Wild grasses as the reservoirs of infection of rust species for winter soft wheat in the Northern CaucasusWild grasses as the reservoirs of infection of rust species for winter soft wheat in the Northern Caucasus

Common winter wheat is the main grain crop cultivated in the North Caucasus. Rust disease damage is one of the factors limiting wheat productivity. There are three species of rust in the region: leaf (Puccinia triticina), stem (P. graminis) and stripe rust (P. striiformis), and their significance varies from year to year. The most common is leaf rust, but in the last decade the frequency of its epiphytotic development has significantly decreased. At the same time, an increase in the harmfulness of stripe rust (P. striiformis) is noted. Stem rust in the region is mainly absent or observed at the end of the wheat growing season to a weak degree. Only in some years with favorable weather conditions its mass development is noted on susceptible cultivars. It is believed that the sources of infection with rust species in the North Caucasus are infested soft wheat crops, wild-growing cereals and exodemic infection carried by air currents from adjacent territories. In the North Caucasus, forage and wild grasses are affected by Puccinia species almost every year. Depending on weather conditions, the symptom expression is noted from late September to December and then from late February to May–June. Potentially, an autumn infection on grasses can serve as a source for infection of winter soft wheat cultivars sown in October. The purpose of these studies is to characterize the virulence of P. triticina, P. graminis, P. striiformis on wild cereals and to assess the specialization of causative agents to winter wheat in the North Caucasus. Infectious material represented by leaves with urediniopustules of leaf, stem and stripe rusts was collected from wild cereals (Poa spp., Bromus spp.) in the Krasnodar Territory in October–November 2019. Uredinium material from P. triticina, P. striiformis, and P. graminis was propagated and cloned. Monopustular Puccinia spp. isolates were used for virulence genetics analysis. In experiments to study the specialization of rust species from wild-growing cereals on common wheat, 12 winter cultivars were used (Grom, Tanya, Yuka, Tabor, Bezostaya 100, Yubileynaya 100, Vekha, Vassa, Alekseich, Stan, Gurt, Bagrat). These cultivars are widely cultivated in the North Caucasus region and are characterized by varying degrees of resistance to rust. Additionally, wheat material was inoculated with Krasnodar populations of P. triticina, P. striiformis, P. graminis from common wheat. In the virulence analysis of P. triticina on cereal grasses, four phenotypes (races) were identified: MCTKH (30 %), TCTTR (30 %), TNTTR (25 %), MHTKH (15 %), and five were identified in P. graminis (RKMTF (60 %), TKTTF, RKLTF, QKLTF, LHLPF (10 % each). Among P. striiformis isolates, three phenotypes were identified using the International and European sets of differentiating cultivars – 111E231 (88 %), 111E247 (6 %) and 78E199 (6 %). Using isogenic Avocet lines, 3 races were also identified, which differed among themselves in virulence to the Yr1, Yr11, Yr18 genes (with the prevalence of virulent ones (94 %)). Composite urediniums’ samples (a mixture of all identified races) of grass rust of each species were used to inoculate winter wheat cultivars. The most common winter wheat cultivars (75 %) were characterized by a resistant response when infected with P. graminis populations from common wheat and cereal grasses. All these cultivars were developed using donors of the rye translocation 1BL.1RS, in which the Lr26, Sr31, and Yr9 genes are localized. The number of winter wheat cultivars resistant to leaf rust in the seedling phase was lower (58 %). At the same time, all the studied cultivars in the seedling phase were susceptible to P. striiformis to varying degrees. The virulence analysis of the leaf, stem and stripe rust populations did not reveal significant differences in the virulence of the pathogens between wild-growing cereals and soft wheat. Urediniomaterial of all studied rust species successfully infested soft wheat cultivars. The results obtained indicate that grasses are rust infection reservoirs for common wheat crops in the North Caucasus.

