number signifies Tokyo, not translocation.)

sp: spray
VR. Between leu-5 (3 to 9%) and am (1 to 8%). Linked to cot-4 (11%) (122, 839, 1036).

Grows initially as colonies that are flat on the surface, and then aerial mycelium fans upward (789). Photographs of allele B132 (278, 296). For ultrastructure and intraconidial conidia, see references cited in reference 1088. Cell wall analysis (278). Reduced amount of cell wall peptides (1165). Morphology similar to that of cot-4 (at 25 C), sn, and cum mutants (PB). Excellent female fertility. Used as lawn for mating type tests on plates (990).

spco: spreading colonial
Symbol and name used in reference 382 for mutants that begin growth on agar as a colony but do not remain restricted, spreading to cover the agar surface. Mutant genes of the series spco-3 to spco-15, described in reference 382, were sometimes assigned to new spco loci without having been tested for allelism with already named morphological mutations having similar map locations. Growth rates and other characteristics of 11 spco mutants are described and analyzed in references 1085 and 1086.

spco-1: spreading colonial-1
See col-4.

spco-2: spreading colonial-2
See wa.

spco-3: spreading colonial-3
See spco-7.

spco-4: spreading colonial-4
VIIL. Linked to do (<1%) and nic-3 (1%, probably to the left) (816).

Fine hyphae (382). Initially aconidial. Capable of conidiating on the surface of complete medium (D.D. Perkins, unpublished data). Hyphae extend faster within agar medium than on the surface, resulting in a dense hemispherical colony, most of which is embedded (1085).

spco-5: spreading colonial-5
VII. Linked to nt (20%) and col-17 (6%) (382).

Homozygous spco-5 x spco-5 crosses make abnormal, nonlinear asci (1007). Reduced amount of cell wall peptides (1165). Complements col-2 and spco-4 (382).

spco-6: spreading colonial-6
Linked to do (10%), spco-5 (8%), and nt (20%) (382).

Complements col-17, col-2, spco-4, and spco-5 (382).

spco-7: spreading colonial-7
Near ad-1 (0/65). Right of ylo-1 (4%); left of T(AR209) and trp-2 (16-21%) (PB). (382)

Complements moe-2. Allele R2365 preferred, for excellent growth, conidiation, and fertility (PB). Allele R2365, called spco-3, was incorrectly assigned to V (42% recombination with inl (382). R2365 x spco-7 (R2457) crosses result in small perithecia devoid of ascospores (PB).

spco-8: spreading colonial-8
IV. Linked to pan-1 (23%) (382).

spco-9: spreading colonial-9
VR. Linked to asn (6%); right of met-3 (18%) (698).

Complements ro-5, cot-2, and smco-6. Morphologically distinct from col-9, but allelism tests were inconclusive (382, 698).

spco-10: spreading colonial-10
VR. Between ilv-1 (24%) and inl (5%) (21 asci) (382, 698).

spco-11: spreading colonial-11
I. Linked to mating type (17%) and mo-5 (18%) (382).

Occasionally conidiates at the top of slants (382).

spco-12: spreading colonial-12
I. Linked to mating type (20 to 35%), mo-5 (5%), and spco-11 (43%) (382).

Downy center and lacy growing border (382). Reduced amount of cell wall peptides (1165). Hyphal growth highly branched (1086).

spco-13: spreading colonial-13
VI. Linked to trp-2 (16%) and the centromere (1/10 asci) (382).

May be allelic with spco-7 or moe-2 (crosses and heterokaryons unsuccessful (382)

spco-14: spreading colonial-14
II. Linked to arg-5 (7%) (382).

Complements da and bal. A few scattered conidia (382).

spco-15: spreading colonial-15
III. Linked to spg (10%), pro-1 (18%), and the centromere (0/10 asci).

Recombines with col-14 and col-16. Complements mo-4, col-14, and col-16 (382).

Stock lost? A morphological mutation in FGSC stock no. 2389, which is designated spco-15 (R2537), is not linked to III (PB).

spe-1: spermidine-1
VR. Linked to cyh-2 (2%); left of inl (12%) (657, PB).

Uses putrescine, spermidine, or spermine. Affects ornithine decarboxylase (L-ornithine carboxy-lyase) (Fig. 10). Does not suppress pro-4 (657). Excretes yellow pigment into synthetic cross medium (PB). Meiosis normal in homozygous crosses (on 50 µg of spermidine per ml), which produce mostly white and a few viable black ascospores (N.B. Raju, personal communication; R. H. Davis, personal communication). Formerly called put-1.

spg: sponge
III. Between acr-2 (1 to 11%) and ser-1 (896).

