scholarly journals Secondary Metabolites of Pseudomonas aeruginosa LV Strain Decrease Asian Soybean Rust Severity in Experimentally Infected Plants

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1495
Author(s):  
Igor Matheus Oliveira dos Santos ◽  
Valéria Yukari Abe ◽  
Kenia de Carvalho ◽  
André Riedi Barazetti ◽  
Ane Stéfano Simionato ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Secondary Metabolites ◽  
Spore Germination ◽  
Soybean Rust ◽  
Asian Soybean Rust ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related ◽  
Soybean Plants ◽  
Lesion Frequency

Asian Soybean Rust (ASR), a disease caused by Phakopsora pachyrhizi, causing yield losses up to 90%. The control is based on the fungicides which may generate resistant fungi. The activation of the plant defense system, should help on ASR control. In this study, secondary metabolites of Pseudomonas aeruginosa LV strain were applied on spore germination and the expression of defense genes in infected soybean plants. The F4A fraction and the pure metabolites were used. In vitro, 10 µg mL−1 of F4A reduced spore germination by 54%, while 100 µg mL−1 completely inhibited. Overexpression of phenylalanine ammonia lyase (PAL), O-methyltransferase (OMT) and pathogenesis related protein-2 (PR-2; glucanases) defense-related genes were detected 24 and 72 h after soybean sprouts were sprayed with an organocopper antimicrobial compound (OAC). Under greenhouse conditions, the best control was observed in plants treated with 60 µg mL−1 of PCA, which reduced ASR severity and lesion frequency by 75% and 43%, respectively. Plants sprayed with 2 and 20 µg mL−1 of F4A also decreased severity (41%) and lesion frequency (32%). The significant reduction in spore germination ASR in plant suggested that the strain of these metabolites are effective against P. pachyrhizi, and they can be used for ASR control.

scholarly journals Winter Survival of the Soybean Rust Pathogen, Phakopsora pachyrhizi, in Florida

Plant Disease ◽  
2008 ◽  
Vol 92 (11) ◽  
pp. 1551-1558 ◽  
Author(s):  
Wayne M. Jurick ◽  
Dario F. Narvaez ◽  
Meghan M. Brennan ◽  
Carrie L. Harmon ◽  
James J. Marois ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Spore Germination ◽  
Soybean Rust ◽  
Inoculum Potential ◽  
Phakopsora Pachyrhizi ◽  
Southwest Florida ◽  
Rust Pathogen ◽  
Over Time ◽  
Time Freezing

Soybean rust (SBR) survival and host availability (kudzu, Pueraria spp.) were assessed from November 2006 through April 2007 at six sites from the panhandle to southwest Florida. Micro loggers recorded both temperature and relative humidity hourly at each location. Periods of drought and cumulative hours below 0°C correlated with kudzu defoliation. Inoculum potential from detached kudzu leaves was evaluated in vitro under various temperature and relative humidity levels. Kudzu leaves with SBR kept at 4°C produced viable urediniospores with the highest germination at all moisture levels over time. Freezing temperatures (–4 and –20°C) drastically reduced spore germination. However, when leaves were incubated at low (<35%) relative humidity, inoculum potential was prolonged. Results from this study demonstrate that both temperature and relative humidity impact P. pachyrhizi in the field and in vitro, and that detached kudzu leaves have the potential to serve as an inoculum source in kudzu stands.

scholarly journals An Overview of the Epidemiology of Phakopsora pachyrhizi in the State of Mato Grosso, Brazil

2021 ◽  
Vol 13 (6) ◽  
pp. 110
Author(s):  
Erlei Melo Reis ◽  
Wanderlei Dias Guerra ◽  
Mateus Zanatta ◽  
Laércio Zambolim
Keyword(s):  
Environmental Effect ◽  
The State ◽  
Soybean Rust ◽  
Economic Sustainability ◽  
Phakopsora Pachyrhizi ◽  
Airborne Spores ◽  
Mato Grosso ◽  
Asian Soybean Rust ◽  
Weed Plants ◽  
Soybean Plants

