| Cln21, a novel hypha-specific cyclin-related protein, and Ume6regulate Candida albicans hyphal morphogenesis. C. albicans cells undergo yeast-like development and cannot germinate nomal hypha under inducement conditions when Cln21and Ume6were knocked out seperately. The role of these genes in Aspergillus nidulans has not been reported. In our study, homologous genes of C. albicans cln21and ume6in A. nidulans were deleted, which, we thought, may change other developmental mechanisms of A. nidulans.Mutants of A. nidulans, ΔUmel, ΔUme2, ΔUme3, ΔClnl, ΔCln4, ΔCln5and ΔCln6, were constructed. Though the hypha of mutants are all normal, the color of AClnl, ΔCln4, and ACln6colonies changed from dark-green to yellowish-brown gradually when culture temperature rise from28℃to37℃and then42℃. Analysed with scanning electron microscope (SEM), the color changes were caused by the reduction of conidiophore quantity and the underdeveloped conidiospores. Four mutant strains, ΔCln1-4, experienced a reduction of conidia quantity and were sensitive to temperature compared with wild type. At28℃, the number of conidia of AClnl,2and4reduced to48.7%,68.6%and51.4%of the wild type. At42℃, the number of conidia of AClnl,2and4reduced to6.6%,10%,47.9%and4.8%of the wild type. Detection of mRNA level of some conidiation-specific genes revealed that relative expression level of brlA, abaA and wet A of mutants, was much lower than that of wild type after the hypha was exposed in the air for15h, which, we thought, was the main reason leading to the underdeveloped conidiospores and the low quantity of conidium. Significant change of relative expression level of heat shock protein encoding genes hsp30and hsp70compared with wild type was detected. Therefore, the putative A. nidulans cyclins encoding genes, clnl, cln4, cln5and cln6are involved in sporulation and the asexual development of mutants are more sensitive to temperature, which leads to bad environment adaption ability. |
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