Epigenetic regulation of geminivirus pathogenesis: a case of relentless recalibration of defence responses in plants

2020 ◽  
Vol 71 (22) ◽  
pp. 6890-6906 ◽  
Author(s):  
Fauzia Zarreen ◽  
Supriya Chakraborty
Keyword(s):  
Viral Genome ◽  
Current Knowledge ◽  
Plant Viruses ◽  
Limited Evidence ◽  
Host Proteins ◽  
Crop Species ◽  
Cellular Processes ◽  
Wide Range ◽  
Defence Responses ◽  
Epigenetic Processes

Abstract Geminiviruses constitute one of the largest families of plant viruses and they infect many economically important crops. The proteins encoded by the single-stranded DNA genome of these viruses interact with a wide range of host proteins to cause global dysregulation of cellular processes and help establish infection in the host. Geminiviruses have evolved numerous mechanisms to exploit host epigenetic processes to ensure the replication and survival of the viral genome. Here, we review our current knowledge of diverse epigenetic processes that have been implicated in the regulation of geminivirus pathogenesis, including DNA methylation, histone post-transcriptional modification, chromatin remodelling, and nucleosome repositioning. In addition, we discuss the currently limited evidence of host epigenetic defence responses that are aimed at counteracting geminivirus infection, and the potential for exploiting these responses for the generation of resistance against geminiviruses in crop species.

scholarly journals Unconventional Myosins: How Regulation Meets Function

2019 ◽  
Vol 21 (1) ◽  
pp. 67 ◽  
Author(s):  
Natalia Fili ◽  
Christopher P. Toseland
Keyword(s):  
Molecular Motors ◽  
Current Knowledge ◽  
Local Environment ◽  
Structural Features ◽  
Regulatory Mechanisms ◽  
Tight Control ◽  
Cellular Processes ◽  
Binding Partners ◽  
Wide Range ◽  
Multiple Levels

Unconventional myosins are multi-potent molecular motors that are assigned important roles in fundamental cellular processes. Depending on their mechano-enzymatic properties and structural features, myosins fulfil their roles by acting as cargo transporters along the actin cytoskeleton, molecular anchors or tension sensors. In order to perform such a wide range of roles and modes of action, myosins need to be under tight regulation in time and space. This is achieved at multiple levels through diverse regulatory mechanisms: the alternative splicing of various isoforms, the interaction with their binding partners, their phosphorylation, their applied load and the composition of their local environment, such as ions and lipids. This review summarizes our current knowledge of how unconventional myosins are regulated, how these regulatory mechanisms can adapt to the specific features of a myosin and how they can converge with each other in order to ensure the required tight control of their function.

Creating a customized intracellular niche: subversion of host cell signaling byLegionellatype IV secretion system effectors

2015 ◽  
Vol 61 (9) ◽  
pp. 617-635 ◽  
Author(s):  
Ernest C. So ◽  
Corinna Mattheis ◽  
Edward W. Tate ◽  
Gad Frankel ◽  
Gunnar N. Schroeder
Keyword(s):  
Host Cell ◽  
Legionella Pneumophila ◽  
Current Knowledge ◽  
Secretion System ◽  
Effector Proteins ◽  
Cellular Processes ◽  
Type Iv ◽  
Open Questions ◽  
Exact Function ◽  
Wide Range

The Gram-negative facultative intracellular pathogen Legionella pneumophila infects a wide range of different protozoa in the environment and also human alveolar macrophages upon inhalation of contaminated aerosols. Inside its hosts, it creates a defined and unique compartment, termed the Legionella-containing vacuole (LCV), for survival and replication. To establish the LCV, L. pneumophila uses its Dot/Icm type IV secretion system (T4SS) to translocate more than 300 effector proteins into the host cell. Although it has become apparent in the past years that these effectors subvert a multitude of cellular processes and allow Legionella to take control of host cell vesicle trafficking, transcription, and translation, the exact function of the vast majority of effectors still remains unknown. This is partly due to high functional redundancy among the effectors, which renders conventional genetic approaches to elucidate their role ineffective. Here, we review the current knowledge about Legionella T4SS effectors, highlight open questions, and discuss new methods that promise to facilitate the characterization of T4SS effector functions in the future.

scholarly journals Pinus pinaster Early Hormonal Defence Responses to Pinewood Nematode (Bursaphelenchus xylophilus) Infection

