Aged Switchgrass Seed Lot\u27s Response to Dormancy-breaking Chemicals

Aged switchgrass seed lots can display various levels of dormancy. Under-standing the causes for this dormancy will provide better insight into seed physiology, and potentially lead to treatments that reduce variability in seed germination assays. The effects of sodium nitroprusside, potassium ferro-cyanide and hydrogen peroxide on the germination of eight aged switch-grass (Panicum virgatum L.) seed lots, seven of which were produced in the same year at a single experiment station, were examined. Seed germination demonstrated a significant seed lots × days and treatments × days effect. However, responses of individual seed lots to specific chemicals varied considerably. Genetically related seed lots did not display similar responses to the treatments, while switchgrass derived from a different germplasm exhibited a more similar response. Coleoptile emergence was significantly improved by chemical treatments and showed a significant seed lots × treatment interaction. Together, these results indicate (1) chemicals releasing re-active nitrogen species or peroxide can overcome residual dormancy and stimulate seed germination and coleoptile emergence in diverse switchgrassseed lots, and (2) multiple mechanisms, to some extent under genetic control, appear to direct switchgrass seed germination

Editorial: Genomic Approaches for Improvement of Understudied Grasses

Grasses are diverse, spanning native prairies to high-yielding grain cropping systems. They are valued for their beauty and useful for soil stabilization, pollution mitigation, biofuel production, nutritional value, and forage quality; grasses encompass the most important grain crops in the world. There are thousands of distinct grass species and many have promiscuous hybridization patterns, blurring species boundaries. Resources for advancing the science and knowledgebase of individual grass species or their unique characteristics varies, often proportional to their perceived value to society. For many grasses, limited genetic information hinders research progress. Presented in this research topic is a brief snapshot of creative efforts to apply modern genomics research methodologies to the study of several minor grass species

Genomic Approaches for Improvement of Understudied Grasses

Grasses are diverse, spanning native prairies to high-yielding grain cropping systems. They are valued for their beauty and useful for soil stabilization, pollution mitigation, biofuel production, nutritional value, and forage quality; grasses encompass the most important grain crops in the world. There are thousands of distinct grass species and many have promiscuous hybridization patterns, blurring species boundaries. Resources for advancing the science and knowledgebase of individual grass species or their unique characteristics varies, often proportional to their perceived value to society. For many grasses, limited genetic information hinders research progress. Presented in this research topic is a brief snapshot of creative efforts to apply modern genomics research methodologies to the study of several minor grass species

Dephosphorylation of the Thylakoid Membrane Light-Harvesting Complex-II by a Stromal Protein Phosphatase

Light-harvesting complex-II (LHC-II) phosphatase activity has generally been examined in the intact thylakoid membrane. A recent report of peptide-phosphatase activity associated with the chloroplast stromal fraction (Hammer, M.E et al. (1995) Photosynth Res 44:107–115) has led to the question of whether this activity is capable of dephosphorylating membrane-bound LHC-II. To this end, heat-treated thylakoid membranes were examined as a potential LHC-II phosphatase substrate. Following incubation of the thylakoid membrane at 60 °C for 15 min, the endogenous protein phosphatase and kinase activities were almost eliminated. Heat-inactivated phosphomembranes exhibited minimal dephosphorylation of the light harvesting complex-II. Peptide-phosphatase activities isolated from the thylakoid and stromal fraction were able to dephosphorylate LHC-II in heat-inactivated phosphomembranes. The stromal phosphatase showed highest activity against LHC-II at pH 9. Dephosphorylation of the LHC-II by the stromal enzyme was not inhibited by molybdate, vanadate or tungstate ions, but was partially inhibited by EDTA and a synthetic phosphopeptide mimicking the LHC-II phosphorylation site. Thus, the previously identified stromal phosphatase does appear capable of dephosphorylating authentic LHC-II in vivo

Registration of NE Trailblazer C-1, NE Trailblazer C0, NE Trailblazer C2, NE Trailblazer C3, NE Trailblazer C4, and NE Trailblazer C5 Switchgrass Germplasms

NE Trailblazer C-1 (GP-101, PI 672015), NE Trailblazer C0 (GP-100, PI 672014), NE Trailblazer C2 (GP-102, PI 672016), NE Trailblazer C3 (GP-103, PI 672017), NE Trailblazer C4 (GP-104, PI 672018), and NE Trailblazer C5 (GP-105, PI 672019) switchgrass (Panicum virgatum L.) germplasms were released by the USDA-ARS and the University of Nebraska-Lincoln on 10 Sept. 2014. These germplasms were developed by six generations of divergent breeding for in vitro dry matter digestibility (IVDMD). As a result of the multigenerations of recurrent breeding, the resulting populations differ significantly for IVDMD and for 25 other forage quality or biomass composition traits, including both acid detergent and Klason lignin. Plants in the high IVDMD populations also had altered anatomical structure. The lignin concentration of the stems was altered more than that of the leaves. The germplasm populations also differ significantly for winter survival. Altering plant composition by selection for IVDMD adversely affected the winter survival fitness of the resulting populations by unknown mechanisms. Plants from these germplasms can be used in genetics studies for determining the inheritance of multiple biomass composition traits and for identifying genes controlling specific biomass composition properties and winter survival of switchgrass and other perennial grasses

