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Differential pathogenicity and genetic diversity among Fusarium pseudograminearum isolates from Huang-huai wheat growing region of China

Honglian Li: Department of Plant Pathology, Henan Agricultural University

<div><em>Fusarium pseudograminearum</em> (teleomorph <em>Gibberella coronicola</em>) is the main causal agent of Fusarium crown rot (FCR) of wheat, an important soil-borne disease throughout Huang-huai wheat growing region in China. To date, however, the pathogenicity differentiation and genetic diversity of this pathogen have been rarely reported. In this study, pathogenicity test of 34 <em>F. pseudograminearum</em> isolates in greenhouse and analysis of genetic diversity of a collection of 192 <em>F. pseudograminearum</em> isolates using universal rice primers (URP) PCR method were carried out. The result of the disease index value ranging from 6.67 to 91.11 indicated the obvious pathogenic differentiation in <em>F. pseudograminearum</em><em> populations</em>, but not correlated with geographic origin. Further clustering analysis of 192 <em>F. pseudograminearum</em> isolates resolved at least 8 sub-clusters with 87.12% of the polymorphic loci. For the 8 geographical populations, the genetic diversity within each population is significantly higher than among populations, whereas there might be partial gene flows among different populations. UPGMA dendrogram based Nei's genetic distance indicated that eight populations were divided into two main groups including Hebei and three Henan populations, with Shanxi, Shaanxi and two Shandong populations. In general, both pathogenicity and molecular variation of these isolates were not correlated significantly with geographic origin that would make the controlling of this disease more difficult. These results will contribute to monitoring the dynamic of FCR caused by <em>F. pseudograminearum</em> and meanwhile providing a guideline for plant breeding efforts and developing other disease management strategies aimed at reducing FCR in Huang-huai wheat growing region of China.</div>