The transcriptome of conidia of Aspergillus niger was analysed during the first 8 hours of germination. Dormant conidia started to grow isotropically 2 hours after inoculation in liquid medium. Isotropic growth changed to polarized growth after 6 hours, which coincided with one round of mitosis. Dormant conidia contained transcripts from 4626 genes. The number of genes with transcripts decreased to 3557 after 2 hours of germination, after which an increase was observed with 4780 expressed genes 8 h after inoculation. Dormant conidia had the most unique RNA composition. The correlation coefficient between the RNA profiles of t = 0 h and t = 8 h was 0.46. They were between 0.768208;0.93 when profiles of 2, 4 and 6 h were compared with that of 8 h. Dormant conidia were characterized by high levels of transcripts of genes involved in the formation of protecting components such as trehalose, mannitol, protective proteins (e.g. heat shock proteins and catalase). Transcripts belonging to the Functional Gene Categories (FunCat) protein synthesis, cell cycle and DNA processing and respiration were overrepresented in the up8208;regulated genes at t = 2, whereas metabolism and cell cycle and DNA processing were overrepresented in the up8208;regulated genes at t = 4 h. At t = 6 h and t = 8 h No functional gene classes were over8208; or under8208;represented in the differentially expressed genes. Taken together, it is concluded that the transcriptome of conidia changes dramatically during the first two hours and that initiation of protein synthesis and respiration are important during early stages of germination.
Full conference title:
11 th European Conference on Fungal Genetics
- ECFG 11th (2012)