Population Genetic Structure of Puccinia striiformis in Northwestern China

Abstract

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most important fungal diseases of wheat in China. Xinjiang, Qinghai, and Gansu Provinces, located in the northwest of China, are the key regions for interregional epidemics of wheat stripe rust due to their geographic as well as crop-planting features, in relation to pathogen’s life cycle, reproduction, and population genetics. To study the population genetic structures of the pathogen in these areas, 217 isolates of P. striiformis f. sp. tritici were collected from different geographic locations at various elevations in the three provinces. The amplified fragment length polymorphism (AFLP) genotypes and virulence phenotypes were analyzed for Xinjiang, Qinghai, and Gansu populations. Frequent genotypic exchanges between Xinjiang and Qinghai and between Qinghai and Gansu populations were detected, demonstrating that the populations of Xinjiang and Gansu may not be completely isolated. Genotypic diversity in Gansu Province was much higher than that in Xinjiang or Qinghai Province. The Xinjiang population was genetically closer to the Qinghai population than to the Gansu population. The race dynamic patterns in Qinghai were consistent with those in Gansu but the similar component pattern of the race dynamics in Xinjiang appeared late, following those in Gansu and other interior epidemic regions of China. No significant correlation between the AFLP genetic distance and the virulence distance in the Xinjiang, Qinghai, and Gansu populations was determined. A possible recombination signature of the pathogen population was detected in Gansu population and some subpopulations in Qinghai but not in Xinjiang population.

Population Genetic Structures of Puccinia striiformis f. sp. tritici in the Gansu-Ningxia Region and Hubei Province, China

“…Genomic DNAs of the Pst urediniospores were extracted with the cetyltrimethylammonium bromide (CTAB) method [16]. In total, 567 DNA samples were extracted.…”

Population genetic structure of Puccinia striiformis f. sp. tritici at the junction of Gansu, Sichuan and Shaanxi Provinces in China

“…In previous studies, genetic relationships among geographical or temporal subpopulations were determined by diversity, pair-wise genetic differentiation (Gst, Fst or φpt), phylogenetic analysis, and shared genotypes (Liu et al 2011;Lu et al 2011;Liang et al 2013;Wang et al 2013;Wan et al 2015) etc. These methods provide descriptive results to a certain degree for inferring genetic relationships (Liang et al 2013;Wan et al 2015), and usually emphasize the variance among subpopulations (Estoup and Guillemaud 2010). However, the variance among individuals cannot be ignored since several studies confirmed that a large proportion of variance exists among individuals of Pst (Lu et al 2011;Wan et al 2015).…”

“…These methods provide descriptive results to a certain degree for inferring genetic relationships (Liang et al 2013;Wan et al 2015), and usually emphasize the variance among subpopulations (Estoup and Guillemaud 2010). However, the variance among individuals cannot be ignored since several studies confirmed that a large proportion of variance exists among individuals of Pst (Lu et al 2011;Wan et al 2015). Thus it can introduce errors from defining groups artificially in the analysis of genetic clusters.…”

“…Pst) (Ali et al 2016). Therefore, Ali et al (2016) reported a method using R package CloNcaSe that could estimate both the effective population size (Nc) and the frequency of sexual reproduction (s) more accurately (Liang et al 2013;Wan et al 2015;Ali et al 2016).…”

Molecular evidence for a new dispersal route of inoculum source for Puccinia striiformis f. sp. tritici in central and eastern China

“…The reproductive mode of Puccinia striiformis f. sp.tritici has long been considered as asexual, populations in most areas of the world (Brar et al 2018, Chen et al 2002, Enjalbert et al 2005, Holtz et al 2014 consistent with this hypothesis which have low genetic diversity, meanwhile, populations with high diversity were found in Gansu province (Liang et al 2016, Wan et al 2015, China, and Pakistan (Bahri et al 2011). In our study, plenty of MLGs were re-sampled in different locations, the presence of a particular MLG in great excess is often the most robust and significant evidence of clonal reproduction (Tibayrenc et al 1991).…”