Fruiting Body Formation in Volvariella volvacea Can Occur Independently of Its MAT-A-Controlled Bipolar Mating System, Enabling Homothallic and Heterothallic Life Cycles.
Fruiting Body Formation in Volvariella volvacea Can Occur Independently of Its MAT-A-Controlled Bipolar Mating System, Enabling Homothallic and Heterothallic Life Cycles.
复制标题
Volvariella volvacea中的果实体形成可以独立于其MAT-A控制的双极配合系统，从而实现同质和异性生命周期。
DOI：
10.1534/g3.116.030700
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发表时间：
2016-07-07
期刊：
影响因子：
--
通讯作者：
Xie B
中科院分区：
文献类型：
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作者：
Chen B;van Peer AF;Yan J;Li X;Xie B;Miao J;Huang Q;Zhang L;Wang W;Fu J;Zhang X;Zhang X;Hu F;Kong Q;Sun X;Zou F;Zhang H;Li S;Xie B
草菇是东南亚的重要农作物，但不稳定的结果给其生产和育种带来了严重的挑战。由于多核的性质，典型的缺乏钳连接，以及不完全确定的有性生殖系统，解释不一致结实的努力变得复杂。在这项研究中，我们解决了草菇的生活史使用全基因组测序，MAT位点的克隆，孢子的核型分析，和结实测定。孢子的显微镜分析以前表明可能共存的异宗配合和同宗配合的生活周期。我们的MAT位点的分析表明，只有MAT-A，而不是MAT-B，控制异核化。因此，异宗配合的生活史是两极的。利用分子标记对单孢子分离物进行核型分析，支持异源孢子的存在。然而，大多数SSI显然不是杂合，但包含结构变异（SV）标记有关的两个等位基因的父母。异核体杂交，自交不育的同核体可以产生子实体，同意两极异宗配合。同时，一些具有两个不同MAT-A位点的SSIs也产生子实体，支持次级同宗配合。接下来，明确仅包含一个MAT-A基因座（同宗配合）的SSI也能够结果，这表明自花可育的SSI根据定义不是次级同宗配合，并且必须存在第三个生命周期或遗传机制。SV标记之间的重组是正常的，但在24个SV标记中有10个在孢子中呈1：2或1：3分布，并且大量SSI含有双SV标记。这表明自私的基因，并可能部分非整倍体。
Volvariella volvacea is an important crop in Southeast Asia, but erratic fruiting presents a serious challenge for its production and breeding. Efforts to explain inconsistent fruiting have been complicated by the multinucleate nature, typical lack of clamp connections, and an incompletely identified sexual reproductive system. In this study, we addressed the life cycle of V. volvacea using whole genome sequencing, cloning of MAT loci, karyotyping of spores, and fruiting assays. Microscopy analysis of spores had previously indicated the possible coexistence of heterothallic and homothallic life cycles. Our analysis of the MAT loci showed that only MAT-A, and not MAT-B, controlled heterokaryotization. Thus, the heterothallic life cycle was bipolar. Karyotyping of single spore isolates (SSIs) using molecular markers supported the existence of heterokaryotic spores. However, most SSIs were clearly not heterokaryotic, yet contained structural variation (SV) markers relating to both alleles of both parents. Heterokaryons from crossed, self-sterile homokaryons could produce fruiting bodies, agreeing with bipolar heterothallism. Meanwhile, some SSIs with two different MAT-A loci also produced fruiting bodies, which supported secondary homothallism. Next, SSIs that clearly contained only one MAT-A locus (homothallism) were also able to fruit, demonstrating that self-fertile SSIs were not, per definition, secondary homothallic, and that a third life cycle or genetic mechanism must exist. Finally, recombination between SV markers was normal, yet 10 out of 24 SV markers showed 1:2 or 1:3 distributions in the spores, and large numbers of SSIs contained doubled SV markers. This indicated selfish genes, and possibly partial aneuploidy.