scholarly journals Elucidation of the genetic control of carbohydrate partitioning in Zea mays

2019 ◽  
Author(s):  
◽  
Benjamin Thomas Julius
Keyword(s):  
Zea Mays ◽  
Genetic Control ◽  
Stress Responses ◽  
Leaf Tissue ◽  
Phloem Loading ◽  
Primary Cell Wall ◽  
Future Research ◽  
Crystalline Cellulose ◽  
Carbohydrate Partitioning ◽  
Transporter Family

Carbohydrate partitioning, the process of transporting carbohydrates from sites of synthesis in hotosynthetic tissue to developing sink tissues, is crucial for the growth, development, and yield in plants and crops. Anatomical, physiological, and biochemical studies have shed light on this process; however, there is not much known in regards to the genetic control of carbohydrate partitioning. The work described here uses forward and reverse genetic methods to further elucidate the genetic control of carbohydrate partitioning in Zea mays (maize). Chapter 1 reviews what is currently known regarding the function of sugar transporters in the phloem loading and unloading pathways. Additionally, the importance and role of carbohydrate partitioning during abiotic and biotic stress responses is discussed. Chapters 2-4 describe the characterization and cloning of the allelic recessive mutants carbohydrate partitioning defective28 (cpd28) and carbohydrate partitioning defective47 (cpd47) (Chapter 2) and the semi-dominant gain-of-function mutant Carbohydrate partitioning defective1 (Cpd1) (Chapters 3 and 4). All three mutant's hyper-accumulate carbohydrates in their mature leaves due to decreased sucrose export. The cpd28 and cpd47 mutations decrease the amount of crystalline cellulose and likely impair primary cell wall development. The Cpd1 mutation results in the unregulated deposition of the callose in the phloem of leaf and root tissue. Chapter 5 summarizes the Sugars Will Eventually Exit Tissue (SWEET) transporter family and their function across a number of plant species. In this review I was responsible for the generation of a 15 angiosperm protein phylogenetic analysis describing the relationship and structure found in the transporter family. Chapter 6 builds upon the phylogentic study performed in Chapter 5 and identifies and characterizes the function of the SWEET13a, SWEET13b, and WEET13c transporters in the phloem loading pathway in maize utilizing CRISPR/Cas9 mutagenesis. Chapter 7 summarizes the discoveries made in the previous chapters, their contribution to the field, and discusses future research directions. Appendix A describes a protocol I optimized for the fixation, embedding, sectioning, Laser Capture Microdissection, and RNA-sequencing of desired cell groups in mature maize leaf tissue. Appendix B describes the characterization and cloning of the recessive mutant carbohydrate partitioning defective33 (cpd33) and its role in plasmodesmatal function. I contributed to the cloning of cpd33. Appendix C analyzes the expression levels and potential roles of SWEET and TST transporters in sweet and grain sorghum. I was responsible for the expression analysis of the SWEET genes discussed in this publication.

Ultrastructure of Plant Leaf Tissue Infected with Mite-Borne Viral-Like Pathogens

1970 ◽  
Vol 28 ◽  
pp. 178-179 ◽  
Author(s):  
O. E. Bradfute ◽  
R. E. Whitmoyer ◽  
L. R. Nault
Keyword(s):  
Triticum Aestivum ◽  
Zea Mays ◽  
Electron Microscope ◽  
Hordeum Vulgare ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Leaf Tissue ◽  
Leaf Ultrastructure ◽  
Double Membrane ◽  
Aceria Tulipae

A pathogen transmitted by the eriophyid mite, Aceria tulipae, infects a number of Gramineae producing symptoms similar to wheat spot mosaic virus (1). An electron microscope study of leaf ultrastructure from systemically infected Zea mays, Hordeum vulgare, and Triticum aestivum showed the presence of ovoid, double membrane bodies (0.1 - 0.2 microns) in the cytoplasm of parenchyma, phloem and epidermis cells (Fig. 1 ).

scholarly journals Mitochondrial redox systems as central hubs in plant metabolism and signalling

2021 ◽  
Author(s):  
Olivier Van Aken
Keyword(s):  
Stress Responses ◽  
Plant Mitochondria ◽  
Nuclear Gene ◽  
Tca Cycle ◽  
Cellular Damage ◽  
Future Research ◽  
Antioxidant Systems ◽  
Plant Metabolism ◽  
Redox Systems ◽  
Glutathione Cycle

