Academic literature on the topic 'Plant Development Biology'
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Journal articles on the topic "Plant Development Biology"
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de Folter, Stefan. "Plant Biology: Gynoecium Development with Style." Current Biology 30, no. 23 (December 2020): R1420—R1422. http://dx.doi.org/10.1016/j.cub.2020.10.040.
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Niklas, Karl J., and Ulrich Kutschera. "The evolutionary development of plant body plans." Functional Plant Biology 36, no. 8 (2009): 682. http://dx.doi.org/10.1071/fp09107.
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Evolutionary developmental biology, cladistic analyses, and paleontological insights make it increasingly clear that regulatory mechanisms operating during embryogenesis and early maturation tend to be highly conserved over great evolutionary time scales, which can account for the conservative nature of the body plans in the major plant and animal clades. At issue is whether morphological convergences in body plans among evolutionarily divergent lineages are the result of adaptive convergence or ‘genome recall’ and ‘process orthology’. The body plans of multicellular photosynthetic eukaryotes (‘plants’) are reviewed, some of their important developmental/physiological regulatory mechanisms discussed, and the evidence that some of these mechanisms are phyletically ancient examined. We conclude that endosymbiotic lateral gene transfers, gene duplication and functional divergence, and the co-option of ancient gene networks were key to the evolutionary divergence of plant lineages.
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Brophy, Jennifer A. N. "Toward synthetic plant development." Plant Physiology 188, no. 2 (December 14, 2021): 738–48. http://dx.doi.org/10.1093/plphys/kiab568.
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Abstract The ability to engineer plant form will enable the production of novel agricultural products designed to tolerate extreme stresses, boost yield, reduce waste, and improve manufacturing practices. While historically, plants were altered through breeding to change their size or shape, advances in our understanding of plant development and our ability to genetically engineer complex eukaryotes are leading to the direct engineering of plant structure. In this review, I highlight the central role of auxin in plant development and the synthetic biology approaches that could be used to turn auxin-response regulators into powerful tools for modifying plant form. I hypothesize that recoded, gain-of-function auxin response proteins combined with synthetic regulation could be used to override endogenous auxin signaling and control plant structure. I also argue that auxin-response regulators are key to engineering development in nonmodel plants and that single-cell -omics techniques will be essential for characterizing and modifying auxin response in these plants. Collectively, advances in synthetic biology, single-cell -omics, and our understanding of the molecular mechanisms underpinning development have set the stage for a new era in the engineering of plant structure.
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Scheres, B. "Rooting plant development." Development 140, no. 5 (February 12, 2013): 939–41. http://dx.doi.org/10.1242/dev.093559.
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Morohoshi, Noriyuki. "New Development of Tree Biology." Journal of Plant Research 114, no. 4 (December 2001): 471. http://dx.doi.org/10.1007/pl00014013.
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Clark, Steven. "Plant Development." Cell 114, no. 1 (July 2003): 11–12. http://dx.doi.org/10.1016/s0092-8674(03)00516-6.
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Walton, Jonathan D. "Renaissance of Plant Biology The Molecular Basis of Plant Development Robert Goldberg." BioScience 40, no. 3 (March 1990): 208–9. http://dx.doi.org/10.2307/1311368.
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Elitaş, Meltem, Meral Yüce, and Hikmet Budak. "Microfabricated tools for quantitative plant biology." Analyst 142, no. 6 (2017): 835–48. http://dx.doi.org/10.1039/c6an02643e.
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The development of microfabricated devices that will provide high-throughput quantitative data and high resolution in a fast, repeatable and reproducible manner is essential for plant biology research.
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Trewavas, A. J. "Signalling Plant Development." BioEssays 21, no. 10 (September 23, 1999): 893. http://dx.doi.org/10.1002/(sici)1521-1878(199910)21:10<893::aid-bies14>3.0.co;2-6.
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Duckett, Catherine M., and John C. Gray. "Illuminating plant development." BioEssays 17, no. 2 (February 1995): 101–3. http://dx.doi.org/10.1002/bies.950170204.
Full textDissertations / Theses on the topic "Plant Development Biology"
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Puzey, Joshua Robert. "Plant MicroRNA Evolution and Mechanisms of Shape Change in Plants." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10143.
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Plant microRNAs have been shown to have important roles in regulating diverse processes ranging from reproductive development to stress response. In the first two chapters, I focus on miRNA diversity in Aquilegia studying both anciently evolved broadly conserved and rapidly evolving species specific miRNAs. In chapter one, I utilize Aquilegia's critical phylogenetic position between the well developed models Arabidopsis thaliana and Oryza sativa to study the evolution of ancient miRNAs across the angiosperms. In chapter two, I utilize smallRNA high-throughput sequencing to annotate Aquilegia specific miRNAs and, in the process, uncover the novel regulation of a floral homeotic gene by an Aquilegia-specific miRNA. In chapter three, I look at the tissue specific development of miRNA regulation in the bioenergetically relevant model organism Populus trichocarpa. High-throughput smallRNA sequencing from four diverse tissue sets including leaves, xylem, mechanically treated xylem, and pooled vegetative and reproductive tissues were analyzed, revealing a total of 155 previously unannotated miRNAs, most of which are P. trichocarpa specific. Expanding on my work with the petal identity pathway, I turned a broader analysis of Aquilegia petal spurs. Petal spurs are the distinguishing characteristic of Aquilegia and are argued to be a key innovation in the adaptive radiation of the genus. In the fourth chapter, I explore the cellular basis of extreme spur length diversity in the genus and find that a single parameter, cell shape, can explain this morphological range. Next, I seek to describe the cellular patterns that give rise to a spur primoridia from an initially flat laminar petal and find that spur initiation is characterized by concentrated, prolonged, and oriented cell divisions. Inspired by this quantitative analysis of growth, chapter five looks at the mechanisms of shape change in cucumber tendrils. I find that anisotropic contraction of a multi-layered gelatinous fiber ribbon explains coiling in cucumbers. Surprisingly, we discover that tendrils display twistless-overwinding when pulled and exhibit an unforeseen force-extension response as a result. These results provide the design basis for twistless springs with tunable mechanical responses and serve as a clear example of how the biological systems can inspire applied mechanical designs.
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van, Zyl Albertha R. "Development of plant-produced Bluetongue virus vaccines." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/28248.
