关键词: 酸腐病菌；PacC；生物信息学；pH值；表达模式

Abstract: Studies have shown that Geotrichum citri-aurantii can adjust the pH of infection sites to enhance its pathogenicity, and PacC, a key transcription factor in the pH signal transduction pathway, plays an important role in fungal response to environmental pH changes, but the role of PacC in G. citri-aurantii remains unclear. In this study, two candidate PacC genes were annotated from the genome of G. citri-aurantii and analyzed by bioinformatics methods and their expression patterns under different pH conditions were also studied. The results showed that PacC1 and PacC2 belonged to the C2H2 protein family, and were closely related to the PacC of Penicillium digitatum. PacC1 and PacC2 had differences in chromosomal location, protein molecular mass and isoelectric point. Under in vitro conditions, G. citri-aurantii could adapt to a wide range of pH, and the optimal pH value was found to be 3.0. The expression of PacC1 and PacC2 was regulated by pH, and their expression trends were similar. Under in vivo conditions, the pH of sour rot lesions in ‘Miyagawa-wase’ mandarin fruit tissue at pH > 3.0 decreased significantly with the progression of the disease, while the pH of sour rot lesions in Eureka lemon fruit tissue at pH < 3.0 increased significantly, and the relative expression levels of PacC1 and PacC2 showed an increasing trend. In conclusion, it can be seen that the environmental pH affects the growth of G. citri-aurantii, which in turn regulates the environmental pH. Due to the differences in gene structure and physicochemical properties, the degree and mode of pH response are different between the two PacC genes. They play an important role in the wide pH adaptability of G. citri-aurantii and in accelerating its infection process in citrus fruit.

Key words: Geotrichum citri-aurantii; PacC; bioinformatics; pH; expression pattern