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'MN‐Torgy' (Reg. no. CV‐1203, PI 698205) hard red spring wheat (Triticum aestivium L.) was released by the University of Minnesota Agricultural Experiment Station in 2020 because of its high grain yield, disease resistance, and end‐use quality characteristics. MN‐Torgy is a medium‐maturity cultivar with above average plant height despite containing the semi‐dwarfing allele Rht24b. MN‐Torgy has moderate resistance to Fusarium head blight (caused primarily by Fusarium graminearum Schwabe) and good resistance to prevalent races of pathogens causing leaf rust (Puccinia triticina Eriks.) and stem rust (Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn.) and is well adapted to the north‐central United States. MN‐Torgy also has good adult plant resistance to the Ug99 family of stem rust races. Core Ideas: MN‐Torgy is a new hard red spring wheat cultivar.MN‐Torgy spring wheat has field resistance to the Ug99 family of stem rust races.MN‐Torgy spring wheat is moderately resistant to Fusarium head blight. [ABSTRACT FROM AUTHOR]

The development of wheat (Triticum aestivum L.) cultivars resistant to Fusarium head blight (FHB) (caused by Fusarium graminearum Schwabe) requires screening methodologies that accurately characterize reaction to this disease. The objectives of this study were (i) to characterize the stability of cultivars for their FHB reaction and (ii) to define an optimum resource allocation for FHB evaluation. Fourteen cultivars were evaluated in FHB-screening nurseries at two locations across a 4-yr period. Field data were used to calculate disease incidence (INC) as the frequency of symptomatic spikes and disease index (DIS) as the mean disease score of all spikes. FHB reaction also was evaluated on harvested grain as percent visually scabby kernels (VSK) and deoxynivalenol (DON) concentration. Significant differences among cultivars for all FHB parameters were found in each environment. Pearson correlation coefficients among FHB parameters were positive and highly significant, ranging from 0.32 between INC and DON to 0.72 between INC and DIS. Spearman rank correlation coefficients for yearly cultivar rankings and Kendall's coefficient of concordance were high, indicating similarity of the rankings of the tested cultivars in different environments. Visually scabby kernels was the FHB parameter with highest similarity for cultivar ranking across environments. Most of the cultivars, including susceptible ones, expressed stability for FHB reaction. Optimum resource allocation for DIS was most affected by the number of environments with three being the minimum to accurately characterize a genotype's resistance level. Using more than three replications or scoring more than 10 spikes per plot had little practical value in characterizing FHB reaction., FUSARIUM HEAD BLIGHT, caused primarily by Fusarium graminearum, is an important disease throughout major spring wheat-production regions of the USA, Canada, and other parts of the world. Even low disease [...]

Fusarium head blight (FHB) is a disease problem (primarily caused by Fusarium graminearum Schwabe) that affects the quality and yield of barley (Hordeum vulgare L.) grain. The objectives of this study were to identify the location of quantitative trait loci (QTL) for resistance to FHB in a two-rowed by six-rowed population, to examine the association of FHB resistance with heading date and the Vrs1 (two-rowed spike morphology) locus, to validate the location of the major FHB resistance QTL primarily detected in the field, and to identify simple sequence repeat (SSR) markers linked to the QTL for FHB resistance. We created a genetic map of 143 molcular markers from a population derived from the parents Fredrickson (two-rowed, moderately resistant) and Stander (six-rowed, susceptible). The Fredrickson/Stander population was evaluated in two field environments by a grain spawn inoculation method, two field environments by a spray inoculation, and two greenhouse environments. QTL analysis detected three distinct regions on chromosome 2(2H) associated with FHB resistance; two of these regions were also associated with resistance to deoxynivalenol (DON) accumulation. One FHB resistance QTL was also associated with heading date, while another FHB resistance QTL was found associated with the Vrs1 locus. The third FHB resistance QTL was detected only in the greenhouse, but was coincident with a QTL for resistance to DON accumulation in the field. All three QTL were detected in the greenhouse, indicating that this environment may be useful for selecting FHB resistant barley genotypes. SSR markers were identified that are linked with each QTL and could prove useful for marker-assisted trait manipulation. Finally, the two major QTL detected in the field were validated using an independent population with Fredrickson and Stander parents., FUSARIUM HEAD BLIGHT has become a significant disease problem in barley in several regions around the world. In 1993, FHB reemerged in the northern Great Plains causing about $406 million [...]

Fusarium head blight continues to be a threat to spring wheat (Triticum aestivum L.) production in the north‐central region of the United States. 'Lang‐MN' (Reg. no. CV‐1182, PI 687038) hard red spring wheat was released by the University of Minnesota Agricultural Experiment Station in 2017 because it combines the best available Fusarium head blight resistance with high grain yield, grain protein concentration, and good end‐use quality characteristics. Lang‐MN is a mid‐late maturity cultivar that also has acceptable lodging resistance despite its above average plant height owing to its lack of the semi‐dwarfing genes Rht‐B1 or Rht‐D1 but presence of Rht24. Lang‐MN has good resistance to the prevalent races of leaf rust, stripe rust, and stem rust and is well adapted to the north‐central United States. [ABSTRACT FROM AUTHOR]

`McVey' is a hard red spring wheat (Triticum aestivum L.) (Reg. no. CV-894, PI 612966) cooperatively developed and released by the Minnesota Agricultural Experiment Station and USDA-ARS in February 1999. [...]

`HJ98' is a hard red spring wheat (Triticum aestivum L.) (Reg. no. CV-872, PI 608723) cooperatively developed and released by the Minnesota Agricultural Experiment Station and USDA-ARS in February 1998. [...]

