Phenotyping and Genotyping Analyses Reveal the Spread of Puccinia striiformis f. sp. tritici Aeciospores From Susceptible Barberry to Wheat in Qinghai of China

Abstract

<i>Puccinia striiformis</i> f. sp. <i>tritici</i> Eriks., the cause of wheat yellow or stripe rust on wheat, undergoes sexual reproduction on barberry, but it is unclear if barberry plays any role in stripe rust epidemics under natural conditions. <i>P. striiformis</i> f. sp. <i>tritici</i> was isolated from its alternate host barberry (<i>Berberis</i> spp.) and primary host wheat in the vicinity of barberry by inoculation of aeciospores and urediniospores on Mingxian 169 cultivar in Qinghai province of China in 2018. The <i>P. striiformis</i> f. sp. <i>tritici</i> isolates from barberry and wheat were characterized to virulence patterns by inoculation on 24 differentials bearing <i>Yr</i> gene under control conditions and analyzed using 12 polymorphic simple sequence repeat (SSR) markers. The occurrence frequency of <i>P. striiformis</i> f. sp. <i>tritici</i> on barberry was 1.87% by inoculation aecia, collected from barberry on Mingxian 169 of wheat. A close virulence relationship was presented between <i>P. striiformis</i> f. sp. <i>tritici</i> isolates from both barberry and wheat based on virulence simple matching coefficient and principal coordinates analysis (PCoA). Additionally, the same genetic ancestry, based on structure analysis by STRUCTURE program and genetic relationship analyses using discriminant analysis of principal components and PCoA, was shared between <i>P. striiformis</i> f. sp. <i>tritici</i> isolates from barberry and those from wheat. Together, all the results indicated that the role of barberry in providing aeciospores as an inoculum source causing wheat stripe rust epidemic in Qinghai in spring is of considerable importance.