Phosphate-induced resistance to pathogen infection in Arabidopsis

In nature, plants are concurrently exposed to a number of abiotic and biotic stresses. Our understanding of convergence points between responses to combined biotic/abiotic stress pathways remains, however, rudimentary. Here we show that MIR399 overexpression, loss-of-function of PHO2 (PHOSPHATE2), or treatment with high Pi, is accompanied by an increase in phosphate (Pi) content and accumulation of reactive oxygen species (ROS) in Arabidopsis thaliana. High Pi plants (e.g. miR399 overexpressor, pho2 mutant, and plants grown under high Pi supply) exhibited resistance to infection by necrotrophic and hemibiotrophic fungal pathogens. In the absence of pathogen infection, the expression level of genes in the salicylic acid (SA)- and jasmonic acid (JA)-dependent signaling pathways was higher in high Pi plants compared to wild type plants, which is consistent with increased levels of SA and JA in non-infected high Pi plants. During infection, an opposite regulation in the two branches of the JA pathway (ERF1/PDF1.2 and MYC2/VSP2) occurs in high Pi plants. Thus, while the ERF1-PDF1 branch positively responds to fungal infection, the MYC2/VSP2 branch is negatively regulated during pathogen infection in high Pi plants. This study supports that Pi accumulation promotes resistance to infection by fungal pathogens in Arabidopsis, while providing a basis to better understand crosstalk between Pi signaling and hormonal signalling pathways for modulation of plant immune responses.

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NITROGEN LIMITATION ADAPTATION functions as a negative regulator of Arabidopsis immunity

10.1101/2021.12.09.471910 ◽

2021 ◽

Author(s):

Beatriz Val Torregrosa ◽

Mireia Bundo ◽

Tzyy Jen Chiou ◽

Victor Flors ◽

Blanca San Segundo

Keyword(s):

Immune Responses ◽

Transcriptional Activation ◽

Fungal Pathogens ◽

Nitrogen Limitation ◽

Negative Regulator ◽

Loss Of Function ◽

Wild Type ◽

Pathogen Infection ◽

Fungal Elicitors ◽

Resistance To Infection

Background: Phosphorus is an important macronutrient required for plant growth and development. It is absorbed through the roots in the form of inorganic phosphate (Pi). To cope with Pi limitation, plants have evolved an array of adaptive mechanisms to facilitate Pi acquisition and protect them from stress caused by Pi starvation. The NITROGEN LIMITATION ADAPTION (NLA) gene plays a key role in the regulation of phosphate starvation responses (PSR), its expression being regulated by the microRNA miR827. Stress caused by Pi limiting conditions might also affect the plant response to pathogen infection. However, cross-talk between phosphate signaling pathways and immune responses remains unclear. Results: In this study, we investigated whether NLA plays a role in Arabidopsis immunity. We show that loss-of-function of NLA and MIR827 overexpression causes an increase in phosphate (Pi) content which results in resistance to infection by the fungal pathogen Plectosphaerella cucumerina. The nla mutant plants accumulated callose in their leaves, a response that is also observed in wild-type plants that have been treated with high Pi. We also show that pathogen infection and treatment with fungal elicitors is accompanied by transcriptional activation of MIR827 and down-regulation of NLA. Upon pathogen challenge, nla plants exhibited higher levels of the phytoalexin camalexin compared to wild type plants. Camalexin level also increases in wild type plants treated with high Pi. Furthermore, the nla mutant plants accumulated salicylic acid (SA) and jasmonic acid (JA) in the absence of pathogen infection whose levels further increased upon pathogen. Conclusions: This study shows that NLA acts as a negative regulator of Arabidopsis immunity. Overaccumulation of Pi in nla plants positively affects resistance to infection by fungal pathogens. This piece of information reinforces the idea of signaling convergence between Pi and immune responses for the regulation of disease resistance in Arabidopsis.

