Rhythmic conidiation in constant light in vivid mutants of Neurospora crassa.
In Neurospora crassa, a circadian rhythm of conidiation (asexual spore formation) can be seen on the surface of agar media. This rhythm has a period of 22 hr in constant darkness (D/D). Under constant illumination (L/L), no rhythm is visible and cultures show constant conidiation. However, here we report that strains with a mutation in the vivid (vvd) gene, previously shown to code for the photoreceptor involved in photo-adaptation, exhibit conidiation rhythms in L/L as well as in D/D. The period of the rhythm of vvd strains ranges between 6 and 21 hr in L/L, depending upon the intensity of the light, the carbon source, and the presence of other mutations. Temperature compensation of the period also depends on light intensity. Dark pulses given in L/L shift the phase of the rhythm. Shifts from L/L to D/D show unexpected after effects; i.e., the short period of a vvd strain in L/L gradually lengthens over 2-3 days in D/D. The rhythm in L/L requires the white collar (wc-1) gene, but not the frequency (frq) gene. FRQ protein shows no rhythm in L/L in a vvd strain. The conidiation rhythm in L/L in vvd is therefore driven by a FRQ-less oscillator (FLO).
Schneider
Kevin
K
Division of Biological Sciences, University of California, San Diego, California 92093-0116, USA.
Perrino
Sabrina
S
Oelhafen
Kim
K
Li
Sanshu
S
Zatsepin
Artiom
A
Lakin-Thomas
Patricia
P
Brody
Stuart
S
D002940:Circadian Rhythm; D003624:Darkness; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000528:radiation effects; D005800:Genes, Fungal; D008027:Light; D009154:Mutation; D009492:Neurospora crassa / Q000235:genetics / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects*; D013172:Spores, Fungal / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects*; D013696:Temperature; D013997:Time Factors
C087405:FRQ protein, Neurospora crassa; D005656:Fungal Proteins; C423283:VVD protein, Neurospora crassa