Xiaoping Xing

New pathotypes of Heterodera avenae (cereal cyst nematode) from winter wheat in Zhengzhou, Henan, China

A growing recognition of the importance of the cereal cyst nematode, Heterodera avenae in winter wheat in China has highlighted the need to better understand local pathotype diversity, as this knowledge is needed to effectively deploy host resistance. Two populations of H. avenae, one each from Xushui and Xingyuang, villages near Zhengzhou, Henan, on the Huang Huai flood plain where 50% of China’s wheat is grown, were typed using 23 standard international differentials and a common local cultivar Wenmai 19. These populations were found to be previously undescribed pathotypes. It is proposed that the pathotype code, Ha43, be applied to the population from Xushui, which was consistently characterised over two seasons and differs from the most similar pathotype, Ha13, by being avirulent in oat cv. Sivan and wheat cvv. Loros and Iskamish K-2-light. Wenmai 19 was found to be susceptible to both populations. Australasian Plant Pathology Society 2010

Molecular characterisation of cereal cyst nematodes in winter wheat on the Huang-Huai floodplain of China using RFLP and rDNA-ITS sequence analyses

In response to the recent discovery of Heterodera filipjevi central Henan and the uncertain taxonomic status of Heterodera avenae more widely in China, heteroderid specimens from winter wheat at 21 locations in Henan and adjacent provinces were subjected to RFLP and rDNA-ITS sequence analysis. H. filipjevi was found in six locations in Henan, including two mixed with H. avenae; H. avenae being found at all other locations. A new RFLP profile type was found for H. filipjevi, three new types for H. avenae and the Australian type (Heterodera australis) were found for the first time in China (at two locations). Otherwise, H. avenae and H. filipjevi were of RFLP types previously reported in China. Phylogenic analysis of the rDNA sequences showed H. filipjevi in China was less diverse than H. avenae, with greatest similarity to specimens from Italy and the USA, which is consistent with a more recent introduction. In contrast, H. avenae in China was clearly distinct from H. avenae found elsewhere, except for the discovery of the Australian types. Although the Australian types clustered together, this fell within the variation found for the remainder of the specimens from China, which may represent a single species. These data reveal additional genetic diversity within the two cereal cyst nematode species in China, which is likely to have implications for the development of their control by host resistance.