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The MicroRNA miR773 Is Involved in the Arabidopsis Immune Response to Fungal Pathogens

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-05-17-0108-r ◽

2018 ◽

Vol 31 (2) ◽

pp. 249-259 ◽

Cited By ~ 16

Author(s):

Raquel Salvador-Guirao ◽

Patricia Baldrich ◽

Detlef Weigel ◽

Ignacio Rubio-Somoza ◽

Blanca San Segundo

Keyword(s):

Fungal Pathogens ◽

Adaptive Responses ◽

Defense Gene Expression ◽

Pathogen Infection ◽

Defense Gene ◽

Biotic Stresses ◽

Molecular Pattern ◽

Pathogen Challenge ◽

Wide Range ◽

Resistance To Infection

MicroRNAs (miRNAs) are 21- to 24-nucleotide short noncoding RNAs that trigger gene silencing in eukaryotes. In plants, miRNAs play a crucial role in a wide range of developmental processes and adaptive responses to abiotic and biotic stresses. In this work, we investigated the role of miR773 in modulating resistance to infection by fungal pathogens in Arabidopsis thaliana. Interference with miR773 activity by target mimics (in MIM773 plants) and concomitant upregulation of the miR773 target gene METHYLTRANSFERASE 2 (MET2) increased resistance to infection by necrotrophic (Plectosphaerrella cucumerina) and hemibiotrophic (Fusarium oxysporum, Colletototrichum higginianum) fungal pathogens. By contrast, both MIR773 overexpression and MET2 silencing enhanced susceptibility to pathogen infection. Upon pathogen challenge, MIM773 plants accumulated higher levels of callose and reactive oxygen species than wild-type plants. Stronger induction of defense-gene expression was also observed in MIM773 plants in response to fungal infection. Expression analysis revealed an important reduction in miR773 accumulation in rosette leaves of plants upon elicitor perception and pathogen infection. Taken together, our results show not only that miR773 mediates pathogen-associated molecular pattern-triggered immunity but also demonstrate that suppression of miR773 activity is an effective approach to improve disease resistance in Arabidopsis plants.

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Somatic production of reactive oxygen species does not predict its production in sperm cells across Drosophila melanogaster lines

BMC Research Notes ◽

10.1186/s13104-021-05550-7 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Biz R. Turnell ◽

Luisa Kumpitsch ◽

Anne-Cécile Ribou ◽

Klaus Reinhardt

Keyword(s):

Reactive Oxygen Species ◽

Drosophila Melanogaster ◽

Reactive Oxygen ◽

Future Research ◽

Ros Production ◽

Oxygen Species ◽

Loss Of Function ◽

Wild Type ◽

Ros Scavenging ◽

Transport Chain

Abstract Objective Sperm ageing has major evolutionary implications but has received comparatively little attention. Ageing in sperm and other cells is driven largely by oxidative damage from reactive oxygen species (ROS) generated by the mitochondria. Rates of organismal ageing differ across species and are theorized to be linked to somatic ROS levels. However, it is unknown whether sperm ageing rates are correlated with organismal ageing rates. Here, we investigate this question by comparing sperm ROS production in four lines of Drosophila melanogaster that have previously been shown to differ in somatic mitochondrial ROS production, including two commonly used wild-type lines and two lines with genetic modifications standardly used in ageing research. Results Somatic ROS production was previously shown to be lower in wild-type Oregon-R than in wild-type Dahomey flies; decreased by the expression of alternative oxidase (AOX), a protein that shortens the electron transport chain; and increased by a loss-of-function mutation in dj-1β, a gene involved in ROS scavenging. Contrary to predictions, we found no differences among these four lines in the rate of sperm ROS production. We discuss the implications of our results, the limitations of our study, and possible directions for future research.

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Recent Development on Plant Aldehyde Dehydrogenase Enzymes and Their Functions in Plant Development and Stress Signaling

Genes ◽

10.3390/genes12010051 ◽

2020 ◽

Vol 12 (1) ◽

pp. 51

Author(s):

Adesola J. Tola ◽

Amal Jaballi ◽

Hugo Germain ◽

Tagnon D. Missihoun

Keyword(s):

Plant Development ◽

Critical Analysis ◽

Current Knowledge ◽

Stress Signaling ◽

Oxygen Species ◽

Abiotic And Biotic Stresses ◽

Aldehyde Dehydrogenases ◽

Biotic Stresses ◽

Wide Range ◽

Excessive Accumulation

Abiotic and biotic stresses induce the formation of reactive oxygen species (ROS), which subsequently causes the excessive accumulation of aldehydes in cells. Stress-derived aldehydes are commonly designated as reactive electrophile species (RES) as a result of the presence of an electrophilic α, β-unsaturated carbonyl group. Aldehyde dehydrogenases (ALDHs) are NAD(P)+-dependent enzymes that metabolize a wide range of endogenous and exogenous aliphatic and aromatic aldehyde molecules by oxidizing them to their corresponding carboxylic acids. The ALDH enzymes are found in nearly all organisms, and plants contain fourteen ALDH protein families. In this review, we performed a critical analysis of the research reports over the last decade on plant ALDHs. Newly discovered roles for these enzymes in metabolism, signaling and development have been highlighted and discussed. We concluded with suggestions for future investigations to exploit the potential of these enzymes in biotechnology and to improve our current knowledge about these enzymes in gene signaling and plant development.

