Regional and temporal differentiation of virulence phenotypes of Puccinia triticina from common wheat in Russia during the period 2001–2018

Abstract

| INTRODUC TI ONLeaf rust, caused by the fungus Puccinia triticina, is the most common rust disease on wheat in Russia and its destructiveness has varied over time and between regions (Sanin, 2012). The use of resistant varieties is the most effective and environmentally friendly method of protection of wheat against leaf rust.Analysis of the population structure of P. triticina and its variability allows for the development of specific wheat varieties resistant to leaf rust and adjustment of their deployment in each separate region.P. triticina has a long history of population studies since physiologic specialization of wheat leaf rust was first described (Mains and Jackson, 1926). The first set of differentials, consisting of eight wheat varieties with different resistance genes (Malakoff [Lr1 gene], Carina [Lr2b = Lr2 2 ], Brevit [Lr2c = Lr2 3 ], Webster [Lr2a], Loros [Lr2 4 ], Mediterranean [Lr3a], Hussar [Lr11], and Democrat [Lr3a]), was suggested by Mains and Jackson (1926) and widely used for analysingAbstract Leaf rust, caused by the fungus Puccinia triticina, is one of the most damaging rust diseases of wheat in Russia. Populations of P. triticina were monitored in seven regions of Russia from 2001 to 2018, with a total of 5,191 single urediniospore isolates from bread wheat (Triticum aestivum) being analysed. Populations have changed significantly in all regions since 2012, after 2 years of drought (2010-2011). Regional collections of P. triticina were also significantly different between the two periods 2001-2009 and 2012-2018, with changes along two geographic gradients from West Siberia to the north-west and south-west (North Caucasia) of the European part of Russia. All tested isolates were avirulent to resistance gene Lr9 in 2001-2009 but, since 2010, virulence to Lr9 has occurred and annually increased in the Asian part of Russia (Ural and West Siberia) due to deployment of cultivars with the Lr9 gene. Virulence to Lr2a and Lr15 was considerably lower in Dagestan (6%-33%) andall European regions (35%-67%) than in Asian regions (84%-96%). During 2001-2009, virulence on Lr1 was also lower in Dagestan (33%) and the European regions (50%-77%) than in Asia (91%-96%); however, by 2012-2018, nearly all isolates were virulent on Lr1. Remarkable changes were observed in frequencies of P. triticina races defined by their virulence/avirulence to Lr1 and Lr2a genes. We postulate the P. triticina population in Dagestan is specific to that area and pathogen populations in European and Asian parts of Russia are distinct. K E Y W O R D SKosman distance, leaf rust, Lr resistance genes, population structure, Triticum aestivum | 861 GULTYAEVA ET AL.

Genetic Protection of Soft Wheat from Diseases in the Southern Ural of Russia and Virulence Variability of Foliar Pathogens

“…Cultivars protected by this gene were only grown to a limited extent in the southern Ural. However, they were widely grown in Volga regions bordering with Cis-Urals, and isolates virulent to the Lr19 gene dominated in these populations [25][26][27].…”

“…However, no populations of the pathogen in the region were found to have virulence to both Lr9 and Lr26, or both Lr19 and Lr26. Virulence to Lr9 (or Lr19), and Lr1, Lr2a, Lr2b, Lr2c, Lr3a, Lr3bg, Lr3ka, Lr10, Lr14a, Lr14b, Lr15, Lr17, Lr18, Lr20 and Lr30 is widespread [22][23][24][25].…”

“…Resistance genes, Lr29, Lr41, Lr42, Lr45, Lr47, Lr50, Lr51, Lr53 and Lr57, have had high effectiveness in the southern Ural over a long period, as well as in other regions of Russia. Isolates virulent to TcLr24 and TcLr28 were detected before 2010, but not since [25]. Some of these genes are used in modern breeding in the southern Ural (e.g., Lr29, Lr45, Lr47 Lr53 and Lr57).…”

Virulence Phenotypes of Siberian Wheat Stem Rust Population in 2017–2018

“…0.232-0.344 for the KW dispersion, Table 3) and similar to P. triticina asexual population with KW values ranging between 0.09 and 0.11 (Gultyaeva et al, 2020). The Altai samples consisted of several closely related rare virulence phenotypes.…”

Assessing new SSR markers for utility and informativeness in genetic studies of brown rust fungi on wheat, triticale, and rye

“…9 and 11 of Jost (2008) based on the KW diversity (eq. 1 in Gultyaeva et al, 2020). as explained in Kosman et al (2014; p. 565) for a pool P of all isolates from a set of k collections of size n i , N = n 1 + n 2 + … + n k , µ i = n i / N ( i = 1, 2, …, k ).…”