Studies On The Systematics Of The Genus Paecilomyces Bainier In China And The Pathogenicity Of Some Isolates

1. The investigation and morphological studies of the genus Paecilomyces inChina.It is significantly important to investigate the biodiversity of Paecilomyces and theirgeographical distribution in china.Based on the taxonomic references, the characters and history of the genus Paecilomyces wassummarized. The studies were supported by two National Natural Science Fundation of China. theresults are as follows:[1] Author thought that the Paecilomyces genus contained sixty-four valid units by collectingand studying the references on 125 Paecilomyces species published in the whole world. Amongthem, entomopathogenic species were up to 53.1％of all members in the genus which showed thatPaecilomyces was really important resources of entomopathogenic fungi.[2] The database of known Paecilomyces species was established by Access software basedon morphological characters. This database was an important foundation for establishing the Deltasystem of entomogenous Paecilomyces species which was convenient and fast to classify theunknown isolates.[3] Systematic study of Paecilomyces in China was carried out. From 32 provinces and citiesin China, 298 Paecilomyces isolates were isolated from 975 soil samples and 164 infected insects.Along with the specimens deposited in the Institute of Fungus Resources at Guizhou University, atotal of 313 Paecilomyces isolates were observed and studied. Based on phenetic characters, 39species in China which compose 60.9％of the all species of genus Paecilomyces in the wholeworld were described in details. A diversity of Paecilomyces has been showed in China. Amongthose, 20 known species, 3 new records, 1 new combination and 15 new species。In addition, four new reports of related genus were isolated. They were Mariannaea elegans(Corda) Samson var. punicea Samson,Chrysosporium indicum (H.S. Randhawa & R.S. Sandhu)Garg,Chrysosporium lobatum Scharapov and Tolypocladium nubicola Bissett.There were also some intercalary strains between the genus Paecilomyces and its alliesincluding P.sp A7-1,P.sp A17-2,P.sp A18-1,P.sp A19-3,P.sp A40-1,P.sp A43,P.sp A62-1,P.sp DH3-1,P.sp LN2-9,P.sp 3'29-1 and P.sp D23-1. Their classification need to rely on themolecular technique.[4] Paecilomyces spp. were widely distributed in China. The Paecilomyces speciesdescribed in China composed 60.9％of the whole genus. Paecilomyces strains were isolated fromvarious habits such as soils, plants and infected insects. As far as host was concerned, they canparasitize the imago, larvae or pupae of various insects such as Leptoptera, Coleoptera, Hemiptera,Hemenoptera and other animals such as nematodes and spiders. However, different species hadobvious differences in distribution. For example, P. lilacinus and P marquandii can be isolatedfrom almost all soils, while P.nostocoides and some monophialidic species were rare.From the results, the check rate of strains in the South was higher than that in the North.Further, the check rate from soil samples was higher than other habits, which showed that the soilis the main habit of microorganisms and new species.2. The application studies of Delta system on entomogenous Paecilomycesspecies in China.Based on the access database of phenetic characters, the Delta system for twenty-four entomogenous Paecilomyces species in China were establish as follows:[1] Establishment of Delta system for entomogenous Paecilornyces species in China. Thissystem was the foundation to expand its function.[2] Automatic realization of key of entomogenous Paecilomyces species in China.Accomplishment of natural description of entomogenous Paecilomyces species in China.Establishment of distance matrix and phenetic tree of entomogenous Paecilomyces species inChina. Realization of interactive automatic identification among entomogenous Paecilomyces spp.3. Studies on the molecular phylogenetics of Paecilomyces spp. in ChinarDNA sequences from the strains under this study and their allies in Genbank were aligned.The phylogenetic trees were inferred by using Neighour-joining method (NJ), Most parsimonymethod (MP) and unweighted pair-group method with arithmetic mean (UPGMA) in Mega3.1 andPAUP4b 10 with 1000 bootstrap replications.[1] Molecular identification for new Paecilomyces spp.Based on the ITS 1-5.8S-ITS2 rDNA sequences of our new species and their allieslownloaded by blast in Genbank, the phylogenetic tree was infered. The following new specieswere supported by both phyiogenetic tree and morphological characters:P tenuis Y.F.Han & Z.Q.Liang, P. purpurseus Z.Q.Liang & Y.F.Han, P. verticillatusZ.Q.Liang, Z.Li & Y.F.Han, P cylindricosporus Z.Q.Liang & Y. F. Hart, P huaxiensis Z.Q.Liang& Y.F.Han and P parvosporus Y.F.Han & Z.Q.Liang[2] Establishment of a new genus—Taifanglan Z.Q.Liang, Y.F.Han & H.L.ChuBased on ITS 1-5.8S-ITS2 and 18S rDNA sequeces of some Paecilomyces species and theirrelated species including eight monophialidic species isolated from soil samples, the phylogenetictree was constructed. The results showed that eight monophialidic species had close relations withSordariales. The results of morphological characters and molecular phylogenetic analysis showedthe monophialidic species were distinguished. We therefore propose to establish a new genus—Taifanglan. There were eleven members in the new genus, including three new species and eightnew combination. We also described the characters of the new genus.