Linked to sc (<1%) and thi-4 (0/103) (816, P13).

Conidiating spreading colonies. Morphology distinct from that of sc mutants. Good viability. Growth on minimal medium of Vogel (1103) is less spreading than on crossing medium of Westergaard and Mitchell (1134) (PB). Hyphae fuse to form bundles (382). Reduced amount of cell wall peptides (1165).

ss: synaptic sequence
IL. Linked very close to nit-2 (< 0.2%) (161).

When there is heterozygosity for alleles ssE ssS, and ssC (from Emerson, St. Lawrence, and Costa Rica wild types) recombination within nit-2 is reduced 2- to 20-fold, but crossing over in the flanking interval un-5 to nit-2 or nit-2 to leu-3 is not affected. ss heterozygosity acts multiplicatively with rec-1+ to reduce recombination within the nit-2 locus 100-fold. (161)

ssu: supersuppresor
Nonsense suppressors (either proved or putative). In a few cases, putative missense mutations were also suppressed (749). Allele specific but not locus specific. Often infertile or only slightly fertile (ssu-3) when used as the female parent, forming no perithecia or empty perithecia (954). Strains of genotype ssu-1;am or ssu-2;am or ssu-3;am or ssu-4;am or ssu-5, but not ssu-6, are cold sensitive, showing less than half the wild-type growth rate at 10°C on minimal medium (894). Nucleus-restricted action has been studied in heterokaryons (409). Interaction of certain supersuppressors with certain ad-3B alleles produces erratic stop-start growth (408). For tabular summaries of action on differential test alleles, see references 145, 955, and 957.

ssu-1: supersuppressor-1
VIIR. Right of met-7 (14%). Left of nt (23%) and of missense suppressor su(trp-3td201)-1 (10%) (954).

Allele WRN33 selected (953) as suppressor of nonsense mutation am(17), which may be either amber or ochre but cannot be UGA (956). Inserts tyrosine in the site where the wild type has glutamate (956). Used to identify suppressible alleles of aro(p), trp-1, trp-2, trp-3 (953, 144, 183), and ad-3B (749). Although perhaps the most efficient of known ssu mutations, ssu-1 restores only about 20% of the wild-type amount of normal glutamate dehydrogenase in the double mutant with am allele (17) (reference 956).

ssu-2: supersuppressor-2
I. Linked to mt (22%), probably between the centromere (7%) and al-2 (26%). Recombines with ssu-3 (954).

Allele WRU35 selected (954) as a coincident suppressor of nonsense mutations trp-3 (td140) and am(17), which may be either amber or ochre but cannot be UGA (956). Also suppresses certain nonsense alleles of trp-1, trp-2, and ad-3B (see reference 955).

ssu-3: supersuppressor-3
I. Linked to mt (22%), probably between the centromere (10%) and al-2 (33%) (954).

Allele WRU118 selected (954) as a coincident suppressor of nonsense mutations trp-3 (td140) and am(17), which may be either amber or ochre but cannot be UGA (956). Fails to suppress most nonsense mutations that are suppressed by ssu-1 and ssu-2 (see reference 955). Probably specifies insertion of an amino acid different from that inserted by ssu-1 or ssu-4 (Seale and Kinniburgh, cited in reference 955).

ssu-4: supersuppressor-4
VIIL. Between nic-3 (28%) and met-7 (20%) (954).

Allele WRU18 selected (954) as a suppressor of nonsense mutations trp-3 (td140) and am(17), which may be either amber or ochre but cannot be UGA (956). Also suppresses certain nonsense alleles of trp-1 and ad-3B (see references 749 and 955).

ssu-5: supersuppressor-5
III or IV (145).

Allele Y319-45 selected as a suppressor of a nonsense allele of aro(p) (145). Also suppresses the nonsense mutation trp-3 (td140) and certain ad-3B alleles, but not am(17) (see references 145, 749, and 957).

ssu-6: supersuppressor-6
VR. Linked to his-1 (4%) (145).

Allele Y319-45 selected as a suppressor of a nonsense allele of aro(p) (145). Also suppresses certain nonsense alleles of trp-3 and his-3, but not am(17) (references 145, 749, 957).

ssu-7: supersuppressor-7
VIL. Between ad-8 (8%) and ylo-1 (14%) (954).

