scholarly journals Reprogramming and remodeling: transcriptional and epigenetic regulation of salicylic acid-mediated plant defense

2020 ◽  
Vol 71 (17) ◽  
pp. 5256-5268 ◽  
Author(s):  
Jian Chen ◽  
Michael Clinton ◽  
Guang Qi ◽  
Daowen Wang ◽  
Fengquan Liu ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Transcription Factors ◽  
Plant Defense ◽  
Epigenetic Regulation ◽  
Current Knowledge ◽  
Plant Immunity ◽  
Defense Responses ◽  
Transcriptional Networks ◽  
Transcriptional Reprogramming ◽  
Genomic Tools

Abstract As a plant hormone, salicylic acid (SA) plays essential roles in plant defense against biotrophic and hemibiotrophic pathogens. Significant progress has been made in understanding the SA biosynthesis pathways and SA-mediated defense signaling networks in the past two decades. Plant defense responses involve rapid and massive transcriptional reprogramming upon the recognition of pathogens. Plant transcription factors and their co-regulators are critical players in establishing a transcription regulatory network and boosting plant immunity. A multitude of transcription factors and epigenetic regulators have been discovered, and their roles in SA-mediated defense responses have been reported. However, our understanding of plant transcriptional networks is still limited. As such, novel genomic tools and bioinformatic techniques will be necessary if we are to fully understand the mechanisms behind plant immunity. Here, we discuss current knowledge, provide an update on the SA biosynthesis pathway, and describe the transcriptional and epigenetic regulation of SA-mediated plant immune responses.

scholarly journals How activated NLRs induce anti-microbial defenses in plants

2021 ◽  
Author(s):  
Farid El Kasmi
Keyword(s):  
Cell Death ◽  
Current Knowledge ◽  
Plant Immunity ◽  
Defense Responses ◽  
Cellular Activity ◽  
Leucine Rich Repeat ◽  
Virulence Proteins ◽  
Transcriptional Reprogramming ◽  
Infected Cells ◽  
Signaling Components

Plants utilize cell-surface localized and intracellular leucine-rich repeat (LRR) immune receptors to detect pathogens and to activate defense responses, including transcriptional reprogramming and the initiation of a form of programmed cell death of infected cells. Cell death initiation is mainly associated with the activation of nucleotide-binding LRR receptors (NLRs). NLRs recognize the presence or cellular activity of pathogen-derived virulence proteins, so-called effectors. Effector-dependent NLR activation leads to the formation of higher order oligomeric complexes, termed resistosomes. Resistosomes can either form potential calcium-permeable cation channels at cellular membranes and initiate calcium influxes resulting in activation of immunity and cell death or function as NADases whose activity is needed for the activation of downstream immune signaling components, depending on the N-terminal domain of the NLR protein. In this mini-review, the current knowledge on the mechanisms of NLR-mediated cell death and resistance pathways during plant immunity is discussed.

scholarly journals Method for the Production and Purification of Plant Immuno-Active Xylanase from Trichoderma

2021 ◽  
Vol 22 (8) ◽  
pp. 4214
Author(s):  
Gautam Anand ◽  
Meirav Leibman-Markus ◽  
Dorin Elkabetz ◽  
Maya Bar
Keyword(s):  
Immune System ◽  
Plant Defense ◽  
Plant Immunity ◽  
Xylanase Activity ◽  
Hydrolytic Enzymes ◽  
Adaptive Immune System ◽  
Defense Responses ◽  
Plant Defense Responses ◽  
Xylanase Production ◽  
Ideal System

Plants lack a circulating adaptive immune system to protect themselves against pathogens. Therefore, they have evolved an innate immune system based upon complicated and efficient defense mechanisms, either constitutive or inducible. Plant defense responses are triggered by elicitors such as microbe-associated molecular patterns (MAMPs). These components are recognized by pattern recognition receptors (PRRs) which include plant cell surface receptors. Upon recognition, PRRs trigger pattern-triggered immunity (PTI). Ethylene Inducing Xylanase (EIX) is a fungal MAMP protein from the plant-growth-promoting fungi (PGPF)–Trichoderma. It elicits plant defense responses in tobacco (Nicotiana tabacum) and tomato (Solanum lycopersicum), making it an excellent tool in the studies of plant immunity. Xylanases such as EIX are hydrolytic enzymes that act on xylan in hemicellulose. There are two types of xylanases: the endo-1, 4-β-xylanases that hydrolyze within the xylan structure, and the β-d-xylosidases that hydrolyze the ends of the xylan chain. Xylanases are mainly synthesized by fungi and bacteria. Filamentous fungi produce xylanases in high amounts and secrete them in liquid cultures, making them an ideal system for xylanase purification. Here, we describe a method for cost- and yield-effective xylanase production from Trichoderma using wheat bran as a growth substrate. Xylanase produced by this method possessed xylanase activity and immunogenic activity, effectively inducing a hypersensitive response, ethylene biosynthesis, and ROS burst.

scholarly journals Induction, modification, and transduction of the salicylic acid signal in plant defense responses.

