Taxonomy And Phylogenetic Study Of Amygdalaria And Porpidia From China

Amygdalaria and Porpidia belong to Lecideaceae,Lecideales,Lecanoromycetes,Ascomycota.They are important components of crustaceous lichens.Before this study,8 species of Amygdalaria and 47 species of Porpidia were reported in the world,3 species of Amygdalaria and 20 species of Porpidia were reported in China.The two genera share many common features,including: thallus crustose;apothecia lecideine,usually sessile to immersed;paraphyses strongly branched and anastomosing;asci clavate,8-spored,Porpidia-type;ascospores simple,colourless,halonate,usually ellipsoid;conidia simple,colourless,bacilliform.According to the current definition of the two genera,the main differences between them are as follows: 1.The spores of Amygdalaria are larger than Porpidia;2.Amygdalaria with cephalodium;3.The tops of the paraphysis of Amygdalaria are usually moniliform or submoniliform;4.Compared with Porpidia,Amygdalaria with higher hymenium and thicker exciple.However,in our previous investigation,we found that the characteristics of some species were intermediate between the two genera,and preliminary molecular phylogenetic studies showed that Amygdalaria were nested within Porpidia.The two genera,especially Porpidia,are widely distributed in China.However,most of taxonomic studies on them,including the most recent published work,have been based solely on comparisons of morphological features and secondary compounds.Only a few molecular phylogenetic studies focused on them separately.So,the genera delimitations,species delimitations and phylogenetic relationships between these two genera have remained problematic.Following traditional classification methods(studies on the type specimens,morphology,anatomy,chemistry and geography)and genotypic study(using sequences from ITS,mt SSU,nr LSU,RPB1 and RPB2)to test species boundaries,the present project will ascertain the concept of species and genera,and establish a reasonable and natural classification system.And the results are as follows:1.Based on the morphological features,anatomical characteristics,and the location in phylogenetic tree,Porpidia can be divided into four groups(Porpidia macrocarpa group,P.speirea group,P.albocaerulescens group,P.chungii group).In future studies,the species can be preliminarily divided according to the width of excipular hyphae and secondary metabolites by traditional classification methods,and further studies can be conducted on the basis of four groups.2.For the first time,multiple gene loci(ITS,mt SSU,nr LSU,RPB1,RPB2)were connected and molecular phylogenetic analysis of two genera of lichens was conducted by using maximum likelihood method and Bayesian inference.The results showed that Amygdalaria could form a good independent cladism,but the cladism was nested within Porpidia.This study combined molecular systematic analysis with traditional taxonomy and suggested that the scope of the genus Porpidia should be expanded to include the genus Amygdalaria.It may also exist as a subgroup of the macrocarpa group(sister taxa to the cinereoatra subgroup).3.The result of the geographical distribution of lichens in China showed that Porpidia is a widespread genus in China,especially in high altitude areas,and 76% of the species are distributed at the lowest altitude of more than 1000 m,among which P.albocaerulescens is widely distributed.It is widely distributed in 22 provinces(municipality)of China and has strong adaptability to the environment.It can be seen from the distribution map of species quantity in each province that Yunnan province has the highest species richness,followed by Sichuan province.Of the species found and reported in China,68% were found in Yunnan province and 44% in Sichuan province.It laid the foundation for further research on species diversity of lichen in this genus.4.One new species and two new recorded species of Amygdalaria,four new species,two new recorded species and one suspected species of Porpidia were reported in the process of studying the species diversity of Amygdalaria and Porpidia.This study has improved the research on Amygdalaria and Porpidia in China,proved the species composition and distribution characteristics of two genera,providing basic data for compiling lichens in China,providing ideas and foundation for further study Amygdalaria and Porpidia.