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In sorghum [Sorghum bicolor (L.) Moench] the Maturity (Ma1, Ma2, Ma3, Ma4, Ma5, Ma6) and Dwarf (Dw1, Dw2, Dw3, Dw4) loci, encode genes controlling flowering time and plant height, respectively, which are critical for designing sorghum ideotypes for a maturity timeframe and a harvest method. Publicly available whole-genome resequencing data from 860 sorghum accessions was analyzed in silico to identify genomic variants at 8 of these loci (Ma1, Ma2, Ma3, Ma5, Ma6, Dw1, Dw2, Dw3) to identify novel loss of function alleles and previously characterized ones in sorghum germplasm. From ~ 33 million SNPs and ~ 4.4 million InDels, 1445 gene variants were identified within these 8 genes then evaluated for predicted effect on the corresponding encoded proteins, which included newly identified mutations (4 nonsense, 15 frameshift, 28 missense). Likewise, most accessions analyzed contained predicted loss of function alleles (425 ma1, 22 ma2, 40 ma3, 74 ma5, 414 ma6, 289 dw1, 268 dw2 and 45 dw3) at multiple loci, but 146 and 463 accessions had no predicted ma or dw mutant alleles, respectively. The ma and dw alleles within these sorghum accessions represent a valuable source for manipulating flowering time and plant height to develop the full range of sorghum types: grain, sweet and forage/biomass. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Deleterious mutations predicted in the sorghum (Sorghum bicolor) Maturity (Ma) and Dwarf (Dw) genes from whole-genome resequencing" published in Scientific Reports. The correction addresses errors in the original article, including changes to the Introduction and Results sections, as well as corrections to identified alleles and variants. The correction also includes changes to the sources of data used in the study. The original article has been corrected. [Extracted from the article]

Sorghum (Sorghum bicolor (L.) Moench) is a diverse C4 crop used for feed, food and grain- or juice-based bioethanol, with potential for lignocellulosic biofuels. Sorghum is inherently drought tolerant, but it is vulnerable to stalk rots caused by Fusarium thapsinum and Macrophomina phaseolina, especially during water stress. Post-flowering non-senescent lines (Stay-green), associated with drought and stalk rot resistance, tend to have higher levels of the cyanogenic glycoside, dhurrin, than post-flowering senescent sorghums. The goal of this study was to identify grain sorghum lines with stalk rot resistance, but with low levels of dhurrin for grain and forage uses. Stay-green and senescent lines were screened for response to the two stalk pathogens. Greenhouse and field assessments indicated that four lines had increased resistance: Plant Introduction (PI) 267,379, PI 533882, PI 534053 and PI 534133. When dhurrin levels of greenhouse-grown flag-leaves were assessed using HPLC, only PI 267379 and the senescent check BTx623 had significantly less dhurrin than the Stay-green check BTx642. For field-grown flag-leaves, PI 267379, PI 533882 and BTx623 had significantly lower dhurrin levels than BTx642. Field-grown lines were visually scored post-anthesis for percent senescent leaves to indicate degree of leaf greenness. The PI 533882 and PI 534133 had percent senescence ratings similar to or lower than that of BTx642 while PI 267379 and PI 534053 had ratings significantly higher. Among lines exhibiting increased resistance to stalk rot, PI 267379 and PI 533882 show promise for developing grain and forage sorghums with stalk rot resistance. [ABSTRACT FROM AUTHOR]