Metabolites ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 227
Author(s):  
Ana M. Rodrigues ◽  
Swen Langer ◽  
Isabel Carrasquinho ◽  
Ed Bergström ◽  
Tony Larson ◽  
...  
Keyword(s):  
Pinus Pinaster ◽  
Current Knowledge ◽  
Acid Methyl Ester ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Pinewood Nematode ◽  
Crop Species ◽  
Jasmonic Acid Methyl Ester ◽  
Defence Responses ◽  
Pinus Spp

The pinewood nematode (PWN) is the causal agent of pine wilt disease, a pathology that affects conifer forests, mainly Pinus spp. PWN infection can induce the expression of phytohormone-related genes; however, changes at the early phytohormone level have not yet been explored. Phytohormones are low-abundance metabolites, and thus, difficult to quantify. Moreover, most methodologies focus mainly on Arabidopsis or crop species. This work aimed to validate a fast (run time 6.6 min) liquid chromatography-triple quadrupole tandem mass spectrometry (LC-QqQ-MS/MS) analytical method to quantify 14 phytohormones in Pinus pinaster stem tissues. This method was further applied to evaluate, for the first time, early phytohormone changes in susceptible and resistant phenotypes of P. pinaster 24, 48 and 72 h after inoculation (HAI) with PWN. A significant increase in salicylic acid (SA, 48 and 72 HAI) and jasmonic acid methyl ester (JA-ME, 72 HAI) was observed in susceptible phenotypes. Results indicate that the higher susceptibility of P. pinaster to PWN infection might result from an inefficient trigger of hypersensitive responses, with the involvement of JA and SA pathways. This work provides an important update in forest research, and adds to the current knowledge of Pinus spp. defence responses to PWN infection.

Bemisia tabaci (MEAM1) (silverleaf whitefly).

2021 ◽  
Author(s):  
Andrew Cuthbertson
Keyword(s):  
Bemisia Tabaci ◽  
Plant Viruses ◽  
Biological Traits ◽  
Vegetable Crops ◽  
Indigenous Plants ◽  
Crop Species ◽  
Wide Range ◽  
The World ◽  
High Level ◽  
Agricultural Regions

Abstract The exact origin of the MEAM1 species of Bemisia tabaci, and the reasons why it became such an important pest are still not fully known. MEAM1 was first identified in the mid 1980s when it invaded the southern states of North America. Vast numbers of whiteflies were found to be infesting winter vegetable crops and consequently caused an estimated $500 million loss to the 1991 winter harvest in California. Investigations led to the assumption that the B biotype had spread to the USA on ornamental plants that were being transported around the world. Species such as poinsettia and gerbera were highlighted as probable hosts. During the 1990s MEAM1 was reported on every continent. Biological traits of MEAM1 implied that it had evolved within intensive agricultural regions with exposure to pesticides and modern cultural practices. These included an ability to feed and develop on a wide range of plant and crop species, a high level of fecundity and a predisposition to develop resistance to a wide range of pesticides. MEAM1 is also an effective vector of many different plant viruses which, in conjunction with its high level of polyphagy, make it extremely problematic within agricultural regions where crops may be susceptible to viruses acquired from indigenous plants. Despite B. tabaci being a tropical/sub-tropical whitefly species, MEAM1 is often transported on plant species to temperate regions of the world. Within these cooler regions, MEAM1 can survive within a protected environment and could feasibly spread virus diseases to new locations. It is for this reason that B. tabaci and members of its species complex, including MEAM1, are on EPPO A2 Alert list.

scholarly journals Variability, Functions and Interactions of Plant Virus Movement Proteins: What Do We Know So Far?

2021 ◽  
Vol 9 (4) ◽  
pp. 695
Author(s):  
Gaurav Kumar ◽  
Indranil Dasgupta
Keyword(s):  
Current Knowledge ◽  
Plant Viruses ◽  
Host Protein ◽  
Size Exclusion ◽  
Host Proteins ◽  
Movement Proteins ◽  
Core Function ◽  
Intercellular Channels ◽  
Pass Through ◽  
Cellular Components

