Screening of an Ethyl Methane Sulfonate Mutagenized Population of a Wheat Cultivar Susceptible to Fusarium Head Blight Identifies Resistant Variants

Abstract

Fusarium head blight (FHB) primarily caused by Fusarium graminearum is a key disease of small grains. Diseased spikes show symptoms of premature bleaching shortly after infection and have aborted or shriveled seeds, resulting in reduced yields. The fungus also deteriorates quality and safety of the grain due to production of mycotoxins, especially deoxynivalenol (DON), which can result in grain being docked or rejected at the point of sale. Genetic host resistance to FHB is quantitative and no complete genetic resistance against this devastating disease is available. Alternative approaches to develop new sources of FHB resistance are needed. In this study, we performed extensive forward genetic screening of the M4 generation of an EMS induced mutagenized population of cultivar Jagger to isolate variants with FHB resistance. In field testing, 74 mutant lines were found to have resistance against FHB spread and 30 lines out of these also had low DON content. Subsequent testing over two years in controlled greenhouse conditions revealed ten M6 lines showing significantly lower FHB spread. Seven and six lines out of those 10 lines also had reduced DON content and lower FDKs, respectively. Future endeavors will include identification of the mutations that led to resistance in these variants.

Reducing the generation time in winter wheat cultivars using speed breeding

“…Though cultural practices are an important aspect of increasing wheat productivity, genetic gain stands to be a major player in remedying an impending issue (Hawkesford et al., 2013; Mueller et al., 2012). Breeders have a toolbox in front of them, that is, growing as the cost of sequencing goes down, and the availability of genetic resources increases (Chhabra, Singh et al., 2021; Chhabra, Tiwari et al., 2021; Dong et al., 2020; Liang et al., 2017; Sánchez‐Martín et al., 2016; Walkowiak et al., 2020). We have the ability now to make accurate crosses using genetic markers or predict the breeding value of new varieties using genomic selection, technologies that did not exist during the Green Revolution (Bassi et al., 2016; Gupta et al., 2010; Pingali, 2012).…”

Important wheat diseases in the US and their management in the 21st century

“…Wheat RPL3 gene family, Ethylene Insensitive 2 (EIN2), TaLpx-1 gene and transcription factor gene TaNFXL1 were reported as susceptibility genes for FHB in wheat ( Lucyshyn et al., 2007 ; Brauer et al., 2019 ). EMS mutagenized populations can be utilized to find resistance against FHB ( Rawat et al., 2019 ; Singh et al., 2019 ; Chhabra et al., 2021a ). Chromosome arms 2DS, 3DL, 4DS and 7AS were also reported in the literature to be harboring major effect susceptibility genes for FHB ( Basnet et al., 2012 ; Garvin et al., 2015 ; Hales et al., 2020 ; Chhabra et al., 2021b ).…”

Approaching 25 years of progress towards Fusarium head blight resistance in southern soft red winter wheat (Triticum aestivum L.)

“…With this stated, knowledge remains limited about S genes in wheat and their potential to increase FHB resistance (Chhabra, Tiwari, et al, 2021; Fabre et al, 2020; Hales et al, 2020). However, wheat TILLING populations and their forward genetic screening suggest an exciting route to perform genome‐wide discovery of novel S genes (Chhabra, Singh, et al, 2021). In the study by Chhabra, Tiwari, et al (2021), the authors screened a highly susceptible winter wheat EMS‐induced TILLING population of cultivar ‘Jagger’, and repetitive phenotypic validations of mutant phenotypes allowed them to identify 12 different phenotypic mutants.…”

“…Garvin et al (2015) further showed that deletion of 19% of the chromosome 3DL arm increases FHB resistance (Garvin et al, 2015). A more recent study by Hales et al (2020) reported that deletion of a 32‐Mb region on chromosome 4D significantly increased FHB resistance while (Chhabra, Singh, et al, 2021) later identified a major and conserved S factor or gene on wheat chromosome 7A localized in a 40‐Mb region. These studies indicate that engineering S genes using a precise and efficient gene‐editing approach has great potential to enhance FHB resistance in wheat (Garcia‐Ruiz et al, 2021; Zaidi et al, 2018).…”