Allele WRU7 selected (954) as a coincident suppressor of nonsense mutations trp-3 (td140) and am(17), which may be either amber or ochre but cannot be UGA (956). Also suppresses nonsense alleles of trp-1, trp-2, and ad-3B. ssu-7 shows the widest spectrum of the known supersuppressors (955). Allele Y319-37 of ssu-8, which is in IR, has erroneously been called ssu-7 in some FGSC lists and by Griffiths (408).

ssu-8: supersuppressor-8
IR. Linked to al-2 (2 to 8%) (145).

Allele Y319-37 selected as suppressor of an aro(p) nonsense allele (145). Also suppresses certain nonsense alleles of trp-3, his-3 (reference 145) and ad-3B (reference 749). Allele Y319-37 (FGSC no. 1749), also called 54-su37, was initially thought to be a possible allele of ssu-2 and thus was listed as ssu-2 (?); later it was designated ssu-8 (145). It has been erroneously called ssu-7 in various FGSC lists and by Griffiths (408) and has been erroneously stated to be in linkage group VI (the location of the real ssu-7).

ssu-9: supersuppressor-9
Linkage not known. Locus distinct from other ssu genes (955).

Allele WRU98 selected (see 955) as coincident suppressor of nonsense mutations trp-3 (td140) and am(17), which may be either amber or ochre but cannot be UGA (956). Also suppresses nonsense alleles at trp-1 and trp-2 (see reference 955).

ssu-10: supersuppressor-10
Linkage not known. Locus distinct from other ssu genes (955).

Allele RWU121 selected (see reference 955) as a coincident suppressor of nonsense mutations trp-3 (td140) and am(17), which may be either amber or ochre but cannot be UGA (956). Also suppresses nonsense alleles at trp-1, trp-2, and ad-3B (955).

ssu(WRU79): supersuppressor (WRU79)
Linkage not known. Locus distinct from other ssu genes (955).

Selected (955) as coincident suppressor of nonsense mutations trp-3 (td140) and am(17), which may be either amber or ochre but cannot be UGA (956). Also suppresses nonsense alleles at trp-1, trp-2, and ad-3B. Spectrum resembles ssu-1 (955).

st: sticky
IR. Between ad-3B (5%) and thi-1 (14%) (789).

Mycelia adhere to needle. Subtle morphological difference from wild type. Exudate sometimes present (789). Grows poorly from conidial inocula on to minimal medium, with ballooning of hyphal tips not alleviated by mannose (D.D. Perkins, unpublished data).

su: suppressor
su is used to designate the mutant suppressor allele, and su+ is used to designate the wild-type nonsuppressor allele. Usage for Neurospora thus follows the long-established usage for Drosophila and other higher organisms.

su(arg-1)-1: suppressors of arg-1
Unmapped. Not linked to arg-1.

Restores 23 to 36% of the wild-type L-citrulline:L-aspartate ligase activity to arg-1 mutant 46004. Called arg-1R26, arg-1R3, s-26, and s-3. (62).

su(bal): suppressor of balloon
I. Linked to mating type (13%) (948).

Doubles the linear growth rate of the mutant bal. Decreases the Km of glucose-6-phosphate dehydrogenase in the double mutant bal;su(bal). Photographs of bal and bal;su(bal). (948). Called su-B.

su(col-2): suppressor of colonial-2
IL. Tightly linked to mating type (0/837) (948).

Increases linear growth rate of the mutant col-2 10-fold. Morphology is wild type in the absence of col-2. Influences electrofocusing patterns of col-2 glucose-6-phosphate dehydrogenase and, in the absence of col-2, of the normal enzyme. Photographs of col-2 and col-2;su(col-2). (948). Called su-C.

su(cot-1): suppressor of cot-1
See gul.

su(ile-1): suppressor of isoleucine-1
VR. Right of met-3 (4%) (J.A. Kinsey, personal communication),

Suppresses requirement of ile-1 (J.A. Kinsey, personal communication).

su(inl): suppressor of inositol
Independent of inl.

Partial suppressor; allele specific. Restores limited ability to synthesize inositol to strains carrying allele 37401, allowing suboptimal growth on minimal medium. (390).

su(met-2): suppressor of met-2
Unmapped. Not tested for allelism with su(met-7)-1 or su(met-7)-2.

