The role of vegetative cell fusions in the lifestyle of the wheat fungal pathogenZymoseptoria tritici

Abstract

26The ability of fungal cells to undergo cell fusion allows them to maximize their overall 27 fitness. In this study, we characterized the role of the so gene orthologous in 28Zymoseptoria tritici and the biological contribution of vegetative cell fusions in the 29 lifestyle of this latent necrotrophic fungus. Firstly, we show that Z. tritici undergoes 30 self-fusion between distinct cellular structures and its mechanism is dependent on the 31 initial cell density. Next, the deletion of ZtSo resulted in the loss of cell-to-cell 32 communication affecting both hyphal and germlings fusion. We show that Z. tritici 33 mutants for MAP kinase-encoding ZtSlt2 (orthologous MAK-1) and ZtFus3 34 (orthologous MAK-2) genes also fail to undergo self-stimulation and self-fusion, 35demonstrating the functional conservation of this signaling mechanism across 36 species. Additionally, the DZtSo mutant was severely impaired in melanization, which 37 leads us to identify a trade-off between fungal growth and melanization. Though it has 38 been proposed that So is a scaffold protein for MAP kinase genes from the CWI 39 pathway, its deletion did not affect the cell wall integrity of the fungus. Finally, we 40 demonstrated that anastomose is dispensable for pathogenicity, but essential for the 41 fruiting body development and its absence abolish the asexual reproduction of Z. tritici. 42Taken together, our data show that ZtSo is required for fungal development, while 43 vegetative cell fusions are essential for fungal fitness. 44 45 46 47 48 49 50

The apoplastic space of two wheat genotypes provide highly different environment for pathogen colonization: Insights from proteome and microbiome profiling

“…Plant inoculations were performed as previously described (28). In brief, the IPO323 strain was grown in 50 mL of YMS medium in a rotary shaker for five days at 18°C.…”