Pathogenomic Analysis of Wheat Yellow Rust Lineages Detects Seasonal Variation and Host Specificity

Abstract

Recent disease outbreaks caused by (re-)emerging plant pathogens have been associated with expansions in pathogen geographic distribution and increased virulence. For example, in the past two decades’ wheat yellow (stripe) rust, Puccinia striiformis f. sp. tritici, has seen the emergence of new races that are adapted to warmer temperatures, have expanded virulence profiles, and are more aggressive than previous races, leading to wide-scale epidemics. Here, we used field-based genotyping to generate high-resolution data on P. striiformis genetics and carried out global population analysis. We also undertook comparative analysis of the 2014 and 2013 UK populations and assessed the temporal dynamics and host specificity of distinct pathogen genotypes. Our analysis revealed that P. striiformis lineages recently detected in Europe are extremely diverse and in fact similar to globally dispersed populations. In addition, we identified a considerable shift in the UK P. striiformis population structure including the first identification of one infamous race known as Kranich. Next, by establishing the genotype of both the pathogen and host within a single infected field sample, we uncovered evidence for varietal specificity for genetic groups of P. striiformis. Finally, we found potential seasonal specificity for certain genotypes of the pathogen with several lineages identified only in samples collected in late spring and into the summer, whereas one lineage was identified throughout the wheat growing season. Our discovery of which wheat varieties are susceptible to which specific P. striiformis isolates, and when those isolates are prevalent throughout the year, represents a powerful tool for disease management.

Advances in understanding obligate biotrophy in rust fungi

“…This fungus has caused important coffee yield losses across Africa, Asia and South America with an estimated market value of US$2-3 billion annually (Talhinhas et al, 2017). Rust fungi are subjected to rigorous surveillance and monitoring against their potentially devastating effects on global crop production (Singh et al, 2011;Bueno-Sancho et al, 2017).…”

“…Three M. lini avirulence genes (AvrL567, AvrP4 and Avr123) were found under positive selection at the intraspecific and/or interspecific levels (Dodds et al, 2004;Barrett et al, 2009). A genome-wide search for single nucleotide polymorphisms or insertion/deletion in rust fungal isolates has enabled the detection of avirulence candidates among secreted protein genes (Cantu et al, 2013;Bruce et al, 2014;Persoons et al, 2014;Upadhyaya et al, 2014;Bueno-Sancho et al, 2017;Cuomo et al, 2017;Wu et al, 2017). Sequencing large volumes of isolates is now possible for relatively low cost, and highdensity genetic maps can be constructed through the resequencing of progenies or by restriction site detection sequencing (RAD-seq) in rust fungi (Pernaci et al, 2014;Anderson et al, 2016;Yuan et al, 2018).…”

Significance of Recent Discoveries in Stripe Rust Management

“…Abundance of alternate host (Berberis spp.) in the regions propose the area as credible center of origin or in any case the nearer to its center of origin of PST (Bueno-Sancho et al, 2017). However, more investigation from east Asian to central Asia regions may generate valuable information.…”

“…Stripe rust is the alarm for wheat production in the world and has been increasingly destructive in many countries including Pakistan (Solh et al 2012). The reduced yield due to this disease may lead to severe economic losses (Ali et al, 2017). Thus, control of the disease is crucial to ensure food security.…”

Threats of Tar Spot Complex disease of maize in the United States of America and its global consequences

“…In addition to the declining per capita arable land and other resources, the emergence and spread of devastating crop diseases has been challenging sustainable crop production (Bueno-Sancho et al 2017). For example, the first introduction of wheat stripe rust pathogen (Puccinia striiformis) into Australia in 1978 and a secondary significant invasion of a different aggressive race of the same pathogen in 2002 (Wellings 2007;Loladze et al 2014) have led to a number of commercially grown wheat cultivars to succumb to the disease resulting in significant economic losses.…”