Isolated as a suppressor of met-2 allele H98 (B.S. Strauss and S. Tokuno, via FGSC). Suppresses leaky mutants blocked between cysteine and homocysteine. It is probably the suppressor used by Wiebers and Garner (1136) to show that the suppressed strain differs from wild type in being able to incorporate sulfur from S-methyl-cysteine into cysteine regardless of the sulfate concentration. The suppressor does not have significantly increased acetylhomoserine sulfhydrylase (547). The FGSC number is 690.

su(met-7)-1: suppressor-1 of met-7
IR. Linked to al-2 (1%) (386). Selected as reversions of met-7 (4894) by Giles (386). All spontaneous reversions were at this locus. Suppresses met-7 (4894) and met-2 (H98). Not tested for suppression of other alleles or loci. Suppressed strains attain wild-type growth on minimal medium after initial retardation, which is alleviated by methionine (386). This is apparently the suppressor used by Fischer (347) to show that the suppressor restores cystathionase I and II activities to 4894 and H98, respectively. Called S-1, FGSC 39.

su(met-7)-2: suppressor-2 of met-7
Unmapped.

Suppresses met-7 (4894). Not tested for suppression of other mutants. Selected as a revertant of met-7 (4894) by Giles (386). Recovered less frequently than su(met-7)-1 and only after irradiation. Called S-2. (386).

su([mi-1]-1: suppressor-1 of [mi-1]
IIIR. Linked to ad-4 (14%) (567, 568).

Restores normal growth rate; alleviates deficient cyanide-sensitive respiration of [mi-1] = [poky]) and another group I cytoplasmic mutant. No effect on group II cytoplasmic mutant [mi-3] (85, 204, 568). Mitochondrial ribosomal subunit ratios and cytochrome spectrum (204). Called sup-1.

su([mi-1])-3: suppressor-3 of [mi-1]
II. Linked to fl (31%). Not allelic with su([mi-2])-4 or su([mi-1])-10: 20 and 25% unsuppressed progeny from intercrosses (567, 568).

Restores normal growth rate, alleviates deficient cyanide-sensitive respiration of [mi-1] ([poky]) and another group I cytoplasmic mutant. No effect on group II cytoplasmic mutant [mi-3] (85, 204, 568). Effects on mitochondrial cytochromes and ribosomal subunits (204). Called sup-3 (568).

su([mi-1])-4: suppressor-4 of [mi-1]
II. Linked to fl (22%) and arg-5 (40%). Not allelic with su([mi-1])-3 or su([mi-1])-10: 20 and 25% unsuppressed progeny from intercrosses (567, 568).

Restores normal growth rate, alleviates deficient cyanide-sensitive respiration of [mi-1] ([poky]) and another group I cytoplasmic mutant. No effect on group II cytoplasmic mutant [mi-3] (85, 204, 568). Mitochondrial ribosomal subunit ratios and cytochrome spectrum (204). Called sup-4 (568).

su([mi-1])-5: suppressor-5 of [mi-1]
VIIL. Left of nic-3 (23%) (567, 568). Possibly allelic with cyt-7 (87).

Restores normal growth rate; alleviates deficient cyanide-sensitive respiration of [mi-1] ([poky]) and another group I cytoplasmic mutant. No effect on group II cytoplasmic mutant [mi-3] (85, 204, 568). Mitochondrial ribosome profile and cytochrome spectra (204). Affects mitochondrial large subunit assembly. With wild-type mitochondria, causes cold sensitivity (203). Called sup-5 (568) and suI-5 (203).

su([mi-1])-10: suppressor-10 of [mi-1]
II. Linked to arg-5 (29%) and fl (24%) (567,568). Not allelic with su([mi-1])-3 or su([mi-1])-4: 25% unsuppressed progeny from intercrosses (568).

Restores normal growth rate; alleviates deficient cyanide-sensitive respiration of [mi-1] ([poky]) and all other group I cytoplasmic mutants. No effect on group II cytoplasmic mutant [mi-3] (85, 204, 568). Cytochrome spectrum (204). Called sup-10 (568).

su([mi-1])-14: suppressor-14 of [mi-1]
IV. Linked to arg-2 (14%) (567, 568).

Restores normal growth rate; alleviates deficient cyanide-sensitive respiration of [mi-1] ([poky]) and all other group I cytoplasmic mutants. No effect on group II cytoplasmic mutant [mi-3] (85, 204, 568). Cytochrome spectrum (204). Called sup-14 (568).

su([mi-1])-f: suppressor-f of [mi-1]
VR. Left of inl (10%) (986).

