The Phylogeny Of Didymiaceae In Typical Ecological Environments Of China

Myxogastrea is a special group of the Protozoa,they had both characters of fungi and protozoa.Myxomycetes can be found in humid environment and widely distributed globally.They usually live on rotten wood,dead branches,leaves and so on.Didymiaceae belongs to Physarales,Physarales is the largest order of Myxomycetes,including 41% of Myxomycetes species.Till now,208 species have been reported which belong to 7 genera of Didymiaceae,while 81 species belonging to 6 genera of Didymiaceae have been recorded in China,accounting for 38.94% of the world reports.Majority of the Didymiaceae species have not been reported in China,and more investigation collection is still needed.We performed a comprehensive study of Didymiaceae using morphological and molecular methods.From July 2016 to December 2018,1546 specimens of Myxomycetes were collected from Xizang,Heilongjiang,Jilin and Liaoning Province,of which 385 belong to Didymiaceae.A total of 36 species belonging to 5 genera of Didymiaceae were identified.Among them,3 were newly recorded of Didymium species in China,Didymium inconspicuum Nann.-Bremek.& D.W.,Didymium karstensii Nann.-Bremek.,and Didymium rugulosporum Kowalski.Three new recorded species in Jilin Province: Diderma cinereum Morgan,Didymium eximium Peck,and Didymium applanatum Nann.-Bremek.;two new recorded species in Liaoning Province: Diderma globosum Pers.and Didymium difforme(Pers.)Gray;six new recorded species in Heilongjiang Province: Diderma radiatum(L.)Morgan,Didymium anellus Morgan,Didymium orthonemata H.W.Keller & T.E.Brooks,Didymium ovoideum Nann.-Bremek.,Didymium trachysporum G.Lister and Didymium verrucosporum A.L.Welden;five new recorded species in Gansu Province: Diderma radiatum,Didymium anellus,Didymium bahiense Gottsb.,Didymium intermedium J.Schr?t.and Didymium ovoideum;three new recorded species in Yunnan Province: Didymium bahiense,Didymium eximium and Didymium minus(Lister)Morgan.Detailed information of Myxomycetes of Didymiaceae such as specimen number,habitat and distribution area were recorded.Combing our data and data fromliterature,we compiled the directory of Didymiaceae in China,we analyzed the distribution of Didymiaceae in China,and listed the new national records of Didymiacea.Didymiaceae species are most abundant in the Jilin Province and the subtropical zone.Using 36 SSU rRNA sequences from 17 species belonging to 4 genera of Didymiaceae,the phylogenetic relationship of the Didymiaceae was carried out by the Bayesian method.Phylogeney analysis showed that Diderma globosum located at the front and was in a separate branch.It was presumed that Diderma was the first to differentiate and Didymium was a relatively advanced group.Diachea bulbillosa(Berk.& Broome)Lister and Didymium leoninum Berk.& Broome is on the same branch,and their location is consistent with the results of morphological classification.Didymium anellus and Didymium inconspicuum are on the same small branch,and their common morphological features are sessile sporocarps and columella absent;Didymium eximium,Didymium iridis(Ditmar)Fr.,Didymium verrucosporum and Didymium squamolosum(Alb.& Schwein.)Fr.& Palmquist are on the same branch,and their common morphological features are stalked sporocarps and the columella significant.On this branch,it is clearly separated according to the presence or absence of the stalk and columella.There are two small branches in the genetic distance of Didymium nigripes(Link)Fr..Samples collected from Tibet gathered together,samples collected from Heilongjiang and Jilin Province gathered together,and form sister groups with the support of higher bootstrap.There is no significant correlation in genetic distance between different substrata of D.nigripes.