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Bluetongue is a disease of domestic and wild ruminants caused by Bluetongue virus (BTV). It has caused several serious outbreaks, the most recent occurring in Northern Europe in 2006 during which high mortality rates of livestock were reported. The only vaccines currently approved and commercially available for use are live-attenuated or inactivated virus strains and although these are effective, there is the risk of reversion in the case of live-attenuated strains to more virulent forms by recombination. Another drawback associated with the use of live-attenuated virus vaccines is that they are not DIVA (differentiate infected from vaccinated animals) compliant, this means that naturally infected animals cannot be distinguished from vaccinated animals. Recombinantly produced vaccines would be preferable to minimize the risks associated with live-attenuated virus vaccines and also enable the development of candidate vaccines that are DIVA-compliant. A number of recombinant vaccine candidates have been developed against BTV, with the most promising vaccine consisting of BTV virus-like particles (VLPs). BTV VLPs were successfully produced in insect cells by the co-expression of the four BTV capsid proteins (VP2, VP3, VP5 and VP7). Sheep vaccinated with insect cell-produced BTV VLPs were shown to be protected against challenge with wild type virus. However, the high costs associated with the production and scale-up of BTV VLPs in insect cells has possibly limited their widespread application. Plants – such as N. benthamiana – provides a safe, efficient and cost effective system for the production of recombinant proteins. In this study the best plant expression vector with which to co-express the four BTV serotype 8 (BTV-8) VPs – which direct formation of BTV-8 VLPs – was identified. Expression and purification of the BTV-8 VLPs was optimised with the aim of producing a VLP-based vaccine for BTV-8. It was further undertaken to develop two novel second generation plant-produced protein body (PB) vaccines that are DIVA compliant. Mice were immunised with the plantproduced VLP and PB vaccines in order to analyse their ability to elicit humoral immune responses.
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Dennis, Susan Jennifer. "Development of plant-produced African horse sickness vaccines." Thesis, Faculty of Science, 2019. http://hdl.handle.net/11427/33687.
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African horse sickness is a devastating disease that causes great suffering and many fatalities amongst horses in sub-Saharan Africa. It is caused by nine different serotypes of the orbivirus African horse sickness virus (AHSV) and it is spread by Culicoid midges. The disease has significant economic consequences for the equine industry both in southern Africa and increasingly further afield as the geographic distribution of the midge vector broadens with global warming and climate change. Live attenuated vaccines (LAV) have been used with relative success for many decades, but carry the risk of reversion to virulence and/or genetic re-assortment between outbreak and vaccine strains. Furthermore, the vaccines lack DIVA capacity, the ability to distinguish between vaccine-induced immunity and that induced by natural infection. These concerns have motivated interest in the development of new, more favourable recombinant vaccines, initially focusing on the use of insect and mammalian cell expression systems. More recently, several studies have demonstrated the potential for using plant expression systems for the production of virus-like particles (VLPs), which are excellent vaccine candidates, as they do not contain virus genetic material and are DIVA compliant. A vaccine alternative to the currently used live vaccine necessarily needs to provide protection against all nine serotypes of the virus. Cross-protection has been shown to exist between certain serotypes of the virus and as capsid protein VP2 is the protein responsible for AHSV serotype specificity, the idea of a plant-produced VLP vaccine containing a representative VP2 protein from each of the different serotype groups, was conceived. Such a vaccine would potentially provideprotection against all 9 serotypes of the virus and would have DIVA capability. Furthermore, it would address local concerns regarding the use of a live vaccine and would serve as a potentially acceptable prophylactic or rapid response antidote in the wider international context. This work describes two approaches in the development of VLP vaccines in plants. In the first part of this study, the ability of 2 different serotypes of plant-produced AHSV VLPs to safely stimulate an immune response in horses, was investigated. Co-infiltration of Nicotiana benthamiana plants with Agrobacterium constructs encoding the four AHSV serotype 5 structural proteins VP2, VP3, VP5 and VP7, was shown to result in assembly of complete VLPs. Furthermore, co-infiltration with the constructs, encoding VP3 and VP7, together with constructs encoding the two outer capsid proteins VP2 and VP5 of a second serotype, AHSV 4, resulted in assembly of complete AHSV 4 VLPs. Horses vaccinated with plant-produced AHSV 4 and 5 VLPs, all seroconverted after two doses of the vaccine and the virus neutralization titres indicated that the plant-produced VLP vaccines are likely to be at least as effective as the current LAV in protecting against AHSV 4 or AHSV 5. However, they have the added advantage of being free from any of the associated risks of a live vaccine, such as reversion to virulence or genetic re-assortment with field or vaccine strains. In the second part of the study, the use of the so-called SpyTag/SpyCatcher or bacterial “superglue” technology was investigated. This technology is based on the peptide SpyTag irreversibly coupling to the SpyCatcher protein, forming an isopeptide bond when the two are mixed together. The plant-based expression system was used to produce Spy VLPs consisting of either Acinetobacter phage (AP205) VLPs or tobacco mosaic virus (TMV) VLPs displaying a SpyTag or SpyCatcher peptide. In addition, AHSV 5 VP2 displaying SpyTag was expressed in plants and several coupling strategies were tested to determine whether AP205 particles displaying AHSV 5 VP2 could be formed as a result of binding between the SpyTag/SpyCatcher moieties of the recombinant proteins. Although it was not proven that coupling occurred, this research will pave the way towards developing a multivalent vaccine platform whereby VP2 of different AHSV serotypes can be displayed on the Spy VLP surface to allow optimal presentation of these proteins to the animal's immune system. Together, the results obtained in this study show that there is great potential for the production of novel, diverse, efficacious and economically viable AHSV VLP vaccines in plants.
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Anna, Newman-Griffis Hare. "Plant nuclear envelope-associated proteins function in development and symbiosis." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1542733901078983.
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Catarino, Bruno. "Evolution of bHLH transcription factors that control epidermal cell development in plants." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:88f764a3-dfe9-432f-a33a-3db3981c21d9.
