TABLE 1.
Case studies for a linkage of dimorphic transition with conidiation and/or expression of key developmental activators in B. bassiana
| Gene mutant | Gene annotation | Dimorphic transitiona
|
Conidiation and yield loss (%)b |
Repression of brlA, abaA, and wetA, respectively (%)c |
Reference | |
|---|---|---|---|---|---|---|
| Status in vivo |
% decrease in vitro (medium) |
|||||
| Δgcn5 | Histone acetyltransferase Gcn5 | SB | 92 (T) | SD, 97 | 99, 89, 84 | 8 |
| Δmst2 | Histone acetyltransferase Mst2 | NE | 65 (T) | SD, 75 | 94, 72, 75 | 9 |
| Δhos2 | Histone deacetylase Hos2 | NE | 32 (C), 52 (T) | SD, 76 | 94, 88, 68 | 10 |
| Δrpd3 | Histone deacetylase Rpd3 | SB | 93 (C), 95 (T) | ESD, 97 | 94, 98, 57 | 11 |
| Δste7 | Fus3-cascaded MAPK kinase | NE | 68 (T) | SD, 77 | 84, 90, 97 | 12 |
| Δvvd | Blue-light photoreceptor VVD | SB | 40 (C), 97 (T) | ESD, 60 | 90, 94, 75 | 6 |
| Δkrs | Lysyl-tRNA synthetase KRS | SB | 58 (C), 71 (T) | SD 20 | 80, 81, 77 | 16 |
| ΔVLP4 | Vacuole-localized protein 4 | SB | 99 (T) | ESD, 80 | 99, 99, 94 | 14 |
| ΔcypB | Cyclophilin B (CypB) | NE | 48 (C), 83 (T) | SD, 47 | 97, 95, 75 | 17 |
| ΔvmaH | Vacuolar ATPase subunit H | NE | 60 (T) | ESD, 40 | NE | 15 |
| Δnhx1 | Na+/H+ antiporter Nhx1 | SB | 72 (C), 86 (T) | ESD, 85 | NE | 13 |
| ΔGEL1 | Gelsolin GEL1 | NE | 90 (S) | ESD, 68 | NE | 7 |
| Δmas5 | DnaJ protein Mas5 | SB | 59 (S) | ND, 50 | NE | 4 |
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.
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.
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.