1. Ablova I.B., Bespalova L.A., Khudokormova Zh.N., Vasiliev A.V., Davoyan E.R., Afanasenko O.S., Baranova O.A., Klevtsova S.V., Boyko A.P. Achievements and prospects of breeding for resistance to stem rust at the Lukyanenko Krasnodar Research Institute of Agriculture. In: Third All-Russian and International Conference Current Issues of Plant Immunity to Pests. St. Petersburg, October 23- 26, 2012. St. Petersburg, 2012;2:190-195. (in Russian)

2. Anpilogova L.K., Alekseeva T.P., Levashova G.I., Vaganova O.F. Effective genes for resistance of adult wheat plants to leaf, stem, and yellow rusts and powdery mildew and their use in breeding in the North Caucasus. In: Sokolova M.S., Ugryumova E.P. (Eds.). Production of Environmentally Friendly Crop Products: Regional Recommendations. Pushchino, 1995;1:79-100. (in Russian)

3. Berlyand-Kozhevnikov V.M., Dmitriev A.P., Budashkina E.B., Shitova I.T., Reiter B.G. Wheat Resistance to Leaf Rust (Genetic Diversity of Fungus Populations and Host Plant Populations). Novosibirsk: Nauka Publ., 1978. (in Russian)

4. Bespalova L.A., Romanenko A.A., Kudryashov I.N., Ablova I.B., Mudrova A.A., Kotunenko V.Ya., Borovik A.N., Nabokov G.D., Lysak N.I., Gritsay V.A., Filobok V.A., Puzyrnaya O.Yu., Kerimov V.R., Mokhova L.M., Khudokormova Zh.N., Panchenko V.V., Yanovskiy A.S., Novikov A.V., Levchenko Yu.G., Kalmysh A.P., Efimenko I.V., Zinovkina O.A., Guenkova E.A., Agaev R.A., Agaeva E.V., Kotlyarov D.V., Tsvirinko V.G., Kuzilova N.M., Tarkhov A.S., Ponomarev D.A., Mikhalko A.V., Davoyan R.O., Kolesnikova O.F., Bukreeva G.I., Melnikova E.E., Domchenko M.I., Vasilyeva A.M., Efremenkova V.I., Novikova S.V. Wheat and Triticale Varieties: Catalog. Krasnodar, 2020. (in Russian)

5. Borisenko A.N. Wheat leaf rust Puccinia triticina Er. races in Kyrgyzstan, Kazakhstan, West Siberia, and the Southern Urals. Mikologiya i Fitopatologiya = Mycology and Phytopathology. 1970;31(5):55-59. (in Russian)

6. Budarina N.A. On the source of wheat infection with leaf rust in Crimea. Trudy Krymskoy Gosudarstvennoy Kompleksnoy Selskokhozyaystvennoy Opytnoy Stantsii = Proceedings of the Crimean State Complex Agricultural Experimental Station. Simferopol: Krymizdat Publ., 1955;1:193-196. (in Russian)

7. Cheng P., Chen X.M., See D.R. Grass hosts harbor more diverse isolates of Puccinia striiformis than cereal crops. Phytopathology. 2016;106(4):362-371. DOI 10.1094/PHYTO-07-15-0155-R.

8. Gassner G., Straib W. Untersuchungen über die infektionsbedingungen von Puccinia glumarum und Puccinia graminis. Arb. Biol. Reichsanst. Land Forstwirtsch. 1928;16(4):609-629.

9. Gultyaeva E.I., Shaydayuk E.L. Virulence of Russian populations of the stripe rust causal agent. Mikologiya i Fitopatologiya = Mycology and Phytopathology. 2020;54(4):299-304. DOI 10.31857/S0026364820040042. (in Russian)

10. Gultyaeva E.I., Shaydayuk E.L., Kosman E.G. Regional and temporal differentiation of virulence phenotypes of Puccinia triticina from common wheat in Russia during the period 2001–2018. Plant Pathol. 2020;69(5):860-871. DOI 10.1111/ppa.13174.

11. Hovmøller M.S., Sørensen C.K., Walter S., Justesen A.F. Diversity of Puccinia striiformis on cereals and grasses. Annu. Rev. Phytopathol. 2011;49(1):197-217. DOI 10.1146/annurev-phyto072910-095230.

