| Species of Diaporthe have broad host ranges and are widely distributed,occurring as plant pathogens,endophytes or saprobes,which can cause various diseases such as dieback,cankers and leaf spots.Diaporthe species are responsible for the growth weekness or die of plant hosts,which can lead to significant economic and ecological losses.Species in Diaporthe were originally identified based on morphological characters(especially asexual morph),cultural characteristics and host association.However,more than one species of Diaporthe can often be recovered from a single host,while one species can be associated with many different hosts.Host association has been shown to bear little significance when referring to phylogenetic relationships.With the increase of new species,the utility of morphology has generally been shown to be of little use for species identification as there is considerable plasticity of the characters.Additionally,most species were recorded without available type speciemens and ex-type strains,leading to confusions of identification.Furthermore,the poor taxonomic system makes great difficulties to species identification and the control of plant diseases.Therefore,the present study aims at collecting fresh specimens to reveal species boundaries and clarify host ranges based on morphology and phylogeny.Totally 214 specimens were collected from fifteen provinces of China.Morphological observation includes the features of fruit bodies,conidia and ascospores.Meanwhile,phylogenetic analyses were performed based on MP,ML and Baysian methods,combined the rDNA internal transcribed spacer(ITS)region,calmodulin(cal),histone H3(his3),partial translation elongation factor 1-alpha(tefl-α)and beta-tubulin(tub2)genes to analyze the relationship among Diaporthe.The main results in the current study are as follows:1.Described the morphology,distribution and host ranges of 38 Diaporthe species from host plants of 22 families in China.Of which twenty-one new species have been published,i.e.,D.acerigena、D alangii、D.betulae、D.betulicola、D.betulina、D.caryae、D.cercidis、D.chensiensis、D.cinnamomi,D.conica、D.fraxinicola、D.juglandicola、D.kadsurae、D.padina、D.rostrata、D.sambucus、D.schisandrae、D.sennae、D.sennicola,D.tibetensis、D.ukurunduensis.The most common species,D.eres,was found in Araliaceae,Ericaceae,Fagaceae,Juglandaceae,Meliaceae,Rosaceae and Salicaceae plants,distributed in Beijing,Jiangsu,Jiangxi,Henan,Heilongjiang,Ningxia and Shandong Province.2.Determined the morphological classification standard of Diaporthe at the species level.The classification of sexual morph is mainly based on the features of perithecia.The arrangement,morphology and size of ascospores in asci are an important basis for classification.For asexual morph,the presence or absence of central column and black conceptacle,the type of conidiomata,branching characteristics of conidiophores,the shape and size of conidia are mainly used as classification standard.Besides,cultural characteristics and hosts are taken as the auxiliary classification basis.3.Analyzed the relationships of Diaporthe species based on polygenic phylogeny.The current results showed that ITS,cal,his3,tefl-a and tub2 genes have significant inter-and intra-distance,which can be used for rapid identification to Diaporthe species as the DNA barcoding candidate.4.The polygene molecular database was conducted,which is suitable for the classification of Diaporthe eres species complex.The current results indicated that cal-tef1-α-tub2 genes have significant inter-and intra-distance,which can be used for rapid identification to Diaporthe eres complex. |