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The colonization of the arid continental surface by plants was one of the milestones in Earth's history. Morphological innovations, such as the origin of complex 3D tissues, allowed the successful colonization and radiation of plants on land. The epidermis is the outermost plant tissue that constitutes the interface between the plant and the environment. Thus, the evolution of epidermal cells was crucial for the adaptation of plants on the terrestrial arid environment. I undertook a combined approach that aims to understand the evolutionary trends that drove land plant colonization and the genetic mechanisms that underlie the development of the epidermis. This approach includes: 1) analyses of plant transcription factors (TFs) families distribution and diversification, with a particular focus on the basic Helix-Loop-Helix (bHLH) TF family, and 2) functional characterization of a putatively conserved bHLH TF subfamily involved in epidermal cell development in land plants. Here, I showed that there was a stepwise increase in the number of transcription factor (TF) families and bHLH subfamilies that predated the colonization of the terrestrial surface by plants. The subsequent increase in TF number on land was through duplication within pre-existing TF families and subfamilies. Moreover, a similar trend occurred in metazoan bHLH TF, suggesting that the majority of innovation in plant and metazoan TF families occurred in the Precambrian before the Phanerozoic radiation of land plants and metazoans. Furthermore, I demonstrated that the function of IIIf bHLH TFs in controlling the development of the epidermal cell layer is conserved between liverworts and angiosperms. This suggests that IIIf bHLH TFs are ancient and conserved regulators of epidermal cell development since the early colonization of the land by plants. Moreover, these bHLH TFs were recruited during the evolution of land plants to control the development of seemingly unrelated morphological characters in specific lineages of extant land plants. The recruitment of ancient developmental regulators to control distinct and unrelated developmental processes in land plants might underlie the huge morphological and taxonomic radiation of plants on land.
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Cao, Jingyi. "CELL TYPE-SPECIFIC ALTERNATIVE POLYADENYLATION IN ARABIDOPSIS DURING DEVELOPMENT AND STRESS RESPONSE." Miami University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=miami1492702815819455.
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Hable, Whitney Elizabeth 1967. "Expression and regulation of phytoene desaturase during maize seed development." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/282172.
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An essential component of development is the accumulation of specific metabolites in a temporal and tissue-specific manner. The growth regulator abscisic acid (ABA), which accumulates at a specific time during seed development, is required for seed maturation and prevents the premature developmental switch from dormancy to germination ABA accumulates differently in two tissues of the seed; levels in the embryo are several-fold higher than in the endosperm and the temporal accumulation of ABA is also different between these tissues. To begin to understand how ABA accumulation is regulated during seed development, the regulation of ABA biosynthesis was investigated. The approach taken was to examine the expression of the biosynthetic enzyme, phytoene desaturase (PDS), which catalyzes a regulated step in ABA synthesis in several other organisms (Bramley, 1985, Sandmann et al., 1989, Hugueney et al., 1992 and Giuliano et al., 1993). Unlike ABA accumulation, PDS transcript and protein levels were higher in the endosperm than in the embryo. The spatial difference in PDS levels did correlate with levels of the pathway intermediate, beta-carotene, suggesting that PDS may control the synthesis of ABA precursors while subsequent enzymes may regulate ABA accumulation. The temporal expression of Pds was also unrelated to ABA accumulation. In the endosperm, transcript levels were initially high and declined during desiccation while protein levels remained high throughout development. In the embryo, transcript levels were low and constant while protein levels declined. There are several maize mutants (viviparous mutants) disrupted in ABA biosynthesis, resulting in decreased levels of ABA and premature germination. Analysis of the Pds allele and transcript in the viviparous-5 mutant showed that the gene contains multiple insertions and deletions, giving rise to a larger transcript. In addition, the 55 kDa PDS protein was not detected in the vp5 mutant by immunoblot analysis, indicating that the vp5 phenotype results from a mutation at the PDS locus. To determine whether the wild type protein encoded by the ABA mutant, vp2, or the pathway intermediate, lycopene, regulate PDS, transcript and protein levels were compared in wild type and mutant (vp2 and vp7, respectively) seeds. The levels of PDS were not significantly different in vp2 or vp7 wild type and mutant seeds, suggesting that neither the VP2 protein nor lycopene regulate PDS at the steady-state transcript or protein level.
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Landberg, Katarina. "TERMINAL FLOWER2, the Arabidopsis HETEROCHROMATIN PROTEIN1 Homolog, and its Involvement in Plant Development." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7502.
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Zhang, Chang. "Abscisic Acid And Nitrate Transporter Mtlatd/nip Signaling In Root And Nodule Development In Medicago Truncatula." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/380.
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Abscisic acid (ABA) is a plant hormone that regulates various developmental processes and environmental stress responses. ABA modulates growth of both primary roots and lateral roots, helping to shape root architecture. The lateral root organ defective (latd) mutants, disrupted in the MtLATD/NIP gene, encoding a nitrate transporter, have severe root growth defects that can be rescued by applying ABA. However, the way in which ABA stimulates latd root growth is unclear, and the downstream components of MtLATD/NIP and ABA signaling are completely unknown. To answer these questions, this dissertation focuses on two major potential downstream regulators: Reactive Oxygen Species (ROS) and transcription factors (TFs).
ROS are important signaling molecules required in ABA-induced stomatal closure under drought or osmotic stresses, but their role in ABA regulation of root development is unclear. I found that latd mutant roots have increased ROS levels, and the expression level of several MtRboh genes, which encode major ROS-producing enzymes, the NADPH oxidases, is also increased. ABA decreases the amount of ROS in latd roots and also reduces expression of MtRbohC, in particular. In addition, I observed that latd mutant roots have cell elongation defects, which can also be rescued by exogenous ABA. I demonstrated that pharmaceutically decreasing ROS levels using an NADPH oxidase inhibitor, or reducing the expression of MtRbohC using RNA interference can increase cell elongation and stimulate lateral root elongation in latd roots. These findings have revealed a mechanism by which ABA restores root growth in latd mutant roots via regulating ROS levels, and identified MtRbohC as an important downstream target of ABA signaling mediated by MtLATD/NIP.