Restores normal growth rate; alleviates deficient cyanide-sensitive respiration of [mi-1] ([poky]) (693) and all other group I cytoplasmic mutants, but not group II or group III mutants (88, 395). su([mi-1])-f differs from other known [mi-1] suppressors in not restoring salicyl bydroxamic acid insensitivity (568). Cytochrome spectrum (85). Used for studying oscillations in membrane potential (402). Symbol changed from f

su([mi-3])-]: suppressors of [mi-3]
IR. Linked to al-2 (4%); right of nit-1 (17%) (395).

Restores normal growth rate and cytochrome spectrum to [mi-3], a group II cytoplasmic mutant (89, 395). Does not suppress the mutant phenotype of group I or group III cytoplasmic mutants (88).

su(mtr)-1: suppressor-1 of mtr
IR. Right of his-2 (2%) (1018).

Selected in the double mutant trp-1;mtr by increased uptake of tryptophan (1018) or as his+ revertants of his-2;mtr strains on histidine plus excess arginine (107). Still resistant to 4-methyltryptophan, but now sensitive to p-fluorophenylalanine (1018). The effect of su(mtr)-1 on mtr is locus specific. su(mtr)-1 appears to have a changed regulation for amino acid transport system II (776). Possibly allelic with lysR (565).

su(mtr26): suppressor of mtr allele 26
VIR. Linked to pan-2 and trp-2 (106).

Allele-specific partial suppressor of the poor growth of the double mutant mtr(26);trp-1 on low levels of tryptophan. [mtr(26) is a putative frameshift.] (106).

su(pan-2Y153M66): suppressor of pan-2 allele Y153M66
Not mapped.

Allele-specific suppressor; not effective on three other pan-2 alleles or on four supersuppressible alleles at trp-3 and am-1 (188).

su(pe): suppressor of pe microconidiation
Perhaps linked to pe (18%) in linkage group II (415).

Restores ability of the col-1;pe double mutant to produce macroconidia rather than exclusively nucroconidia (415, 416). Called sum. See col-1.

su([poky])
see su([mi-1]).

su(pro-3): suppressor of pro-3
IR. Linked to al-2 (2%). Possibly allelic with arg-6 (0/154) (1129).

Suppresses the requirement of the mutant pro-3 (= arg-8) for proline, ornithine, citrulline, or arginine. This is due to a feedback-insensitive omithine synthetic pathway (1129), which allows ornithine to spill over into the proline path.

su(rg-2): suppressor of rg-2
Not linked to rg-1 or rg-2.

Suppresses rg-2 in N. sitophila. Found in N. sitophila. Not studied in N. crassa. (680).

su(trp-3): suppressor of trp-3
Most suppressors of trp-3 whose allele numbers are prefaced "td" were assigned numbers corresponding to the allele numbers of the td strains in which they were originally discovered. These have been retained as suppressor locus numbers. Thus, su(trp-3td2)-2 is the original suppressor discovered in strain td2; the number 2 does not imply that there was a previously discovered suppressor of trp-3 allele td2. This system was not used for the suppressors of td201, which are numbered conventionally. For a review of early work, see reference 1167.

su(trp-3td2)-2: suppressors of trp-3 allele td2
III. Linked to leu-1 (22%) (581).

Allele specific. Suppresses allele td2 but does not suppress td6, td7l, or any other allele from td1 through td34 (580, 1169). This and the other listed suppressors of td2 were not tested on later trp-3 alleles that fall in the same complementation group as td2. Although suppressed mutants grow on minimal medium, growth is stimulated by addition of tryptophan. Suppressed trp-3;su colonies are morphologically distinguishable from those of the wild type. Tryptophan synthetase is formed at levels below that of the wild type. Originated in trp-3 allele td2 (originally numbered S1952) (1166, 1169). Called su-2 (388) and su2 (1169).

su(trp-3td2)-2a: suppressor-2a of trp-3 allele td2
Linked to al-2 (15%) (581).

Isolated (1170) as one of four additional suppressors of td2, numbered su2a, su2b, su2c, and su2d. All are nonallelic with su2 and with each other, with the possible exception of su2b and su2c (1170). None was tested for allelism with su(trp-3td6), which also suppresses td2. su2b, su2c, and su2d are unmapped. Erroneously printed as su-2a (581). The a does not refer to mating type.

su(trp-3td3): suppressor of trp-3 allele td3
Not mapped.