Abstract Plant mitochondria are indispensable for plant metabolism and are tightly integrated into cellular homeostasis. This review provides an update on the latest research concerning the organisation and operation of plant mitochondrial redox systems, and how they affect cellular metabolism and signalling, plant development and stress responses. New insights into the organisation and operation of mitochondrial energy systems such as the tricarboxylic acid (TCA) cycle and mitochondrial electron chain (mtETC) are discussed. The mtETC produces reactive oxygen and nitrogen species, which can act as signals or lead to cellular damage, and are thus efficiently removed by mitochondrial antioxidant systems, including Mn-superoxide dismutase, ascorbate-glutathione cycle and thioredoxin-dependent peroxidases. Plant mitochondria are tightly connected with photosynthesis, photorespiration and cytosolic metabolism, thereby providing redox-balancing. Mitochondrial proteins are targets of extensive post-translational modifications, but their functional significance and how they are added or removed remains unclear. To operate in sync with the whole cell, mitochondria can communicate their functional status via mitochondrial retrograde signalling to change nuclear gene expression, and several recent breakthroughs here are discussed. At a whole organism level, plant mitochondria thus play crucial roles from the first minutes after seed imbibition, supporting meristem activity, growth and fertility, until senescence of darkened and aged tissue. Finally, plant mitochondria are tightly integrated with cellular and organismal responses to environmental challenges such as drought, salinity, heat and submergence, but also threats posed by pathogens. Both the major recent advances and outstanding questions are reviewed, which may help future research efforts on plant mitochondria.

scholarly journals Can neuroscience help to understand narcissism? A systematic review of an emerging field

2021 ◽  
Vol 4 ◽  
Author(s):  
Emanuel Jauk ◽  
Philipp Kanske
Keyword(s):  
Systematic Review ◽  
Stress Responses ◽  
Interpersonal Functioning ◽  
Integrative Model ◽  
Experimental Investigations ◽  
Future Research ◽  
Pathological Narcissism ◽  
Ego Threat ◽  
Self Reports ◽  
And Behavior

Abstract Narcissism is a Janusian personality construct, associated with both grandiose self-assuredness and dominance, as well as vulnerable insecurity and reactivity. Central questions of intra- and interpersonal functioning in narcissism are still a matter of debate. Neuroscience could help to understand the paradoxical patterns of experience and behavior beyond the limitations of self-reports. We provide a systematic review of 34 neuroscience studies on grandiose, vulnerable, pathological narcissism, and Narcissistic Personality Disorder (NPD), spanning experimental investigations of intra- and interpersonal mechanisms, research on neurophysiological and neuroendocrine aspects of baseline function, and brain structural correlates. While neuroscience has scarcely directly studied vulnerable narcissism, grandiose narcissism is associated with heightened vigilance to ego threat and stress responses following ego threat, as well as heightened stress indicators in baseline measures. Such responses are not commonly observed in self-reports, highlighting the potential of neuroscience to augment our understanding of self-regulatory dynamics in narcissism. Interpersonal functioning is characterized by deficits in social–affective processes. Both involve altered activity within the salience network, pointing to a double dissociation regarding the expression of narcissism and self/other oriented situational focus. Findings are summarized in an integrative model providing testable hypotheses for future research along with methodological recommendations.

scholarly journals Crosstalk between endoplasmic reticulum stress and oxidative stress: a dynamic duo in multiple myeloma

2021 ◽  
Author(s):  
Sinan Xiong ◽  
Wee-Joo Chng ◽  
Jianbiao Zhou
Keyword(s):  
Oxidative Stress ◽  
Multiple Myeloma ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Cell Fate ◽  
Stress Responses ◽  
Plasma Cells ◽  
Reactive Oxygen Species Generation ◽  
Future Research ◽  
And Oxidative Stress

AbstractUnder physiological and pathological conditions, cells activate the unfolded protein response (UPR) to deal with the accumulation of unfolded or misfolded proteins in the endoplasmic reticulum. Multiple myeloma (MM) is a hematological malignancy arising from immunoglobulin-secreting plasma cells. MM cells are subject to continual ER stress and highly dependent on the UPR signaling activation due to overproduction of paraproteins. Mounting evidence suggests the close linkage between ER stress and oxidative stress, demonstrated by overlapping signaling pathways and inter-organelle communication pivotal to cell fate decision. Imbalance of intracellular homeostasis can lead to deranged control of cellular functions and engage apoptosis due to mutual activation between ER stress and reactive oxygen species generation through a self-perpetuating cycle. Here, we present accumulating evidence showing the interactive roles of redox homeostasis and proteostasis in MM pathogenesis and drug resistance, which would be helpful in elucidating the still underdefined molecular pathways linking ER stress and oxidative stress in MM. Lastly, we highlight future research directions in the development of anti-myeloma therapy, focusing particularly on targeting redox signaling and ER stress responses.