TFs act as regulatory nodes controlling the transcription of gene clusters and playing a crucial role in plant growth and development. Using a high-throughput TF profiling approach, I have identified 20 TFs that exhibit altered expression levels in latd mutant roots as compared to wild type, 60% of which can be restored to normal levels by ABA. My analysis also revealed that ABA regulates the expression of a different set of TFs in latd roots, suggesting that MtLATD/NIP is crucial for ABA regulation of TF expression. Moreover, ABA changes the TFs regulated by MtLATD/NIP almost completely, indicating a tight control of ABA on TFs regulated by MtLATD/NIP. Surprisingly, I found that the expression of NODULATION SIGNALING PATHWAY 2 (MtNSP2), a GRAS family TF required for nodulation, is regulated by MtLATD/NIP, ABA and nitrate in non-symbiotic roots. In symbiotic roots, MtLATD/NIP is required for the transcriptional signaling pathway downstream of MtNSP2 in the epidermis as well as induction of MtNSP2 expression by cytokinin and subsequent activation of its downstream targets in the cortex. These findings indicate that MtLATD/NIP functions in nodulation signal transduction upstream of MtNSP2, and mediates crosstalk with cytokinin.
Together, these two approaches have begun to characterize a signaling pathway downstream of ABA and MtLATD/NIP that involves ROS, MtNSP2, and a core group of TFs in the regulation of root development and nodulation in M. truncatula.
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Logsdon, Charles A. "Mutants of Arabidopsis thaliana exhibiting abnormal gravitropism and seedling plastid development." [Bloomington, Ind.] : Indiana University, 2005. http://wwwlib.umi.com/dissertations/fullcit/3162266.
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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2005.Title from PDF t.p. (viewed Dec. 2, 2008). Source: Dissertation Abstracts International, Volume: 66-01, Section: B, page: 0146. Chair: Roger P. Hangarter.
Books on the topic "Plant Development Biology"
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I, Jenkins Gareth, Schuch Wolfgang, and Society for Experimental Biology (Great Britain), eds. Molecular biology of plant development. Cambridge: Published for the Society for Experimental Biology by the Company of Biologists Ltd., Dept. of Zoology, University of Cambridge, 1991.
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1954-, Smith Alison M., ed. Plant biology. New York, NY: Garland Science, 2009.
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Pua, E. C. Plant developmental biology - biotechnological perspectives. Heidelberg: Springer, 2010.
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Plant developmental biology: Methods and protocols. New York: Humana, 2010.
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1948-, Gresshoff Peter M., ed. Plant biotechnology and development. Boca Raton: CRC Press, 1992.
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Stephen, Day, ed. Mechanisms in plant development. Oxford: Blackwell, 2003.
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A, Altman, Waisel Yoav, and International Symposium on the Biology of Root Formation and Development (2nd : 1996 : Jerusalem), eds. Biology of root formation and development. New York: Plenum Press, 1997.
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Oenothera: Contributions of a plant to biology. Berlin: Springer-Verlag, 1994.
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A, Larkins B., and Vasil I. K, eds. Cellular and molecular biology of plant seed development. Dordrecht: Kluwer Academic Publishers, 1997.
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Gloria, Coruzzi, Puigdomènech Pere, North Atlantic Treaty Organization. Scientific Affairs Division., and NATO Advanced Study Institute on Molecular Biology (7th : 1993 : Cala Viñas, Mallorca, Spain), eds. Plant molecular biology: Molecular genetic analysis of plant development and metabolism. Berlin: Springer-Verlag, 1994.
Find full textBook chapters on the topic "Plant Development Biology"
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Lack, Andrew, and David Evans. "Features of growth and development." In Plant Biology, 163–66. 2nd ed. London: Taylor & Francis, 2021. http://dx.doi.org/10.1201/9780203002902-51.
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Bouchez, David, Daniël Van Damme, Joanna Boruc, Estelle Schaefer, and Martine Pastuglia. "Cell Division Plane Determination in Plant Development." In Cell Biology, 1–26. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4614-7881-2_15-1.
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Lack, Andrew, and David Evans. "Physiology of floral initiation and development." In Plant Biology, 183–84. 2nd ed. London: Taylor & Francis, 2021. http://dx.doi.org/10.1201/9780203002902-54.
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Johnson, Mark A., and Benedikt Kost. "Pollen Tube Development." In Plant Developmental Biology, 155–76. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-765-5_11.
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Uhrig, Joachim F., and Martin Hülskamp. "Trichome Development in Arabidopsis." In Plant Developmental Biology, 77–88. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-765-5_6.
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Fiume, Elisa, Helena R. Pires, Jin Sun Kim, and Jennifer C. Fletcher. "Analyzing Floral Meristem Development." In Plant Developmental Biology, 131–42. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-765-5_9.
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Carles, Cristel C., Chan Man Ha, Ji Hyung Jun, Elisa Fiume, and Jennifer C. Fletcher. "Analyzing Shoot Apical Meristem Development." In Plant Developmental Biology, 105–29. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-765-5_8.
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Perbal, Gérald. "Plant Development in Microgravity." In Fundamentals of Space Biology, 227–90. New York, NY: Springer New York, 2006. http://dx.doi.org/10.1007/0-387-37940-1_6.
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Perilli, Serena, and Sabrina Sabatini. "Analysis of Root Meristem Size Development." In Plant Developmental Biology, 177–87. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-765-5_12.
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Lyndon, R. F., and D. Francis. "Plant and organ development." In 10 Years Plant Molecular Biology, 51–68. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2656-4_4.
Full textConference papers on the topic "Plant Development Biology"
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Agarwal, Pinky. "SUPER STARCHY1 Regulates Rice Grain Development." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.399383.
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Israeli, Alon. "Auxin-GA interaction in tomato leaf development." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.1048279.
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Yu, Yunqing. "Characterization of Shattering1 in abscission zone development of Setaria viridis." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.1053033.
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Leon Intriago, Briggitte Alexandra. "Development of a caffeine quantification technique for Ilex guayusa leaves." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.1053437.
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Wang, Fuxi. "INVESTIGATING PLANT MERISTEM DEVELOPMENT BY STUDYING A SUPPRESSOR OF tso1 MUTANTS." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.1053041.
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Haro von Mogel, Karl. "Development of HLB Resistant Citrus Varieties for California Using CRISPR-Cas9." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.1061157.
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Takasaki, Hirori. "ELONGATION OF SILIQUES WITHOUT POLLINATION 3 regulates ovule development in Arabidopsis." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.1052638.
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Zelinsky, Ellen. "A deeply conserved polygalacturonase functions in flower development in Arabidopsis thaliana." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.989681.
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Vetrici, Mariana. "Douglas-fir LEAFY COTYLEDON1 as a central processing unit during seed development." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.1053030.