Fusarium culmorum (Fc) and F. graminearum (Fg) belong to the predominant causal agents of fusarium crown and root rot (FCR) in wheat. While many studies have been done to investigate crown rot, including stem base infection, root colonization and mycotoxin production associated with root rot is not well understood. In this study the impact of mycotoxins on the colonization of wheat roots and stem bases was analysed by using Fc and Fg isolates that varied in both quantity and types of trichothecenes they produce. Seedling inoculations in growth chambers with a high deoxynivalenol (DON)‐ and 3‐acetyldeoxynivalenol (3ADON)‐producing isolate led to more severe symptoms and 20‐times greater colonization of the stem base, as measured by Fc DNA accumulation, than isolates that produced less DON/3ADON. In contrast to stem base colonization, in vitro inoculations of roots with a Tri5 deletion mutant deficient in Fg trichothecene production led to three‐times higher colonization than the wildtype. Furthermore, an Fc isolate that produced low levels of zearalenone resulted in twice the level of colonization of a high DON/3ADON‐producing isolate included in the study. When root inoculation with a low DON/3ADON‐producing Fc isolate was supplemented with exogenous DON, DON production decreased by more than half per unit weight of Fc DNA, and root colonization doubled compared to the untreated control. Therefore, in contrast to its potential role as an aggressiveness factor in stem base infection, trichothecene production by Fc and Fg is detrimental to the early stages of wheat root colonization in FCR. [ABSTRACT FROM AUTHOR]

'Ulen' is a hard red spring wheat (Triticum aestivum L.) (Reg. no. CV-984, PI 639921) cultivar developed and released by the Minnesota Agricultural Experiment Station in cooperation with USDA-ARS in [...]

'Oklee' is a hard red spring wheat (Triticum aestivum L.) (Reg. no. CV-963, PI 634553) developed and released by the Minnesota Agricultural Experiment Station in cooperation with USDA-ARS in January [...]

`Lacey' a six-rowed spring barley (Hordeum vulgare L.) (Reg. no. CV-290, PI 613603), was developed by the Minnesota Agricultural Experiment Station and released in February 2000. It was developed in [...]

`MNBrite' (Reg. no. CV-275, PI 603050) is a spring barley (Hordeum vulgate L.) developed by the Minnesota Agricultural Experiment Station and released in February 1998. MNBrite was developed in a [...]

The presence of Fusarium spp. was examined in the residues of wheat, barley, corn, sunflower, pasture, and gramineous weed species common in wheat and barley cropping systems collected from no-tillage and reduced-tillage plots from February 2001 to March 2003 in Uruguay. Gibberella zeae was recovered from residues of wheat, barley, corn, sunflower, fescue, and the gramineous weeds Digitaria sanguinalis, Setaria spp., Lolium multifiorum, and Cynodon dactyIon, except from birdsfoot trefoil or white clover. Of the Fusarium spp. obtained, G. zeae was the most frequently recovered from wheat and barley residues, while other species were more common in other crops. G. zeae declined over time in all residues examined. Wheat and barley residues produced more ascospores of G. zeae than corn or other gramineous residues. Sunflower residue did not support ascospore production, indicating that it probably did not contribute to primary inoculum. Wheat and barley residues supported G. zeae colonization longer in no-till than in reduced-tillage production systems and, thus, may represent major contributors to Fusarium head blight (FHB) inoculum in Uruguay. The presence of C. zeae in the gramineous components of pastures, weed species, and sunflower should be considered when implementing control strategies for FHB. [ABSTRACT FROM AUTHOR]

Survival and inoculum production of Gibberella zeae (Schwein.) Petch (anamorph Fusarium graminearum (Schwabe)), the causal agent of Fusarium head blight of wheat and barley, was related to the rate of wheat (Triticum aestivum L.) residue decomposition. Infested wheat residue, comprising intact nodes, internodes, and leaf sheaths, was placed in fiberglass mesh bags on the soil surface and at 7.5- to 10-cm and 15- to 20-cm depths in chisel-plowed plots and 15 to 20 cm deep in moldboard-plowed plots in October 1997. Residue was sampled monthly from April through November during 1998 and every 2 months through April to October 1999. Buried residue decomposed faster than residue placed on the soil surface. Less than 2% of the dry-matter residue remained in buried treatments after 24 months in the field, while 25% of the residue remained in the soil-surface treatment. Survival of G. zeae on node tissues was inversely related to the residue decomposition rate. Surface residue provided a substrate for G. zeae for a longer period of time than buried residue. Twenty-four months after the initiation of the trial, the level of colonization of nodes in buried residue was half the level of colonization of residue on the soil surface. Colonization of node tissues by G. zeae decreased over time, but increased for other Fusarium spp. Ascospores of G. zeae were still produced on residue pieces after 23 months, and these spores were capable of inducing disease. Data from this research may assist in developing effective management strategies for residues infested with G. zeae. [ABSTRACT FROM AUTHOR]

Relates the percent of Amelanchier alnifolia, commonly known as saskatoon leaf area infected to the relative concentration of Entomosporium mespili conidia released from the infected tissue and the development of a regression equation for the relationship. Identification when the E.mespili conidia are released in relation to prevailing environmental conditions during the growing season; Determination whether the amount of conidia released is related to the amount of rainfall during precipitation events.

The article offers information the registration of Ada hard red spring wheat cultivar, which was developed and released by the Minnesota Agricultural Experiment Station together with the U.S. Department of Agriculture's (USDA) Agricultural Research Service. High grain yield and protein content, leaf rust resistance, and straw strength were among the basis used in releasing Ada. The bread making properties of Ada were also evaluated by the USDA Spring Wheat Quality Laboratory. Information about the loaf, grain, and protein volume of the wheat were also provided.

