Current views on temperature-modulated R gene-mediated plant defense responses and tradeoffs between plant growth and immunity

2019 ◽  
Vol 50 ◽  
pp. 9-17 ◽  
Author(s):  
Jelli Venkatesh ◽  
Byoung-Cheorl Kang
Keyword(s):  
Plant Growth ◽  
Plant Defense ◽  
Defense Responses ◽  
R Gene ◽  
Plant Defense Responses

Application of Chitosan in Plant Defense Responses to Biotic and Abiotic Stresses

2020 ◽  
Author(s):  
Wasinee Pongprayoon ◽  
Thanapoom Siringam ◽  
Atikorn Panya ◽  
Sittiruk Roytrakul
Keyword(s):  
Secondary Metabolites ◽  
Plant Growth ◽  
Plant Defense ◽  
Abiotic Stresses ◽  
Proteinase Inhibitors ◽  
Signal Transduction Pathway ◽  
Defense Responses ◽  
Plant Responses ◽  
Plant Defense Responses ◽  
Biotic And Abiotic Stress

Chitosan, a copolymer of N-acetyl-D-glucosamine and D-glucosamine, which possesses properties that make it useful in various fields, is produced by the deacetylation of chitin derivatives. It is used in agriculture as a biostimulant for plant growth and protection, it also induces several responsive genes, proteins, and secondary metabolites in plants. Chitosan elicits a signal transduction pathway and transduces secondary molecules such as hydrogen peroxide and nitric oxide. Under biotic stress, chitosan can stimulate phytoalexins, pathogenesis-related proteins, and proteinase inhibitors. Pretreatment of chitosan before exposure to abiotic stresses (drought, salt, and heat) induces plant growth, production of antioxidant enzymes, secondary metabolites, and abscisic acid (ABA). It also causes changes in physiology, biochemistry, and molecular biology of the plant cells. However, plant responses depend on different chitosan-based structures, concentrations, species, and developmental stages. This review collects updated information on chitosan applications, particularly in plant defense responses to biotic and abiotic stress conditions.

scholarly journals Effectors from Wheat Rust Fungi Suppress Multiple Plant Defense Responses

2017 ◽  
Vol 107 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Sowmya R. Ramachandran ◽  
Chuntao Yin ◽  
Joanna Kud ◽  
Kiwamu Tanaka ◽  
Aaron K. Mahoney ◽  
...  
Keyword(s):  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Hypersensitive Response ◽  
Defense Responses ◽  
Effector Proteins ◽  
R Gene ◽  
Plant Defense Responses ◽  
Functional Studies ◽  
Rust Diseases ◽  
Suppression Assay

Fungi that cause cereal rust diseases (genus Puccinia) are important pathogens of wheat globally. Upon infection, the fungus secretes a number of effector proteins. Although a large repository of putative effectors has been predicted using bioinformatic pipelines, the lack of available high-throughput effector screening systems has limited functional studies on these proteins. In this study, we mined the available transcriptomes of Puccinia graminis and P. striiformis to look for potential effectors that suppress host hypersensitive response (HR). Twenty small (<300 amino acids), secreted proteins, with no predicted functions were selected for the HR suppression assay using Nicotiana benthamiana, in which each of the proteins were transiently expressed and evaluated for their ability to suppress HR caused by four cytotoxic effector‐R gene combinations (Cp/Rx, ATR13/RPP13, Rpt2/RPS‐2, and GPA/RBP‐1) and one mutated R gene—Pto(Y207D). Nine out of twenty proteins, designated Shr1 to Shr9 (suppressors of hypersensitive response), were found to suppress HR in N. benthamiana. These effectors varied in the effector-R gene defenses they suppressed, indicating these pathogens can interfere with a variety of host defense pathways. In addition to HR suppression, effector Shr7 also suppressed PAMP-triggered immune response triggered by flg22. Finally, delivery of Shr7 through Pseudomonas fluorescens EtHAn suppressed nonspecific HR induced by Pseudomonas syringae DC3000 in wheat, confirming its activity in a homologous system. Overall, this study provides the first evidence for the presence of effectors in Puccinia species suppressing multiple plant defense responses.

scholarly journals Stress-Responsive Alternative Sigma Factor SigB Plays a Positive Role in the Antifungal Proficiency ofBacillus subtilis

