Mapping Key Genetic Factors in Spring Wheat for Disease Resistance

Jenn Hoskins
11th June, 2024

Mapping Key Genetic Factors in Spring Wheat for Disease Resistance

Image Source: Natural Science News, 2024

Key Findings

  • The study, conducted by the Agricultural Research Center (ARC) in the USA, focused on enhancing Fusarium head blight (FHB) resistance in wheat
  • Researchers identified 45 quantitative trait loci (QTL) associated with FHB resistance, with two significant QTL located on chromosomes 4AL and 4BL
  • The study highlighted the importance of using moderate rather than elite wheat crosses to discover new resistance alleles and improve wheat's resilience to FHB
Fusarium head blight (FHB) is a significant disease impacting wheat production, leading to reduced yield and quality. Traditional breeding approaches often rely on a limited pool of elite alleles, which can inadvertently advance pathogenic alleles. This study, conducted by the Agricultural Research Center (ARC), introduces new alleles derived from moderate rather than elite wheat crosses to enhance FHB resistance[1]. The research focused on crossing 'Parshall', a wheat variety with moderate resistance, with 'Reeder', which is moderately susceptible to FHB. The resulting population, consisting of 110 recombinant inbred lines (RILs), was tested across three states and multiple years in the USA, under both open-field and greenhouse conditions. The study assessed key traits related to FHB, such as incidence, severity, and index. A genetic map comprising 1417 centiMorgans (cM) of SNP/DArT markers was created. Through composite interval mapping, the study identified 45 quantitative trait loci (QTL) associated with FHB resistance. Two consistent QTL, located on chromosomes 4AL and 4BL, were found to be significant. The QTL on 4A correlated with previously identified FHB resistance, while the 4B QTL was linked to pathogen-responsive regions. These findings build upon earlier research that identified various mechanisms and genes involved in FHB resistance. For instance, previous studies have shown that the resistance locus Fhb1 in wheat genotype Nyubai leads to cell wall thickening due to the deposition of specific metabolites[2]. Additionally, research has identified candidate genes associated with FHB resistance, such as WFhb1_c1, which is related to the Fhb1 locus and may encode a pectin methyl esterase inhibitor[3]. In the current study, the 1- and 2-dimensional genome scans revealed 16 QTL and six pairs of interacting markers for resistance, with additive effects ranging from 0.17% to 2.19%. The study also examined additive × environment interactions, which varied between 0.04% and 3.18%, highlighting the significant impact of environmental factors on FHB resistance. Furthermore, three pairs of QTL with additive × additive effects were identified, with interactions ranging from 0.15% to 0.30%. The environmental interaction at these loci varied between 0.03% and 1%, confirming the role of genotype × environment (G × E) interactions in FHB resistance. The discovery of hidden heritable epistasis in the PR population for FHB resistance is a crucial finding. Epistasis refers to the interaction between different genes, where the effect of one gene is modified by one or several other genes. This hidden heritable epistasis can help breeders develop wheat lines that are better equipped to handle varying environmental conditions, thereby improving yield stability. This study's findings are particularly relevant in the context of previous research on wheat resistance to other pathogens. For example, the identification of the MlLX99 gene in the wheat cultivar Liangxing 99, which provides resistance to powdery mildew, demonstrates the potential for discovering new resistance loci in wheat[4]. By exploring moderate rather than elite crosses, this study offers a novel approach to enhancing FHB resistance and contributes to the broader understanding of plant-pathogen interactions. In conclusion, the ARC study provides valuable insights into the genetic basis of FHB resistance in wheat. The identification of new QTL and the discovery of hidden heritable epistasis offer promising avenues for breeding more resilient wheat varieties. These findings, combined with previous research on FHB and other wheat diseases, underscore the importance of leveraging diverse genetic resources to improve crop resistance and ensure food security in the face of changing environmental conditions.

AgricultureGeneticsPlant Science

References

Main Study

1) Mapping of main and hidden epistatic QTL effects in spring wheat population using medium parental FHB resistance

Published 10th June, 2024

https://doi.org/10.1007/s44372-024-00001-6

Related Studies

2) Integrated metabolo-proteomic approach to decipher the mechanisms by which wheat QTL (Fhb1) contributes to resistance against Fusarium graminearum.

https://doi.org/10.1371/journal.pone.0040695

3) Identification of functional genic components of major fusarium head blight resistance quantitative trait loci in wheat cultivar Sumai 3.

https://doi.org/10.1094/MPMI-10-12-0235-R

4) Genetic analysis and detection of the gene MlLX99 on chromosome 2BL conferring resistance to powdery mildew in the wheat cultivar Liangxing 99.

https://doi.org/10.1007/s00122-013-2194-6


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