Deoxynivalenol (DON) levels are not easily predicted from visual disease assessment, and it is thought likely that environmental conditions such as temperature and moisture influence DON accumulation. This field study examined the influence of environmental moisture on DON accumulation in Fusarium-infected wheat (Triticum aestivum). The effect of extended mist irrigation applied from inoculation (at anthesis) until harvest was compared with mist irrigation applied from inoculation until disease assessment (at early dough), as is generally applied in screening nurseries used for germplasm selection and cultivar improvement. DON concentrations were quantified in kernels at early dough, hard dough, kernel hard, and maturity. Kernels from plots with extended mist irrigation generally had lower DON concentrations than those from plots where mist irrigation was not applied following disease assessment. DON concentrations tended to decrease from disease assessment until harvest, regardless of the irrigation treatment. DON concentrations in the cultivars moderately resistant to Fusarium head blight were lower than those in the susceptible cultivar. Environmental moisture is an important factor determining the DON content of Fusarium-infected wheat. [ABSTRACT FROM AUTHOR]

One of the major concerns with Fusarium head blight (FHB) of barley is the potential health risks to livestock and humans through the accumulation of the mycotoxin deoxynivalenol (DON) in infected grain. To define the role of the host in DON accumulation during the early stages of disease development, we conducted a series of greenhouse experiments. We inoculated single spikelets of greenhouse-grown plants with Fusarium graminearum, moved the plants to a dew chamber, and harvested the inoculated spikelets after 72 h for DON analysis. We conducted a quantitative trait locus (QTL) analysis using a genetic mapping population, constructed with the parents Stander and Frederickson, that segregated for DON accumulation after single-spikelet inoculation in two experiments. A single QTL on chromosome 3 explained 18 and 35% of the phenotypic variation in the two experiments. To validate this QTL for DON accumulation, we used a DNA marker to select near-isogenic lines from a family from the mapping population that was segregating at this QTL. Disease symptom development was similar between the nearisogenic lines; however, the mean DON concentration of the lines homozygous for the allele from the high DON parent was 2.5-fold more than the lines homozygous for the alternate allele. A time course experiment showed that this effect on toxin accumulation was observed at 10 days post inoculation. The near-isogenic lines developed in this study should prove useful for further exploration of the role of DON in FHB. [ABSTRACT FROM AUTHOR]

Integrated Fusarium head blight (FHB) management programs consisting of different combinations of cultivar resistance class and an application of the fungicide prothioconazole + tebuconazole at or after 50% early anthesis were evaluated for efficacy against FHB incidence (INC; percentage of diseased spikes), index (IND; percentage of diseased spikelets per spike), Fusarium damaged kernel (FDK), deoxynivalenol (DON) toxin contamination, grain yield, and test weight (TW) in inoculated field trials conducted in 11 U.S. states in 2014 and 2015. Mean log response ratios and corresponding percent control values for INC, IND, FDK, and DON, and mean differences in yield and TW relative to a nontreated. inoculated susceptible check (S_CK), were estimated through network meta-analyses as measures of efficacy. Results from the analyses were then used to estimate the economic benefit of each management program for a range of grain prices and fungicide applications costs. Management programs consisting of a moderately resistant (MR) cultivar treated with the fungicide were the most efficacious, reducing INC by 60 to 69%, IND by 71 to 76%, FDK by 66 to 72%, and DON by 60 to 64% relative to S_CK, compared with 56 to 62% for INC, 68 to 72% for IND, 66 to 68% for FDK, and 58 to 61% for DON for programs with a moderately susceptible (MS) cultivar. The least efficacious programs were those with a fungicide application to a susceptible (S) cultivar, with less than a 45% reduction ot INC, IND, FDK, or DON. All programs were more efficacious under conditions favorable for FHB compared with less favorable conditions, with applications made at 50% early anthesis being of comparable efficacy to those made 2 to 7 days later. Programs with an MS cultivar resulted in the highest mean yield increases relative to S_CK (541 to 753 kg/ha), followed by programs with an S cultivar (386 to 498 kg/ha) and programs with an MR cultivar (250 to 337 kg/ha). Integrated management programs with an MS or MR cultivar treated with the fungicide at or after 50% early anthesis were the most likely to result in a 50 or 75% control of IND, FDK, or DON in a future trial. At a fixed fungicide application cost, these programs were $4 to S319/MT more economically beneficial than corresponding fungicide-only programs, depending on the cultivar and grain price. These findings demonstrate the benefits of combining genetic resistance with a prothioconazole + tebuconazole treatment to manage FHB, even if that treatment is applied a few days after 50% early anthesis. [ABSTRACT FROM AUTHOR]

Field trials were conducted in 17 U.S. states to evaluate the effects of quinone outside inhibitor (QoI) and demethylation inhibitor (DMI) fungicide programs on Fusarium head blight index (IND) and deoxynivalenol (DON) toxin in wheat. Four DMI-only treatments applied at Feekes 10.5.1, five QoI-only treatments applied between Feekes 9 or Feekes 10.5, three QoI+DMI mixtures applied at Feekes 10.5, and three treatments consisting of a QoI at Feekes 9 followed by a DMI at Feekes 10.5.1 were evaluated. Network meta-analytical models were fitted to log-transformed mean IND and DON data and estimated contrasts of log means were used to obtain estimates of mean percent controls relative to the nontreated check as measures of efficacy. Results from the meta-analyses were also used to assess the risk of DON increase in future trials. DMI at Feekes 10.5.1 were the most effective programs against IND and DON and the least likely to increase DON in future trials. QoI-only programs increased mean DON over the nontreated checks and were the most likely to do so in future trials, particularly when applied at Feekes 10.5. The effects of QoI+DMI combinations depended on the active ingredients and whether the two were applied as a mixture at heading or sequentially. Following a Feekes 9 QoI application with a Feekes 10.5.1 application of a DMI reduced the negative effect of the QoI on DON but was not sufficient to achieve the efficacy of the Feekes 10.5.1 DMI-only treatments. Our results suggest that one must be prudent when using QoI treatments under moderate to high risk of FHB, particularly where the QoI is used without an effective DMI applied in combination or in sequence. [ABSTRACT FROM AUTHOR]