2019 ◽  
Vol 85 (9) ◽  
Author(s):  
M. Bartolini ◽  
S. Cogliati ◽  
D. Vileta ◽  
C. Bauman ◽  
W. Ramirez ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Plant Growth ◽  
Plant Defense ◽  
Defense Responses ◽  
Phytopathogenic Fungi ◽  
Plant Diseases ◽  
Phytopathogenic Fungus ◽  
Plant Defense Responses ◽  
Content Type ◽  
Regulatory Pathways

ABSTRACTDifferentBacillusspecies with PGPR (plant growth-promoting rhizobacterium) activity produce potent biofungicides and stimulate plant defense responses against phytopathogenic fungi. However, very little is known about how these PGPRs recognize phytopathogens and exhibit the antifungal response. Here, we report the antagonistic interaction betweenBacillus subtilisand the phytopathogenic fungusFusarium verticillioides. We demonstrate that this bacterial-fungal interaction triggers the induction of the SigB transcription factor, the master regulator ofB. subtilisstress adaptation. Dual-growth experiments performed with live or dead mycelia or culture supernatants ofF. verticillioidesshowed that SigB was activated and required for the biocontrol of fungal growth. Mutations in the different regulatory pathways of SigB activation in the isogenic background revealed that only the energy-related RsbP-dependent arm of SigB activation was responsible for specific fungal detection and triggering the antagonistic response. The activation of SigB increased the expression of the operon responsible for the production of the antimicrobial cyclic lipopeptide surfactin (thesrfAoperon). SigB-deficientB. subtiliscultures produced decreased amounts of surfactin, andB. subtiliscultures defective in surfactin production (ΔsrfA) were unable to control the growth ofF. verticillioides.In vivoexperiments of seed germination efficiency and early plant growth inhibition in the presence ofF. verticillioidesconfirmed the physiological importance of SigB activity for plant bioprotection.IMPORTANCEBiological control using beneficial bacteria (PGPRs) represents an attractive and environment-friendly alternative to pesticides for controlling plant diseases. Different PGPRBacillusspecies produce potent biofungicides and stimulate plant defense responses against phytopathogenic fungi. However, very little is known about how PGPRs recognize phytopathogens and process the antifungal response. Here, we report howB. subtilistriggers the induction of the stress-responsive sigma B transcription factor and the synthesis of the lipopeptide surfactin to fight the phytopathogen. Our findings show the participation of the stress-responsive regulon of PGPRBacillusin the detection and biocontrol of a phytopathogenic fungus of agronomic impact.

scholarly journals An efficient direct screening system for microorganisms that activate plant immune responses based on plant–microbe interactions using cultured plant cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mari Kurokawa ◽  
Masataka Nakano ◽  
Nobutaka Kitahata ◽  
Kazuyuki Kuchitsu ◽  
Toshiki Furuya
Keyword(s):  
Immune Responses ◽  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Large Scale ◽  
Plant Cells ◽  
Defense Responses ◽  
Root Tip ◽  
General Strategy ◽  
Plant Defense Responses ◽  
Microbe Interactions

AbstractMicroorganisms that activate plant immune responses have attracted considerable attention as potential biocontrol agents in agriculture because they could reduce agrochemical use. However, conventional methods to screen for such microorganisms using whole plants and pathogens are generally laborious and time consuming. Here, we describe a general strategy using cultured plant cells to identify microorganisms that activate plant defense responses based on plant–microbe interactions. Microbial cells were incubated with tobacco BY-2 cells, followed by treatment with cryptogein, a proteinaceous elicitor of tobacco immune responses secreted by an oomycete. Cryptogein-induced production of reactive oxygen species (ROS) in BY-2 cells served as a marker to evaluate the potential of microorganisms to activate plant defense responses. Twenty-nine bacterial strains isolated from the interior of Brassica rapa var. perviridis plants were screened, and 8 strains that enhanced cryptogein-induced ROS production in BY-2 cells were selected. Following application of these strains to the root tip of Arabidopsis seedlings, two strains, Delftia sp. BR1R-2 and Arthrobacter sp. BR2S-6, were found to induce whole-plant resistance to bacterial pathogens (Pseudomonas syringae pv. tomato DC3000 and Pectobacterium carotovora subsp. carotovora NBRC 14082). Pathogen-induced expression of plant defense-related genes (PR-1, PR-5, and PDF1.2) was enhanced by the pretreatment with strain BR1R-2. This cell–cell interaction-based platform is readily applicable to large-scale screening for microorganisms that enhance plant defense responses under various environmental conditions.

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
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