Plant Pathology Group, Institute of Integrative Biology, ETH Zürich, 8092, Zürich, Switzerland.
New Address: Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, UK.
BMC Biol. 2020 Aug 11;18(1):99. doi: 10.1186/s12915-020-00838-9.
The ability of fungal cells to undergo cell-to-cell communication and anastomosis, the process of vegetative hyphal fusion, allows them to maximize their overall fitness. Previous studies in a number of fungal species have identified the requirement of several signaling pathways for anastomosis, including the so far best characterized soft (So) gene, and the MAPK pathway components MAK-1 and MAK-2 of Neurospora crassa. Despite the observations of hyphal fusions' involvement in pathogenicity and host adhesion, the connection between cell fusion and fungal lifestyles is still unclear. Here, we address the role of anastomosis in fungal development and asexual reproduction in Zymoseptoria tritici, the most important fungal pathogen of wheat in Europe.
We show that Z. tritici undergoes self-fusion between distinct cellular structures, and its mechanism is dependent on the initial cell density. Contrary to other fungi, cell fusion in Z. tritici only resulted in cytoplasmic mixing but not in multinucleated cell formation. The deletion of the So orthologous ZtSof1 disrupted cell-to-cell communication affecting both hyphal and germling fusion. We show that Z. tritici mutants for MAPK-encoding ZtSlt2 (orthologous to MAK-1) and ZtFus3 (orthologous to MAK-2) genes also failed to undergo anastomosis, demonstrating the functional conservation of this signaling mechanism across species. Additionally, the ΔZtSof1 mutant was severely impaired in melanization, suggesting that the So gene function is related to melanization. Finally, we demonstrated that anastomosis is dispensable for pathogenicity, but essential for the pycnidium development, and its absence abolishes the asexual reproduction of Z. tritici.
We demonstrate the role for ZtSof1, ZtSlt2, and ZtFus3 in cell fusions of Z. tritici. Cell fusions are essential for different aspects of the Z. tritici biology, and the ZtSof1 gene is a potential target to control septoria tritici blotch (STB) disease.
真菌细胞进行细胞间通讯和吻合的能力，即营养菌丝融合的过程，使它们能够最大限度地提高整体适应性。在许多真菌物种中的先前研究已经确定了几个信号通路对吻合的要求，包括迄今为止最好表征的柔软（So）基因，以及粗糙脉孢菌的 MAPK 途径成分 MAK-1 和 MAK-2。尽管观察到菌丝融合参与了致病性和宿主黏附，但细胞融合与真菌生活方式之间的联系仍不清楚。在这里，我们研究了吻合在小麦欧洲最重要真菌病原体小麦基腐病菌（Zymoseptoria tritici）中的真菌发育和无性繁殖中的作用。
我们表明，Z. tritici 在不同的细胞结构之间发生自我融合，其机制取决于初始细胞密度。与其他真菌不同，Z. tritici 中的细胞融合仅导致细胞质混合，而不会形成多核细胞。So 同源物 ZtSof1 的缺失破坏了细胞间通讯，影响了菌丝和芽生体的融合。我们表明，MAPK 编码基因 ZtSlt2（与 MAK-1 同源）和 ZtFus3（与 MAK-2 同源）的缺失突变体也无法进行吻合，证明了这种信号机制在物种间的功能保守性。此外，ΔZtSof1 突变体在黑化中受到严重损害，表明 So 基因功能与黑化有关。最后，我们证明了吻合对于致病性不是必需的，但对于分生孢子体的发育是必需的，并且其缺失会废除 Z. tritici 的无性繁殖。
我们证明了 ZtSof1、ZtSlt2 和 ZtFus3 在 Z. tritici 细胞融合中的作用。细胞融合对于 Z. tritici 的不同生物学方面都是必不可少的，而 ZtSof1 基因是控制叶枯病（STB）的潜在靶标。
Zotero 插件
