Barley lys3 mutants are unique amongst shrunken-endosperm mutants in having abnormally large embryos

Cook, Frederick R.; Hughes, Nathan; Nibau, Cândida; Orman-Ligeza, Beata; Schatlowski, Nicole; Uauy, Cristóbal; Trafford, Kay

doi:10.1016/j.jcs.2018.04.013

Cited by 16 publications

(10 citation statements)

References 22 publications

(22 reference statements)

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“…Using BSR-seq and genetic fine mapping, we determined that the BPBF Q58L missense mutation is responsible for the lys3a mutant's pleiotropic defects. In addition to a drastic reduction in the accumulation of B-and C-hordeins (Doll, 1983), this mutant exhibits multiple other effects, including an increase in the accumulation of free and protein-bound Lys (Køie and Doll, 1979), an increase in the embryo size (Cook et al, 2018), a reduction in starch accumulation, shrunken seeds, and a decrease in yield (Munck and Jespersen, 2009). However, concerted breeding efforts aimed at increasing yield while maintaining the high-Lys phenotype, without regard to the hordein phenotype, minimized the negative effects of the mutation.…”

Section: Discussionmentioning

confidence: 99%

Development of Decreased-Gluten Wheat Enabled by Determination of the Genetic Basis of lys3a Barley

et al. 2019

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Celiac disease is the most common food-induced enteropathy in humans, with a prevalence of approximately 1% worldwide. It is induced by digestion-resistant, proline-and glutamine-rich seed storage proteins, collectively referred to as gluten, found in wheat (Triticum aestivum). Related prolamins are present in barley (Hordeum vulgare) and rye (Secale cereale). The incidence of both celiac disease and a related condition called nonceliac gluten sensitivity is increasing. This has prompted efforts to identify methods of lowering gluten in wheat, one of the most important cereal crops. Here, we used bulked segregant RNA sequencing and map-based cloning to identify the genetic lesion underlying a recessive, low-prolamin mutation (lys3a) in diploid barley. We confirmed the mutant identity by complementing the lys3a mutant with a transgenic copy of the wild-type barley gene and then used targeting-induced local lesions in genomes to identify induced single-nucleotide polymorphisms in the three homeologs of the corresponding wheat gene. Combining inactivating mutations in the three subgenomes of hexaploid bread wheat in a single wheat line lowered gliadin and low-molecular-weight glutenin accumulation by 50% to 60% and increased free and proteinbound lysine by 33%.

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Section: Discussionmentioning

confidence: 99%

Development of Decreased-Gluten Wheat Enabled by Determination of the Genetic Basis of lys3a Barley

et al. 2019

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“…Using BSR-seq and genetic fine mapping, we determined that the lys3a missense mutation is responsible for the pleiotropic defects found in lys3a barley. In addition to a drastic reduction in the accumulation of B and C hordeins [66] , this mutant exhibits multiple other effects including an increase in the accumulation of free and protein-bound lysine [18], an increase in the embryo size [67], a reduction in starch accumulation as well as shrunken seeds and a decrease in yield [68]. Concerted breeding efforts, whose objective was to increase yield while maintaining the high lysine phenotype, without regard to the hordein phenotype, however, minimized the negative effects of the mutation.…”

Section: Discussionmentioning

confidence: 99%

Development of reduced gluten wheat enabled by determination of the genetic basis of thelys3alow hordein barley mutant

Moehs

Austill

Holm

et al. 2018

Preprint

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Celiac disease is the most common food-induced enteropathy in humans with a prevalence of approximately 1% world-wide [1]. It is induced by digestion-resistant, proline-and glutamine-rich seed storage proteins, collectively referred to as "gluten," found in wheat. Related prolamins are present in barley and rye. Both celiac disease and a related condition called non-celiac gluten sensitivity (NCGS) are increasing in incidence [2] [3]. This has prompted efforts to identify methods of lowering gluten in wheat, one of the most important cereal crops. Here we used BSR-seq (Bulked Segregant RNA-seq) and map-based cloning to identify the genetic lesion underlying a recessive, low prolamin mutation (lys3a) in diploid barley. We confirmed the mutant identity by complementing the lys3a mutant with a transgenic copy of the wild type barley gene and then used TILLING (Targeting Induced Local Lesions in Genomes)[4] to identify induced SNPs (Single Nucleotide Polymorphisms) in the three homoeologs of the corresponding wheat gene. Combining inactivating mutations in the three sub-genomes of hexaploid bread wheat in a single wheat line lowered gliadin and low molecular weight glutenin accumulation by 50-60% and increased free and protein-bound lysine by 33%. This is the first report of the combination of mutations in homoeologs of a single gene that reduces gluten in wheat.Gluten is the common name for a complex mixture of approximately 100 proline-and glutamine-rich seed storage proteins found in wheat endosperm. In hexaploid bread wheat, in particular, gluten is responsible for the unique viscoelastic properties of dough used for making leavened bread. Related prolamins known as hordeins in barley and secalins in rye, but lacking the viscoelastic properties of wheat gluten, are found in the endosperms of these related cereals. Among gluten proteins, the most important for the elasticity and strength of bread dough are the polymeric high molecular weight glutenins [5]; monomeric gluten proteins, primarily gliadins, which are classified based on size, charge and repetitive amino acid sequences into α, β, γ and ω types, contribute to the viscosity of gluten [6] [7].Gluten is the causative factor of celiac disease, the most common food-induced autoimmune enteropathy in humans [1]. Celiac disease is found primarily in individuals expressing human leukocyte antigen (HLA) alleles DQ2 and/or DQ8. Immunodominant peptide epitopes have been found in α gliadins [8] and in ω gliadins of wheat and in C hordeins of barley [9]. Additional epitopes are also found in LMW and HMW-glutenins, gamma-gliadins from wheat and B and gamma hordeins from barley [10] [9]. Celiac disease patients exhibit a range of intestinal and extra-intestinal symptoms of which the most common is flattening of the villi of the small intestine, which can lead to poor absorption of nutrients and other pathological consequences. The only current treatment is a life-long avoidance of all gluten in the diet,which can be challenging given the prevalent use of gluten in diver...

