Induction of Chlorosis, ROS Generation and Cell Death by a Toxin Isolated from<i>Pyricularia oryzae</i>

Tsurushima, Tetsu; Minami, Yukari; Miyagawa, Hisashi; Nakayashiki, Hitoshi; Tosa, Yukio; Mayama, Shigeyuki

doi:10.1271/bbb.100404

Cited by 5 publications

(4 citation statements)

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“…The non‐host selective toxins pyricularin, pyriculol‐related compounds (e.g. epipyriculol, epidihydropyriculol, pyriculariol and pyricuol), tenuazonic acid and picolinic acid (PA) were produced by P. oryzae on rice leaves (Kim et al , Tsurushima et al ). The tenuazonic acid, PA and pyriculol are of greater importance for blast symptoms development on rice (Umetsu et al , Yoder , Iwahashi et al , Jacob et al ).…”

Section: Introductionmentioning

confidence: 99%

Picolinic acid spray stimulates the antioxidative metabolism and minimizes impairments on photosynthesis on wheat leaves infected by Pyricularia oryzae

Aucique‐Pérez

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Neto

et al. 2019

Physiologia Plantarum

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Fungal pathogens produce toxins that are important for their pathogenesis and/or aggressiveness towards their hosts. Picolinic acid (PA), a non-host selective toxin, causes lesions on rice leaves resembling those originated from Pyricularia oryzae infection. Considering that non-host selective toxins can be useful for plant diseases control, this study investigated whether the foliar spray with PA on wheat (Triticum aestivum L.) plants, in a non-phytotoxic concentration, could increase their resistance to blast, stimulate the anti-oxidative metabolism, and minimize alterations in photosynthesis. The PA spray at concentrations greater than 0.1 mg ml −1 caused foliar lesions, compromised the photosynthesis and was linked with greater accumulation of hydrogen peroxide (H 2 O 2 ) and superoxide anion radical (O 2 •− ). Fungal mycelial growth, conidia production and germination decreased by PA at 0.3 mg ml −1 . Blast severity was significantly reduced by 59 and 23%, respectively, at 72 and 96 h after inoculation for plants sprayed with PA (0.1 mg ml −1 ) at 24 h before fungal inoculation compared to non-sprayed plants. Reduction on blast symptoms was linked with increases on ascorbate peroxidase (EC 1.superoxide dismutase (EC 1.15.1.1) activities, lower H 2 O 2 and O 2•− accumulation, reduced malondialdehyde production as well as less impairments to the photosynthetic apparatus. A more efficient antioxidative metabolism that rapidly scavenges the reactive oxygen species generated during P. oryzae infection, without dramatically decreasing the photosynthetic performance, was a remarkable effect obtained with PA spray.Abbreviations -A, net CO 2 assimilation rate; APX, ascorbate peroxidase; BS, blast severity; CAT, catalase; C i , internal CO 2 concentration; E, transpiration rate; F m , maximum fluorescence image; F v /F m , variable-to-maximum chlorophyll fluorescence ratio; GPX, glutathione peroxidase; g s , stomatal conductance to water vapor; GST, glutathione-S-transferase; hai, hours after inoculation; H 2 O 2 , hydrogen peroxide; MDA, malondialdehyde; O 2 •− , superoxide anion radical; PA, picolinic acid; POX, peroxidase; q P , coefficient for photochemical quenching; SOD, superoxide dismutase; Y(II), effective photosystem II quantum yield; Y(NO), quantum yield of non-regulated energy dissipation; Y(NPQ), quantum yield of regulated energy dissipation.

