scholarly journals Chloroplast movement and positioning protein CHUP1 is required for focal immunity against Phytophthora infestans

2021 ◽  
Author(s):  
Zachary Savage ◽  
Jessica L. Erickson ◽  
Jennifer Prautsch ◽  
Andrada I. Balmez ◽  
Yasin Tumtas ◽  
...  
Keyword(s):  
Phytophthora Infestans ◽  
Photosynthetic Activity ◽  
Chloroplast Movement ◽  
Wall Material ◽  
Oxygen Species ◽  
Immune Challenge ◽  
Potato Blight ◽  
Knock Out ◽  
A Cell

When a plant detects a pathogen, chloroplasts terminate photosynthetic activity and uptake vital roles in the immune system to help stave off infection, including the production of defense hormone precursors and antimicrobial reactive oxygen species. Additionally, chloroplasts associate with the nucleus and produce greater numbers of tubular extensions called stromules during immune challenge. We previously showed that during infection by the potato blight pathogen Phytophthora infestans, chloroplasts accumulate at the pathogen haustoria, hyphal extensions that are accommodated within the host cell. However, the extent to which chloroplast positioning around haustoria, or at the nucleus, contributes to immunity during infection remains unknown. Here we show a striking increase in the susceptibility to P. infestans of Nicotiana benthamiana CRISPR knock-out lines lacking the chloroplast movement and anchoring gene, CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1). However, the positioning of chloroplasts around the haustorium or nucleus is not impaired in the absence of CHUP1. Further, loss of CHUP1 leads to an extreme clustering of chloroplasts around the nucleus in the presence and absence of infection, showing that greater chloroplast-nucleus association does not necessarily equate to more robust immunity. While plants lacking CHUP1 have reduced basal stromules, they are still able to induce stromules following immune stimulation, indicating that multiple populations of stromules exist. Lastly, we found that CHUP1 is required for proper deposition of callose - a cell wall material implicated in pathogen penetration resistance - around P. infestans haustorium, but not for other core immune processes. Our results implicate chloroplasts in plant focal immunity and point to a key role of CHUP1 in facilitating the deposition of defense material at the pathogen interface.

scholarly journals CRISPR/Cas9-Mediated SlMYBS2 Mutagenesis Reduces Tomato Resistance to Phytophthora infestans

2021 ◽  
Vol 22 (21) ◽  
pp. 11423
Author(s):  
Chunxin Liu ◽  
Yiyao Zhang ◽  
Yinxiao Tan ◽  
Tingting Zhao ◽  
Xiangyang Xu ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Gene Knockout ◽  
Disease Index ◽  
Oxygen Species ◽  
Wild Type ◽  
Pr Genes ◽  
Knock Out ◽  
Pathogenesis Related

Phytophthora infestans (P. infestans) recently caused epidemics of tomato late blight. Our study aimed to identify the function of the SlMYBS2 gene in response to tomato late blight. To further investigate the function of SlMYBS2 in tomato resistance to P. infestans, we studied the effects of SlMYBS2 gene knock out. The SlMYBS2 gene was knocked out by CRISPR-Cas9, and the resulting plants (SlMYBS2 gene knockout, slmybs2-c) showed reduced resistance to P. infestans, accompanied by increases in the number of necrotic cells, lesion sizes, and disease index. Furthermore, after P. infestans infection, the expression levels of pathogenesis-related (PR) genes in slmybs2-c plants were significantly lower than those in wild-type (AC) plants, while the number of necrotic cells and the accumulation of reactive oxygen species (ROS) were higher than those in wild-type plants. Taken together, these results indicate that SlMYBS2 acts as a positive regulator of tomato resistance to P. infestans infection by regulating the ROS level and the expression level of PR genes.

scholarly journals Abscisic Acid in Coordination with Nitrogen Alleviates Salinity-Inhibited Photosynthetic Potential in Mustard by Improving Proline Accumulation and Antioxidant Activity

Stresses ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 162-180
Author(s):  
Arif Majid ◽  
Bilal A. Rather ◽  
Asim Masood ◽  
Zebus Sehar ◽  
Naser A. Anjum ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Enzymes ◽  
Abscisic Acid ◽  
Photosynthetic Activity ◽  
Thiobarbituric Acid ◽  
Salinity Treatment ◽  
Oxygen Species ◽  
Thiobarbituric Acid Reactive Substances ◽  
Photosynthetic Potential

This investigation was done to assess the role of abscisic acid (ABA; 25 µM) and/or nitrogen (N; 10 mM) in the alleviation of salinity (NaCl; 100 mM)-induced reduction in photosynthetic activity and growth, N and sulfur (S) assimilation of mustard (Brassica juncea L.) cv. RH0-749. Salinity treatment caused oxidative stress and significantly elevated the content of both H2O2 and thiobarbituric acid reactive substances (TBARS), and impaired photosynthetic activity and growth, but increased the content of nitrogenous osmolyte proline and the activity of antioxidant enzymes involved in the metabolism of reactive oxygen species. The application of 25 µM ABA under a controlled condition negatively affected photosynthesis and growth. However, ABA, when combined with N, minimized oxidative stress and mitigated the salinity-inhibited effects by increasing the activity of antioxidant enzymes (superoxide dismutase, SOD; glutathione reductase, GR; ascorbate peroxidase, APX) and proline content. Overall, the supplementation of 10 mM N combined with 25 µM ABA provides an important strategy for enhancing the photosynthetic potential of B. juncea under saline conditions.

scholarly journals Human vtRNA1-1 Levels Modulate Signaling Pathways and Regulate Apoptosis in Human Cancer Cells

Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 614 ◽  
Author(s):  
Lisamaria Bracher ◽  
Iolanda Ferro ◽  
Carlos Pulido-Quetglas ◽  
Marc-David Ruepp ◽  
Rory Johnson ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Lines ◽  
Human Cancer ◽  
Apoptosis Resistance ◽  
Protein Coding ◽  
Knock Out ◽  
Human Cancer Cells ◽  
Extrinsic Apoptosis ◽  
A Cell

Regulatory non-protein coding RNAs perform a remarkable variety of complex biological functions. Previously, we demonstrated a role of the human non-coding vault RNA1-1 (vtRNA1-1) in inhibiting intrinsic and extrinsic apoptosis in several cancer cell lines. Yet on the molecular level, the function of the vtRNA1-1 is still not fully clear. Here, we created HeLa knock-out cell lines revealing that prolonged starvation triggers elevated levels of apoptosis in the absence of vtRNA1-1 but not in vtRNA1-3 knock-out cells. Next-generation deep sequencing of the mRNome identified the PI3K/Akt pathway and the ERK1/2 MAPK cascade, two prominent signaling axes, to be misregulated in the absence of vtRNA1-1 during starvation-mediated cell death conditions. Expression of vtRNA1-1 mutants identified a short stretch of 24 nucleotides of the vtRNA1-1 central domain as being essential for successful maintenance of apoptosis resistance. This study describes a cell signaling-dependent contribution of the human vtRNA1-1 to starvation-induced programmed cell death.

scholarly journals Evidence of a role for radiation-induced lysosomal damage in non-targeted effects: an experimental and theoretical analysis

2015 ◽  
Author(s):  
Scott Bright ◽  
Alexander George Fletcher ◽  
David Fell ◽  
Munira A. Kadhim
Keyword(s):  
Human Fibroblasts ◽  
Radiation Response ◽  
Oxygen Species ◽  
Simple Mathematical Model ◽  
Subcellular Organelles ◽  
Potential Mediator ◽  
A Cell ◽  
Radiation Induced ◽  
Bistable Mechanism

A well-known DNA-damaging agent and carcinogen, ionizing radiation (IR) can also exert detrimental effects in cells not directly exposed to it, through "non-targeted effects" (NTE). Whilst NTE are known to contribute to radiation-induced damage, their mechanism of induction and propagation remains incompletely understood. To investigate the possible role of lysosomes, key subcellular organelles, in NTE we used acridine orange uptake and relocation methods to monitor lysosomal permeability in irradiated and bystander human fibroblasts. As a potential mediator of lysosomal changes, oxidative stress was measured using the H2DCFDA assay for total reactive oxygen species (ROS). IR was found to induce significant lysosomal permeability in the first hour post irradiation, with reduced permeability persisting up to 24 hours. This occurred in conjunction with an increase in ROS in directly irradiated cells, in contrast with a decrease in ROS in bystander cells. Based on these observations we constructed a simple mathematical model of ROS-induced lysosomal damage, based on a bistable mechanism where a sufficiently strong IR insult can shift a cell from a 'low ROS, high lysosome' to a 'high ROS, low lysosome' state. This has profound cellular implications in radiation response and advances our understanding for the sub-cellular involvement in non-targeted effects.

scholarly journals Construction of fibronectin conditional gene knock-out mice and the effect of fibronectin gene knockout on hematopoietic, biochemical and immune parameters in mice

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10224
Author(s):  
Xiaohong Yuan ◽  
Shu Yang ◽  
Wen Li ◽  
Jinggang Li ◽  
Jia Lin ◽  
...  
Keyword(s):  
Gene Knockout ◽  
Vascular Endothelial ◽  
Wild Type ◽  
Knock Out ◽  
Immune Parameters ◽  
A Cell ◽  
Serum Biochemical ◽  
Knock Out Mice ◽  
Biochemical Indices

Fibronectin (FN) is a multi-functional glycoprotein that primarily acts as a cell adhesion molecule and tethers cells to the extra cellular matrix. In order to clarify the effect of FN deficiency on hematopoiesis, biochemical and immune parameters in mice. We constructed a tamoxifen-induced conditional (cre-loxp system) fibronectin knock-out (FnKO) mouse model on a C57BL/6 background, and monitored their behavior, fertility, histological, hematopoietic, biochemical and immunological indices. We found that the Fn KO mice had reduced fertility, high platelet counts, smaller bone marrow megakaryocytes and looser attachment between the hepatocyte and vascular endothelial junctions compared to the wild type (WT) mice. In contrast, the behavior, hematological counts, serum biochemical indices and vital organ histology were similar in both Fn KO and WT mice. This model will greatly help in elucidating the role of FN in immune-related diseases in future.

Role of reactive oxygen species in cell signalling pathways

2001 ◽  
Vol 29 (2) ◽  
pp. 345-349 ◽  
Author(s):  
J. T. Hancock ◽  
R. Desikan ◽  
S.J. Neill
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Signalling ◽  
Reactive Oxygen ◽  
Signalling Pathways ◽  
Oxygen Species ◽  
Phagocytic Cells ◽  
Mitogen Activated Protein ◽  
A Cell ◽  
Activate Cell

Reactive oxygen species (ROS) were originally thought to only be released by phagocytic cells during their role in host defence. It is now clear that ROS have a cell signalling role in many biological systems, both in animals and in plants. ROS induce programmed cell death or necrosis, induce or suppress the expression of many genes, and activate cell signalling cascades, such as those involving mitogen-activated protein kinases.

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