Identification and Characterization of a Soybean Ethylene-Responsive Element-Binding Protein Gene Whose mRNA Expression Changes During Soybean Cyst Nematode Infection

Ethylene-responsive element-binding proteins (EREBPs) are members of a family of plant transcription factors. Conserved EREBP domains of these proteins bind to the GCC box, an ethylene-responsive promoter element found in many pathogenesis-related (PR) genes. Using degenerate primers to the EREBP domain from diverse plant species, an EREBPhomolog was isolated from a soybean cDNA library. Gel mobility-shift assays revealed that the translation product of this cDNA bound specifically to GCC box sequences. We, therefore, named this gene Glycine max ethylene-responsive element-binding protein 1 (GmEREBP1), i.e., a gene coding for the first confirmed GCC box-binding protein of soybean. GmEREBP1 mRNA abundance was analyzed by RNA blot hybridizations in soybean roots and shoots of cultivars Corsoy 79 and Hartwig, which are susceptible and resistant, respectively, to the soybean cyst nematode (Heterodera glycines). These analyses revealed that GmEREBP1 is expressed in a root-preferential manner and that GmEREBP1 mRNA abundance is changed after H. glycines infection. GmEREBP1 mRNA abundance decreased in infected (susceptible) ‘Corsoy 79’ roots, whereas it increased in abundance in infected (resistant) ‘Hartwig’ roots. Furthermore, ethephon treatment repressed GmEREBP1 mRNA accumulation in both cultivars, whereas wounding increased expression in both cultivars. These changes in mRNA steady-state levels suggest that GmEREBP1 plays a role in soybean-H. glycines interactions

Expression of an Arabidopsis phosphoglycerate mutase homologue is localized to apical meristems, regulated by hormones, and induced by sedentary plant-parasitic nematodes

We previously isolated a partial soybean cDNA clone whose transcript abundance is increased upon infection by the sedentary, endoparasitic soybean cyst nematode Heterodera glycines. We now isolated the corresponding full-length cDNA and determined that the predicted gene product was similar to the group of cofactor-dependent phosphoglycerate mutase/bisphosphoglycerate mutase enzymes (PGM/bPGM; EC 5.4.2.1/5.4.2.4). We designated the corresponding soybean gene GmPGM. PGM and bPGM are key catalysts of glycolysis that have been well characterized in animals but not plants. Using the GmPGM cDNA sequence, we identified a homologous Arabidopsis thaliana gene, which we designatedAtPGM. Histochemical GUS analyses of transgenic Arabidopsis plants containing theAtPGMpromoter::GUS construct revealed that the AtPGM promoter directs GUS expression in uninfected plants only to the shoot and root apical meristems. In infected plants, GUS staining also is evident in the nematode feeding structures induced by the cyst nematode Heterodera schachtii and by the root-knot nematode Meloidogyne incognita. Furthermore, we discovered that the AtPGM promoter was down-regulated by abscisic acid and hydroxyurea, whereas it was induced by sucrose, oryzalin, and auxin, thereby revealing expression characteristics typical of genes with roles in meristematic cells. Assessment of the auxin-inducible AUX1 gene promoter (a gene coding for a polar auxin transport protein) similarly revealed feeding cell and meristem expression, suggesting that auxin may be responsible for the observed tissue specificity of the AtPGM promoter. These results provide first insight into the possible roles of PGM/bPGM in plant physiology and in plant-pathogen interactions

GmEREBP1 Is a Transcription Factor Activating Defense Genes in Soybean and Arabidopsis

