Molecular Systematics And DNA Barcode Of Aschersonia

Aschersonia members mainly parasitize whitefly and scale insects,which indicates it's of great importance to identify Aschersonia species for better application.Molecular phylogeny of Aschersonia and its reconstruction of classification system were studied based on morphological data coupled with appropriate genes as molecular marker.Aschersonia DNA barcode was investigated for the first time to facilitate the detection of new species and cryptic species,and species identification of Aschersonia.The main findings were as follows.(1)Strains collected in 2010-2012 were identified primarily based on morphological characteristics.12 Aschersonia species and 7 new species were identified at the morphological level.(2)Phylogenetic trees constructed using sequences of LSU,RPB1 and EF-la,and combined RPB1 and EF-la genes were the best by a single gene and multi-gene analysis.Each species used in the study was clustered and clearly distinguished in the trees.The results indicated that RPB1 gene combined with EF-1? gene used as Aschersonia molecular markers was suitable,which can be used for Aschersonia phylogenetic study.(3)MDYS2010-35 and HNXL2012-03 were determined as the same new species of Aschersonia based on combination of molecular phylogeny with morphological features,WYFC2010-01 and ZJJ2010-08 were identified as two different new species as well.(4)Divergence time of Aschersonia species was calculated by the Nei'formula using Balansia henningsiana as outgroup strain.Divergence time between Aschersonia and B.henningsiana should be about 850000-1045000 years ago.(5)Studies on Aschersonia DNA barcode were conducted in this work.The findings indicated that single gene such as LSU,RPB1 and EF-la,and multi-gene were not suitable for Aschersonia DNA barcode.However,Aschersonia resolution was higher using gene RPB1 coupled with EF-1?,which would be used as a supplementary DNA barcode of Aschersonia.But the core code of Aschersonia DNA barcode needs further study.