image: Comparison of trap formation and nematocidal activity of the wild-type (WT) and mutant strains. A, Trap formation induced with nematodes for 48 h post-induction (hpi). B, Observation of infecting hyphae at 48 hpi. H indicates infecting hyphae. C, The number of nematode-infesting hyphae. D, Traps produced at 24 and 48 hpi. E, Percentages of nematodes captured by WT and mutant strains at 12, 24, 36, and 48 hpi. F, Trap morphology of WT, ΔAopkc, and ΔAoswi6 strains. Arrows indicate ED bodies in trap cells. The data are presented as the mean ± SD of three independent experiments. *p < 0.05, **p < 0.01, and ***p < 0.001 vs. WT. Photo and data analysis: Meihua Xie. view more
Credit: ©Science China Press
This study is led by Prof. Ke-Qin Zhang and Dr. Jinkui Yang (State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University). In this study, three components of the CWI signaling pathway were characterized in A. oligospora using gene disruption and multi-omics approaches. The analyses of phenotypic traits and metabolic profiles conducted in this study indicated that AoPKC, AoSLT2, and AoSWI6 play important roles in hyphal growth and development, conidiation, stress response, CWI, secondary metabolism, trap formation, and pathogenicity of A. oligospora (see image below). Importantly, the ΔAoslt2 mutant had a phenotype and metabolic profile distinct from those of the ΔAopkc and ΔAoswi6 strains, which were similar to each other.
The researchers further predicted and analyzed the regulatory network of AoSWI6 through String (http://string-db.org/) and yeast two hybrid (Y2H), and found that AoPKC interacted with AoBCK1 and AoSWI6, whereas AoSLT2 interacted with AoCDC2 and AoSWI6, suggesting that AoPKC can directly regulate AoSWI6 in A. oligospora.
In addition, the researchers compared the transcriptome profile between the wild-type strain and ΔAoswi6 mutant strains, and the disruption of Aoswi6 resulted in the upregulation of genes associated with DNA repair (mismatch, base excision, and nucleotide excision repair), which indicates that AoSWI6 plays an important role in maintaining DNA stability and repair in A. oligospora.
“Our results suggest that PKC-SWI6 signaling plays a crucial role in growth, development, and pathogenicity of A. oligospora, which deepens our understanding of the regulatory mechanism of asexual development，trap morphogenesis and lifestyle transition in nematode-trapping fungi. ” Yang says.
See the article:
PKC-SWI6 signaling regulates asexual development, cell wall integrity, stress response, and lifestyle transition in the nematode-trapping fungus Arthrobotrys oligospora
https://doi.org/ 10.1007/s11427-022-2118-0
Journal
Science China Life Sciences