
The author explores the crucial role of the TOR signaling pathway in regulating vegetative development, aflatoxin biosynthesis, and pathogenicity in Aspergillus flavus through the identification and characterization of key genes involved.


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The target of rapamycin (TOR) signaling pathway is highly conserved and plays a crucial role in diverse biological processes in eukaryotes. However, the underlying mechanism of the TOR pathway in A. flavus remains elusive. In this study, we identified and characterized seven genes encoding various components of the TOR pathway in A. flavus, and investigated their biological function. The FK506-binding protein Fkbp3 and its lysine succinylation are important for aflatoxin production and rapamycin resistance. As a significant downstream effector molecule of the TorA kinase, the Sch9 kinase regulates aflatoxin B1 (AFB1) synthesis, osmotic and calcium stress response in A. flavus, and this regulation is mediated through its S\_TKc, S\_TK_X domains, and the ATP binding site at K340. We also showed that the Sch9 kinase may have a regulatory impact on the high-osmolarity glycerol (HOG) signaling pathway. TipA, the other downstream component of the TorA kinase, plays a significant role in regulating sclerotia formation and cell wall stress response in A. flavus . The members of the TapA-phosphatase complexes, SitA and Ppg1, are crucial for various biological processes in A. flavus , including vegetative growth, sclerotia formation, AFB1 biosynthesis, and pathogenicity. Furthermore, we showed that SitA and Ppg1 are involved in regulating lipid droplets (LDs) biogenesis and cell wall integrity (CWI) signaling pathways. In addition, another phosphatase complex, Nem1/Spo7, plays critical roles in hyphal development, conidiation, aflatoxin, and lipid droplets biogenesis. This study provides an important insight into the regulatory network of the TOR signaling pathway and the molecular mechanism of aflatoxin biosynthesis in A. flavus .

### Competing Interest Statement

The authors have declared no competing interest.

The TOR signaling pathway regulates vegetative development, aflatoxin biosynthesis, and pathogenicity in Aspergillus flavus

the-role-of-tor-signaling-pathway-in-a-flavus-development-and-aflatoxin-biosynthesis


The Role of TOR Signaling Pathway in A. flavus Development and Aflatoxin Biosynthesis


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Slu7 in Cryptococcus neoformans plays a crucial role in regulating nuclear positioning during mitosis through efficient RNA splicing.


The position of the nucleus before it divides during mitosis is variable in different budding yeasts. Studies in the pathogenic intron-rich fungus Cryptococcus neoformans reveal that the nucleus moves entirely into the daughter bud before its division. Here, we report functions of a zinc finger motif containing spliceosome protein C. neoformans Slu7 (CnSlu7) in cell cycle progression. The budding yeast and fission yeast homologs of Slu7 have predominant roles for intron 3’ splice site definition during pre-mRNA splicing. Using a conditional knockdown strategy, we show CnSlu7 is an essential factor for viability and is required for efficient cell cycle progression with major role during mitosis. Aberrant nuclear migration, including improper positioning of the nucleus as well as the spindle, were frequently observed in cells depleted of CnSlu7. However, cell cycle delays observed due to Slu7 depletion did not activate the Mad2-dependent spindle assembly checkpoint (SAC). Mining of the global transcriptome changes in the Slu7 knockdown strain identified downregulation of transcripts encoding several cell cycle regulators and cytoskeletal factors for nuclear migration, and the splicing of specific introns of these genes was CnSlu7 dependent. To test the importance of splicing activity of CnSlu7 on nuclear migration, we complemented Slu7 knockdown cells with an intron less PAC1 minigene and demonstrated that the nuclear migration defects were significantly rescued. These findings show that CnSlu7 regulates the functions of diverse cell cycle regulators and cytoskeletal components, ensuring timely cell cycle transitions and nuclear division during mitosis.

### Competing Interest Statement

The authors have declared no competing interest.

Cryptococcus neoformans Slu7 ensures nuclear positioning during mitotic progression through RNA splicing

Cryptococcus-neoformans-Slu7-Role-in-Nuclear-Positioning-During-Mitosis


Cryptococcus neoformans Slu7 Role in Nuclear Positioning During Mitosis