Integration of host resistance and prothioconazole + tebuconazole fungicide application at anthesis to manage Fusarium head blight (FHB) and deoxynivalenol (DON) in wheat was evaluated using data from over 40 trials in 12 U.S. states. Means of FHB index (index) and DON from up to six resistance class-fungicide management combina-tions per trial (susceptible treated [S_TR] and untreated [S_UT]; moderately susceptible treated [MS_TR] and untreated [MS_UT]; moderately resistant treated [MR_TR] and untreated [MR_UT]) were used in multivariate meta-analyses, and mean log response ratios across trials were estimated and transformed to estimate mean percent control ( C ) due to the management combinations relative to S_UT. All combinations led to a significant reduction in index and DON (P < 0.001). MR_TR was the most effective combination, with a C of 76% for index and 71% for DON, followed by MS_TR (71 and 58%, re-spectively), MRJJT (54 and 51%, respectively), S_TR (53 and 39%, respectively), and MS_UT (43 and 30%, respectively). Calculations based on the principle of treatment independence showed that the combination of fungicide application and resistance was additive in terms of percent control for index and DON. Management combina-tions were ranked based on percent control relative to S_UT within each trial, and nonparametric analyses were performed to determine management combination stability across environments (trials) using the Kendall coefficient of concordance (W). There was a significant concordance of management combinations for both index and DON (P < 0.001), indicating a nonrandom ranking across environments and relatively low variability in the within-environment ranking of manage-ment combinations. MR_TR had the highest mean rank (best control relative to S_UT) and was one of the most stable management com-binations across environments, with low rank stability variance (0.99 for index and 0.67 for DON). MS_UT had the lowest mean rank (poor-est control) but was also one of the most stable management combina-tions. Based on Piepho's nonparametric rank-based variance homo-geneity U test, there was an interaction of management combination and environment for index (P = 0.011) but not for DON (P = 0.147), indicating that the rank ordering for index depended somewhat on environment. In conclusion, although the magnitude of percent control will likely vary among environments, integrating a single tebuconazole + prothioconazole application at anthesis with cultivar resistance will be a more effective and stable management practice for both index and DON than either approach used alone. [ABSTRACT FROM AUTHOR]

Septoria speckled leaf blotch (SSLB), caused by Septoria passerinii Sacc., and net form net blotch (NB), caused by Pyrenophora teres f. teres Drechsler, are fungal diseases that decrease the yields of barley in the Upper Midwest. An effective way to manage these diseases is to plant resistant cultivars. To characterize the genetics of resistance to both pathogens, two advanced barley breeding lines, one resistant to NB (M120) and another resistant to SSLB (Sep2-72), were crossed, creating a population of 115 recombinant inbred lines. The two parents and the population were evaluated in three greenhouse seedling assays for each pathogen and for simple-sequence repeat and diversity arrays technology markers. Composite interval mapping revealed two major quantitative trait loci (QTL) associated with NB on chromosome 6H, located in bins 2 and 6. The QTL located in bin 6 explained 19 to 48% of the phenotypic variation and the QTL located in bin 2 explained 25 to 44% of the phenotypic variation. A new locus for resistance to SSLB, Rsp4, was identified on chromosome 6H, located in bins 3 to 4. Mapping these genes in elite breeding germplasm will accelerate the development and utilization of marker-assisted selection to enhance resistance to these diseases. [ABSTRACT FROM AUTHOR]

The Fusarium head blight (FHB) pathogen Fusarium graminearum produces the trichothecene mycotoxin deoxynivalenol and reduces wheat yield and grain quality. Spring wheat ( Triticum aestivum ) genotype CB037 was transformed with constitutive expression (CE) constructs containing sorghum ( Sorghum bicolor ) genes encoding monolignol biosynthetic enzymes caffeoyl coenzyme A (CoA) 3- O -methyltransferase ( SbCCoAOMT ), 4-coumarate-CoA ligase ( Sb4CL ), or coumaroyl shikimate 3-hydroxylase ( SbC3'H ) or monolignol pathway transcriptional activator SbMyb60 . Spring wheats were screened for type I (resistance to initial infection, using spray inoculations) and type II (resistance to spread within the spike, using single-floret inoculations) resistances in the field (spray) and greenhouse (spray and single floret). Following field inoculations, disease index, percentage of Fusarium -damaged kernels (FDK), and deoxynivalenol measurements of CE plants were similar to or greater than those of CB037. For greenhouse inoculations, the area under the disease progress curve (AUDPC) and FDK were determined. Following screens, focus was placed on two each of SbC3'H and SbCCoAOMT CE lines because of trends toward a decreased AUDPC and FDK observed following single-floret inoculations. These four lines were as susceptible as CB037 following spray inoculations. However, single-floret inoculations showed that these CE lines had a significantly reduced AUDPC ( P < 0.01) and FDK ( P ≤ 0.02) compared with CB037, indicating improved type II resistance. None of these CE lines had increased acid detergent lignin compared with CB037, indicating that lignin concentration may not be a major factor in FHB resistance. The SbC3'H and SbCCoAOMT CE lines are valuable for investigating phenylpropanoid-based resistance to FHB., Competing Interests: The author(s) declare no conflict of interest.