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Harkey, Alexandria. "Identification of gene regulatory networks controlling ethylene-regulated root development in Arabidopsis." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.1049279.
Full textReports on the topic "Plant Development Biology"
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Ohad, Nir, and Robert Fischer. Control of Fertilization-Independent Development by the FIE1 Gene. United States Department of Agriculture, August 2000. http://dx.doi.org/10.32747/2000.7575290.bard.
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A fundamental problem in biology is to understand how fertilization initiates reproductive development. During plant reproduction, one sperm cell fuses with the egg to form an embryo, whereas a second sperm cell fuses with the adjacent central cell nucleus to form the endosperm tissue that supports embryo and/or seedling development. To understand the mechanisms that initiate reproduction, we have isolated mutants of Arabidopsis that allow for replication of the central cell and subsequent endosperm development without fertilization. In this project we have cloned the MEA gene and showed that it encode a SET- domain polycomb protein. Such proteins are known to form chromatin-protein complexes that repress homeotic gene transcription and influence cell proliferation from Drosophylla to mammals. We propose a model whereby MEA and an additional polycomb protein we have cloned, FIE , function to suppress a critical aspect of early plant reproduction and endosperm development, until fertilization occurs. Using a molecular approach we were able to determine that FIE and MEA interact physically, suggesting that these proteins have been conserved also during the evolution of flowering plants. The analysis of MEA expression pattern revealed that it is an imprinted gene that displays parent-of- origin-dependent monoallelic expression specifically in the endosperm tissue. Silencing of the paternal MEA allele in the endosperm and the phenotype of mutant mea seeds support the parental conflict theory for the evolution of imprinting in plants and mammals. These results contribute new information on the initiation of endosperm development and provide a unique entry point to study asexual reproduction and apomixis which is expected to improve crop production.
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Jung, Carina, Karl Indest, Matthew Carr, Richard Lance, Lyndsay Carrigee, and Kayla Clark. Properties and detectability of rogue synthetic biology (SynBio) products in complex matrices. Engineer Research and Development Center (U.S.), September 2022. http://dx.doi.org/10.21079/11681/45345.
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Synthetic biology (SynBio) aims to rationally engineer or modify traits of an organism or integrate the behaviors of multiple organisms into a singular functional organism through advanced genetic engineering techniques. One objective of this research was to determine the environmental persistence of engineered DNA in the environment. To accomplish this goal, the environmental persistence of legacy engineered DNA building blocks were targeted that laid the foundation for SynBio product development and application giving rise to “post-use products.” These building blocks include genetic constructs such as cloning and expression vectors, promoter/terminator elements, selectable markers, reporter genes, and multi-cloning sites. Shotgun sequencing of total DNA from water samples of pristine sites was performed and resultant sequence data mined for frequency of legacy recombinant DNA signatures. Another objective was to understand the fate of a standardized contemporary synthetic genetic construct (SC) in the context of various chassis systems/genetic configurations representing different degrees of “genetic bioavailability” to the environmental landscape. These studies were carried out using microcosms representing different environmental matrices (soils, waters, wastewater treatment plant (WWTP) liquor) and employed a novel genetic reporter system based on volatile organic compounds (VOC) detection to assess proliferation and persistence of the SC in the matrix over time.
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Phillips, Donald, and Yoram Kapulnik. Using Flavonoids to Control in vitro Development of Vesicular Arbuscular Mycorrhizal Fungi. United States Department of Agriculture, January 1995. http://dx.doi.org/10.32747/1995.7613012.bard.
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Vesicular-arbuscular mycorrhizal (VAM) fungi and other beneficial rhizosphere microorganisms, such as Rhizobium bacteria, must locate and infect a host plant before either symbiont profits. Although benefits of the VAM association for increased phosphorous uptake have been widely documented, attempts to improve the fungus and to produce agronomically useful amounts of inoculum have failed due to a lack of in vitro production methods. This project was designed to extend our prior observation that the alfalfa flavonoid quercetin promoted spore germination and hyphal growth of VAM fungi in the absence of a host plant. On the Israeli side of the project, a detailed examination of changes in flavonoids and flavonoid-biosynthetic enzymes during the early stages of VAM development in alfalfa found that VAM fungi elicited and then suppressed transcription of a plant gene coding for chalcone isomerase, which normally is associated with pathogenic infections. US workers collaborated in the identification of flavonoid compounds that appeared during VAM development. On the US side, an in vitro system for testing the effects of plant compounds on fungal spore germination and hyphal growth was developed for use, and intensive analyses of natural products released from alfalfa seedlings grown in the presence and absence of microorganisms were conducted. Two betaines, trigonelline and stachydrine, were identified as being released from alfalfa seeds in much higher concentrations than flavonoids, and these compounds functioned as transcriptional signals to another alfalfa microsymbiont, Rhizobium meliloti. However, these betaines had no effect on VAM spore germination or hyphal growth i vitro. Experiments showed that symbiotic bacteria elicited exudation of the isoflavonoids medicarpin and coumestrol from legume roots, but neither compound promoted growth or germination of VAM fungi in vitro. Attempts to look directly in alfalfa rhizosphere soil for microbiologically active plant products measured a gradient of nod-gene-inducing activity in R. meliloti, but no novel compounds were identified for testing in the VAM fungal system in vitro. Israeli field experiments on agricultural applications of VAM were very successful and developed methods for using VAM to overcome stunting in peanuts and garlic grown in Israel. In addition, deleterious effects of soil solarization on growth of onion, carrot and wheat were linked to effects on VAM fungi. A collaborative combination of basic and applied approaches toward enhancing the agronomic benefits of VAM asociations produced new knowledge on symbiotic biology and successful methods for using VAM inocula under field conditions
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Dickman, Martin B., and Oded Yarden. Genetic and chemical intervention in ROS signaling pathways affecting development and pathogenicity of Sclerotinia sclerotiorum. United States Department of Agriculture, July 2015. http://dx.doi.org/10.32747/2015.7699866.bard.