Modifying lignin content and composition of cell walls are key targets for bioenergy feedstock improvement for a range of renewable chemical applications. Sorghum (Sorghum bicolor) is a drought-tolerant C4 grass being developed as a dedicated bioenergy feedstock. The monolignol biosynthetic pathway produces the hydroxycinnamic subunits of lignin, a major target to increase the energy content of sorghum biomass for thermal bioenergy conversion processes. SbMyb60 is a transcription factor linked to the activation of the monolignol biosynthetic pathway and caffeoyl CoA O-methyltransferase (SbCCoAOMT) is a S-adenosyl methionine (SAM)–dependent O-methyltransferase responsible for the methylation of caffeoyl-CoA to generate feruloyl-CoA in this pathway. Overexpression of each gene resulted in increased energy content of biomass and increased levels of several aromatic compounds in previous greenhouse experiments. To assess how SbMyb60 and SbCCoAOMT overexpression lines performed under field conditions, these lines were planted in field trials over two growing seasons, 2017 and 2018, and the effects on lignin composition and content as well as agronomic traits were assessed. Field-grown plants of SbMyb60 and SbCCoAOMT overexpression lines had increased total energy and phenolic compounds. Furthermore, two SbMyb60 transgenic events, SbMyb-10a and SbMyb-15a, with decreased stover yield and seed set were combined with three sorghum lines, N32, N4692, and Tx3118, to investigate whether yield reduction could be rescued. Hybrids improved yield of SbMyb60-15a; however, hybrids were unable to improve performance for SbMyb60-10a. Overall, these results demonstrated that field-grown sorghum overexpressing SbMyb60 or SbCCoAOMT can have biomass with increased phenolic compounds and total energy. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB), caused mainly by Fusarium graminearum, can result in devastating economic losses in small grain cereal crops. Management of FHB is by a combination of strategies and tactics including cultivar resistance, fungicide application at anthesis, and cultural practices such as crop rotation, tillage, and irrigation management. This study evaluated, under field conditions, the effects of fungicide chemical class (triazole versus strobilurin), fungicide application timing, and environment on FHB and its associated mycotoxin deoxynivalenol (DON). A moderately resistant hard red winter wheat cultivar, Overland, consistently had lower levels of FHB index (= index), Fusarium-damaged kernels (FDK), and DON, and higher yield compared to the susceptible hard red winter wheat cultivar Overley. The most effective fungicide treatment in reducing FHB, FDK, DON, and yield loss was Prosaro® (prothioconazole + tebuconazole) applied at early anthesis (BBCH 61; hereafter referred to as anthesis). Application of Prosaro 6 days post anthesis (DPA) achieved a slightly lower but comparable efficacy to that achieved by the anthesis application. Application of Prosaro at 12 DPA was least effective. The strobilurin fungicide Headline® (pyraclostrobin) was less effective than Prosaro in controlling FHB, FDK, and DON. In both cultivars, index, FDK, and DON were higher and yield was lower under irrigated compared to rain-fed conditions. These differences were more pronounced in a wet compared to a relatively dry growing season. The results from this study indicate that effective management of FHB can be achieved by combining cultivar resistance with a triazole fungicide applied at anthesis, and the window of fungicide application can be extended by up to 6 days post anthesis. [ABSTRACT FROM AUTHOR]

Ferulate 5-hydroxylase (F5H) of the monolignol pathway catalyzes the hydroxylation of coniferyl alcohol, coniferaldehyde and ferulic acid to produce 5-hydroxyconiferyl moieties, which lead to the formation of sinapic acid and syringyl (S) lignin monomers. In contrast, guaiacyl (G) lignin, the other major type of lignin monomer, is derived from polymerization of coniferyl alcohol. In this study, the effects of manipulating S-lignin biosynthesis in sorghum (Sorghum bicolor) were evaluated. Overexpression of sorghum F5H (SbF5H), under the control of the CaMV 35S promoter, increased both S-lignin levels and the ratio of S/G lignin, while plant growth and development remained relatively unaffected. Maüle staining of stalk and leaf midrib sections from SbF5H overexpression lines indicated that the lignin composition was altered. Ectopic expression of SbF5H did not affect the gene expression of other monolignol pathway genes. In addition, brown midrib 12-ref (bmr12-ref), a nonsense mutation in the sorghum caffeic acid O-methyltransferase (COMT) was combined with 35S::SbF5H through cross-pollination to examine effects on lignin synthesis. The stover composition from bmr12 35S::SbF5H plants more closely resembled bmr12 stover than 35S::SbF5H or wild-type (WT) stover; S-lignin and total lignin concentrations were decreased relative to WT or 35S::SbF5H. Likewise, expression of upstream monolignol biosynthetic genes was increased in both bmr12 and bmr12 35S::SbF5H relative to WT or 35S::SbF5H. Overall, these results indicated that overexpression of SbF5H did not compensate for the loss of COMT activity. Key message: Overexpression of F5H in sorghum increases S-lignin without increasing total lignin content or affecting plant growth, but it cannot compensate for the loss of COMT activity in monolignol synthesis. [ABSTRACT FROM AUTHOR]