This review seeks to expand the knowledge about the epidemiology of Asian sybean rust in the state of Mato Grosso and contribute to ensuring the economic sustainability of soybean crop. It is discussed the Phakopsora pachyrhizi potential of dispersal from Asia to South America and finally to Mato Grosso state. The origin of the Asian soybean rust inoculum within Mato Grosso is addressed by the survival in volunteer and soybean weed plants (Pitelli, 2015) in other crops such as cotton. Data on the adverse environmental effect on the soybean plants survival are shown mainly the water deficit from June to August. Reports on the effect air temperature and mainly solar radiation on the mortality of airborne spores during their anemophilous spread on sunny days are also discussed. This increase of knowledge aims to make the soybean-free period more efficient by the knowledge on the soybean plants survival and on the fungus viability in the month of August. Due to the proximity of soybean farms, during the soybean-free period, in other states (Tocantins, Goi&aacute;s, Rond&ocirc;nia, etc.) and in other neighbor countries we discuss the likelihood that inoculum in the state may also originate in out-of-state crops during the Mato Grosso soybean-free period.

Use of a Canopy Opener in Fungicide Applications to Improve Asian Soybean Rust Control

2017 ◽  
Vol 60 (6) ◽  
pp. 1819-1825 ◽  
Author(s):  
Bianca Moura ◽  
Carolina Cardoso Deuner ◽  
Gustavo Luiz Visintin ◽  
Walter Boller
Keyword(s):  
Grain Yield ◽  
Plant Architecture ◽  
Spray Deposition ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Droplet Deposition ◽  
Asian Soybean Rust ◽  
Negative Effect ◽  
Soybean Plants ◽  
Pesticide Deposition

Abstract. In soybeans, the leaves of the upper canopy often act as a shield against fungicide penetration, preventing pesticide deposition on target. Fungicide applications to control Asian soybean rust (ASR) are especially difficult because the infection usually starts on the lower canopy. In this study, soybean plants of an early indeterminate cultivar and a determinate cultivar were sprayed with the fungicide azoxystrobin + benzovindiflupyr at six different times of the day with or without the addition of a curtain of chains on the spray boom, which acted as a canopy opener. The number of uredia of cm-2 and grain yield were measured to evaluate application efficacy. We found that the use of the curtain of chains reduced ASR control on the upper canopy for the indeterminate cultivar; however, less of a negative effect was observed for the determinate cultivar. The curtain of chains improved ASR control on the lower and middle canopies at more hours of the day for the determinate cultivar. For both cultivars, the curtain of chains increased ASR control at 6:00, 9:00, and 18:00 h on the lower canopy. Grain yield was also higher with the curtain of chains at 6:00 and 9:00 h for the determinate cultivar. Our results showed that using the curtain of chains could improve fungicide droplet deposition on the lower canopy, leading to greater ASR control and possibly increasing yield. However, it is important to consider the plant architecture and hour of application to maximize the benefit of the curtain of chains. Keywords: Canopy opener, Fungicide penetration, Phakopsora pachyrhizi, Plant architecture, Spray deposition.

scholarly journals Zinc binding regulates amyloid-like aggregation of GAPR-1

2019 ◽  
Vol 39 (2) ◽  
Author(s):  
Jie Sheng ◽  
Nick K. Olrichs ◽  
Willie J. Geerts ◽  
Xueyi Li ◽  
Ashfaq Ur Rehman ◽  
...  
Keyword(s):  
Conformational Change ◽  
Tertiary Structure ◽  
Secretory Protein ◽  
Titration Calorimetry ◽  
Secretory Proteins ◽  
Dependent Manner ◽  
Sequence Motifs ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related

