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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Publications at this Location » Publication #380631
Research Project: Genetic Enhancement of Sunflower Yield and Tolerance to Biotic Stress

Location: Sunflower and Plant Biology Research

Title: Discovery and mapping of two new rust resistance genes, R17 and R18, in sunflower using genotyping by sequencing

Author
item Qi, Lili
item TALUKDER, ZAHIRUL - North Dakota State University
item MA, GUOJIA - North Dakota State University
item LI, XUEHUI - North Dakota State University

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2021
Publication Date: 4/10/2021
Citation: Qi, L., Talukder, Z., Ma, G., Li, X. 2021. Discovery and mapping of two new rust resistance genes, R17 and R18, in sunflower using genotyping by sequencing. Theoretical and Applied Genetics. 134:2291-2301. https://doi.org/10.1007/s00122-021-03826-x.
DOI: https://doi.org/10.1007/s00122-021-03826-x

Interpretive Summary: Sunflower is an important oil crop grown in many countries and supplies 11% of crude vegetable oil production in the world. Rust is a serious fungal disease in sunflower-growing areas worldwide with increasing importance in North America in recent years due to frequent changes in pathogen populations. The emergence of novel pathogen virulence has rendered most commercial hybrids susceptible to rust; therefore, it is necessary to discover novel rust resistance genes for breeding efforts and, ultimately, long-term management of sunflower rust. In the present study, we discovered two new rust resistance genes, R17 and R18, introduced from South Africa, and molecularly mapped them to sunflower chromosome 13. Two germplasms, HA-R18 and HA-R19, were developed with resistance to the most predominant and virulent rust races, respectively, and the molecular markers tightly linked to R17 and R18 identified in this study would be useful for marker-assisted selection efforts for R17 and R18 and gene pyramiding in sunflower breeding programs to extend durable resistance.

Technical Abstract: Rust, caused by the fungus Puccinia helianthi Schw., is one of the most serious diseases of sunflower in the world. The rapid changes that occur in the virulence characteristics of pathogen populations present a continuous threat to the effectiveness of existing rust-resistant hybrids. Thus, there is a continued need for the characterization of genetically diverse sources of rust resistance. In this study we report to identify two new rust resistance genes, R17 and R18, from the sunflower lines, KP193 and KP199, introduced from South Africa. The inheritance of rust resistance was investigated in both lines using two mapping populations developed by crossing the resistant plants selected from KP193 and KP199 with a common susceptible parent HA 89. The F2 populations were first genotyped using genotyping by sequencing for mapping of the rust genes and further saturated with markers in the target region. Molecular mapping positioned the two genes at the lower end of sunflower chromosome 13 within a large gene cluster. Two cosegregating SNP markers, SFW01497 and SFW08875, were distal to R17 at a 1.9 cM genetic distance, and a marker cluster with five cosegregating SNPs was proximal to R17 at 0.7 cM. R18 cosegregated with the SNP marker SFW04317 and was proximal to two cosegregating SNPs, SFW01497 and SFW05453, at 1.9 cM. These maps provide markers for stacking R17 or R18 with other broadly effective rust resistance genes to extend the durability of rust resistance. The relationship of the six rust resistance genes in the cluster was discussed.