Genome Wide Association Study of Karnal Bunt Resistance in a Wheat Germplasm Collection from Afghanistan

Vikas Gupta,Philomin Juliana,Pawan K Singh,Najibeh Ataei,Guillermo Fuentes-Davila,Xinyao He,Rajiv K Sharma,Susanne Dreisigacker,Naresh Kumar

doi:10.3390/ijms20133124

Abstract

Karnal bunt disease of wheat, caused by the fungus Neovossia indica, is one of the most important challenges to the grain industry as it affects the grain quality and also restricts the international movement of infected grain. It is a seed-, soil- and airborne disease with limited effect of chemical control. Currently, this disease is contained through the deployment of host resistance but further improvement is limited as only a few genotypes have been found to carry partial resistance. To identify genomic regions responsible for resistance in a set of 339 wheat accessions, genome-wide association study (GWAS) was undertaken using the DArTSeq® technology, in which 18 genomic regions for Karnal bunt resistance were identified, explaining 5–20% of the phenotypic variation. The identified quantitative trait loci (QTL) on chromosome 2BL showed consistently significant effects across all four experiments, whereas another QTL on 5BL was significant in three experiments. Additional QTLs were mapped on chromosomes 1DL, 2DL, 4AL, 5AS, 6BL, 6BS, 7BS and 7DL that have not been mapped previously, and on chromosomes 4B, 5AL, 5BL and 6BS, which have been reported in previous studies. Germplasm with less than 1% Karnal bunt infection have been identified and can be used for resistance breeding. The SNP markers linked to the genomic regions conferring resistance to Karnal bunt could be used to improve Karnal bunt resistance through marker-assisted selection.

Highlights

Wheat (Triticum aestivum L.) is one of the most important staple cereals grown worldwide contributing about 21% of the energy intake of the world population [1]
Sschi.o2w01i9n, g20,s3ig12n4ificant MTAs were tested for linkage disequilibrium (LD) among each o6tohfe1r5, 24 and the results showed that two SNPs on 5BL (1079540 and 1083023) were in LD, indicating that they
The current study made use of a germplasm collection comprising of Afghan landraces and breeding lines mostly of CIMMYT origin disseminated to the country to identify new Karnal bunt resistance sources that can be integrated into the breeding programs to diversify resistance to this disease

Summary

Introduction

Wheat (Triticum aestivum L.) is one of the most important staple cereals grown worldwide contributing about 21% of the energy intake of the world population [1]. The disease is characterized by the replacement of a part of the seed with a black powdery mass of spores. This disease affects the grain weight and the grain quality of wheat due to the production of trimethylamine with an unpleasant rotten fishy smell [2]. Trade liberalization, globalization and international transportation of people and commodities have increased the potential for disease incursion [12,13]. Once this pathogen is established in the soil, it is very difficult to eradicate [14,15]. Countries such as Australia, USA, EU countries and China have imposed strict quarantine regulations regarding the import/export of wheat grains to prevent the accidental entry of the pathogen [16,17]

Methods

Findings

Discussion

Conclusion