Leaf structure in relation to solute transport and phloem loading in Zea mays L.

Planta ◽  
1978 ◽  
Vol 138 (3) ◽  
pp. 279-294 ◽  
Author(s):  
R. F. Evert ◽  
W. Eschrich ◽  
W. Heyser
Keyword(s):  
Zea Mays ◽  
Solute Transport ◽  
Zea Mays L ◽  
Phloem Loading ◽  
Leaf Structure

scholarly journals Epigenetic Responses to Temperature and Climate

2020 ◽  
Vol 60 (6) ◽  
pp. 1469-1480 ◽  
Author(s):  
Beth A McCaw ◽  
Tyler J Stevenson ◽  
Lesley T Lancaster
Keyword(s):  
Temperature Change ◽  
Stress Responses ◽  
Environmental Temperature ◽  
Environmental Control ◽  
Global Climate ◽  
Thermal Adaptation ◽  
Epigenetic Inheritance ◽  
Epigenetic Modifications ◽  
Future Research ◽  
Adaptation To Climate Change

Synopsis Epigenetics represents a widely accepted set of mechanisms by which organisms respond to the environment by regulating phenotypic plasticity and life history transitions. Understanding the effects of environmental control on phenotypes and fitness, via epigenetic mechanisms, is essential for understanding the ability of organisms to rapidly adapt to environmental change. This review highlights the significance of environmental temperature on epigenetic control of phenotypic variation, with the aim of furthering our understanding of how epigenetics might help or hinder species’ adaptation to climate change. It outlines how epigenetic modifications, including DNA methylation and histone/chromatin modification, (1) respond to temperature and regulate thermal stress responses in different kingdoms of life, (2) regulate temperature-dependent expression of key developmental processes, sex determination, and seasonal phenotypes, (3) facilitate transgenerational epigenetic inheritance of thermal adaptation, (4) adapt populations to local and global climate gradients, and finally (5) facilitate in biological invasions across climate regions. Although the evidence points towards a conserved role of epigenetics in responding to temperature change, there appears to be an element of temperature- and species-specificity in the specific effects of temperature change on epigenetic modifications and resulting phenotypic responses. The review identifies areas of future research in epigenetic responses to environmental temperature change.

scholarly journals A Novel WRKY Transcription Factor from Ipomoea trifida, ItfWRKY70, Confers Drought Tolerance in Sweet Potato

2022 ◽  
Vol 23 (2) ◽  
pp. 686
Author(s):  
Sifan Sun ◽  
Xu Li ◽  
Shaopei Gao ◽  
Nan Nie ◽  
Huan Zhang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Transgenic Plants ◽  
Drought Tolerance ◽  
Sweet Potato ◽  
Stress Responses ◽  
Leaf Tissue ◽  
Stomatal Aperture ◽  
Ros Scavenging ◽  
Ipomoea Trifida ◽  
Positive Role

WRKY transcription factors are one of the important families in plants, and have important roles in plant growth, abiotic stress responses, and defense regulation. In this study, we isolated a WRKY gene, ItfWRKY70, from the wild relative of sweet potato Ipomoea trifida (H.B.K.) G. Don. This gene was highly expressed in leaf tissue and strongly induced by 20% PEG6000 and 100 μM abscisic acid (ABA). Subcellar localization analyses indicated that ItfWRKY70 was localized in the nucleus. Overexpression of ItfWRKY70 significantly increased drought tolerance in transgenic sweet potato plants. The content of ABA and proline, and the activity of SOD and POD were significantly increased, whereas the content of malondialdehyde (MDA) and H2O2 were decreased in transgenic plants under drought stress. Overexpression of ItfWRKY70 up-regulated the genes involved in ABA biosynthesis, stress-response, ROS-scavenging system, and stomatal aperture in transgenic plants under drought stress. Taken together, these results demonstrated that ItfWRKY70 plays a positive role in drought tolerance by accumulating the content of ABA, regulating stomatal aperture and activating the ROS scavenging system in sweet potato.

