病原體酵母“白念珠菌”過去曾被認(rèn)為是嚴(yán)格無性生殖的,，但現(xiàn)在人們知道，這種生物有一個(gè)秘密交配循環(huán),。交配通常涉及a-細(xì)胞類型和alpha-細(xì)胞類型的融合,，與相關(guān)酵母“釀酒酵母”中所見的類似,。
現(xiàn)在,，另外一種新穎的有性生殖模式已在“白念珠菌”中被發(fā)現(xiàn)：在特定情況下,，即在沒有為一種分泌出的蛋白酶編碼的BAR1基因存在的情況下，高效同性交配可在a-型細(xì)胞之間進(jìn)行,。“白念珠菌”的同性交配與相關(guān)真菌病原體“新型隱球菌”的同性交配之間的相似性提出一個(gè)可能性：這種類型的“同宗配合”也許可幫助這些物種在哺乳動(dòng)物宿主體內(nèi)更加具有適應(yīng)性,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 460, 890-893 (13 August 2009) | doi:10.1038/nature08252
Homothallic and heterothallic mating in the opportunistic pathogen Candida albicans
Kevin Alby1, Dana Schaefer1 & Richard J. Bennett1
1 Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island 02912, USA
Candida albicans is the most common fungal pathogen in humans, causing both debilitating mucosal infections and potentially life-threatening systemic infections1, 2. Until recently, C. albicans was thought to be strictly asexual, existing only as an obligate diploid. A cryptic mating cycle has since been uncovered in which diploid a and cells undergo efficient cell and nuclear fusion, resulting in tetraploid a/ mating products3, 4, 5, 6. Whereas mating between a and cells has been established (heterothallism), we report here two pathways for same-sex mating (homothallism) in C. albicans. First, unisexual populations of a cells were found to undergo autocrine pheromone signalling and same-sex mating in the absence of the Bar1 protease. In both C. albicans and Saccharomyces cerevisiae, Bar1 is produced by a cells and inactivates mating pheromone , typically secreted by cells7, 8, 9, 10. C. albicans bar1 a cells were shown to secrete both a and mating pheromones; -pheromone activated self-mating in these cells in a process dependent on Ste2, the receptor for -pheromone. In addition, pheromone production by cells was found to promote same-sex mating between wild-type a cells. These results establish that homothallic mating can occur in C. albicans, revealing the potential for genetic exchange even within unisexual populations of the organism. Furthermore, Bar1 protease has an unexpected but pivotal role in determining whether sexual reproduction can potentially be homothallic or is exclusively heterothallic. These findings also have implications for the mode of sexual reproduction in related species that propagate unisexually, and indicate a role for specialized sexual cycles in the survival and adaptation of pathogenic fungi.
