| Ambrosia beetles are known as ecological and economic important forest pests.The host range of these beetles appear to be very wide,including a variety of conifers and hardwoods.These beetles have caused great damage to the subtropical and tropical forestry as well as potential safety hazards.The symbiotic fungi provide the beetles essential food source during the colonization.Some fungal species are tree pathogens which can weaken the host resistance,or cause disease on the host trees.The main purpose of this study is to identify the ambrosia fungi based on morphological features and DNA sequences,as well as the evaluation of DNA barcoding of the dominant fungal species Fusarium.Finally,93 pieces of ambrosia beetle and wood tunnel samples were collected from in Guangzhou in Guangdong,Jiangxi and Fujian Provinces.Three beetle species were recognized based on morphological identification,including Xylosandrus cf.brives,X.discolor and Platypus sp.And a total of 238 fungal cultures were obtained after isolation and purification.21 genera were identifies based on morphology and phylogenetic analyses(Maximum Likelihood)of internal transcribed spacer(ITS)gene region,including Byssochlamys,Curvularia,Cyberlindnera,Cytospora,Diaporthe,Diplodia,Fusarium,Geosmithia,Lasiodiplodia,Massarina,Ophiostoma,Paraconiothyrium,Penicillium,Phaeoacremonium,Phialemoniopsis,Phoma,Prosthecium,Raffaelea,Schizophyllum,Sporothrix and Verticillium.Of these fungi,Fusarium and Geosmithia are widely distributed and dominant species,especially the former species which accounted 35% of all species.Deep Phylogenetic analyses were conducted on Fusarium fungi based on ITS,TEF,and TUB gene regions.Five species were identified,these included two known species(F.ambrosium and F.decemcelluare)and three undescribed species.The TEF gene region had highest resolution in distinguishing theFusarium species and was recommended to use as barcoding gene for the Fusarium solani complex.Furthermore,morphology characterization was conducted on all five Fusarium species.This study provided a preliminary result of diversity and dominant species of ambrosia fungi in Guangzhou and surrounding areas,which was helpful for the quarantine,management and control of ambrosia beetles and their symbiotic fungal disease. |
