Studies On The Phylogeny Of White Rust Fungus In Xinjiang And Its Relationship With Host Evolution

White rust fungus is an obligate parasitic pathogenic oomycete of angiosperms worldwide,which can harm a variety of wild plants and agricultural and forestry cash crops.The most typical parasitic cruciferous oil crops can cause crop yields as high as 90% to 100%,causing huge economic losses to agricultural production.The effective identification and identification of white rust species is the basis for disease prevention and control.The early classification and identification of white rust fungi in my country were mostly based on morphological characteristics and host plants,resulting in extremely unclear definition of species,and the differences between species and hosts The relationship is still fuzzy.In recent years,the development of molecular systematics has provided an effective way for the effective identification of white rust species and the discussion of the relationship between species and hosts.However,research on white rust based on morphological characteristics,host range and molecular systematics is rarely reported.In this study,more than 130 samples of white rust pathogens were collected from in Xinjiang different altitudes,At the same time,the domestic collection specimens and the white rust specimens collected from Sichuan,Chongqing,Shanxi,and Yunnan were borrowed for reference.Based on morphological characteristics,host range,and molecular systematic analysis,the white rust fungi collected from Xinjiang are distributed in three genera: Albugo,Wilsoninia,and Pustula.The genus Albugo contains 6 species,Albugo arenosa,Albugo candida,and Albugo ipomoeae-panduratea,Albugo koreana,Albugo lepidii,of which Albugo arabidis is the new species reported in this study;Wilsoninia contains 4 species,Wilsoniana amaranthi,Wilsoniana bliti,Wilsoniana portulacae and the new species Wilsoniana xinjiangensis discovered in this study;Pustula contains 5 species,namely Pustula cancriniae,Pustula helianthicola,Pustula junggarensis,Pustula spinulosa and Pustula xinyuanensis.According to the morphological characteristics,describe each species in detail and compile a classification key.The phylogenetic tree of white rust and its host was constructed.Through the co-evolutionary system analysis,it was finally confirmed that the evolution stage of white rust and its host experienced 11 co-speciation events,1 replication event,2 replication and cross-host transmission events,8 loss events and 11 branch failure events.Albugo experienced 5 cooperative speciation events,1 replication event,1 replication and cross-host transmission event,8 loss events and 10 branch failure events.Pustula experienced four cospeciation events,one replication event and crosshost transmission event.Wilsoniana experienced three collaborative speciation events and one branch failure event.According to the results of correlation analysis,The results showed that there were different synergistic differentiation events among different genera,it is clear that the three events of co-speciation,loss and differentiation failure are the main pathways of speciation in the evolution of the parasitic system between white rust and host plants.