Systematic Study On Rinodina On The Qinghai-Tibet Plateau

The genus Rinodina(Physciaceae,lichenized Ascomycota)is of high biodiversity,with about 300 species worldwide,of which 51 species have been reported in China.Qinghai-Tibet Plateau is rich in biodiversity that 25 Rinodina species have been reported in this region,accounting for nearly half of the total species of the genus reported in China.However,due to the lack of systematic and taxonomic studies,the specific species composition of Rinodina in this region is still unclear.In this research,taxonomy and molecular systematics are combined to study the Rinodina and Dimelaena species in the Qinghai-Tibet Plateau region and its adjacent areas in China.Firstly,taxonomic methods were used to study over 300 Rinodina and Dimelaena specimens,of which the morphological and anatomic characteristics were observed and measured.Besides,spot tests and TLC methods were used to analyze the lichen characteristic chemicals.Secondly,molecular systematic methods were used.The apothecia or partial parts of thalli were extracted as molecular materials.Totally 140 DNA segments including 80 ITS,36 mtSSU and 24 nrLSU,were obtained by PCR amplification,and the phylogenetic analyses were performed by computer software such as Geneious,MAFFT,Sequence Matrix,Raxml,Mr Bayes and Figtree.In the present study,24 Rinodina species are reported in this region,including 1 new combination,4 new records in China and 3 expected new species,as well as 3 Dimelaena species,including 1 new combination and 1 expected new species.Besides,9 species and 1variety of Rinodina,and 1 species of Buellia,for which the holotype were collected from the Qinghai-Tibet Plateau or its adjacent areas,were studied,and the specimens from the holotype localities,the chemical information and related molecular sequences were obtained.Furthermore,2 new combinations,Rinodina sarcogynoides(H.Magn.)Q.Y.Zhong & Li S.Wang and Dimelaena setschwana Q.Y.Zhong & Li S.Wang,and 5 new recorded species for China,including R.cf.archaea,R.cf.bolanderi,R.cf.cacaotina and R.cf.pachysperma are reported in this study.This thesis provides a key to the Rinodina and Dimelaena species on the Qinghai-Tibet Plateau or its adjacent areas in China,as well as the detailed descriptions,morphologic and microscopic pictures,distributional diagrams and taxonomic discussions.Besides,on the basis of previous studies,the ascospore types of Rinodina are reclassified here that 14 ascospore types are identified,including Beltraminia-type,Bicincta-type,Bischoffii-type,Conradia-type,Dirinaria-type,Milvina-type,Mischoblastia-type,Orcularia-type,Pachysporaria-type,Physcia-type,Physconia-type,Polyblastidium-type,Submuriform-type and Tunnicata-type.The pictures,descriptions and Chinese names of these ascospore types are provided.Moreover,the phylogenetic analysis results based on concatenated ITS-mtSSU-nrLSU sequence matrix suggest that the genus Rinodina is a polyphyletic group belonging to Physciaceae.It shares a common ancestor with the genera Anaptychia,Heterodermia,Hyperphyscia,Phaeophyscia,Phaeorrhiza,Physcia,and Physconia,which are mainly composed of foliose,fruticose or squamulose lichen species.On the other hand,the genus Dimelaena is not in Physciaceae and not closed to Rinodina.The above results are consistent with the previous studies.This study provides a basis for the study on the biodiversity of Rinodina in China,the lichen flora of the Qinghai-Tibet Plateau and the phylogeny of the family Physciaceae.