Ethylene-responsive element-binding proteins (EREBPs) are plant-specific transcription factors, many of which have been linked to plant defense responses. Conserved EREBP domains bind to the GCC box, a promoter element found in pathogenesis-related (PR) genes. We previously identified an EREBP gene from soybean (GmEREBP1) whose transcript abundance decreased in soybean cyst-nematode-infected roots of a susceptible cultivar, whereas it increased in abundance in infected roots of a resistant cultivar. Here, we report further characterization of this gene. Transient expression analyses showed that GmEREBP1 is localized to the plant nucleus and functions as a transcriptional activator in soybean leaves. Transgenic soybean plants expressing GmEREBP1 activated the expression of the ethylene (ET)-responsive gene PR2 and the ET- and jasmonic acid (JA)-responsive gene PR3, and the salicylic acid (SA)-responsive gene PR1 but not the SA-responsive PR5. Similarly, transgenic Arabidopsis plants expressing GmEREBP1 showed elevated mRNA abundance of the ET-regulated gene PR3 and the ET- and JA-regulated defense-related gene PDF1.2 but not the ET-regulated GST2, and the SA-regulated gene PR1 but not the SA-regulated PR2 and PR5. Transgenic soybean and Arabidopsis plants inoculated with cyst nematodes did not display a significantly altered susceptibility to nematode infection. These results collectively show that GmEREBP1 functions as a transacting inducer of defense gene expression in both soybean and Arabidopsis and mediates the expression of both ET- and JA- and SA-regulated defense-related genes in these plant species

Gene discovery in EST sequences from the wheat leaf rust fungus Puccinia triticina sexual spores, asexual spores and haustoria, compared to other rust and corn smut fungi

© 2011 Xu et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.DOI: 10.1186/1471-2164-12-161Background.Rust fungi are biotrophic basidiomycete plant pathogens that cause major diseases on plants and trees world-wide, affecting agriculture and forestry. Their biotrophic nature precludes many established molecular genetic manipulations and lines of research. The generation of genomic resources for these microbes is leading to novel insights into biology such as interactions with the hosts and guiding directions for breakthrough research in plant pathology. Results. To support gene discovery and gene model verification in the genome of the wheat leaf rust fungus, Puccinia triticina (Pt), we have generated Expressed Sequence Tags (ESTs) by sampling several life cycle stages. We focused on several spore stages and isolated haustorial structures from infected wheat, generating 17,684 ESTs. We produced sequences from both the sexual (pycniospores, aeciospores and teliospores) and asexual (germinated urediniospores) stages of the life cycle. From pycniospores and aeciospores, produced by infecting the alternate host, meadow rue (Thalictrum speciosissimum), 4,869 and 1,292 reads were generated, respectively. We generated 3,703 ESTs from teliospores produced on the senescent primary wheat host. Finally, we generated 6,817 reads from haustoria isolated from infected wheat as well as 1,003 sequences from germinated urediniospores. Along with 25,558 previously generated ESTs, we compiled a database of 13,328 non-redundant sequences (4,506 singlets and 8,822 contigs). Fungal genes were predicted using the EST version of the self-training GeneMarkS algorithm. To refine the EST database, we compared EST sequences by BLASTN to a set of 454 pyrosequencing-generated contigs and Sanger BAC-end sequences derived both from the Pt genome, and to ESTs and genome reads from wheat. A collection of 6,308 fungal genes was identified and compared to sequences of the cereal rusts, Puccinia graminis f. sp. tritici (Pgt) and stripe rust, P. striiformis f. sp. tritici (Pst), and poplar leaf rust Melampsora species, and the corn smut fungus, Ustilago maydis (Um). While extensive homologies were found, many genes appeared novel and species-specific; over 40% of genes did not match any known sequence in existing databases. Focusing on spore stages, direct comparison to Um identified potential functional homologs, possibly allowing heterologous functional analysis in that model fungus. Many potentially secreted protein genes were identified by similarity searches against genes and proteins of Pgt and Melampsora spp., revealing apparent orthologs. Conclusions. The current set of Pt unigenes contributes to gene discovery in this major cereal pathogen and will be invaluable for gene model verification in the genome sequence