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Combined Abiotic Stresses Repress Defense and Cell Wall Metabolic Genes and Render Plants More Susceptible to Pathogen Infection

Plants ◽

10.3390/plants10091946 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1946

Author(s):

Nasser Sewelam ◽

Mohamed El-Shetehy ◽

Felix Mauch ◽

Veronica G. Maurino

Keyword(s):

Cell Wall ◽

Heat Stress ◽

Disease Resistance ◽

Pseudomonas Syringae ◽

Plant Disease Resistance ◽

Abiotic Stresses ◽

Defense Genes ◽

Pathogen Infection ◽

Abiotic And Biotic Stresses ◽

Biotic Stresses

Plants are frequently exposed to simultaneous abiotic and biotic stresses, a condition that induces complex responses, negatively affects crop productivity and is becoming more exacerbated with current climate change. In this study, we investigated the effects of individual and combined heat and osmotic stresses on Arabidopsis susceptibility to the biotrophic pathogen Pseudomonas syringae pv. tomato (Pst) and the necrotrophic pathogen Botrytiscinerea (Bc). Our data showed that combined abiotic and biotic stresses caused an enhanced negative impact on plant disease resistance in comparison with individual Pst and Bc infections. Pretreating plants with individual heat or combined osmotic-heat stress strongly reduced the expression of many defense genes including pathogenesis-related proteins (PR-1 and PR-5) and the TN-13 gene encoding the TIR-NBS protein, which are involved in disease resistance towards Pst. We also found that combined osmotic-heat stress caused high plant susceptibility to Bc infection and reduced expression of a number of defense genes, including PLANT DEFENSIN 1.3 (PDF1.3), BOTRYTIS SUSCEPTIBLE 1 (BOS1) and THIONIN 2.2 (THI2.2) genes, which are important for disease resistance towards Bc. The impaired disease resistance against both Pst and Bc under combined abiotic stress is associated with reduced expression of cell wall-related genes. Taken together, our data emphasize that the combination of global warming-associated abiotic stresses such as heat and osmotic stresses makes plants more susceptible to pathogen infection, thus threatening future global food security.

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The role of chloroplasts in plant pathology

Essays in Biochemistry ◽

10.1042/ebc20170020 ◽

2017 ◽

Vol 62 (1) ◽

pp. 21-39 ◽

Cited By ~ 17

Author(s):

Robert G. Sowden ◽

Samuel J. Watson ◽

Paul Jarvis

Keyword(s):

Gene Expression ◽

Reactive Oxygen Species ◽

Abiotic Stress Tolerance ◽

Oxygen Species ◽

Host Gene Expression ◽

Host Proteins ◽

Abiotic And Biotic Stresses ◽

Biotic Stresses ◽

Chloroplast Proteome

Plants have evolved complex tolerance systems to survive abiotic and biotic stresses. Central to these programmes is a sophisticated conversation of signals between the chloroplast and the nucleus. In this review, we examine the antagonism between abiotic stress tolerance (AST) and immunity: we propose that to generate immunogenic signals, plants must disable AST systems, in particular those that manage reactive oxygen species (ROS), while the pathogen seeks to reactivate or enhance those systems to achieve virulence. By boosting host systems of AST, pathogens trick the plant into suppressing chloroplast immunogenic signals and steer the host into making an inappropriate immune response. Pathogens disrupt chloroplast function, both transcriptionally—by secreting effectors that alter host gene expression by interacting with defence-related kinase cascades, with transcription factors, or with promoters themselves—and post-transcriptionally, by delivering effectors that enter the chloroplast or alter the localization of host proteins to change chloroplast activities. These mechanisms reconfigure the chloroplast proteome and chloroplast-originating immunogenic signals in order to promote infection.