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Abstract: The long-term goals of our research are to understand the regulation of sclerotial development and pathogenicity in S. sclerotior11111. The focus in this project was on the elucidation of the signaling events and environmental cues involved in the regulation of these processes, utilizing and continuously developing tools our research groups have established and/or adapted for analysis of S. sclerotiorum, Our stated objectives: To take advantage of the recent conceptual (ROS/PPs signaling) and technical (amenability of S. sclerotiorumto manipulations coupled with chemical genomics and next generation sequencing) developments to address and extend our fundamental and potentially applicable knowledge of the following questions concerning the involvement of REDOX signaling and protein dephosphorylation in the regulation of hyphal/sclerotial development and pathogenicity of S. sclerotiorum: (i) How do defects in genes involved in ROS signaling affect S. sclerotiorumdevelopment and pathogenicity? (ii) In what manner do phosphotyrosinephosphatases affect S. sclerotiorumdevelopment and pathogenicity and how are they linked with ROS and other signaling pathways? And (iii) What is the nature of activity of newly identified compounds that affect S. sclerotiori,111 growth? What are the fungal targets and do they interfere with ROS signaling? We have met a significant portion of the specific goals set in our research project. Much of our work has been published. Briefly. we can summarize that: (a) Silencing of SsNox1(NADPHoxidase) expression indicated a central role for this enzyme in both virulence and pathogenic development, while inactivation of the SsNox2 gene resulted in limited sclerotial development, but the organism remained fully pathogenic. (b) A catalase gene (Scatl), whose expression was highly induced during host infection is involved in hyphal growth, branching, sclerotia formation and infection. (c) Protein tyrosine phosphatase l (ptpl) is required for sclerotial development and is involved in fungal infection. (d) Deletion of a superoxidedismutase gene (Sssodl) significantly reduced in virulence on both tomato and tobacco plants yet pathogenicity was mostly restored following supplementation with oxalate. (e) We have participated in comparative genome sequence analysis of S. sclerotiorumand B. cinerea. (f) S. sclerotiorumexhibits a potential switch between biotrophic and necrotrophic lifestyles (g) During plant microbe interactions cell death can occur in both resistant and susceptible events. Non pathogenic fungal mutants S. sclerotior111n also cause a cell death but with opposing results. We investigated PCD in more detail and showed that, although PCD occurs in both circumstances they exhibit distinctly different features. The mutants trigger a restricted cell death phenotype in the host that unexpectedly exhibits markers associated with the plant hypersensitive (resistant) response. Using electron and fluorescence microscopy, chemical effectors and reverse genetics, we have established that this restricted cell death is autophagic. Inhibition of autophagy rescued the non-pathogenic mutant phenotype. These findings indicate that autophagy is a defense response in this interaction Thus the control of cell death, dictated by the plant (autophagy) סr the fungus (apoptosis), is decisive to the outcome of certain plant microbe interactions. In addition to the time and efforts invested towards reaching the specific goals mentioned, both Pls have initiated utilizing (as stated as an objective in our proposal) state of the art RNA-seq tools in order to harness this technology for the study of S. sclerotiorum. The Pls have met twice (in Israel and in the US), in order to discuss .נחd coordinate the research efforts. This included a working visit at the US Pls laboratory for performing RNA-seq experiments and data analysis as well as working on a joint publication (now published). The work we have performed expands our understanding of the fundamental biology (developmental and pathogenic) of S. sclerotioז111וז. Furthermore, based on our results we have now reached the conclusion that this fungus is not a bona fide necrotroph, but can also display a biotrophic lifestyle at the early phases of infection. The data obtained can eventually serve .נ basis of rational intervention with the disease cycle of this pathogen.
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Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion, and Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, October 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
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Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.
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Sessa, Guido, and Gregory Martin. MAP kinase cascades activated by SlMAPKKKε and their involvement in tomato resistance to bacterial pathogens. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7699834.bard.
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The research problem: Pseudomonas syringae pv. tomato (Pst) and Xanthomonas campestrispv. vesicatoria (Xcv) are the causal agents of tomato bacterial speck and spot diseases, respectively. These pathogens colonize the aerial parts of the plant and cause economically important losses to tomato yield worldwide. Control of speck and spot diseases by cultural practices or chemicals is not effective and genetic sources of resistance are very limited. In previous research supported by BARD, by gene expression profiling we identified signaling components involved in resistance to Xcvstrains. Follow up experiments revealed that a tomato gene encoding a MAP kinase kinase kinase (MAPKKKe) is required for resistance to Xcvand Pststrains. Goals: Central goal of this research was to investigate the molecular mechanisms by which MAPKKKεand associated MAP kinase cascades regulate host resistance. Specific objectives were to: 1. Determine whether MAPKKKεplays a broad role in defense signaling in plants; 2. Identify components of MAP kinase cascades acting downstream of MAPKKKε; 3. Determine the role of phosphorylation-related events in the function of MAPKKKε; 4. Isolate proteins directly activated by MAPKKKε-associatedMAPK modules. Our main achievements during this research program are in the following major areas: 1. Characterization of MAPKKKεas a positive regulator of cell death and dissection of downstream MAP kinase cascades (Melech-Bonfil et al., 2010; Melech-Bonfil and Sessa, 2011). The MAPKKKεgene was found to be required for tomato resistance to Xcvand Pstbacterial strains and for hypersensitive response cell death triggered by different R gene/effector gene pairs. In addition, overexpression analysis demonstrated that MAPKKKεis a positive regulator of cell death, whose activity depends on an intact kinase catalytic domain. Epistatic experiments delineated a signaling cascade downstream of MAPKKKεand identified SIPKK as a negative regulator of MAPKKKε-mediated cell death. Finally, genes encoding MAP kinase components downstream of MAPKKKεwere shown to contribute to tomato resistance to Xcv. 2. Identification of tomato proteins that interact with MAPKKKεand play a role in plant immunity (Oh et al., 2011). We identified proteins that interact with MAPKKKε. Among them, the 14-3-3 protein TFT7 was required for cell death mediated by several R proteins. In addition, TFT7 interacted with the MAPKK SlMKK2 and formed homodimersin vivo. Thus, TFT7 is proposed to recruit SlMKK2 and MAPKKK client proteins for efficient signal transfer. 3. Development of a chemical genetic approach to identify substrates of MAPKKKε-activated MAP kinase cascades (Salomon et al., 2009, 2011). This approach is based on engineering the kinase of interest to accept unnatural ATP analogs. For its implementation to identify substrates of MAPKKKε-activated MAP kinase modules, we sensitized the tomato MAP kinase SlMPK3 to ATP analogs and verified its ability to use them as phosphodonors. By using the sensitized SlMPK3 and radiolabeled N6(benzyl)ATP it should be possible to tag direct substrates of this kinase. 4. Development of methods to study immunity triggered by pathogen-associated molecular patterns (PAMPs) in tomato and N. benthamiana plants (Kim et al., 2009; Nguyen et al. 2010). We developed protocols for measuring various PTI-associatedphenotypes, including bacterial populations after pretreatment of leaves with PAMPs, induction of reporter genes, callose deposition at the cell wall, activation of MAP kinases, and a luciferase-based reporter system for use in protoplasts. Scientific and agricultural significance: Our research activities discovered and characterized a signal transduction pathway mediating plant immunity to bacterial pathogens. Increased understanding of molecular mechanisms of immunity will allow them to be manipulated by both molecular breeding and genetic engineering to produce plants with enhanced natural defense against disease. In addition, we successfully developed new biochemical and molecular methods that can be implemented in the study of plant immunity and other aspects of plant biology.