Abstract Members of the CAP superfamily (Cysteine-rich secretory proteins, Antigen 5, and Pathogenesis-related 1 proteins) are characterized by the presence of a CAP domain that is defined by four sequence motifs and a highly conserved tertiary structure. A common structure–function relationship for this domain is hitherto unknown. A characteristic of several CAP proteins is their formation of amyloid-like structures in the presence of lipids. Here we investigate the structural modulation of Golgi-Associated plant Pathogenesis Related protein 1 (GAPR-1) by known interactors of the CAP domain, preceding amyloid-like aggregation. Using isothermal titration calorimetry (ITC), we demonstrate that GAPR-1 binds zinc ions. Zn2+ binding causes a slight but significant conformational change as revealed by CD, tryptophan fluorescence, and trypsin digestion. The Zn2+-induced conformational change was required for the formation of GAPR-1 oligomers and amyloid-like assemblies in the presence of heparin, as shown by ThT fluorescence and TEM. Molecular dynamics simulations show binding of Zn2+ to His54 and His103. Mutation of these two highly conserved residues resulted in strongly diminished amyloid-like aggregation. Finally, we show that proteins from the cysteine-rich secretory protein (CRISP) subfamily are also able to form ThT-positive structures in vitro in a heparin- and Zn2+-dependent manner, suggesting that oligomerization regulated by metal ions could be a common structural property of the CAP domain.

scholarly journals Pathogenesis-Related Protein Expression in the Apoplast of Wheat Leaves Protected Against Leaf Rust Following Application of Plant Extracts

2014 ◽  
Vol 104 (9) ◽  
pp. 933-944 ◽  
Author(s):  
Rabia Naz ◽  
Asghari Bano ◽  
Neil L. Wilson ◽  
David Guest ◽  
Thomas H. Roberts
Keyword(s):  
Protein Expression ◽  
Leaf Rust ◽  
Disease Incidence ◽  
Puccinia Triticina ◽  
Calotropis Procera ◽  
Leaf Extracts ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related ◽  
Wheat Leaves

Leaf rust (Puccinia triticina) is a major disease of wheat. We tested aqueous leaf extracts of Jacaranda mimosifolia (Bignoniaceae), Thevetia peruviana (Apocynaceae), and Calotropis procera (Apocynaceae) for their ability to protect wheat from leaf rust. Extracts from all three species inhibited P. triticina urediniospore germination in vitro. Plants sprayed with extracts before inoculation developed significantly lower levels of disease incidence (number of plants infected) than unsprayed, inoculated controls. Sprays combining 0.6% leaf extracts and 2 mM salicylic acid with the fungicide Amistar Xtra at 0.05% (azoxystrobin at 10 μg/liter + cyproconazole at 4 μg/liter) reduced disease incidence significantly more effectively than sprays of fungicide at 0.1% alone. Extracts of J. mimosifolia were most active, either alone (1.2%) or in lower doses (0.6%) in combination with 0.05% Amistar Xtra. Leaf extracts combined with fungicide strongly stimulated defense-related gene expression and the subsequent accumulation of pathogenesis-related (PR) proteins in the apoplast of inoculated wheat leaves. The level of protection afforded was significantly correlated with the ability of extracts to increase PR protein expression. We conclude that pretreatment of wheat leaves with spray formulations containing previously untested plant leaf extracts enhances protection against leaf rust provided by fungicide sprays, offering an alternative disease management strategy.

scholarly journals Spray volumes and fungicide rates on Asian soybean rust control

2019 ◽  
Vol 45 (3) ◽  
pp. 255-260
Author(s):  
Amanda Chechi ◽  
Carlos Alberto Forcelini ◽  
Walter Boller
Keyword(s):  
Grain Yield ◽  
Disease Control ◽  
Statistical Difference ◽  
Soybean Rust ◽  
The Third ◽  
Asian Soybean Rust ◽  
Field Control ◽  
Spray Volume ◽  
Soybean Plants ◽  
Best Disease

ABSTRACT The aim of this study was to assess the effect of different spray volumes and fungicide rates on Asian soybean rust control. Experiments were conducted in the field and in the laboratory during 2014 and 2016. We varied the fungicide rates (45 + 52.5, 60 + 70 and 75 + 87.5 g a.i. ha-1 for the mixture trifloxystrobin + prothioconazole, and 45 + 22.5, 60 + 30 and 75 + 37.5 g a.i. ha-1 for azoxystrobin + benzovindiflupyr) and the spray volume (100, 150 and 200 L ha-1) for application on soybean plants in the field. Another experiment was conducted in the laboratory, using the recommended rates of the fungicides trifloxystrobin + prothioconazole (60 + 70 g a.i. ha-1) and azoxystrobin + benzovindiflupyr (60 + 30 g a.i. ha-1). The spray volume of 200 L ha-1 resulted in the best disease control only for the third out of three applications carried out in the field (control between 68.4% and 70.1%). However, there was no statistical difference in grain yield for all tested spray volumes when we used the recommended fungicide rates (3422, 3526 and 3601 kg ha-1) or higher rates (3529, 3586 and 3550 kg ha-1). The decrease in the fungicide rate directly implied reduced rust control for both experiments (20 to 39% in the field and up to 71.4% in the laboratory).