[3] Studies on the genetic diversity of Paecilomyces cateniannulatus.Nineteen sequences consisted of sixteen strains collected by authors and three from Genbankwere aligned and used for constructing phylogenetic trees by NJ and MP in PAUP4b10. Theresults showed that these strains of P. cateniannulatus had greatly genetic diversity based on theITS 1-5.8S-ITS2 rDNA sequences. Moreover, the genetic differences had certain relativity with thegeography.[4] Molecular phylogenetic analysis ofPaecilomyces spp. in China.Based on the ITS 1-5.8S-ITS2 rDNA sequences of sixty-one Paecilomyces strains and theirrelated species, the phylogenetic tree was constructed. The results of molecular analysis showedthat the genus Paecilomyces were polyphyletic across two subclasses, Sordariomycetidae andEurotiomycetidae and two orders, Hypotiales and Eurotiales. Within the Eurotiales, Paecilomyceswas momophyletic. Within the Hypocreales, Paecilorayces spp. were polyphyletic, acrossClavicipitaceae and Hypocreaceae. From the molecular analysis, oringin temperature of specieswas one of main characters.[5] Molecular identification of some intercalary strains.Phylogenetic tree was constructed used ninety-three Paecilomyces strains and other relatedgenus such as Penicillium, Talaromyces, Byssochlamys and Aphanoascus. The molecular analysis supported the establishment of the three new species and the strains A 18.1, LN2.9, A19.3, A40.1and H3.1 were regarded as new units of Paecilomyces. strain A62.1 had affinity for the genusPenicillium, so we thought A62.1 belonged to the genus Penicillium.4. Primary studies of some Paecilomyces on the pathogenicity Plutellaxylostella (L.)Thirty strains of Paecilomyces and Beauveria isolated from soil samples and infected insectswere studied, the results were as follows:[1] The symptom of infected Plutella xylostella with infection of the strains tested.While the surface of larva infected by Beauveria bassiana became yellow brown, the surfaceinfected by Paecilomyces didn't have any obvious change. After incubation at 25℃, theseinfected insects were covered by white mycelium and conidia.[2] The pathogenicity comparison among different strains tested to Plutella xylostella.From the results, it was obviously defferent in the pathogenicity for different species. About83.33% of all strains had certain pathogenicity on Plutella xylostella, especially P.fumosoroseus,P.cateniannulatus and Beauveria bassiana.Different strains in the same species had large pathogenicity differences on Plutella xylostella.For example, SL.8, SL.7, XS.I and XS.2 strains of P.cateniannulatus were the best in thepathogenicity on Plutella xylostella.In addition, the results showed that the Paecilomyces strains from infected insects had betterpathogenicity than those from soil samples. And it was obviously irrelated between thepathogenicity and geographic origin.[3] Comparison of the conidiation in different strains of P.cateniannulatus.There were very large differences in conidiation among different strains of P.cateniannulatus.For example, the conidiation of XS. 1 strain was more than eleven times higher than XSXY.4 strain.And it was related between conidiation and pathogenicity. The higher in conidiation, the better inpathogenicity and vice versa.[4] Comparison of colonies in different strains of P.cateniannulatus..Colonies were observed and divided into three groups: ridgy, petaline and flat. In comparisingthe colonies and geographic origin, they were found irrelated in different strains of P.cateniannulatus.Analysing the colonies and the pathogenicities on Plutella xylostella, it was found that thestrains with petaline colonies had the best pathogenic effect, secondly ridgy, lastly the flat. Thesedata would provide the information to screen the good strains for biocontrol.[5] The relationships among colony, conidiation, pathogenicity and ITS rDNA regionsequences.It had a certain relationship among colony, conidiation, pathogenicity and ITS rDNA regionfrom the phylogenetic tree by MP, especially the pathogenicity had better rule in the tree.Our studies on classicification of the genus Paecilomyces were based on the classicalclassification, Delta system and molecular phylogenetics. The results showed that it was importantto understand both the morphology and molecular phylogenetics in order to carry out taxonomicstudy of Paecilorayces.