Case studies for a linkage of dimorphic transition with conidiation and/or expression of key developmental activators in B. bassiana

Gene mutantGene annotationDimorphic transitionaConidiation
and yield
loss (%)b
of brlA, abaA,
and wetA,
respectively (%)c
in vivo
% decrease
in vitro
Δgcn5Histone acetyltransferase Gcn5SB92 (T)SD, 9799, 89, 848
Δmst2Histone acetyltransferase Mst2NE65 (T)SD, 7594, 72, 759
Δhos2Histone deacetylase Hos2NE32 (C), 52 (T)SD, 7694, 88, 6810
Δrpd3Histone deacetylase Rpd3SB93 (C), 95 (T)ESD, 9794, 98, 5711
Δste7Fus3-cascaded MAPK kinaseNE68 (T)SD, 7784, 90, 9712
ΔvvdBlue-light photoreceptor VVDSB40 (C), 97 (T)ESD, 6090, 94, 756
ΔkrsLysyl-tRNA synthetase KRSSB58 (C), 71 (T)SD 2080, 81, 7716
ΔVLP4Vacuole-localized protein 4SB99 (T)ESD, 8099, 99, 9414
ΔcypBCyclophilin B (CypB)NE48 (C), 83 (T)SD, 4797, 95, 7517
ΔvmaHVacuolar ATPase subunit HNE60 (T)ESD, 40NE15
Δnhx1Na+/H+ antiporter Nhx1SB72 (C), 86 (T)ESD, 85NE13
ΔGEL1Gelsolin GEL1NE90 (S)ESD, 68NE7
Δmas5DnaJ protein Mas5SB59 (S)ND, 50NE4
  • a The status of dimorphic transition in vivo (SB, severely blocked; NE, not examined) was revealed through microscopic examination of hemolymph samples taken from Galleria mellonella larvae surviving a period after topical application for normal cuticle infection or intrahemocoel injection for cuticle-bypassing infection. The decrease of dimorphic transition in vitro was quantified from submerged liquid cultures of conidia grown in Sabouraud dextrose broth (S), minimal Czapek broth (C), or trehalose-peptone broth (T) mimicking insect hemolymph, as indicated by the abbreviations in parentheses.

  • b Conidiation on the standard medium Sabouraud dextrose agar plus yeast extract (SDAY) under the optimal regime of 25°C in a light/dark cycle of 12:12 suffered severe delay (SD), extremely severe delay (ESD), or no delay (ND). The loss of conidial yield was assessed from the cultures at the end of a 7- to 12-day incubation.

  • c The transcriptional repression of each gene was assessed from the cDNA samples derived from 3-day-old SDAY cultures under the optimal regime. NE, not examined.