Of the various proteins encoded by plant viruses, one of the most interesting is the movement protein (MP). MPs are unique to plant viruses and show surprising structural and functional variability while maintaining their core function, which is to facilitate the intercellular transport of viruses or viral nucleoprotein complexes. MPs interact with components of the intercellular channels, the plasmodesmata (PD), modifying their size exclusion limits and thus allowing larger particles, including virions, to pass through. The interaction of MPs with the components of PD, the formation of transport complexes and the recruitment of host cellular components have all revealed different facets of their functions. Multitasking is an inherent property of most viral proteins, and MPs are no exception. Some MPs carry out multitasking, which includes gene silencing suppression, viral replication and modulation of host protein turnover machinery. This review brings together the current knowledge on MPs, focusing on their structural variability, various functions and interactions with host proteins.

scholarly journals Autophagic degradation of peroxisomes in mammals

2016 ◽  
Vol 44 (2) ◽  
pp. 431-440 ◽  
Author(s):  
Katarzyna Zientara-Rytter ◽  
Suresh Subramani
Keyword(s):  
Mammalian Cells ◽  
Environmental Changes ◽  
Cell Function ◽  
Current Knowledge ◽  
Future Directions ◽  
Cellular Processes ◽  
Wide Range ◽  
Efficient Control ◽  
Autophagic Degradation ◽  
Eukaryotic Organisms

Peroxisomes are essential organelles required for proper cell function in all eukaryotic organisms. They participate in a wide range of cellular processes including the metabolism of lipids and generation, as well as detoxification, of hydrogen peroxide (H2O2). Therefore, peroxisome homoeostasis, manifested by the precise and efficient control of peroxisome number and functionality, must be tightly regulated in response to environmental changes. Due to the existence of many physiological disorders and diseases associated with peroxisome homoeostasis imbalance, the dynamics of peroxisomes have been widely examined. The increasing volume of reports demonstrating significant involvement of the autophagy machinery in peroxisome removal leads us to summarize current knowledge of peroxisome degradation in mammalian cells. In this review we present current models of peroxisome degradation. We particularly focus on pexophagy–the selective clearance of peroxisomes through autophagy. We also critically discuss concepts of peroxisome recognition for pexophagy, including signalling and selectivity factors. Finally, we present examples of the pathological effects of pexophagy dysfunction and suggest promising future directions.

scholarly journals MicroRNAs: crucial regulators of placental development

Reproduction ◽  
2018 ◽  
Vol 155 (6) ◽  
pp. R259-R271 ◽  
Author(s):  
Heyam Hayder ◽  
Jacob O’Brien ◽  
Uzma Nadeem ◽  
Chun Peng
Keyword(s):  
Mrna Stability ◽  
Target Genes ◽  
Current Knowledge ◽  
Mirna Biogenesis ◽  
Placental Development ◽  
Future Directions ◽  
Cellular Processes ◽  
Wide Range ◽  
Canonical Pathways

MicroRNAs (miRNAs) are small non-coding single-stranded RNAs that are integral to a wide range of cellular processes mainly through the regulation of translation and mRNA stability of their target genes. The placenta is a transient organ that exists throughout gestation in mammals, facilitating nutrient and gas exchange and waste removal between the mother and the fetus. miRNAs are expressed in the placenta, and many studies have shown that miRNAs play an important role in regulating trophoblast differentiation, migration, invasion, proliferation, apoptosis, vasculogenesis/angiogenesis and cellular metabolism. In this review, we provide a brief overview of canonical and non-canonical pathways of miRNA biogenesis and mechanisms of miRNA actions. We highlight the current knowledge of the role of miRNAs in placental development. Finally, we point out several limitations of the current research and suggest future directions.

scholarly journals Multifunctional Roles of the Actin-Binding Protein Flightless I in Inflammation, Cancer and Wound Healing

2020 ◽  
Vol 8 ◽  
Author(s):  
Xanthe L. Strudwick ◽  
Allison J. Cowin
Keyword(s):  
Cancer Progression ◽  
Wound Repair ◽  
Actin Polymerization ◽  
Hormone Receptors ◽  
Current Knowledge ◽  
Actin Binding ◽  
Cellular Processes ◽  
Physiological Processes ◽  
Wide Range ◽  
And Migration