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Role of Reactive Oxygen Species in Abiotic and Biotic Stresses in Plants

Acta Phytopathologica et Entomologica Hungarica ◽

10.1556/aphyt.41.2006.1-2.3 ◽

2006 ◽

Vol 41 (1-2) ◽

pp. 23-35 ◽

Cited By ~ 7

Author(s):

M. Pogány ◽

B. D. Harrach ◽

Y. M. Hafez ◽

B. Barna ◽

Z. Király ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Reactive Oxygen ◽

Oxygen Species ◽

Abiotic And Biotic Stresses ◽

Biotic Stresses

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SlWRKY45 Interacts with Jasmonate-ZIM Domain Proteins to Negatively Regulate Defense Against Root Knot Nematode Meloidogyne incognita in Tomato

10.22541/au.164151237.72268573/v1 ◽

2022 ◽

Author(s):

Huang Huang ◽

Wenchao Zhao ◽

Hui Qiao ◽

Chonghua Li ◽

Xuechun Ma ◽

...

Keyword(s):

Meloidogyne Incognita ◽

Defense Responses ◽

Wrky Transcription Factor ◽

Parasitic Nematodes ◽

Allene Oxide ◽

Wild Type ◽

Root Knot Nematode ◽

Abiotic And Biotic Stresses ◽

Biotic Stresses ◽

Gall Index

Root knot nematode (RKN), a kind of plant parasitic nematodes, leads to large reduction of crop yield, and seriously damages the agricultural production. The phytohormone jasmonates (JAs) act as important signals to regulate resistance against multiple abiotic and biotic stresses. However, little is known about the mechanism of JA-mediated defense responses against RKN in tomato. In this study, we found that the WRKY transcription factor SlWRKY45 interacts with most of the Jasmonate-ZIM domain proteins (JAZs) in yeast and plant. Overexpression of SlWRKY45 decreased plant resistance to RKN Meloidogyne incognita with increased gall index. We further generated slwrky45 mutants using the CRISPR/Cas9 technology, and discovered that the gall index and the number of nematodes and females in slwrky45 mutants are significantly reduced compared with wild type, as inoculated with RKN Meloidogyne incognita. Moreover, the contents of jasmonic acid and JA-isoleucine (JA-Ile) were highly increased in slwrky45 mutants with RKN Meloidogyne incognita infection compared with wild type. Furthermore, EMSA, and Dual-LUC assays demonstrated that SlWRKY45 directly binds and represses jasmonate biosynthesis gene ALLENE OXIDE CYCLASE ( AOC). Overall, our findings reveled that JAZ-interaction protein SlWRKY45 negatively controls plant defense against RKN Meloidogyne incognita by the regulation of JA biosynthesis in tomato.

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Beneficial Effect of Root or Foliar Silicon Applied to Cucumber Plants under Different Zinc Nutritional Statuses

Plants ◽

10.3390/plants10122602 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2602

Author(s):

José María Lozano-González ◽

Clara Valverde ◽

Carlos David Hernández ◽

Alexandra Martin-Esquinas ◽

Lourdes Hernández-Apaolaza

Keyword(s):

Foliar Application ◽

Zn Deficiency ◽

Oxygen Species ◽

Fresh Weight ◽

Mineral Concentration ◽

Abiotic And Biotic Stresses ◽

Biotic Stresses ◽

Beneficial Effects ◽

Growing Period ◽

Physiological Processes

Zinc (Zn) is an essential micronutrient involved in a large variety of physiological processes, and its deficiency causes mainly growth and development disturbances, as well as oxidative stress, which results in the overproduction and accumulation of reactive oxygen species (ROS). A possible environmentally friendly solution is the application of silicon (Si), an element that has shown beneficial effects under abiotic and biotic stresses on many crops. Si could be applied through the roots or leaves. The aim of this work is to study the effect of Si applied to the root or shoot in cucumber plants under different Zn statuses (sufficiency, deficiency, and re-fertilization). Cucumber plants were grown in hydroponics, with 1.5 mM Si applied at the nutrient solution or sprayed on the leaves. During the different Zn statuses, SPAD index, fresh weight, ROS, and Si, Zn, P, Cu and B mineral concentration were determined. The results suggested that Si application had no effect during sufficiency and deficiency periods, however, during re-fertilization foliar application of Si, it showed faster improvement in SPAD index, better increment of fresh weight, and a decrease in ROS quantity, probably due to a memory effect promoted by Si previous application during the growing period. In summary, Si application to cucumber plants could be used to prepare plants to cope with a future stress situation, such as Zn deficiency, due to its prompt recovery after overcoming the stress period.

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