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“…There are four characterized lys3 mutant lines, that were identified following chemical mutagenesis: Risø1508 lys3.a, Risø18 lys3.b, and Risø19 lys3.c (derived from the parent cultivar Bomi; Tallberg, 1973;Munck, 1992) and M1460 lys3.d (derived from Minerva; Aastrup, 1983). As described previously, lys3 embryos are larger than normal (Cook et al, 2018; Figure 1A), particularly those of M1460 (325% of fresh weight of the wild type cultivar Minerva; Supplementary Figure S1A). For comparison, we measured the size of the mature embryos of Golden Promise and Maythorpe and both genotypes have normal-sized embryos, similar to Minerva (Supplementary Figure S1A).…”

Section: The Lys3 Mutant M1460 Is Amenable To Transformationmentioning

confidence: 99%

“…Whilst working on mutants of barley affected at the LYS3 locus, we noticed that their developing embryos had an unusual cellular organization reminiscent of callus tissue (Cook et al, 2018). The LYS3 gene encodes a transcription factor called Prolamin Box-Binding Factor, and is expressed in developing and germinating grain (Moehs et al, 2019;Orman-Ligeza et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The LYS3 gene encodes a transcription factor called Prolamin Box-Binding Factor, and is expressed in developing and germinating grain (Moehs et al, 2019;Orman-Ligeza et al, 2019). The scutellar epidermis in lys3 mutants consists of multiple layers of cells instead of the usual single layer (Deggerdal et al, 1986;Cook et al, 2018). As well as abnormal cellular structure, lys3 mutant embryos are larger than normal and the grains show a range of other unusual phenotypes, including high lysine content, shriveled seeds and low starch content (Tallberg, 1973;Doll et al, 1974;Trafford and Fincher, 2014;Cook et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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TRA1: A Locus Responsible for Controlling Agrobacterium-Mediated Transformability in Barley

Orman-Ligeza¹,

Harwood²,

Hedley³

et al. 2020

Front. Plant Sci.

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In barley (Hordeum vulgare L.), Agrobacterium-mediated transformation efficiency is highly dependent on genotype with very few cultivars being amenable to transformation. Golden Promise is the cultivar most widely used for barley transformation and developing embryos are the most common donor tissue. We tested whether barley mutants with abnormally large embryos were more or less amenable to transformation and discovered that mutant M1460 had a transformation efficiency similar to that of Golden Promise. The large-embryo phenotype of M1460 is due to mutation at the LYS3 locus. There are three other barley lines with independent mutations at the same LYS3 locus, and one of these, Risø1508 has an identical missense mutation to that in M1460. However, none of the lys3 mutants except M1460 were transformable showing that the locus responsible for transformation efficiency, TRA1, was not LYS3 but another locus unique to M1460. To identify TRA1, we generated a segregating population by crossing M1460 to the cultivar Optic, which is recalcitrant to transformation. After four rounds of backcrossing to Optic, plants were genotyped and their progeny were tested for transformability. Some of the progeny lines were transformable at high efficiencies similar to those seen for the parent M1460 and some were not transformable, like Optic. A region on chromosome 2H inherited from M1460 is present in transformable lines only. We propose that one of the 225 genes in this region is TRA1.

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Barley lys3 mutants are unique amongst shrunken-endosperm mutants in having abnormally large embryos

Cited by 16 publications

References 22 publications

Development of Decreased-Gluten Wheat Enabled by Determination of the Genetic Basis of lys3a Barley

Development of Decreased-Gluten Wheat Enabled by Determination of the Genetic Basis of lys3a Barley

Development of reduced gluten wheat enabled by determination of the genetic basis of thelys3alow hordein barley mutant

TRA1: A Locus Responsible for Controlling Agrobacterium-Mediated Transformability in Barley

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