Flightless I is an actin-binding member of the gelsolin family of actin-remodeling proteins that inhibits actin polymerization but does not possess actin severing ability. Flightless I functions as a regulator of many cellular processes including proliferation, differentiation, apoptosis, and migration all of which are important for many physiological processes including wound repair, cancer progression and inflammation. More than simply facilitating cytoskeletal rearrangements, Flightless I has other important roles in the regulation of gene transcription within the nucleus where it interacts with nuclear hormone receptors to modulate cellular activities. In conjunction with key binding partners Leucine rich repeat in the Flightless I interaction proteins (LRRFIP)1/2, Flightless I acts both synergistically and competitively to regulate a wide range of cellular signaling including interacting with two of the most important inflammatory pathways, the NLRP3 inflammasome and the MyD88-TLR4 pathways. In this review we outline the current knowledge about this important cytoskeletal protein and describe its many functions across a range of health conditions and pathologies. We provide perspectives for future development of Flightless I as a potential target for clinical translation and insights into potential therapeutic approaches to manipulate Flightless I functions.

scholarly journals Molecular and Cellular Mechanisms Involved in Host-Specific Resistance to Cyst Nematodes in Crops

2021 ◽  
Vol 12 ◽  
Author(s):  
Qi Zheng ◽  
Vera Putker ◽  
Aska Goverse
Keyword(s):  
Crop Production ◽  
Specific Resistance ◽  
Current Knowledge ◽  
Defense Responses ◽  
Cyst Nematode ◽  
Cyst Nematodes ◽  
Cellular Mechanisms ◽  
Crop Species ◽  
Crop Cultivation ◽  
Wide Range

Cyst nematodes are able to infect a wide range of crop species and are regarded as a major threat in crop production. In response to invasion of cyst nematodes, plants activate their innate immune system to defend themselves by conferring basal and host-specific defense responses depending on the plant genotype. Basal defense is dependent on the detection of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs), while host-specific defense mainly relies on the activation of canonical and non-canonical resistance (R) genes or quantitative trait loci (QTL). Currently, application of R genes and QTLs in crop species is a major approach to control cyst nematode in crop cultivation. However, emerging virulent cyst nematode field populations are threatening crop production due to host genetic selection by the application of a limited set of resistance genes in current crop cultivars. To counteract this problem, increased knowledge about the mechanisms involved in host-specific resistance mediated by R genes and QTLs to cyst nematodes is indispensable to improve their efficient and sustainable use in field crops. Despite the identification of an increasing number of resistance traits to cyst nematodes in various crops, the underlying genes and defense mechanisms are often unknown. In the last decade, indebt studies on the functioning of a number of cyst nematode R genes and QTLs have revealed novel insights in how plants respond to cyst nematode infection by the activation of host-specific defense responses. This review presents current knowledge of molecular and cellular mechanisms involved in the recognition of cyst nematodes, the activation of defense signaling and resistance response types mediated by R genes or QTLs. Finally, future directions for research are proposed to develop management strategies to better control cyst nematodes in crop cultivation.

First Detection of Tobacco Mosaic Virus in Tobacco Fields in Northern Lebanon

2020 ◽  
Vol 20 ◽  
Author(s):  
Rami Obeid ◽  
Elias Wehbe ◽  
Mohamad Rima ◽  
Mohammad Kabara ◽  
Romeo Al Bersaoui ◽  
...  
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Viral Genome ◽  
Virus Genome ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Family ◽  
Crop Fields ◽  
Wide Range ◽  
Almost All ◽  
Das Elisa

Background: Tobacco mosaic virus (TMV) is the most known virus in the plant mosaic virus family and is able to infect a wide range of crops, in particularly tobacco, causing a production loss. Objectives: Herein, and for the first time in Lebanon, we investigated the presence of TMV infection in crops by analyzing 88 samples of tobacco, tomato, cucumber and pepper collected from different regions in North Lebanon. Methods: Double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), revealed a potential TMV infection of four tobacco samples out of 88 crops samples collected. However, no tomato, cucumber and pepper samples were infected. The TMV+ tobacco samples were then extensively analyzed by RT-PCR to detect viral RNA using different primers covering all the viral genome. Results and Discussion: PCR results confirmed those of DAS-ELISA showing TMV infection of four tobacco samples collected from three crop fields of North Lebanon. In only one of four TMV+ samples, we were able to amplify almost all the regions of viral genome, suggesting possible mutations in the virus genome or an infection with a new, not yet identified, TMV strain. Conclusion: Our study is the first in Lebanon revealing TMV infection in crop fields, and highlighting the danger that may affect the future of agriculture.

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