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Bar-Joseph, Moshe, William O. Dawson, and Munir Mawassi. Role of Defective RNAs in Citrus Tristeza Virus Diseases. United States Department of Agriculture, September 2000. http://dx.doi.org/10.32747/2000.7575279.bard.
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This program focused on citrus tristeza virus (CTV), the largest and one of the most complex RNA-plant-viruses. The economic importance of this virus to the US and Israeli citrus industries, its uniqueness among RNA viruses and the possibility to tame the virus and eventually turn it into a useful tool for the protection and genetic improvement of citrus trees justify these continued efforts. Although the overall goal of this project was to study the role(s) of CTV associated defective (d)-RNAs in CTV-induced diseases, considerable research efforts had to be devoted to the engineering of the helper virus which provides the machinery to allow dRNA replication. Considerable progress was made through three main lines of complementary studies. For the first time, the generation of an engineered CTV genetic system that is capable of infecting citrus plants with in vitro modified virus was achieved. Considering that this RNA virus consists of a 20 kb genome, much larger than any other previously developed similar genetic system, completing this goal was an extremely difficult task that was accomplished by the effective collaboration and complementarity of both partners. Other full-length genomic CTV isolates were sequenced and populations examined, resulting in a new level of understanding of population complexities and dynamics in the US and Israel. In addition, this project has now considerably advanced our understanding and ability to manipulate dRNAs, a new class of genetic elements of closteroviruses, which were first found in the Israeli VT isolate and later shown to be omnipresent in CTV populations. We have characterized additional natural dRNAs and have shown that production of subgenomic mRNAs can be involved in the generation of dRNAs. We have molecularly cloned natural dRNAs and directly inoculated citrus plants with 35S-cDNA constructs and have shown that specific dRNAs are correlated with specific disease symptoms. Systems to examine dRNA replication in protoplasts were developed and the requirements for dRNA replication were defined. Several artificial dRNAs that replicate efficiently with a helper virus were created from infectious full-genomic cDNAs. Elements that allow the specific replication of dRNAs by heterologous helper viruses also were defined. The T36-derived dRNAs were replicated efficiently by a range of different wild CTV isolates and hybrid dRNAs with heterologous termini are efficiently replicated with T36 as helper. In addition we found: 1) All CTV genes except of the p6 gene product from the conserved signature block of the Closteroviridae are obligate for assembly, infectivity, and serial protoplast passage; 2) The p20 protein is a major component of the amorphous inclusion bodies of infected cells; and 3) Novel 5'-Co-terminal RNAs in CTV infected cells were characterized. These results have considerably advanced our basic understanding of the molecular biology of CTV and CTV-dRNAs and form the platform for the future manipulation of this complicated virus. As a result of these developments, the way is now open to turn constructs of this viral plant pathogen into new tools for protecting citrus against severe CTV terms and development of virus-based expression vectors for other citrus improvement needs. In conclusion, this research program has accomplished two main interconnected missions, the collection of basic information on the molecular and biological characteristics of the virus and its associated dRNAs toward development of management strategies against severe diseases caused by the virus and building of novel research tools to improve citrus varieties. Reaching these goals will allow us to advance this project to a new phase of turning the virus from a pathogen to an ally.
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Palmer, Guy, Varda Shkap, Wendy Brown, and Thea Molad. Control of bovine anaplasmosis: cytokine enhancement of vaccine efficacy. United States Department of Agriculture, March 2007. http://dx.doi.org/10.32747/2007.7695879.bard.
Full textAbstract:
Anaplasmosis an arthropod-born disease of cattle caused by the rickettsia Anaplasma marginale and is an impediment to efficient production of healthy livestock in both Israel and the United States. Currently the only effective vaccines are derived from the blood of infected cattle. The risk of widespread transmission of both known and newly emergent pathogens has prevented licensure of live blood-based vaccines in the U.S. and is a major concern for their continued use in Israel. Consequently development of a safe, effective vaccine is a high priority. In this collaborative project we focused on two approaches to vaccine development. The first focused o n improving antigen delivery to livestock and specifically examined how DNA vaccines could be improved to enhance priming and expansion of the immune response. This research resulted in development and testing of two novel vaccine delivery systems--one that targeted antigen spread among dendritic cells (the key cell in priming immune responses and a follow-on construct that also specifically targeted antigen to the endosomal-lysosomal compartment the processing organelle within the dendritic cell that directs vaccine antigen to the MHC class ll-CD4* T cell priming pathway). The optimized construct targeting vaccine antigen to the dendritic cell MHC class II pathway was tested for ability to prime A. marginale specific immune responses in outbred cattle. The results demonstrated both statistically significant effects of priming with a single immunization, continued expansion of the primary immune response including development of high affinity lgG antibodies and rapid recall of the memory response following antigen challenge. This portion of the study represented a significant advance in vaccine delivery for livestock. Importantly the impact of these studies is not limited to A. marginale a s the targeting motifs are optimized for cattle and can be adapted to other cattle vaccinations by inserting a relevant pathogen-specific antigen. The second approach (which represented an addition to the project for which approval was requested as part of the first annual report) was a comparative approach between A . marginale and the Israel A . centrale vaccines train. This addition was requested as studies on Major Surface Protein( MSP)- 2 have shown that this antigen is highly antigenically variable and presented solely as a "static vaccine" antigen does not give cross-strain immunity. In contrast A. . centrale is an effective vaccine which Kimron Veterinary institute has used in the field in Israel for over 50 years. Taking advantage of this expertise, a broad comparison of wild type A. marginale and vaccine strain was initiated. These studies revealed three primary findings: i) use of the vaccine is associated with superinfection, but absence of clinical disease upon superinfection with A. marginale; ii) the A. centrale vaccine strain is not only less virulent but transmission in competent in Dermacentor spp. ticks; and iii) some but not all MSPs are conserved in basic orthologous structure but there are significant polymorphisms among the strains. These studies clearly indicated that there are statistically significant differences in biology (virulence and transmission) and provide a clear path for mapping of biology with the genomes. Based on these findings, we initiated complete genome sequencing of the Israel vaccine strain (although not currently funded by BARD) and plant to proceed with a comparative genomics approach using already sequenced wild-type A. marginale. These findings and ongoing collaborative research tie together filed vaccine experience with new genomic data, providing a new approach to vaccine development against a complex pathogen.