Bacterial leaf streak, bacterial blight, and black chaff caused by Xanthomonas translucens pathovars are major diseases affecting small grains. Xanthomonas translucens pv. translucens and X. translucens pv. undulosa are seedborne pathogens that cause similar symptoms on barley, but only X. translucens pv. undulosa causes bacterial leaf streak of wheat. Recent outbreaks of X. translucens have been a concern for wheat and barley growers in the Northern Great Plains; however, there are limited diagnostic tools for pathovar differentiation. We developed a multiplex PCR based on whole-genome differences to distinguish X. translucens pv. translucens and X. translucens pv. undulosa . We validated the primers across different Xanthomonas and non- Xanthomonas strains. To our knowledge, this is the first multiplex PCR to distinguish X. translucens pv. translucens and X. translucens pv. undulosa . These molecular tools will support disease management strategies enabling detection and pathovar incidence analysis of X. translucens . [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license., Competing Interests: The author(s) declare no conflict of interest.

Bacterial leaf streak (BLS) of wheat ( Triticum aestivum ), caused by Xanthomonas translucens pv. undulosa , is a disease of major concern in the Northern Great Plains. The host range for X. translucens pv. undulosa is relatively broad, including several small grains and perennial grasses. In Minnesota, X. translucens pv. undulosa was isolated from weedy grasses in and around wheat fields that exhibited BLS symptoms and from cultivated wild rice ( Zizania palustris ) with symptomatic leaf tissue. Currently, no genomic resources are available for X. translucens pv. undulosa strains isolated from non-wheat hosts. In this study, we sequenced and assembled the complete genomes of five strains isolated from weedy grass hosts, foxtail barley ( Hordeum jubatum ), green foxtail ( Setaria viridis ), and wild oat ( Avena fatua ), and from cultivated wild rice and wheat. These five genomes were compared with the publicly available genomes of seven X. translucens pv. undulosa strains originating from wheat and one genome of an X. translucens pv. secalis strain originating from rye ( Secale cereale ). Global alignments of the genomes revealed little variation in genomic structures. Average nucleotide identity-based phylogeny and life identification numbers revealed that the strains share ≥99.25% identity. We noted differences in the presence of Type III secreted effectors, including transcription activator-like effectors. Despite differences between strains, we did not identify unique features distinguishing strains isolated from wheat and non-wheat hosts. This study contributes to the availability of genomic data for X. translucens pv. undulosa from non-wheat hosts, thus increasing our understanding of the diversity within the pathogen population., Competing Interests: The author(s) declare no conflict of interest.

Competing Interests: The author(s) declare no conflict of interest.

Bacterial leaf streak (BLS) primarily affects barley and wheat and is mainly caused by the pathogens Xanthomonas translucens pv. translucens and X. translucens pv. undulosa , respectively. BLS is distributed globally and poses a risk to food security and the supply of malting barley. X. translucens pv. cerealis can infect both wheat and barley but is rarely isolated from these hosts in natural infections. These pathogens have undergone a confusing taxonomic history, and the biology has been poorly understood, making it difficult to develop effective control measures. Recent advancements in the ability and accessibility to sequence bacterial genomes have shed light on phylogenetic relationships between strains and identified genes that may play a role in virulence, such as those that encode Type III effectors. In addition, sources of resistance to BLS have been identified in barley and wheat lines, and ongoing efforts are being made to map these genes and evaluate germplasm. Although there are still gaps in BLS research, progress has been made in recent years to further understand epidemiology, diagnostics, pathogen virulence, and host resistance., Competing Interests: The author(s) declare no conflict of interest.

Xanthomonas translucens pv. translucens (Xtt) is a global barley patho-gen and a concern for resistance breeding and regulation. Long-read whole genome sequences allow in-depth understanding of pathogen diversity. We have completed long-read PacBio sequencing of two Minnesotan Xtt strains and an in-depth analysis of available Xtt genomes. We found that average nucleotide identity (ANI)-based approaches organize Xtt strains different from the previous standard multilocus sequencing analysis approach. According to ANI, Xtt forms a separate clade from X. translucens pv. undulosa and consists of three main groups which are represented on multiple continents. Some virulence factors, such as 17 Type III-secreted effectors, are highly conserved and offer potential targets for the elicitation of broad resistance. However, there is a high degree of variation in virulence factors, meaning that germplasm should be screened for resistance with a diverse panel of Xtt., Competing Interests: The author(s) declare no conflict of interest.

Bacterial leaf streak (BLS), caused chiefly by the pathogen Xanthomonas translucens pv. translucens , is becoming an increasingly important foliar disease of barley in the Upper Midwest. The deployment of resistant cultivars is the most economical and practical method of control. To identify sources of BLS resistance, we evaluated two panels of breeding lines from the University of Minnesota (UMN) and Anheuser-Busch InBev (ABI) barley improvement programs for reaction to strain CIX95 in the field at St. Paul and Crookston, MN, in 2020 and 2021. The percentage of resistant lines in the UMN and ABI panels with mid-season maturity was 1.8% (6 of 333 lines) and 5.2% (13 of 251 lines), respectively. Both panels were genotyped with the barley 50K iSelect SNP array, and then a genome-wide association study was performed. A single, highly significant association was identified for BLS resistance on chromosome 6H in the UMN panel. This association was also identified in the ABI panel. Seven other significant associations were detected in the ABI panel: two each on chromosomes 1H, 2H, and 3H and one on chromosome 5H. Of the eight associations identified in the panels, five were novel. The discovery of resistance in elite breeding lines will hasten the time needed to develop and release a BLS-resistant cultivar., Competing Interests: The author(s) declare no conflict of interest.