Rice (\u3ci\u3eOryza\u3c/i\u3e) hemoglobins [version 2; peer review: 2 approved]

Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice (Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O2-transport, O2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs

Persistence of rye (Secale cereale L.) chromosome arm 1RS in wheat (Triticum aestivum L.) breeding programs of the Great Plains of North America

Rye (Secale cereale L.) chromosome arm 1RS has been used world-wide by wheat (Triticum aestivum L.) breeding programs as a source of pestand pathogen-resistance genes, and to improve grain yield and stress tolerance. The most common vehicles used to access 1RS are various 1AL.1RS and 1BL.1RS wheat-rye chromosomal translocations. Over the past 25 years, advanced North American wheat breeding lines were evaluated, first by assay of secalin storage proteins, and later by use of DNA marker TSM0120, for the presence of these two translocations. Both methods provide accurate and efficient means of identifying and differentiating 1BL.1RS and 1A.1RS. Both 1Al.1RS and 1BL.1RS wheats were found in all tested years. 1AL.1RS lines were more common in southern Great Plains breeding programs. 1AL.1RS lines were released as cultivars at a frequency identical to that of wild-type breeding lines. In contrast, 1BL.1RS breeding lines were developed by breeding programs throughout the Great Plains, but fewer were released as cultivars. Both 1RS translocation types persist in Great Plains breeding programs. The lower rate of release of 1BL.1RS cultivars no doubt is a consequence of the more drastic effects on breadmaking quality relative to those observed with 1AL.1RS

Western Immunoblotting in Avian Shell Gland Sample Immunoblotting Methods1

Avian shell gland tissue was subjected to Western blot analysis using anti-human estrogen receptor- α antibody H222. Initial attempts to obtain consistent, high-quality blots were unsuccessful because, as it turned out, excessive lipid in tissue preparations interfered with protein separation. Incremental additions of acetone eventually proved to be the critical step in solubilizing lipids and allowing consistent separation of bands on gels. A detailed description of the methodology is presented

Chitinases from the Plant Disease Biocontrol Agent, \u3ci\u3eStenotrophomonas maltophilia\u3c/i\u3e C3

Stenotrophomonas maltophilia strain C3, a biocontrol agent of Bipolaris sorokiniana in turfgrass, produced chitinases in broth media containing chitin. Chitinases were partially purified from culture fluid by ammonium sulfate precipitation and chitin affinity chromatography. The chromatography fraction with the highest specific chitinase activity was inhibitory to conidial germination and germ-tube elongation of B. sorokiniana, but it was less inhibitory than the protein fraction or the raw culture filtrate. The fraction exhibited strong exochitinase and weak endochitinase activity. Optimum temperature and pH for chitinase activity were 45 to 50°C and 4.5 to 5.0, respectively. Chitinase activity was inhibited by Hg2+ and Fe3+, but not by other metal ions or enzyme inhibitors. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the chromatography fraction revealed the presence of five protein bands of 25, 32, 48, 65, and 75 kDa. Partial amino acid sequences of the 32-, 65-, and 75-kDa proteins indicated that they are homologous to known bacterial chitinases. There was no homology found in the partial amino acid sequences of the 25- and 48-kDa proteins to any known chitinases. Five chitinase-active proteins were detected in the protein and chromatography fractions by activity gels, but when each protein was extracted and re-electrophoresed separately under denaturing conditions, only 32- or 48-kDa proteins were revealed. It was concluded that strain C3 produces at least two chitinases that are antifungal

Fall armyworm (Spodoptera frugiperda Smith) feeding elicits differential defense responses in upland and lowland switchgrass

Switchgrass (Panicum virgatum L.) is a low input, high biomass perennial grass being developed for the bioenergy sector. Upland and lowland cultivars can differ in their responses to insect herbivory. Fall armyworm [FAW; Spodoptera frugiperda JE Smith (Lepidoptera: Noctuidae)] is a generalist pest of many plant species and can feed on switchgrass as well. Here, in two different trials, FAW larval mass were significantly reduced when fed on lowland cultivar Kanlow relative to larvae fed on upland cultivar Summer plants after 10 days. Hormone content of plants indicated elevated levels of the plant defense hormone jasmonic acid (JA) and its bioactive conjugate JA-Ile although significant differences were not observed. Conversely, the precursor to JA, 12-oxo-phytodienoic acid (OPDA) levels were significantly different between FAW fed Summer and Kanlow plants raising the possibility of differential signaling by OPDA in the two cultivars. Global transcriptome analysis revealed a stronger response in Kanlow plant relative to Summer plants. Among these changes were a preferential upregulation of several branches of terpenoid and phenylpropanoid biosynthesis in Kanlow plants suggesting that enhanced biosynthesis or accumulation of antifeedants could have negatively impacted FAW larval mass gain on Kanlow plants relative to Summer plants. A comparison of the switchgrass-FAW RNA-Seq dataset to those from maize-FAW and switchgrass-aphid interactions revealed that key components of plant responses to herbivory, including induction of JA biosynthesis, key transcription factors and JA-inducible genes were apparently conserved in switchgrass and maize. In addition, these data affirm earlier studies with FAW and aphids that the cultivar Kanlow can provide useful genetics for the breeding of switchgrass germplasm with improved insect resistance