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Twining, Benjamin S., Mak A. Saito, Alyson E. Santoro, Adrian Marchetti, and Naomi M. Levine. US National BioGeoSCAPES Workshop Report. Woods Hole Oceangraphic Institution, January 2023. http://dx.doi.org/10.1575/1912/29604.
Full textAbstract:
BioGeoSCAPES (BGS) is an international program being developed to understand controls on ocean productivity and metabolism by integrating systems biology (‘omics) and biogeochemistry (Figure 1). To ensure global input into the design of the BGS Program, countries interested in participating were tasked with holding an organizing meeting to discuss the country-specific research priorities. A United States BGS planning meeting, sponsored by the Ocean Carbon & Biogeochemistry (OCB) Project Office, was convened virtually November 10-12, 2021. The objectives of the meeting were to communicate the planning underway by international partners, engage the US community to explore possible national contributions to such a program, and build understanding, support, and momentum for US efforts towards BGS. The meeting was well-attended, with 154 participants and many fruitful discussions that are summarized in this document. Key outcomes from the meeting were the identification of additional programs and partners for BGS, a prioritization of measurements requiring intercalibration, and the development of a consensus around key considerations to be addressed in a science plan. Looking forward, the hope is that this workshop will serve as the foundation for future US and international discussions and planning for a BGS program, enabled by NSF funding for an AccelNet project (AccelNet - Implementation: Development of an International Network for the Study of Ocean Metabolism and Nutrient Cycles on a Changing Planet (BioGeoSCAPES)), beginning in 2022.
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Horwitz, Benjamin A., and Barbara Gillian Turgeon. Fungal Iron Acquisition, Oxidative Stress and Virulence in the Cochliobolus-maize Interaction. United States Department of Agriculture, March 2012. http://dx.doi.org/10.32747/2012.7709885.bard.
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Our project focused on genes for high affinity iron acquisition in Cochliobolus heterostrophus, a necrotrophic pathogen of maize, and their intertwined relationship to oxidative stress status and virulence of the fungus on the host. An intriguing question was why mutants lacking the nonribosomal peptide synthetase (NRPS) gene (NPS6) responsible for synthesis of the extracellular siderophore, coprogen, are sensitive to oxidative stress. Our overall objective was to understand the mechanistic connection between iron stress and oxidative stress as related to virulence of a plant pathogen to its host. The first objective was to examine the interface where small molecule peptide and reactive oxygen species (ROS) mechanisms overlap. The second objective was to determine if the molecular explanation for common function is common signal transduction pathways. These pathways, built around sensor kinases, response regulators, and transcription factors may link sequestering of iron, production of antioxidants, resistance to oxidative stress, and virulence. We tested these hypotheses by genetic manipulation of the pathogen, virulence assays on the host plant, and by following the expression of key fungal genes. An addition to the original program, made in the first year, was to develop, for fungi, a genetically encoded indicator of redox state based on the commercially available Gfp-based probe pHyper, designed for animal cell biology. We implemented several tools including a genetically encoded indicator of redox state, a procedure to grow iron-depleted plants, and constructed a number of new mutants in regulatory genes. Lack of the major Fe acquisition pathways results in an almost completely avirulent phenotype, showing how critical Fe acquisition is for the pathogen to cause disease. Mutants in conserved signaling pathways have normal ability to regulate NPS6 in response to Fe levels, as do mutants in Lae1 and Vel1, two master regulators of gene expression. Vel1 mutants are sensitive to oxidative stress, and the reason may be underexpression of a catalase gene. In nps6 mutants, CAT3 is also underexpressed, perhaps explaining the sensitivity to oxidative stress. We constructed a deletion mutant for the Fe sensor-regulator SreA and found that it is required for down regulation of NPS6 under Fe-replete conditions. Lack of SreA, though, did not make the fungus over-sensitive to ROS, though the mutant had a slow growth rate. This suggests that overproduction of siderophore under Fe-replete conditions is not very damaging. On the other hand, increasing Fe levels protected nps6 mutants from inhibition by ROS, implying that Fe-catalyzed Fenton reactions are not the main factor in its sensitivity to ROS. We have made some progress in understanding why siderophore mutants are sensitive to oxidative stress, and in doing so, defined some novel regulatory relationships. Catalase genes, which are not directly related to siderophore biosynthesis, are underexpressed in nps6 mutants, suggesting that the siderophore product (with or without bound Fe) may act as a signal. Siderophores, therefore, could be a target for intervention in the field, either by supplying an incorrect signal or blocking a signal normally provided during infection. We already know that nps6 mutants cause smaller lesions and have difficulty establishing invasive growth in the host. Lae1 and Vel1 are the first factors shown to regulate both super virulence conferred by T-toxin, and basic pathogenicity, due to unknown factors. The mutants are also altered in oxidative stress responses, key to success in the infection court, asexual and sexual development, essential for fungal dissemination in the field, aerial hyphal growth, and pigment biosynthesis, essential for survival in the field. Mutants in genes encoding NADPH oxidase (Nox) are compromised in development and virulence. Indeed the triple mutant, which should lack all Nox activity, was nearly avirulent. Again, gene expression experiments provided us with initial evidence that superoxide produced by the fungus may be most important as a signal. Blocking oxidant production by the pathogen may be a way to protect the plant host, in interactions with necrotrophs such as C. heterostrophus which seem to thrive in an oxidant environment.