Isolation Of Mercury-Resistant Fungi And Their Mercury-Resistant Mechanism

Due to the rapid development of industry and mining,soil heavy metal pollution is becoming increasingly serious,and the situation in China is particularly severe.Mercury(Hg)is a highly toxic global heavy metal pollutant with strong neurotoxicity and teratogenic effects,and has obvious accumulation effects and genotoxicity.The problem of soil mercury pollution has become a worldwide environmental and health problem.In this study,mercury-containing medium were used to screen out mercury-resistant fungi,based on the biovolatilization of mercury,the potential of mercury-resistant fungi were selected.The mercury-resistant fungi with potential application were selected,and the mercury-resistant mechanism of fungi was revealed by the method of whole transcriptome,in order to provide a theoretical basis for the application of mercury-resistant fungi to the restoration of mercury-contaminated environments.In this study,five anti-mercury fungi were isolated from the soil of Dongchuan open-pit mine in Yunnan Province using LB medium containing 20 mg/Lof mercury.According to morphology and ITS sequence analysis,the five fungi(DC-F8,DC-F9,DC-F11,DC-F15,DC-F16)were identified as Aspergillus niger,Aspergillus sydowi,Penicillium janthinellum,Fusarium solani and Penicillium halotolerans.The application characteristics of five fungi were analyzed.In the 5 mg/L mercury-containing LB liquid medium,the volatilization rate of DC-F11 was up to 40.6%.and the total removal rate was 85.0%.Secondly,the volatilization rate of the DC-F9 was 36.8%,the total removal rate was 95.2%.By pot experiment,adding fungi and planting wheat in mercury-contaminated soil confirmed that it could reduce the toxicity of mercury on plants.According to the high-throughput sequencing technology,the transcriptome data of fungi under the two treatments of mercury-fed culture and no mercury control were analyzed.Through in-depth study of differential gene expression and distribution,the mercury-resistant mechanism of fungi was obtained.The mercury-resistant mechanism of fungi is mainly based on two kinds:one is based on the detoxification mechanism of mer,and the other is based on the detoxification mechanism of sulfur metabolism.