scholarly journals The Divergent Roles of the Rice bcl-2 Associated Athanogene (BAG) Genes in Plant Development and Environmental Responses

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2169
Author(s):  
Hailian Zhou ◽  
Jiaying Li ◽  
Xueyuan Liu ◽  
Xiaoshuang Wei ◽  
Ziwei He ◽  
...  
Keyword(s):  
Plant Development ◽  
Stress Responses ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Brown Planthopper ◽  
Protein Structures ◽  
Secondary Growth ◽  
Primary Cell Wall ◽  
Biological Functions ◽  
Group I

Bcl-2-associated athanogene (BAG), a group of proteins evolutionarily conserved and functioned as co-chaperones in plants and animals, is involved in various cell activities and diverse physiological processes. However, the biological functions of this gene family in rice are largely unknown. In this study, we identified a total of six BAG members in rice. These genes were classified into two groups, OsBAG1, -2, -3, and -4 are in group I with a conserved ubiquitin-like structure and OsBAG5 and -6 are in group Ⅱ with a calmodulin-binding domain, in addition to a common BAG domain. The BAG genes exhibited diverse expression patterns, with OsBAG4 showing the highest expression level, followed by OsBAG1 and OsBAG3, and OsBAG6 preferentially expressed in the panicle, endosperm, and calli. The co-expression analysis and the hierarchical cluster analysis indicated that the OsBAG1 and OsBAG3 were co-expressed with primary cell wall-biosynthesizing genes, OsBAG4 was co-expressed with phytohormone and transcriptional factors, and OsBAG6 was co-expressed with disease and shock-associated genes. β-glucuronidase (GUS) staining further indicated that OsBAG3 is mainly involved in primary young tissues under both primary and secondary growth. In addition, the expression of the BAG genes under brown planthopper (BPH) feeding, N, P, and K deficiency, heat, drought and plant hormones treatments was investigated. Our results clearly showed that OsBAGs are multifunctional molecules as inferred by their protein structures, subcellular localizations, and expression profiles. BAGs in group I are mainly involved in plant development, whereas BAGs in group II are reactive in gene regulations and stress responses. Our results provide a solid basis for the further elucidation of the biological functions of plant BAG genes.

scholarly journals Molecular Evolution of Calcium Signaling and Transport in Plant Adaptation to Abiotic Stress

2021 ◽  
Vol 22 (22) ◽  
pp. 12308
Author(s):  
Tao Tong ◽  
Qi Li ◽  
Wei Jiang ◽  
Guang Chen ◽  
Dawei Xue ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Calcium Signaling ◽  
Stress Responses ◽  
Evolutionary Biology ◽  
Regulatory Networks ◽  
Cascade Reactions ◽  
Future Research ◽  
Spatiotemporal Pattern ◽  
Green Plants ◽  
Signaling Components

Adaptation to unfavorable abiotic stresses is one of the key processes in the evolution of plants. Calcium (Ca2+) signaling is characterized by the spatiotemporal pattern of Ca2+ distribution and the activities of multi-domain proteins in integrating environmental stimuli and cellular responses, which are crucial early events in abiotic stress responses in plants. However, a comprehensive summary and explanation for evolutionary and functional synergies in Ca2+ signaling remains elusive in green plants. We review mechanisms of Ca2+ membrane transporters and intracellular Ca2+ sensors with evolutionary imprinting and structural clues. These may provide molecular and bioinformatics insights for the functional analysis of some non-model species in the evolutionarily important green plant lineages. We summarize the chronological order, spatial location, and characteristics of Ca2+ functional proteins. Furthermore, we highlight the integral functions of calcium-signaling components in various nodes of the Ca2+ signaling pathway through conserved or variant evolutionary processes. These ultimately bridge the Ca2+ cascade reactions into regulatory networks, particularly in the hormonal signaling pathways. In summary, this review provides new perspectives towards a better understanding of the evolution, interaction and integration of Ca2+ signaling components in green plants, which is likely to benefit future research in agriculture, evolutionary biology, ecology and the environment.

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