Biodiversity Of Desert Plant Pathogenic Fungi And Molecular Phylogenetics Of Partial Groups In Pan-Junggar Basin

The Junggar Basin,which is located in the hinterland of the Eurasian Continent,is a typical temperate arid desert area,and is a biological transition zone between Europe and Asia.This area contains unique biological resources,but the ecological environments are extremely fragile and plant pathogens are becoming a potential threat to them.Systematic survey of desert plant pathogenic fungi in Junggaer Basin and its surrounding areas had been conducted for five times from June 2011 to October 2016.Four hundred species have been confirmed from a total 3298 collections of desert plant pathogenic fungi,which belong to 23 families and 65 genera,among of them,two families,ten genera and 34 species belonging to Oomycota;14 families,35 genera and 160 species belonging to Ascomycota;seven families,23 genera and 196 species belonging to Basidiomycota.Four genera including Puccinia,Uromyces,Erysiphe and Septoria belonged to the dominant genera which contains 100,38,31 and 29 species,respectively.In this study,the molecular phylogenetic analysis of species on Albuginace,Phragmidium,Septoria and allied genera were conducted,and Alternaria kareliniae and Puccinia tulipae were thought to be a potential threat to the desert ecology,agricultural and forestry production by pathogenicity tests and field investigations.Based on morphology and molecular analysis,two new genera,five new combinations,15 new species,26 new record spcies and re-confirmed 3 species to China were identified.They are new genera: Parasphaerulina B.Xu,S.H.Zhang & Z.D.Jiang,Yunchangia L.Guo & B.Xu;New species: Pustula cancriniae B.Xu & Z.D.Jiang,Pus.junggarensis B.Xu & Z.D.Jiang,Pus.xinyuanensis B.Xu,Y.J.Choi & Z.D.Jiang,Erysiphe acantholimonis J.G.Song,B.Xu & H.D.Shin,Neodidymelliopsis cynanchi B.Xu,S.H.Zhang & Z.D.Jiang,Neoseptoria tienshanensis B.Xu & Z.D.Jiang,Parasphaerulina alhagicola B.Xu,S.H.Zhang & Z.D.Jiang,Septoria convolvulicola B.Xu & Z.D.Jiang,Sep.kareliniae B.Xu & Z.D.Jiang,Sep.oxytropisglabrae B.Xu & Z.D.Jiang,Alternaria kareliniae B.Xu & Z.D.Jiang,Ph.rarispinosum B.Xu,M.Ebinghaus & D.Begerow,Ph.xinjiangensis B.Xu,M.Ebinghaus & D.Begerow,Ph.fructigenum B.Xu,M.Ebinghaus & D.Begerow,Yunchangia puccinelliae L.Guo & B.Xu;New combinations: Caryophylloseptoria dimera(Sacc.)B.Xu & Z.D.Jiang,Par.caraganae(Hennings)B.Xu & Z.D.Jiang,Par.thermopsidis(Murashk)B.Xu,S.H.Zhang & Z.D.Jiang,Sphaerulina caraganae(Henn.)B.Xu,S.H.Zhang & Z.D.Jiang,Sphaerulina scutellariae(Thüm.)B.Xu & Z.D.Jiang;New record species to China: Albugo mauginii,Alb.lepidii,Pseudoidium tribuli,Cercospora armoraciae,Passalora fraxini,Pas.scariolae,Sep.aegopodii,Sep.anchusae,Sep.leucanthemi,Sep.cerastii,Sep.chenopodii,Sep.epilobii,Sep.salvia,Sep.sedi,Sep.senecionis,Sep.sii,Sph.hyperici,Sph.tirolensis,Puccinia cousiniae,Puc.frigida,Puc.reaumuriae,Puc.tulipae,Uromyces acantholimonis,Aecidium cannabis,Aec.pedicularis,Uredo goodyerae;Re-confirmed species: Ph.violaceum,Ph.mexicanum and Puc.Malvacearum;Twenty-seven newly recorded hosts of plant pathogenic fungi were found.The phylogeny analysis of Albuginaceae was carried out based on the cox2 sequences.It was further proved that Albugo,Wilsoniana and Pustula were monophyletic groups and host specificity obviously.Pustula was found on Convolvulaceae for first time in this study,which changed the opinion point that Pustula was not parasitic on Convolvulaceae.According to the phylogeny analysis of Albuginaceae and its relationship with host,the possible evolutionary process of Albuginaceae is proposed.Wilsoniana and Pustula are derived from Albugo;The evolution of host plants passed through gradually from Brassicaceae to Amaranthaceae and then to Asteraceae.During the evolutionary process,they may have many times for host jumps including the parasitism of Albugo from Brassicaceae to Leguminocae and Pustula from Convolvulaceae to Asteraceae.The phylogenetic analysis of Phragmidium based on LSU sequences showed that Phragmidium was a monophyletic group.According to Phragmidium associated with their hosts,the evolution process of Phragmidium is accompanied by frequent hybridization events of Rosaceae showed a reticulate evolutionary lineage;coevolution is at least on a certain taxonomic level detectable,and host jumps occurring rather frequently and playing an important role in the evolution of Phragmidium.We suppose that this reticulate history is blurring more tight co-evolutionary patterns in this host-pathogen system.To clarify the classification of Septoria and allied genera from Xinjiang,morphological observatics were combined with the multi-locus phylogenetic analyses based on ITS,LSU,RPB2,EF-1? and ?-tubulin.The results showed that the delimitation of EF-1?,?-tubulin and RPB2 in species and genera level was higher than ITS and LSU.The combination of the five fragments described above could well elucidate therelationships between Septoria and allied genera,and also shows that Leptothyrium belongs to Mycosphaerellaceae,rather than Sphaeropsicaceae.