Behavioral genomics of honeybee foraging and nest defense

The honeybee has been the most important insect species for study of social behavior. The recently released draft genomic sequence for the bee will accelerate honeybee behavioral genetics. Although we lack sufficient tools to manipulate this genome easily, quantitative trait loci (QTLs) that influence natural variation in behavior have been identified and tested for their effects on correlated behavioral traits. We review what is known about the genetics and physiology of two behavioral traits in honeybees, foraging specialization (pollen versus nectar), and defensive behavior, and present evidence that map-based cloning of genes is more feasible in the bee than in other metazoans. We also present bioinformatic analyses of candidate genes within QTL confidence intervals (CIs). The high recombination rate of the bee made it possible to narrow the search to regions containing only 17–61 predicted peptides for each QTL, although CIs covered large genetic distances. Knowledge of correlated behavioral traits, comparative bioinformatics, and expression assays facilitated evaluation of candidate genes. An overrepresentation of genes involved in ovarian development and insulin-like signaling components within pollen foraging QTL regions suggests that an ancestral reproductive gene network was co-opted during the evolution of foraging specialization. The major QTL influencing defensive/aggressive behavior contains orthologs of genes involved in central nervous system activity and neurogenesis. Candidates at the other two defensive-behavior QTLs include modulators of sensory signaling (Am5HT(7) serotonin receptor, AmArr4 arrestin, and GABA-B-R1 receptor). These studies are the first step in linking natural variation in honeybee social behavior to the identification of underlying genes

Tomato Pathogenesis-related Protein Genes are Expressed in Response to Trialeurodes vaporariorum and Bemisia tabaci Biotype B Feeding

The temporal and spatial expression of tomato wound- and defense-response genes to Bemisia tabaci biotype B (the silverleaf whitefly) and Trialeurodes vaporariorum (the greenhouse whitefly) feeding were characterized. Both species of whiteflies evoked similar changes in tomato gene expression. The levels of RNAs for the methyl jasmonic acid (MeJA)- or ethylene-regulated genes that encode the basic β-1,3-glucanase (GluB), basic chitinase (Chi9), and Pathogenesis-related protein-1 (PR-1) were monitored. GluB and Chi9 RNAs were abundant in infested leaves from the time nymphs initiated feeding (day 5). In addition, GluB RNAs accumulated in apical non-infested leaves. PR-1 RNAs also accumulated after whitefly feeding. In contrast, the ethylene- and salicylic acid (SA)-regulated Chi3 and PR-4 genes had RNAs that accumulated at low levels and GluAC RNAs that were undetectable in whitefly-infested tomato leaves. The changes in Phenylalanine ammonia lyase5 (PAL5) were variable; in some, but not all infestations, PAL5 RNAs increased in response to whitefly feeding. PAL5 RNA levels increased in response to MeJA, ethylene, and abscisic acid, and declined in response to SA. Transcripts from the wound-response genes, leucine aminopeptidase (LapA1) and proteinase inhibitor 2 (pin2), were not detected following whitefly feeding. Furthermore, whitefly infestation of transgenic LapA1:GUS tomato plants showed that whitefly feeding did not activate the LapA1 promoter, although crushing of the leaf lamina increased GUS activity up to 40 fold. These studies indicate that tomato plants perceive B. tabaci and T. vaporariorum in a manner similar to baterical pathogens and distinct from tissue-damaging insects

Ageing, Muscle Power and Physical Function: A Systematic Review and Implications for Pragmatic Training Interventions.