scholarly journals Identification and characterization of a new soybean promoter induced by Phakopsora pachyrhizi, the causal agent of Asian soybean rust

2020 ◽  
Author(s):  
Lisa Cabre ◽  
Stephane Peyrard ◽  
Catherine Sirven ◽  
Laurine Gilles ◽  
Bernard Pelissier ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Green Fluorescence Protein ◽  
Inducible Promoter ◽  
Soybean Rust ◽  
Limited Area ◽  
Phakopsora Pachyrhizi ◽  
Mechanical Wounding ◽  
Rust Disease ◽  
Asian Soybean Rust ◽  
Soybean Plants

ABSTRACTBackgroundPhakopsora pachyrhizi is a biotrophic fungal pathogen responsible for the Asian soybean rust disease causing important yield losses in tropical and subtropical soybean-producing countries. P. pachyrhizi triggers important transcriptional changes in soybean plants during infection, with several hundreds of genes being either up- or downregulated.ResultsBased on published transcriptomic data, we identified a predicted chitinase gene, referred to as GmCHIT1, that was upregulated in the first hours of infection. We first confirmed this early induction and showed that this gene was expressed as early as 8 hours after P. pachyrhizi inoculation. To investigate the promoter of GmCHIT1, transgenic soybean plants expressing the green fluorescence protein (GFP) under the control of the GmCHIT1 promoter were generated. Following inoculation of these transgenic plants with P. pachyrhizi, GFP fluorescence was detected in a limited area located around appressoria, the fungal penetration structures. Fluorescence was also observed after mechanical wounding whereas no variation in fluorescence of pGmCHIT1:GFP transgenic plants was detected after a treatment with an ethylene precursor or a methyl jasmonate analogue.ConclusionWe identified a soybean chitinase promoter exhibiting an early induction by P. pachyrhizi located in the first infected soybean leaf cells. Our results on the induction of GmCHIT1 promoter by P. pachyrhizi contribute to the identification of a new pathogen inducible promoter in soybean and beyond to the development of a strategy for the Asian soybean rust disease control using biotechnological approaches.

Salicylic acid-induced suppression of Meloidogyne incognita infestation of okra and cowpea

Nematology ◽  
2003 ◽  
Vol 5 (5) ◽  
pp. 747-752 ◽  
Author(s):  
Bidyut Nandi ◽  
Santi Prasad Sinha Babu ◽  
Nirmalya Banerjee ◽  
Kabita Kundu
Keyword(s):  
Salicylic Acid ◽  
Meloidogyne Incognita ◽  
Phenylalanine Ammonia Lyase ◽  
Foliar Spray ◽  
In Vitro Test ◽  
Pal Activity ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related ◽  
Vitro Test

AbstractSalicylic acid (SA) applied as 10 mM foliar spray to okra (Abelmoschus esculentus) cv. Purbani Kranti and cowpea (Vigna unguiculata) cv. Pusa Ruby plants 24 h before inoculation of roots with Meloidogyne incognita juveniles, reduced infestation. Salicylic acid had no direct influence on plant growth and did not kill nematodes in an in vitro test. It induced increased accumulation of a 14 kDa pathogenesis-related protein (PR-1) in roots of both non-inoculated and inoculated salicylic acid-sprayed okra but not in the treated leaves. Salicylic acid sprays enhanced phenylalanine ammonia lyase (PAL) activity in roots of both non-inoculated and inoculated cowpea, estimated at 15 days after inoculation. Infected roots had higher PAL activity than roots of the corresponding non-inoculated treatments. Both PAL activity and SA-induced resistance gradually declined with plant age after treatment.

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