Allele specific. Suppresses trp-3 alleles td3, td24, and td71, but not any other alleles from td1 through td34 (580, 1169). Originated in trp-3 (td3). Probably allelic with su24. Called su3 (1169).

su(trp-3td6): suppressor of trp-3 allele td6
Not mapped. Different locus from su(trp-3td2)-2 and su(trp-3td3).

Allele specific. Suppresses trp-3 alleles td6 and td2, but does not suppress any other allele from td1 through td34 (580, 1169). Although suppressed mutants grow on minimal medium, growth is stimulated by the addition of tryptophan and is morphologically distinguishable from that of wild type. Tryptophan synthetase is formed at levels below that of the wild type. Originated in trp-3 (td6). Called su6 (1169).

su(trp-3td201)-1: suppressor-1 of trp-3 allele td201
VIIR. Between met-7 (18%) and arg-10 (7%) (1174). Right of ssu-1 (10 to 13%) (954).

Allele specific. Suppresses missense allele td201, but not eight other alleles (td1, td6, td7, td16, td37R, td71, tdl38R, and td141) (1174). Also does not suppress td2, td3, or td24 (910). A suppressed mutant has a low level of tryptophan synthetase activity, allowing slow growth on minimal medium. Enzyme activity is due to a protein physically like the wild-type enzyme (1174, 1175). Strains carrying the suppressor alone, without td201, grow slightly slower than wild type (910). The suppressor is effective when in another nucleus from td201 in a forced heterokaryon between noncomplementing alleles (td16;su plus td2Ol;su+) (910). Called Su-1 or Su-1td201 in reference 954, su-YS in reference 910, and su1(201) in reference 1173.

su(trp-3td201)-2: suppressor-2 of trp-3 allele td201
VII. Linked but not allelic with su(trp-3td201)-1; probably closer to the centromere (910).

Allele specific. Suppresses missense allele td201, but does not suppress six other alleles (td1, td2, td3, td16, td24, and td71) (910). The suppressed mutant has a low level of tryptophan synthetase activity, allowing slow growth on minimal medium. Enzyme activity is due to a protein physically distinguishable from wildtype tryptophan synthetase, unlike suppressors 1 and 3 (844). Suppressor alone, without td201, grows slightly more slowly than wild type (910). The suppressor is effective when in another nucleus from td201 in a forced heterokaryon between noncomplementing alleles (td16;su plus td201;su+) (910). Called su-R in reference 910 and su-2 in reference 844.

su(trp-3td201)-3: suppressor-3 of trp-3 allele td201
Unmapped. Not linked to su(trp-3td201)-1 or other VII markers.

Allele specific. Suppresses missense allete td201, but not four other alleles (td1, td6, td71, and td141). The one allele tested gave less powerful suppression of td201 than did the known alleles of su(trp-3td201)-1 . The suppressed mutant has a low level of tryptophan synthetase activity, allowing slow growth on minimal medium. Restored enzyme activity is due to a protein physically like that of the wild type. Called su3 and su3(201) (1173).

su(trp-5): suppressor of trp-5
VIL. Closely linked to aro-6 (J.A. Kinsey, personal communication).

Possibly a feedback-negative allele of aro-6, which specifies 3-deoxy-D-arabino-heptulosonic acid-7-phosphate synthase (Tyr) (J.A. Kinsey, personal communication).

su(ure-19): suppressor of ure-1 allele 9
Unmapped, but not linked to ure-1 or ure-2.

Does not suppress ure-2 (allele 47). Suppressed only ure-1 (allele 9) strains from a certain lineage, suggesting that suppression requires a cosuppressor closely linked to ure-1 (9). (121).

suc: succinate
IL. Right of acr-3 (2%). Left of In(H4250) and phe-1 (1%) (578, 816). (482).

Uses acetate, succinate, or any of numerous related compounds (608). Most but not all strains grow better on acetate than on succinate (576). Lacks pyruvate carboxylase activity (72, 578, 1032). Numerous alleles are CO2 remediable (108). Leaky, but less so on higher ammonium concentrations (1031). A special medium has been devised for selective plating (K.D. Munkres, cited in reference 816, p. 248). Most ascospores are poorly pigmented in homozygous suc x suc crosses. Allele KG163 shows greatly reduced recombination in the region between leu-4 and suc, suggesting inversion heterozygosity (576). suc would be named ace-6 except for priority of nomenclature (578).

sup: suppressor
See su.

sw: snow white
See per-1.

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