Bacterial leaf streak (BLS) is a sporadic yet damaging disease of cereals that is growing in importance across the Upper Midwest production region. In barley ( Hordeum vulgare ssp. vulgare ), this disease is caused primarily by the bacterium Xanthomonas translucens pv. translucens . Accessions resistant to BLS have been reported in past studies, but few have been rigorously validated in the field. To identify accessions carrying diverse resistance alleles to BLS, a largescale germplasm screening study was undertaken against strain CIX95 of X. translucens pv. translucens in St. Paul and Crookston, Minnesota, in 2020 and 2021. The germplasm screened was diverse and included adapted breeding lines from two improvement programs, two landrace panels (one global and one from Ethiopia/Eritrea), introgression lines from wild barley ( H. vulgare ssp. spontaneum ) in the genetic background of barley cultivar 'Rasmusson', and an assemblage of accessions previously reported to carry BLS resistance. Of the 2,094 accessions evaluated in this study, 32 (1.5%) exhibited a consistently high level of resistance across locations and years and had heading dates similar to standard cultivars grown in the region. Accessions resistant to BLS were identified from all germplasm panels tested, providing genetically diverse sources for barley improvement programs focused on breeding for resistance to this important bacterial disease.

Frequent occurrences of high levels of Fusarium mycotoxins have been recorded in Norwegian oat grain. To elucidate the influence of tillage operations on the development of Fusarium and mycotoxins in oat grain, we conducted tillage trials with continuous oats at two locations in southeast Norway. We have previously presented the content of Fusarium DNA detected in straw residues and air samples from these fields. Grain harvested from ploughed plots had lower levels of Fusarium langsethiae DNA and HT-2 and T-2 toxins (HT2 + T2) compared to grain from harrowed plots. Our results indicate that the risk of F. langsethiae and HT2 + T2 contamination of oats is reduced with increasing tillage intensity. No distinct influence of tillage on the DNA concentration of Fusarium graminearum and Fusarium avenaceum in the harvested grain was observed. In contrast to F. graminearum and F. avenaceum, only limited contents of F. langsethiae DNA were observed in straw residues and air samples. Still, considerable concentrations of F. langsethiae DNA and HT2 + T2 were recorded in oat grain harvested from these fields. We speculate that the life cycle of F. langsethiae differs from those of F. graminearum and F. avenaceum with regard to survival, inoculum production and dispersal.

Bacterial diseases affecting wheat production in Uruguay are an issue of growing concern yet remain largely uninvestigated in the region. Surveys of 61 wheat fields carried out from 2017 to 2019 yielded a regional collection of 63 strains identified by 16S rRNA gene analysis as Xanthomonas spp. A real-time PCR protocol with species-specific primers previously reported allowed the identification of 44 strains as X. translucens , the causal agent of bacterial leaf streak (BLS) in wheat and other cereal crops. Multilocus sequence analysis of four housekeeping genes ( dnaK , fyuA , gyrB , and rpoD ) revealed that these strains were most closely related to X. translucens pv. undulosa , the pathovar that is most commonly associated with BLS of wheat. Multilocus sequence typing was applied to examine the genetic diversity of X. translucens strains. Strains were assigned to four different sequence types, three of which were previously reported globally. Additionally, 17 Xanthomonas strains not belonging to X. translucens were obtained from diseased wheat leaves. Phylogenetic analysis showed that these strains are closely related to X. prunicola and clustered together with previously uncharacterized Xanthomonas strains isolated from wheat in Minnesota. In planta pathogenicity assays carried out on a BLS-susceptible wheat cultivar showed that X. translucens pv. undulosa strains caused brown necrosis symptoms typical of BLS, whereas non- translucens Xanthomonas sp. strains elicited an atypical symptom of dry necrosis. These findings suggest that local wheat fields are affected by X. translucens pv. undulosa and by a new wheat pathogen within the Xanthomonas genus.

Key Message: Fine mapping of barley 6H pericentromeric region identified FHB QTL with opposite effects, and high grain protein content was associated with increased FHB severity. Resistance to Fusarium head blight (FHB), kernel discoloration (KD), deoxynivalenol (DON) accumulation and grain protein content (GPC) are important traits for breeding malting barley varieties. Previous work mapped a Chevron-derived FHB QTL to the pericentromeric region of 6H, coinciding with QTL for KD resistance and GPC. The Chevron allele reduced FHB and KD, but unfavorably increased GPC. To determine whether the correlations are caused by linkage or pleiotropy, a fine mapping approach was used to dissect the QTL underlying these quality and disease traits. Two populations, referred to as Gen10 and Gen10/Lacey, derived from a recombinant near-isogenic line (rNIL) were developed. Recombinants were phenotyped for FHB, KD, DON, GPC and other agronomic traits. Three FHB, two DON and two KD QTLs were identified. One of the three FHB QTLs, one DON QTL and one KD QTL were coincident with the GPC QTL, which contains the Hv-NAM1 locus affecting grain protein accumulation. The Chevron allele at the GPC QTL increased GPC and FHB and decreased DON and KD. The other two FHB QTL and the other DON and KD QTL were identified in the regions flanking the Hv-NAM1 locus, and the Chevron alleles decreased FHB, DON and KD. Our results suggested that the QTL associated with FHB, KD, DON and GPC in the pericentromeric region of 6H was controlled by both pleiotropy and tightly linked loci. The rNILs identified in this study with low FHB severity and moderate GPC may be used for breeding malting barley cultivars., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Bacterial leaf streak (BLS) of wheat, caused by Xanthomonas translucens pv. undulosa , has been a notable disease in Minnesota wheat fields over the past decade. Potential sources of the pathogen include infested seed and crop debris. Perennial weeds are also considered a possible inoculum source, but no surveys have been conducted to evaluate which X. translucens pathovars are present on weedy grasses that are common in Minnesota wheat fields. Multilocus sequence analysis (MLSA) of four housekeeping genes ( rpoD , dnaK , fyuA , and gyrB ) was used to identify 77 strains isolated from six weedy grass species, wheat, and barley in and around naturally infected wheat fields in Minnesota. The MLSA phylogeny identified all strains originating from weedy grass species, except smooth brome, as X. translucens pv. undulosa , whereas strains isolated from smooth brome were determined to be X. translucens pv. cerealis . In planta character states corroborated these identifications on a subset of 41 strains, as all strains from weedy grasses caused water-soaking on wheat and barley in greenhouse assays. Multilocus sequence typing was used to evaluate genetic diversity and revealed that sequence types of X. translucens pv. undulosa originating from weedy grass hosts are similar to those found on wheat. This study identifies both annual and perennial poaceous weeds common in Minnesota that harbor X. translucens pv. undulosa and expands our understanding of the diversity of the pathogen population.

