A Preliminary Functional Study of The NecArl8 Gene in Neopestalotiopsis cubana

Abstract: [Objective] Neopestalotiopsis cubana is the major pathogen responsible for leaf spot and fruit concentric ring rot of Psidium guajava (guava). Arl8 (ADP-ribosylation factor-like protein 8) protein belongs to the Arf (ADP-ribosylation factor family) superfamily, and is associated with lysosomal processes including localization, trafficking, and fusion. Currently, the function of Arl8 in phytopathogenic fungi remains unclear.[Methods]To elucidate the function of Arl8 in N. cubana, one Arl8 gene was identified from the genome of N. cubana and named NecArl8. The CRISPR/Cas9 genome editing technology was employed to construct the NecArl8 gene knockout mutant (ΔNecArl8) and the complemented strain (ΔNecArl8-C).[Results] It was observed that the conidiation capacity, tolerance to salt and osmotic stresses, and pathogenicity of ΔNecArl8 were significantly decreased, while the tolerance to oxidative stress was significantly increased. RNA-seq sequencing was conducted on ΔNecArl8 and the wild-type strain, followed by the analysis of Differentially Expressed Genes (DEGs).[Conclusion] It was revealed that NecArl8 may affect the pathogenicity of N. cubana to guava by regulating transmembrane transport function. This study lays a theoretical foundation for exploring the pathogenic mechanism of N. cubana and developing new control strategies.