Geographical Correlation and Genetic Diversity of Newly Emerged Races within the Ug99 Lineage of Stem Rust Pathogen, Puccinia graminis f. sp. tritici, in Different Wheat-Producing Areas

Atef Shahin; Yasser S A Mazrou; Reda Ibrahim Omara; Gamalat Hermas; Mohamed Gad; Ola Ibrahim Mabrouk; Kamel A Abd-Elsalam; Yasser Nehela

doi:10.3390/jof8101041

Geographical Correlation and Genetic Diversity of Newly Emerged Races within the Ug99 Lineage of Stem Rust Pathogen, Puccinia graminis f. sp. tritici, in Different Wheat-Producing Areas

J Fungi (Basel). 2022 Sep 30;8(10):1041. doi: 10.3390/jof8101041.

Authors

Atef Shahin¹, Yasser S A Mazrou^{2

3}, Reda Ibrahim Omara¹, Gamalat Hermas¹, Mohamed Gad¹, Ola Ibrahim Mabrouk¹, Kamel A Abd-Elsalam¹, Yasser Nehela⁴

Affiliations

¹ Plant Pathology Research Institute, Agricultural Research Center, Giza 12619, Egypt.
² Business Administration Department, Community College, King Khalid University, Guraiger, Abha 62529, Saudi Arabia.
³ Department of Agriculture Economic, Faculty of Agriculture, Tanta University, Tanta 31511, Egypt.
⁴ Department of Agricultural Botany, Faculty of Agriculture, Tanta University, Tanta 31511, Egypt.

Abstract

Wheat stem rust caused by Puccinia graminis f. sp. tritici is one of the most destructive wheat diseases worldwide. Identifying stem rust races in general, Ug99 lineage particularly, and determining resistance genes are critical goals for disease assessment. Thirty wheat varieties and monogenic lines with major stem rust resistance genes (Sr) were examined here over the course of three succeeding seasons from 2020 to 2022. Fourteen stem rust races have been identified in ten African countries, as well as Central and West Asia and North Africa (CWANA) and ten European countries. The Ug99 group (Clade I) included four races (TTKSK, TTKST, TTKTK, and TTKTT) and was reported in five African countries (Egypt, Kenya, Rwanda, Tanzania, and Uganda) and Iran, but none of the European countries. On the other hand, none of the races in Clade III-B (TTRTF) and Clade IV-B (TKTTF and TTTTF) were found in Egypt. Furthermore, Egyptian races were clustered separately from races identified from other countries, and six races were found only in Egypt, including PKSTC, RKTTH, TKTTC, TTTSK, TCKTC, and TKTTH. Races from Kenya, Tanzania, Uganda, Rwanda, and Iran were all closely associated with one another, according to correlation analysis. However, most races identified from other investigated regions, including Eritrea, Spain, Ethiopia, Morocco, Italy, Poland, Kenya, Tanzania, and Uganda, were adversely linked with Egyptian races. The diagnostic 350 bp long PCR fragment linked with virulence to Sr31, Clement (Sr31), and Brigardier (Sr31) was used to identify the TTKSK (Ug99) race. The identification of the regional associations and genetic diversity of newly emerged races within the Ug99 lineage of P. graminis tritici in Africa, Asia, and Europe is one of the key goals of this study. It will help plant breeders to develop new resistant lines against the virulent races, especially TTKSK (Ug99) and TTTSK. This helps in ensuring global food security in the context of climate change.

Keywords: Sr genes; Ug99; molecular markers; race analysis; stem rust; wheat.

Grants and funding

Program of Research Groups under grant number (RGP 2/67/43)/King Khalid University