The Identificationand Rapdanalysis Of Wheat Root Lesion Pathogens In Henan Province

Wheat root lesion has caused serious economic loss overseas. In 2006, a new disease in wheat root, root lesion nematode, was discovered in the science and technology park of Henan Agricultural University. It was the first report of pratylenchus infecting wheat. The results of field survey in Zhengzhou in 2007 showed that wheat yeild was reduced by 13.58%~15.46% after wheat root lesion nematode infection.In this study wheat root lesion nematode was identified in use of morphology analysis combined with molecular biology method. The results showed that the pathogen causing root lesion disease in wheat was Pratylenchus agilis. Previous study found Pratylenchus agilis infecting crop except wheat, and our study demonstrated that wheat is a newly host for Pratylenchus agilis.Preliminary investigations of the wheat root nematode were conducted in 14 areas of Henan province with 45 sample points. .The results showed that wheat root nematode can be extracted in 9 regions with 35 sample points except Zhumadian(south of Zhengzhou),Zhoukou,Zhongmou(east of Zhengzhou), and it distributed widespreadly and nonuniformly in Henan.We selected 23 typical samples from 35 samples to conduct the morphology and molecular biology analysis. It was found that these samples belonged to 2 different pratylenchus, of which 15 samples were named as Praylenchus agilis and 8 samples as Praylenchus loosi.RAPD technique was used to analyze the genetic diversity of 13 samples from 9 representative areas which were Zhengzhou, Xinxiang, Jiaozuo, Anyang,etc.This study screened 10 optimal polymorphism primers from 100 random primers. 85 RAPD markers were amplified in total, of which 81 markers were polymorphisms markers.The results showed that root lesion nematode was genetically diversified in Henan. NTSYS software was applied for cluster analysis of nematodes in this study. The result indicated that the pathogenic nematodes were divided into two branches and the rangeability of interspecific genetic similarity coefficient was 0.51~0.86. The wheat root lesion nematodes from same area were closely related and gathered together in the phylogenetic tree. Genetic diversity results were identical to that of morphology and molecular biology analysis further confirming the results of the other two identification method.