高亲和性铁离子渗透酶Ftr1和Ftr2调控白念珠菌生长和形态

Regulation of cell growth and filamentation in Candida albicans by high-affinity iron permeases Ftr1 and Ftr2

【目的】通过分析FTR1、FTR2基因缺失株在不同培养条件下的生长情况以及菌丝生长能力,明确高亲和性铁离子渗透酶在白念珠菌生长和形态发生中的功能。【方法】将不同基因型的菌株分别置于不同的培养基和培养温度下进行培养,对其生长速度以及菌丝的生长状态进行观察,获取相应的实验结果。【结果】FTR1或FTR2单基因缺失对于白念珠菌的生长没有显著的影响,但是FTR1、FTR2双基因缺失使白念珠菌在Spider培养基中不能生长,铁离子的增加能够恢复该双基因缺失株的生长能力。FTR1、FTR2双基因缺失株在营养贫瘠的合成培养基上生长速度也较慢。此外,ftr1/frt1菌株的菌丝生长能力增强,而ftr2/ftr2菌株的菌丝生长能力减弱。双突变株ftr1/ftr1 ftr2/ftr2的菌丝生长能力能够恢复到野生对照株的水平。【结论】Ftr1与Ftr2对白念珠菌在微量铁元素环境中的生存有着重要的作用,还参与了白念珠菌对碳源N-乙酰葡萄糖胺、乙醇和甘油等的利用。此外,Ftr1对白念珠菌菌丝生长起负调控作用,Ftr2对菌丝生长起正调控作用。因此,ftr1/ftr1 ftr2/ftr2双基因突变株的菌丝生长能力能够恢复到野生对照株的水平。

[ Objective] To determine the function of high-affinity iron permeases, Ftr1 and Ftr2, we studied cell growth and filamentation ability of the fir1/ftr1 ,fir2/fir2, and fir1/ftr1 fir2/fir2 mutants under different culture conditions. [ Methods] Cells of the wild type and mutants were cultured on different solid media at different temperatures. Cell growth and filamentation were observed. [ Results] Deletion of either one of the FTR genes had no effect on the growth under all conditions tested. Deletion of both FTR1 and FTR2 led to obvious growth defect on Spider media, although addition of FeCl_3 restored their growth. The double mutant also grew much more slowly on nutrients-limited synthetic media such as Lee ＇ s glucose and Lee ＇ s GlcNAc （N-acetylglucosamine）. Moreover, deletion of FTR1 enhanced filamentation, whereas deletion of FTR2 weakened this ability. Deletion of both FTR1 and FTR2 recovered the ability of filamentation. [ Conclusion] Ftrl and Ftr2 are very important for C. albicans growth under iron-limited condition and may participate in the utilization of some carbon sources including GlcNAc, ethnol, and glycerol. Ftr1 plays a negative, whereas Ftr2 plays a positive role in the regulation of filamentation in C. albicans.