Sorghum [ Sorghum bicolor (L.) Moench] has drawn attention as potential feedstock for lignocellulosic biofuels production, and reducing lignin is one way to increase conversion efficiency. Little research has been previously conducted to assess the response of reduced lignin sorghum lines to the Fusarium stalk rot pathogens Fusarium verticillioides and Fusarium proliferatum and the charcoal rot pathogen, Macrophomina phaseolina. Loss of function mutations in either the Brown midrib ( Bmr) 6 or 12 gene that both encode a monolignol biosynthetic enzyme in the pathway that produces subunits of the lignin polymer, results in reduced lignin content. Near-isogenic bmr6, bmr12, and bmr6 bmr12 lines had previously been developed, which were shown to have significantly reduced lignin content and increased levels of soluble phenolics. In the current study, these lines in two backgrounds were shown to not be more susceptible to F. verticillioides, F. proliferatum and M. phaseolina inoculations, and some bmr lines exhibited increased resistance to F. proliferatum and M. phaseolina, compared to wild-type lines. When the Fusarium stalk rot pathogen, Fusarium thapsinum, was grown on methanol soluble stalk extracts from bmr6 and wild-type plants, it grew significantly faster on medium with bmr6 extract than on wild-type extract or controls. This result suggested that factors other than soluble phenolics from the extract, such as cell wall bound phenolics or inducible defense compounds, contributed to increased resistance observed in bmr6 plants. [ABSTRACT FROM AUTHOR]

Sorghum ( Sorghum bicolor (L.) Moench) brown midrib ( bmr) mutant lines have reduced levels of lignin, which is a potentially useful trait for bioenergy production, but the effects of this trait on insect and plant pathogen interactions are unknown under field conditions. Field-grown bmr6, bmr12, and wild-type (WT) plants were examined for insect and disease damage. In most cases, observed frequency, population, or leaf area damage caused by insects or pathogens on bmr6 or bmr12 plants were not greater than those observed on WT plants in the field or laboratory assays. European corn borers [ Ostrinia nubilalis (Hübner)(Lepidoptera: Pyralidae)] often caused lower amounts of leaf damage to bmr6 leaves compared to bmr12 and sometimes WT leaves in the field study. Leaf damage by corn earworms [ Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae)] and fall armyworms [ Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)] in laboratory assays was often lower for bmr versus WT leaves. Incidence of disease lesions was significantly higher on bmr6 compared to WT plants for one of three samplings in 2011, but the opposite trend was observed overall in 2012 and no significant differences were noted in 2013. When corn earworms and fall armyworms were fed the excised pith, bmr6 and/or bmr12 pith caused significant morality to one or both insect species in all 3 years. Damage variability between the 3 years may have been due to hotter and drier than normal conditions in 2012. Thus, bmr lines of sorghum suitable for bioenergy production have potential for sustainable production in the field. [ABSTRACT FROM AUTHOR]

Sorghum is used as bioenergy feedstock, animal feed, and food. Economical methods for disease prevention and control are valuable for producers. Fluorescent Pseudomonas spp. were isolated from sorghum roots and surrounding soil with the goal of finding isolates that significantly inhibited sorghum fungal pathogens. Fluorescent pseudomonads were collected from seedlings of sorghum cultivars RTx433 and Redlan and wheat cultivar Lewjain, grown in two soils. Lewjain is known to support growth of producers of the antibiotic, 2,4-diacetylphloroglucinol (2,4-DAPG). Isolates from all three plants were assessed for hydrogen cyanide (HCN) and extracellular protease production, and for a 2,4-DAPG gene, phlD. Both soil type and plant type affected HCN- and protease-production, but phlD was not affected. Subsets of phlD isolates were chosen to determine phlD genotypes and to conduct in vitro inhibition assays against sorghum pathogens. Most isolates from sorghum and wheat were genotype D, previously associated with superior root colonization. phlD sorghum isolates were co-cultured with five sorghum pathogens. One isolate from each sorghum line exhibited inhibition to all five pathogens but more Redlan isolates were inhibitory to the virulent pathogen, Fusarium thapsinum, than RTx433 isolates. Nearly all inhibitory isolates from either sorghum cultivar were from one soil type. This is consistent with what had been previously observed in field studies: that soil type played a significant role in determining characteristics of fluorescent Pseudomonas spp. isolated from roots or soil, but sorghum genotype also had a considerable effect. [ABSTRACT FROM AUTHOR]

