Effects And Application Of Arsenic Pollution On Rice Root-related Functional Microorganisms

With the rapid development of mining industry in China,arsenic pollution in the environment is becoming more and more serious.High arsenic content in contaminated soil can poison plants,cause serious harm to their growth and development,and reduce crop yield.As the main food crop,rice is also the main route of arsenic exposure.The toxicity and migration capacity of arsenic are closely related to its species and form,as well as the transformation of microorganisms.As a hot spot of direct contact with pollution sources,functional microorganisms in rice roots are particularly important.In addition,rice growth is closely related to irrigation management and control.Under different irrigation conditions,the response mechanism of rice root microorganisms to pollutants was obviously different.However,there are few reports on the changes of rice root and microbial diversity in different growth stages,as well as the dynamic response of microorganisms to arsenic.Therefore,in order to explore the response mechanism of rice root-related microorganisms to arsenic under different REDOX conditions,this paper carried out a study on arsenic contaminated sites based on geochemical analysis,molecular biology analysis,in-situ soil pot experiment and microbial genome analysis.The results are as follows:(1)Arsenic and antimony pollution significantly changed the composition of in situ microbial communities in rice terraces with different arsenic pollution levels.The dominant microbial communities in contaminated soil mainly included Pedosphaeraceae,Nitrosomonadaceae,Halieaceae and Latescibacterota.Based on the predictive analysis of metabolic function,these key groups have the potential to detoxify arsenic and antimony,thus making a potential contribution to the carbon fixation process in the field,and further providing theoretical support for the study of the response mechanism of bacteria to arsenic and antimony and ecological remediation of arsenic and antimony pollution.(2)Different REDOX conditions in rice cultivation are one of the important factors affecting arsenic content in rice grains.As(III)can be easily absorbed by rice roots and transported upward after transformation,which may be the reason for the increase of arsenic uptake by rice under waterlogging conditions.Therefore,preventing arsenic reduction may be an effective method to reduce arsenic content in rice grains.The decrease of arsenic content in rice planted under non-flooding condition was mainly related to the relatively high soil REDOX potential.This study further revealed that although rice yield was significantly reduced under non-waterlogging conditions,arsenic content in plants and rice was significantly reduced compared with waterlogging treatment.Differences in REDOX conditions had limited effects on microbial community structure in rice rhizosphere soil,but had significant effects on selective colonization of endophytic bacteria in plant roots.Streptomyces,Propionivibrio and Actinoplanes were significantly enriched in the rice roots of the two treatments.Macrofactor box predicted that they had arsenic oxidation and arsenic reduction abilities,which might indirectly prevent arsenic transport in rice roots.Through investigation,this paper compared the arsenic pollution conditions of the three pieces of different microbial communities and established through potted plant experiment and research of arsenic pollution in soil under different moisture management and the physical and chemical properties,rice arsenic determination and comparison and analysis of the microbial community,and find several potential of arsenic and may affect the arsenic in rice root morphology changes of microorganisms,It can provide some scientific basis and application research for arsenic contaminated rice field.