Pathogenomic analysis of South African stripe rust populations
H. VAN SCHALKWYK (1), R. Prins (2), Z. Pretorius (1), L. Boyd (3), C. Uauy (4), D. Saunders (5) (1) University of the Free State, South Africa; (2) CenGen (Pty) Ltd and University of the Free State, South Africa; (3) National Institute of Agricultural Botany, United Kingdom; (4) John Innes Centre, United Kingdom; (5) The Genome Analysis Centre and The John Innes Centre, United Kingdom

Stripe (yellow) rust, caused by the fungus Puccinia striiformis f. sp. tritici (PST), is a major threat to wheat cultivation worldwide. PST utilizes water and nutrients from the plant, reducing yield and grain quality. Over the last decade strains with higher infection rates and adaptability to diverse environments were observed. In South Africa (RSA) stripe rust was first detected in 1996, after which three more races were detected via an apparent step-wise virulence gain. A better understanding of the RSA PST races and their global significance is needed. We followed a next generation sequencing approach to determine the relationship between the four historical races and to show their potential origin. We used phylogeny to compare the RSA isolates to isolates from Europe, Pakistan and East Africa, and found that the RSA isolates were most closely related to those from East Africa. Through pairwise comparison of coding regions in the RSA isolates, we identified 29 putative effector proteins as candidates for causing differential virulence profiles. We are now undertaking gene expression profiling to determine if these putative effectors are specifically upregulated during infection. In addition, we sequenced isolates from 2013, 2014 and 2015 to compare current races in the field with the historical isolates. This study provides an in depth view on stripe rust in RSA and adds valuable information about the potential origin and adaptation of stripe rust in South Africa.

Abstract Number: C23-5, P11-393
Session Type: Concurrent