Molecular characterization of wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici) collections from nine countries

Authors: BAI, QING - Washington State University; WAN, ANMIN - Washington State University; WANG, MAINAN - Washington State University; See, Deven; Chen, Xianming

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/27/2021
Publication Date: 8/31/2021
Citation: Bai, Q., Wan, A., Wang, M., See, D.R., Chen, X. 2021. Molecular characterization of wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici) collections from nine countries. International Journal of Molecular Sciences. 22(17). Article 9457. https://doi.org/10.3390/ijms22179457.
DOI: https://doi.org/10.3390/ijms22179457

Interpretive Summary: Stripe rust is one of the most important diseases of wheat worldwide. To understand the worldwide distribution of molecular groups, diversity, differentiation, and migration of the pathogen populations, 567 stripe rust isolates collected from nine countries (China, Pakistan, Italy, Egypt, Ethiopia, Canada, Mexico, Ecuador, and the U.S.) in 2010-2018 were genotyped using 14 codominant simple sequence repeat markers. A total of 433 including 333 new multi-locus genotypes (MLGs) were identified, which were clustered into ten molecular groups (MGs). The MGs and country-wise populations differred in genetic diversity, heterozygosity, and correlation coefficient between the mark and virulence data. Many isolates from different countries, especially the isolates from Mexico, Ecuador, and the U. S. were found to be identical or closely related MLGs; and some of the MGs were present in all countries, indicating the pathogen migrations among different countries. Analysis of molecular variance revealed 78% variation among isolates, 12% variation among countries, and 10% variation among isolates within countries. Only low levels of differentiation were found by the pairwise comparisons of country populations. Of the 10 MGs, five were found to be involved in sexual and/or somatic recombination. The study provides the information on distributions of various genetic groups in different countries, which should be useful to develop strategies for managing stripe rust in the global scale.

Technical Abstract: Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases of wheat worldwide. To understand the worldwide distribution of molecular groups, diversity, differentiation, and migration of the Pst populations, 567 Pst isolates collected from nine countries (China, Pakistan, Italy, Egypt, Ethiopia, Canada, Mexico, Ecuador, and the U.S.) in 2010-2018 were genotyped using 14 codominant simple sequence repeat markers. A total of 433 including 333 new multi-locus genotypes (MLGs) were identified, which were clustered into ten molecular groups (MGs). The MGs and country-wise populations differred in genetic diversity, heterozygosity, and correlation coefficient between the mark and virulence data. Many isolates from different countries, especially the isolates from Mexico, Ecuador, and the U. S. were found to be identical or closely related MLGs; and some of the MGs were present in all countries, indicating Pst migrations among different countries. Analysis of molecular variance revealed 78% variation among isolates, 12% variation among countries, and 10% variation among isolates within countries. Only low levels of differentiation were found by the pairwise comparisons of country populations. Of the 10 MGs, five were found to be involved in sexual and/or somatic recombination. The study provides the information on distributions of various Pst genetic groups in different countries, which should be useful to develop strategies for managing stripe rust in the global scale.