BACKGROUND: The physiological impairments most strongly associated with functional performance in older people are logically the most efficient therapeutic targets for exercise training interventions aimed at improving function and maintaining independence in later life. OBJECTIVES: The objectives of this review were to (1) systematically review the relationship between muscle power and functional performance in older people; (2) systematically review the effect of power training (PT) interventions on functional performance in older people; and (3) identify components of successful PT interventions relevant to pragmatic trials by scoping the literature. METHODS: Our approach involved three stages. First, we systematically reviewed evidence on the relationship between muscle power, muscle strength and functional performance and, second, we systematically reviewed PT intervention studies that included both muscle power and at least one index of functional performance as outcome measures. Finally, taking a strong pragmatic perspective, we conducted a scoping review of the PT evidence to identify the successful components of training interventions needed to provide a minimally effective training dose to improve physical function. RESULTS: Evidence from 44 studies revealed a positive association between muscle power and indices of physical function, and that muscle power is a marginally superior predictor of functional performance than muscle strength. Nine studies revealed maximal angular velocity of movement, an important component of muscle power, to be positively associated with functional performance and a better predictor of functional performance than muscle strength. We identified 31 PT studies, characterised by small sample sizes and incomplete reporting of interventions, resulting in less than one-in-five studies judged as having a low risk of bias. Thirteen studies compared traditional resistance training with PT, with ten studies reporting the superiority of PT for either muscle power or functional performance. Further studies demonstrated the efficacy of various methods of resistance and functional task PT on muscle power and functional performance, including low-load PT and low-volume interventions. CONCLUSIONS: Maximal intended movement velocity, low training load, simple training methods, low-volume training and low-frequency training were revealed as components offering potential for the development of a pragmatic intervention. Additionally, the research area is dominated by short-term interventions producing short-term gains with little consideration of the long-term maintenance of functional performance. We believe the area would benefit from larger and higher-quality studies and consideration of optimal long-term strategies to develop and maintain muscle power and physical function over years rather than weeks

Models of classroom assessment for course-based research experiences

Course-based research pedagogy involves positioning students as contributors to authentic research projects as part of an engaging educational experience that promotes their learning and persistence in science. To develop a model for assessing and grading students engaged in this type of learning experience, the assessment aims and practices of a community of experienced course-based research instructors were collected and analyzed. This approach defines four aims of course-based research assessment—(1) Assessing Laboratory Work and Scientific Thinking; (2) Evaluating Mastery of Concepts, Quantitative Thinking and Skills; (3) Appraising Forms of Scientific Communication; and (4) Metacognition of Learning—along with a set of practices for each aim. These aims and practices of assessment were then integrated with previously developed models of course-based research instruction to reveal an assessment program in which instructors provide extensive feedback to support productive student engagement in research while grading those aspects of research that are necessary for the student to succeed. Assessment conducted in this way delicately balances the need to facilitate students’ ongoing research with the requirement of a final grade without undercutting the important aims of a CRE education

GmEREBP1 Is a Transcription Factor Activating Defense Genes in Soybean and Arabidopsis

Ethylene-responsive element-binding proteins (EREBPs) are plant-specific transcription factors, many of which have been linked to plant defense responses. Conserved EREBP domains bind to the GCC box, a promoter element found in pathogenesis-related (PR) genes. We previously identified an EREBP gene from soybean (GmEREBP1) whose transcript abundance decreased in soybean cyst-nematode-infected roots of a susceptible cultivar, whereas it increased in abundance in infected roots of a resistant cultivar. Here, we report further characterization of this gene. Transient expression analyses showed that GmEREBP1 is localized to the plant nucleus and functions as a transcriptional activator in soybean leaves. Transgenic soybean plants expressing GmEREBP1 activated the expression of the ethylene (ET)-responsive gene PR2 and the ET- and jasmonic acid (JA)-responsive gene PR3, and the salicylic acid (SA)-responsive gene PR1 but not the SA-responsive PR5. Similarly, transgenic Arabidopsis plants expressing GmEREBP1 showed elevated mRNA abundance of the ET-regulated gene PR3 and the ET- and JA-regulated defense-related gene PDF1.2 but not the ET-regulated GST2, and the SA-regulated gene PR1 but not the SA-regulated PR2 and PR5. Transgenic soybean and Arabidopsis plants inoculated with cyst nematodes did not display a significantly altered susceptibility to nematode infection. These results collectively show that GmEREBP1 functions as a transacting inducer of defense gene expression in both soybean and Arabidopsis and mediates the expression of both ET- and JA- and SA-regulated defense-related genes in these plant species.This article is published as Mazarei, Mitra, Axel A. Elling, Tom R. Maier, David P. Puthoff, and Thomas J. Baum. "GmEREBP1 is a transcription factor activating defense genes in soybean and Arabidopsis." Molecular Plant-Microbe Interactions 20, no. 2 (2007): 107-119, doi: 10.1094/MPMI-20-2-0107. Posted with permission.</p