Known by the indigenous peoples of the Great Lakes region of North America as Manoomin, wild rice ( Zizania palustris ) is a native aquatic grass that is honored and central to Anishinaabe culture. Cultivated wild rice, the domesticated form of this cereal bred primarily for resistance to shattering, is grown commercially in paddies. In this study we examined four isolates (CIX303, CIX306, Xt-8, and Xt-22) of Xanthomonas translucens , the causative agent of bacterial leaf streak (BLS) on cereals and weedy grasses, in molecular and host range studies to confirm the pathovar identity of strains associated with cultivated wild rice. Two of the strains examined (CIX303 and CIX306), were isolated from cultivated wild rice in 2016 as part of a survey of the pathogen in Minnesota (Ledman 2019). Xt-8 and Xt-22 are historical strains of X. translucens isolated from symptomatic wild rice leaves collected in Minnesota in the late 1970s that were reported at the time to be X. campestris pv. cerealis (Bowden and Percich 1982). A host range assay was repeated twice in the greenhouse, where two leaves of six seedlings each of hard red spring wheat (cv. RB07), spring barley (cv. Quest), spring rye (cv. Prolific), oat (cv. Ogle), quackgrass, smooth brome grass and cultivated wild rice (cv. Itasca Cycle-12) were inoculated via leaf infiltration (Curland et al. 2020). X. translucens pv. cerealis LMG 679 PT , X. translucens pv. secalis LMG 883 PT , X. translucens pv. translucens LMG 876 T , and X. translucens pv. undulosa LMG 892 PT were included as reference strains. Host response profiles were determined for each strain by recording character states five days post inoculation. Water-soaking and necrosis were considered pathogenic reactions, whereas chlorosis was not. Three pathotype strains, LMG 679 PT , LMG 876 T , and LMG 892 PT , caused water-soaking in cultivated wild rice, whereas LMG 883 PT caused chlorosis. All four strains from cultivated wild rice produced water-soaking on wheat, barley, quackgrass, and cultivated wild rice, chlorosis or water-soaking on rye, chlorosis on oat, and a reddish water-soaking on smooth brome. The character states generated by these four isolates were identical only to the host response profile for LMG 892 PT . LMG 679 PT differed, causing chlorosis on wheat, no symptoms on quackgrass, and water-soaking on smooth brome. A 2645 bp concatenation of housekeeping genes ( rpoD , dnaK , fyuA , gyrB ) was used to perform a Bayesian analysis (GenBank accessions MW528365-MW528384) (Curland et al. 2018, Curland et al. 2020, Young et al. 2008). Subsequent phylogenies grouped all four strains from cultivated wild rice with LMG 892 PT and LMG 883 PT . A pairwise comparison revealed 100% identity between Xt-22 and LMG 892 PT . The percentage identity of CIX303, CIX308, and Xt-8 to LMG 892 PT was 99.96, 99.96, and 99.92, respectively. In contrast, when compared to LMG 679 PT , the four strains from cultivated wild rice had a percent identity between 97.43 and 97.50. Based on host range studies combined with MLSA, we identified recent and historical isolates from Z. palustris as X. translucens pv. undulosa . Pathovar identity of strains causing BLS on cultivated wild rice in Minnesota is crucial when screening breeding materials for disease resistance. Furthermore, given that X. translucens pv. undulosa has been prevalent on wheat in Minnesota (Curland et al. 2018), expanding knowledge of its host range to include cultivated wild rice may inform disease management practices for both crops. References: Bowden, R., and Percich, J. 1982. Phytopath. 73:640-645. Curland, R., et al. 2018. Phytopath. 108:443-453. Curland, R., et al. 2020. Phytopath. 110:257-266. Ledman, K. 2019. M.S. Thesis, Univ. of Minnesota, St. P. Paul, USA. Young, J., et al. 2008. Syst. Appl. Microbiol. 31:366-377.

