Genetic Dissection of Sexual Reproduction in a Primary Homothallic Basidiomycete
Genetic Dissection of Sexual Reproduction in a Primary Homothallic Basidiomycete
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DOI：
10.1371/journal.pgen.1006110
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发表时间：
2016-06-01
期刊：
影响因子：
4.5
通讯作者：
Goncalves, Paula
中科院分区：
文献类型：
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作者：
David-Palma, Marcia;Sampaio, Jose Paulo;Goncalves, Paula
在属于担子菌门的真菌中，性相容性通常由两个遗传上不连锁的 MAT 位点决定，其中一个编码一种或多种信息素受体 (P/R) 和信息素前体，另一个包含至少一对编码同源域 (HD) 转录因子的不同转录基因。大多数物种是异宗性的，这意味着有性繁殖需要两个 MAT 基因座上都具有不同等位基因的性相容个体之间的交配。然而，一些物种已知是同宗性的，一个个体能够在不与基因上不同的伴侣交配的情况下完成性周期。虽然已经对几种担子菌模型物种的异宗体生命周期的分子基础进行了详细剖析，但对同宗共体的分子基础知之甚少。在同宗担子菌酵母法夫酵母的可用基因组草图中发现 P/R 和 HD 基因后，我们利用可用的遗传工具来确定它们在性发育中的作用。两个 P/R 簇，每个簇都含有一个信息素受体和一个信息素前体基因，被发现彼此非常接近，并且被证明形成两个冗余的 P/R 对，每个受体都被最远端信息素前体基因编码的信息素激活。 HD 基因座显然与 P/R 基因座在遗传上没有关联，并编码一对不同转录的 HD1 和 HD2 转录因子，这两者都是正常完成性周期所必需的。考虑到 P. rhodozyma MAT 位点的基因组成，我们假设它主要是同宗有机体，并且我们提出了一个模型来解释该物种性发育所需的分子相互作用的相互作用。红法夫酵母被认为是类胡萝卜素虾青素最有前途的微生物来源之一。这种酵母作为工业生物体的进一步发展将受益于对其有性生殖系统的新见解。
In fungi belonging to the phylum Basidiomycota, sexual compatibility is usually determined by two genetically unlinked MAT loci, one of which encodes one or more pheromone receptors (P/R) and pheromone precursors, and the other comprehends at least one pair of divergently transcribed genes encoding homeodomain (HD) transcription factors. Most species are heterothallic, meaning that sexual reproduction requires mating between two sexually compatible individuals harboring different alleles at both MAT loci. However, some species are known to be homothallic, one individual being capable of completing the sexual cycle without mating with a genetically distinct partner. While the molecular underpinnings of the heterothallic life cycles of several basidiomycete model species have been dissected in great detail, much less is known concerning the molecular basis for homothallism. Following the discovery in available draft genomes of the homothallic basidiomycetous yeast Phaffia rhodozyma of P/R and HD genes, we employed available genetic tools to determine their role in sexual development. Two P/R clusters, each harboring one pheromone receptor and one pheromone precursor gene were found in close vicinity of each other and were shown to form two redundant P/R pairs, each receptor being activated by the pheromone encoded by the most distal pheromone precursor gene. The HD locus is apparently genetically unlinked to the P/R locus and encodes a single pair of divergently transcribed HD1 and HD2 transcription factors, both required for normal completion of the sexual cycle. Given the genetic makeup of P. rhodozyma MAT loci, we postulate that it is a primarily homothallic organism and we propose a model for the interplay of molecular interactions required for sexual development in this species. Phaffia rhodozyma is considered one of the most promising microbial source of the carotenoid astaxanthin. Further development of this yeast as an industrial organism will benefit from new insights regarding its sexual reproduction system.