Characterizations Of The New Distribution And Pathotype Of Cereal Cyst Nematodes On Wheat In Shanxi And Zhejiang

The disease caused by cereal cyst nematodes, is a very serious soil born disease. Its Pathogen mainly is Heterodera avenae, cereal cyst nematode(CCN), which is the most important Plant pathogenic nematodes on the cereal crops in Temperate zone. It had been reported to infect the wheat in more than40countries all over5continents since first detected from Germany in1874. In China, since it was first detected in Tianmen, Hubei in1989, the nematode has been spreaded to16provinces and caused very negative impact to the wheat production.This study mainly made survey of CCN distribution in Shanxi and Zhejiang, morphological and molecular identification of the nematode, and the pathotype of a CCN population from Shanxi. The main results are summarized as follows:In2012-2013,our study dedicated to investigate the CCN distribuction in Shanxi and Zhejiang province. In Zhejiang province, the survey involved19counties of4cities including Jiaxing, Shaoxing, Hangzhou and Ningbo, and108samples were collected. No CCN were detected. In Shanxi province, the investigation was carried out on wheat fields from hundreds of villages in6cities including Yuncheng, Jincheng, Linfen, Changzhi, Jinzhong, and Taiyuan. Totally,493samples with roots and soils were collected. With the nematode extraction and identification, it was found that149out of493were detected with CCN infection. The incidence rate was30.2%. The highest incidence rate occured in Yuncheng, which is46.3%, and the highest population density reached198cysts/100ml soil. The survey found that there are many places with CCN infection not reported before, such as Shangshaowang village in Wenxi county, Jishan county, Yuanqu county, Dahuaishu village in Hongtong county in Linfen city, Qinshui county in Jincheng city, Changzhi county in Changzhi city, etc. No CCN were detected in city Jinzhong,Taiyuan and northwest of Linfen that sampled.By studying the morphological characteristics of CCN populations collected from Shanxi, it turns out that all the populations are similar with Heterodera avenae described by Wang (1991) and Subbotin et al.,and the result of rDNA-ITS PCR amplification of15populations in Shanxi is nearly the same-a sequence with the length of1045bp. Phylogenetic information suggests that the CCN population from new distribuction area in Shanxi shows high homology with CCN population from China reported before (including the provinces of Henan, Anhui, Jiangsu, Beijing, and Hebei) and India. While a little difference with the CCN populations from European countries including Germany, Marocco, Spain, France and UK. This means the CCN from China has its specificity of Genetic features.The pathotype of CCN collected from Shangshaowang village in Wenxi county,Yuncheng sity, Shanxi province were characterized based on the bioassay. The reaction of the nematode to International Test Collection were tested. The result Shows that CCN from Shangshaowang belongs to Hal group, the closest Pathotype is Ha81, But it can not match with the pathotype Hall-Ha81perfectly. Pathotype Ha81can infect the Varieties Martin403-2and Dalmatische while CCN from Shangshaowang can not. Through the Pathotype identification, it was confirmed that the pathotype of CCN in Shangshaowang is similar to that in Taigu, but there still presents some differences.