Plant-parasitic nematodes are very common on cereal crops and cause economic losses via reduction in grain quality and quantity. During 2014, 83 soil samples were collected from wheat and barley fields in 21 districts of 13 provinces across five regions (Central Anatolia, Marmara, Aegean, Southeast Anatolia, and Black Sea Region) of Turkey. Cyst-forming nematodes were found in 66 samples (80%), and the internal transcribed spacer (ITS) sequencing and species-specific PCR identified the species in 64 samples as Heterodera filipjevi, Heterodera latipons, and Heterodera avenae. The predominant pathogenic cereal cyst nematode was H. filipjevi, which was found in all five regions surveyed. H. avenae was only detected in Southeast Anatolia whereas H. latipons was detected in Southeast Anatolia and Central Anatolia. ITS-rDNA phylogenetic analyses showed that H. avenae isolates from China clustered with H. australis, and Turkish isolates were closely related to European and USA isolates of this species. H. filipjevi from Turkey and China were clustered closely with those from the UK, Germany, Russia, and the USA. The density of many of these populations exceeded or approached the maximum threshold level for economic loss. To our knowledge, this is the first report of H. filipjevi in Diyarbakir, Edirne, and Kutahya provinces, and the first report of H. avenae in Diyarbakir Province. These results exhibit the most rigorous analysis to date on the occurrence and distribution of Heterodera spp. in Turkey’s major wheat-producing areas, thus providing a basis for more specific resistance breeding, as well as other management practices.

    Heterodera avenae (cereal cyst nematode, CCN) infects many cereal crops and causes serious yield losses worldwide. Interaction studies investigating H. avenae and its hosts are still in their infancy. In this study, a barley model plant, the Hordeum vulgare cultivar Golden Promise, was investigated for its potential as a candidate model host to study its interaction with H. avenae. CCN-infective juveniles were attracted by the root tips and gathered around the root elongation zones of Golden Promise on 0.7% water agar plates. The juveniles invaded the roots and developed successfully until maturation at 40 days after inoculation in sterile sand soil. The cryotomy and syncytium measurements indicated that the syncytia enlarged gradually throughout the development of the nematodes and caused the corresponding root regions to swell obviously. Quantitative real-time PCR analysis showed that the down-regulation of defence-related barley genes and up-regulation of development-related barley genes contribute to the understanding of compatible interaction between H. avenae and Golden Promise. Barley stripe mosaic virus (BSMV) virus-induced gene silencing (VIGS) can be used in the roots of Golden Promise. In conclusion, the Hordeum vulgare cultivar Golden Promise is a suitable candidate model host for interaction studies with Heterodera avenae. The studies presented above document the first CCN host that not only has published genome context but also be compatible to BSMV VIGS.  

The cereal cyst nematode (CCN, Heteroder aavenae) causes serious yield loss on cereal crops, especially wheat, worldwide. Daxing population in Beijing City and Huangyuan population in Qinghai Province, China, are two CCN populations. In this study, the CCN pathotypes of Daxing and Huangyuan populations were characterized by tests on 23 standard “International Test Assortment” with the local species Wenmai 19 as the susceptible control. Tested materials were grouped by three nematode populations’ virulence on resistant genes (Rha1, Rha2, Rha3, Cre1) and nonresistant genes, varieties and lines. Both Daxing and Huangyuan populations were avirulent to Ortolan (Ha1). Barley cvs. Ortolan, Siri, Morocco, Bajo Aragon 1-1, and Martin 403-2 were all resistant to both populations. Cultivars Herta, Harlan 43 and wheat Iskamish-K-2-light were all susceptible to Huangyuan population, all of them, however, were resistant to Daxing population. The other five oats were all resistant to the two tested CCN populations. Except Iskamisch K-2-light, all the other wheat cultivars (Capa, Loros×Koga, AUS 10894, and Psathias) were susceptible to Daxing population. Because the pathotypes of the two tested CCN populations in Beijing and Qinghai were not identical to any of the 13 pathotypes previously characterized by the test assortment, we classified Daxing and Huangyuan populations as the new pathotypes, named Ha91.