12. Kolmer J.A., Kabdulova M.G., Mustafina M.A., Zhemchuzhina N.S., Dubovoy V. Russian populations of Puccinia triticina in distant regions are not differentiated for virulence and molecular genotype. Plant Pathol. 2015;64(2):328-336. DOI 10.1111/ppa.12248.

13. Krayeva G.A., Matviyenko A.N. The race composition of Puccinia striiformis West. on small grasses in the North Caucasus. Mikologiya i Fitopatologiya = Mycology and Phytopathology. 1974;8(6):521-523. (in Russian)

14. Lesovoy M.P., Tereshchenko B.A. Specialization of Puccinia triticina Erikss. and its races on wild grasses. In: Proceedings of the European and Mediterranean Cereal Rusts Conference. Praha, 1972;171-174. (in Russian)

15. Long D.L., Kolmer J.A. A North American system of nomenclature for Puccinia recondita f. sp. tritici. Phytopathology. 1989; 79(5):525-529. DOI 10.1094/Phyto-79-525.

16. Mains E.B., Jackson H.S. Physiologic specialization in the leaf rust of wheat Puccinia triticina Erikss. Phytopathology. 1926; 16:89-120.

17. McIntosh R.A., Wellings C., Park R.F. Wheat Rusts: an Atlas of Resistance Genes. London: Kluwer Academic Publ., 1995.

18. Mikhailova L.A., Gultyaeva E.I., Mironenko N.V. Methods for Studying the Structure of Populations of the Leaf Rust Causative Agent: Collection of Guidelines on Plant Protection. St. Petersburg: All-Russia Institute of Plant Protection, 1998;105-126. (in Russian)

19. Nazari K., Mafi M., Yahyaoui A., Singh R.P., Park R.F. Detection of wheat stem rust (Puccinia graminis f. sp. tritici) race TTKSK (Ug99) in Iran. Plant Dis. 2009;93(3):317. DOI 10.1094/PDIS93-3-0317B.

20. Paichadze L.V., Yaremenko Z.I. Specialization of the causal agent of yellow rust to wild grasses. Soobshcheniya Akademii Nauk Gruzinskoy SSR = Bulletin of the Academy of Sciences of the Georgian SSR. 1974;76(2):469-471. (in Russian)

21. Popov D.F. Local sources of the causative agent of wheat yellow rust in Altai. Sibirskiy Vestnik = Siberian Herald. 1979;3:63-66. (in Russian)

22. Sanin S.S. Epiphytotics of Cereal Crops Diseases: Theory and Practice. Moscow, 2012;161-166. (in Russian)

23. Sibikeev S.N., Markelova T.S., Druzhin A.E., Vedeneeva M.L., Singh D. Evaluation of a set of introgressive spring bread wheat lines developed for resistance to stem rust race Ug99+Sr24 (TTKST) at the Southeast Agricultural Research Institute. Russ. Agricult. Sci. 2011;37(2):95-97.

24. Sinyak E.V., Volkova G.V., Nadykta V.D. Characteristics of Puccinia graminis f. sp. tritici population by virulence in the North Caucasian region of Russia. Russ. Agricult. Sci. 2014;40(1): 32-34. DOI 10.3103/S1068367414010169.

25. Skolotneva E.S., Kelbin V.N., Morgunov A.I., Boiko N.I., Shamanin V.P., Salina Е.А. Races composition of the Novosibirsk population of Puccinia graminis f. sp. tritici. Mikologiya i Fitopatologiya = Mycology and Phytopathology. 2020;54(1): 49-58. DOI 10.31857/S0026364820010092. (in Russian)

26. Skolotneva E.S., Lekomtseva S.N., Kosman E. The wheat stem rust pathogen in the central region of the Russian Federation. Plant Pathol. 2013;62(5):1003-1010. DOI 10.1111/ppa.12019.

27. Stakman E.C., Stewart D.M., Loegering W.Q. Identification of physiologic races of Puccinia graminis var. tritici. U. S. Dept. Agr. E. 1962; 617:53. https://ufdc.ufl.edu/AA00024889/00001.