Trichothecene mycotoxins such as deoxynivalenol (DON) are virulence factors of Fusarium graminearum , which causes Fusarium head blight, one of the most important diseases of small grain cereals. We previously identified a nonspecific lipid transfer protein (nsLTP) gene, AtLTP4.4 , which was overexpressed in an activation-tagged Arabidopsis line resistant to trichothecin, a type B trichothecene in the same class as DON. Here we show that overexpression of AtLTP4.4 in transgenic wheat significantly reduced F. graminearum growth in 'Bobwhite' and 'RB07' lines in the greenhouse and reduced fungal lesion size in detached leaf assays. Hydrogen peroxide accumulation was attenuated on exposure of transgenic wheat plants to DON, indicating that AtLTP4.4 may confer resistance by inhibiting oxidative stress. Field testing indicated that disease severity was significantly reduced in two transgenic 'Bobwhite' lines expressing AtLTP4.4. DON accumulation was significantly reduced in four different transgenic 'Bobwhite' lines expressing AtLTP4.4 or a wheat nsLTP, TaLTP3 , which was previously shown to have antioxidant activity. Recombinant AtLTP4.4 purified from Pichia pastoris exhibited potent antifungal activity against F. graminearum . These results demonstrate that overexpression of AtLTP4.4 in transgenic wheat suppresses DON accumulation in the field. Suppression of DON-induced reactive oxygen species by AtLTP4.4 might be the mechanism by which fungal spread and mycotoxin accumulation are inhibited in transgenic wheat plants.

Stem rust caused by Puccinia graminis f. sp. tritici ( Pgt ) remains a constraint to wheat production in East Africa. In this study, we characterized the genetics of stem rust resistance, identified QTLs, and described markers associated with stem rust resistance in the spring wheat line CI 14275. The 113 recombinant inbred lines, together with their parents, were evaluated at the seedling stage against Pgt races TTKSK, TRTTF, TPMKC, TTTTF, and RTQQC. Screening for resistance to Pgt races in the field was undertaken in Kenya, Ethiopia, and the United States in 2016, 2017, and 2018. One gene conferred seedling resistance to race TTTTF, likely Sr7a . Three QTL were identified that conferred field resistance. QTL QSr.cdl-2BS.2 , that conferred resistance in Kenya and Ethiopia, was validated, and the marker Excalibur&#95;c7963&#95;1722 was shown to have potential to select for this QTL in marker-assisted selection. The QTL QSr.cdl-3B.2 is likely Sr12 , and QSr.cdl-6A appears to be a new QTL. This is the first study to both detect and validate an adult plant stem rust resistance QTL on chromosome arm 2BS. The combination of field QTL QSr.cdl-2BS.2 , QSr.cdl-3B.2 , and QSr.cdl-6A has the potential to be used in wheat breeding to improve stem rust resistance of wheat varieties., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Kosgey, Edae, Dill-Macky, Jin, Bulbula, Gemechu, Macharia, Bhavani, Randhawa and Rouse.)

Eight advanced durum-breeding lines were treated with 5-methyl-azacytidine to test the feasibility of generating sources of Fusarium head blight (FHB) resistance. Of the 800 treated seeds, 415 germinated and were advanced up to four (M4) generations by selfing. Thirty-two of the resulting 415 M4 lines were selected following preliminary screening and were further tested for FHB resistance for three years at two field locations, and in the greenhouse. Five of the 32 M4 lines showed less than 30% disease severity, as compared to the parental lines and susceptible checks. Fusarium-damaged kernels and deoxynivalenol analyses supported the findings of the field and greenhouse disease assessments. Two of the most resistant M4 lines were crossed to a susceptible parent, advanced to third generation (BC 1 :F 3 ) and were tested for stability and inheritance of the resistance. About, one third of the BC 1 :F 3 lines showed FHB resistance similar to their M4 parents. The overall methylation levels (%) were compared using FASTmC method, which did not show a significant difference between M4 and parental lines. However, transcriptome analysis of one M4 line revealed significant number of differentially expressed genes related to biosynthesis of secondary metabolites, MAPK signaling, photosynthesis, starch and sucrose metabolism, plant hormone signal transduction and plant-pathogen interaction pathways, which may have helped in improved FHB resistance.

The bread-making quality of wheat depends on the viscoelastic properties of the dough in which gluten proteins play an important role. The quality of gluten proteins is influenced by the genetics of the different wheat varieties and environmental factors. Occasionally, a near complete loss of gluten strength, measured as the maximum resistance towards stretching (R max ), is observed in grain lots of Norwegian wheat. It is hypothesized that the loss of gluten quality is caused by degradation of gluten proteins by fungal proteases. To identify fungi associated with loss of gluten strength, samples from a selection of wheat grain lots with weak gluten (n = 10, R max  < 0.3 N) and strong gluten (n = 10, R max  ≥ 0.6 N) was analyzed for the abundance of fungal operational taxonomic units (OTUs) using DNA metabarcoding of the nuclear ribosomal Internal Transcribed Spacer (ITS) region ITS1. The DNA quantities for a selection of fungal pathogens of wheat, and the total amount of fungal DNA, were analyzed by quantitative PCR (qPCR). The mean level of total fungal DNA was higher in grain samples with weak gluten compared to grain samples with strong gluten. Heightened quantities of DNA from fungi within the Fusarium Head Blight (FHB) complex, i.e. Fusarium avenaceum, Fusarium graminearum, Microdochium majus, and Microdochium nivale, were observed in grain samples with weak gluten compared to those with strong gluten. Microdochium majus was the dominant fungus in the samples with weak gluten. Stepwise regression modeling based on different wheat quality parameters, qPCR data, and the 35 most common OTUs revealed a significant negative association between gluten strength and three OTUs, of which the OTU identified as M. majus was the most abundant. The same analysis also revealed a significant negative relationship between gluten strength and F. avenaceum detected by qPCR, although the DNA levels of this fungus were low compared to those of M. majus. In vitro growth rate studies of a selection of FHB species showed that all the tested isolates were able to grow with gluten as a sole nitrogen source. In addition, proteins secreted by these fungi in liquid cultures were able to hydrolyze gluten substrate proteins in zymograms, confirming their capacity to secrete gluten-degrading proteases. The identification of fungi with potential to influence gluten quality can enable the development of strategies to minimize future problems with gluten strength in food-grade wheat., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)