1995 ◽  
Vol 92 (10) ◽  
pp. 4134-4137 ◽  
Author(s):  
Z. Chen ◽  
J. Malamy ◽  
J. Henning ◽  
U. Conrath ◽  
P. Sanchez-Casas ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Plant Defense ◽  
Defense Responses ◽  
Plant Defense Responses

scholarly journals Regulation of Plant Immunity by Nuclear Membrane-Associated Mechanisms

2021 ◽  
Vol 12 ◽  
Author(s):  
Yiling Fang ◽  
Yangnan Gu
Keyword(s):  
Immune System ◽  
Nuclear Membrane ◽  
Immune Activation ◽  
Core Protein ◽  
Current Knowledge ◽  
Plant Immunity ◽  
Defense Responses ◽  
Pathogen Resistance ◽  
Innate Immune ◽  
Nuclear Pore

Unlike animals, plants do not have specialized immune cells and lack an adaptive immune system. Instead, plant cells rely on their unique innate immune system to defend against pathogens and coordinate beneficial interactions with commensal and symbiotic microbes. One of the major convergent points for plant immune signaling is the nucleus, where transcriptome reprogramming is initiated to orchestrate defense responses. Mechanisms that regulate selective transport of nuclear signaling cargo and chromatin activity at the nuclear boundary play a pivotal role in immune activation. This review summarizes the current knowledge of how nuclear membrane-associated core protein and protein complexes, including the nuclear pore complex, nuclear transport receptors, and the nucleoskeleton participate in plant innate immune activation and pathogen resistance. We also discuss the role of their functional counterparts in regulating innate immunity in animals and highlight potential common mechanisms that contribute to nuclear membrane-centered immune regulation in higher eukaryotes.

scholarly journals Proteomic and Transcriptomic Analyses Indicate Metabolic Changes and Reduced Defense Responses in Mycorrhizal Roots of Oeceoclades maculata (Orchidaceae) Collected in Nature

2020 ◽  
Vol 6 (3) ◽  
pp. 148
Author(s):  
Rafael B. S. Valadares ◽  
Silvia Perotto ◽  
Adriano R. Lucheta ◽  
Eder C. Santos ◽  
Renato M. Oliveira ◽  
...  
Keyword(s):  
Plant Defense ◽  
De Novo ◽  
Current Knowledge ◽  
Defense Responses ◽  
Mycorrhizal Symbiosis ◽  
Label Free ◽  
Molecular Events ◽  
Mycorrhizal Roots ◽  
Steady State Levels ◽  
Isobaric Tagging

Orchids form endomycorrhizal associations with fungi mainly belonging to basidiomycetes. The molecular events taking place in orchid mycorrhiza are poorly understood, although the cellular changes necessary to accommodate the fungus and to control nutrient exchanges imply a modulation of gene expression. Here, we used proteomics and transcriptomics to identify changes in the steady-state levels of proteins and transcripts in the roots of the green terrestrial orchid Oeceoclades maculata. When mycorrhizal and non-mycorrhizal roots from the same individuals were compared, 94 proteins showed differential accumulation using the label-free protein quantitation approach, 86 using isobaric tagging and 60 using 2D-differential electrophoresis. After de novo assembly of transcriptomic data, 11,179 plant transcripts were found to be differentially expressed, and 2175 were successfully annotated. The annotated plant transcripts allowed the identification of up- and down-regulated metabolic pathways. Overall, proteomics and transcriptomics revealed, in mycorrhizal roots, increased levels of transcription factors and nutrient transporters, as well as ethylene-related proteins. The expression pattern of proteins and transcripts involved in plant defense responses suggested that plant defense was reduced in O. maculata mycorrhizal roots sampled in nature. These results expand our current knowledge towards a better understanding of the orchid mycorrhizal symbiosis in adult plants under natural conditions.

scholarly journals Regulating the Regulators: The Control of Transcription Factors in Plant Defense Signaling

2018 ◽  
Vol 19 (12) ◽  
pp. 3737 ◽  
Author(s):  
Danny Ng ◽  
Jayami Abeysinghe ◽  
Maedeh Kamali
Keyword(s):  
Transcription Factors ◽  
Plant Defense ◽  
Signaling Pathways ◽  
Stress Responses ◽  
Crop Production ◽  
Defense Responses ◽  
Sequencing Data ◽  
Basic Leucine Zipper ◽  
Master Regulators ◽  
External Threats

Being sessile, plants rely on intricate signaling pathways to mount an efficient defense against external threats while maintaining the cost balance for growth. Transcription factors (TFs) form a repertoire of master regulators in controlling various processes of plant development and responses against external stimuli. There are about 58 families of TFs in plants and among them, six major TF families (AP2/ERF (APETALA2/ethylene responsive factor), bHLH (basic helix-loop-helix), MYB (myeloblastosis related), NAC (no apical meristem (NAM), Arabidopsis transcription activation factor (ATAF1/2), and cup-shaped cotyledon (CUC2)), WRKY, and bZIP (basic leucine zipper)) are found to be involved in biotic and abiotic stress responses. As master regulators of plant defense, the expression and activities of these TFs are subjected to various transcriptional and post-transcriptional controls, as well as post-translational modifications. Many excellent reviews have discussed the importance of these TFs families in mediating their downstream target signaling pathways in plant defense. In this review, we summarize the molecular regulatory mechanisms determining the expression and activities of these master regulators themselves, providing insights for studying their variation and regulation in crop wild relatives (CWR). With the advance of genome sequencing and the growing collection of re-sequencing data of CWR, now is the time to re-examine and discover CWR for the lost or alternative alleles of TFs. Such approach will facilitate molecular breeding and genetic improvement of domesticated crops, especially in stress tolerance and defense responses, with the aim to address the growing concern of climate change and its impact on agriculture crop production.

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