Sorghum [ Sorghum bicolor (L.) Moench] is valued for bioenergy, feed and food. Potential of sorghum genotypes to support differing populations of root- and soil-associated fluorescent Pseudomonas spp. or Fusarium spp., in two soils, was assessed. Culturable pseudomonads were enumerated from roots and soil of sorghum (Redlan and RTx433) and wheat (Lewjain) seedlings repeatedly grown in cycled soils in the growth chamber. Pseudomonads and Fusarium spp. were assessed from roots and soil of field-grown sorghum along with biological control traits hydrogen cyanide (HCN) and 2,4-diacetylphlorogluconol ( phl) production. After four 4-week cycles, soil associated with Redlan seedlings had greater numbers of fluorescent pseudomonads than Lewjain. In dryland field conditions, RTx433 roots had greater numbers of pseudomonads than Redlan before anthesis but similar numbers after. There were no differences in numbers of pseudomonads from dryland soil or roots or soil of irrigated plants. Percentages of HCN-producing root isolates and phl soil isolates declined on irrigated Redlan plants, but percentages of HCN-producers increased in dryland conditions. Redlan roots had greater percentages of Fusarium isolates in the Gibberella fujikuroi complex. Results indicated that sorghum genotype affected root-associated populations of fluorescent Pseudomonas spp. and Fusarium spp. across soil environments. [ABSTRACT FROM AUTHOR]

Hypotheses in which sorghum seedlings [ Sorghum bicolor (L.) Moench] of different genotypes will differentially modify soil microorganisms and will affect subsequent planting of wheat ( Triticum aestivum L.) seedlings, were tested. Wheat cultivar Lewjain, and sorghum genotypes Redlan and RTx433, were planted into soils previously planted with wheat or sorghum in growth chamber experiments. Total culturable fungi and oomycetes, and fluorescent Pseudomonas spp. numbers (cfu) were determined. Pseudomonads were screened for hydrogen cyanide (HCN) production, for the presence of the phlD gene for 2,4-diacetylphloroglucinol production (Phl) and for a region of the operon involved in phenazine-1-carboxylic acid (PCA) production. Pasteurized soils were inoculated with rifampicin-marked strains of Pseudomonas fluorescens then planted with Lewjain, Redlan and RTx433 to assess rhizosphere and soil colonization. Effects of plant species, sorghum genotype and previous crop on culturable fungi and oomycetes, and pseudomonad numbers (cfu g−1 soil) were statistically significant. Soils planted with RTx433 or Lewjain had greater numbers of fungal cfu than soils planted with Redlan. When Lewjain seedlings were grown in soil previously planted with RTx433, there were greater numbers of fungal cfu than when Lewjain was planted into Redlan soil. Wheat planted into wheat soil resulted in statistically significantly fewer numbers of pseudomonads than when planted into sorghum soil. Overall, percentages of HCN-producing pseudomonads increased, especially when wheat seedlings were planted in wheat soil. For most treatments, percent of isolates with Phl declined, except when Redlan was planted into Redlan soil, which resulted in increased Phl isolates. When rifampicin-marked P. fluorescens isolates were applied to pasteurized soil, sorghum seedlings sustained rhizosphere and soil populations similar to those on wheat. Sorghum genotypes may differ in associations with soil microorganisms, suggesting that they may differentially affect numbers of fluorescent pseudomonads in cropping systems. [ABSTRACT FROM AUTHOR]