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Section: Introductionmentioning

confidence: 99%

Picolinic acid spray stimulates the antioxidative metabolism and minimizes impairments on photosynthesis on wheat leaves infected by Pyricularia oryzae

Aucique‐Pérez

Resende

Neto

et al. 2019

Physiologia Plantarum

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“…For example, Magnaporthe grisea was found to produce a species-specific metabolite, pyrichalasin [9,10]. The virulence of the Digitariapathogenic M. grisea strains putatively correlates with the quantity of pyrichalasin H because toxin-free mutants were non-pathogenic -but a comprehensive characterization of these mutants has not been not conducted to date [11].…”

Section: Introductionmentioning

confidence: 99%

“…Additional studies have identified other metabolites produced by Magnaporthe strains, i.e. tenuazonic acid and Magtoxin [10,[12][13][14]. Tenuazonic acid is a mycotoxin synthesized by various plant pathogenic fungi.…”

Section: Introductionmentioning

confidence: 99%

Unravelling the biosynthesis of pyriculol in the rice blast fungus Magnaporthe oryzae

et al. 2017

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Pyriculol was isolated from the rice blast fungus Magnaporthe oryzae and found to induce lesion formation on rice leaves. These findings suggest that it could be involved in virulence. The gene MoPKS19 was identified to encode a polyketide synthase essential for the production of the polyketide pyriculol in the rice blast fungus M. oryzae. The transcript abundance of MoPKS19 correlates with the biosynthesis rate of pyriculol in a time-dependent manner. Furthermore, gene inactivation of MoPKS19 resulted in a mutant unable to produce pyriculol, pyriculariol and their dihydro derivatives. Inactivation of a putative oxidase-encoding gene MoC19OXR1, which was found to be located in the genome close to MoPKS19, resulted in a mutant exclusively producing dihydropyriculol and dihydropyriculariol. By contrast, overexpression of MoC19OXR1 resulted in a mutant strain only producing pyriculol. The MoPKS19 cluster, furthermore, comprises two transcription factors MoC19TRF1 and MoC19TRF2, which were both found individually to act as negative regulators repressing gene expression of MoPKS19. Additionally, extracts of DMopks19 and DMoC19oxr1 made from axenic cultures failed to induce lesions on rice leaves compared to extracts of the wild-type strain. Consequently, pyriculol and its isomer pyriculariol appear to be the only lesioninducing secondary metabolites produced by M. oryzae wild-type (MoWT) under these culture conditions. Interestingly, the mutants unable to produce pyriculol and pyriculariol were as pathogenic as MoWT, demonstrating that pyriculol is not required for infection.

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“…Non-host selective toxins maximize, together with the hydrolytic enzymes, the intensity of the diseases due to inhibition of photosynthesis photochemistry, changes in primary and secondary metabolism, increased production of ROS, loss of cellular homeostasis, and damage to cell membranes (Dong et al 2012, Chen et al 2014. The fungus P. oryzae can produce many non-host selective toxins (e.g., pyricularin, pyriculol-related compounds (epipyriculol, epidihydropyriculol, pyriculariol, and pyricuol), tenuazonic acid, and picolinic acid (PA)) in infected rice leaves (Kim et al 1998, Tsurushima et al 2010. These non-host selective toxins, mainly the PA, reproduced the same symptoms caused by the infection of P. oryzae when sprayed onto wheat leaves (Aucique-Pérez et al 2019).…”

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confidence: 99%

Picolinic acid stress imposed on rice leaves is not alleviated by silicon

Domiciano

Cacique

Freitas

et al. 2020

Trop. plant pathol.

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Blast, caused by Pyricularia oryzae, is one of the most important diseases affecting rice yield worldwide. This study investigated the potential of silicon (Si) to counteract the effect of picolinic acid (PA), a non-host selective toxin produced by P. oryzae, on the photosynthetic performance, on the activities of defense enzymes, and the antioxidative metabolism of rice plants. Plants were grown in nutrient solution containing 0 or 2 mM of Si and non-sprayed or sprayed with PA (0.5 mg PA/ml; 20 ml per plant) at 35 days after emergence. The PA-sprayed plants exhibited necrotic lesions on leaves that resembled those caused by P. oryzae infection. In the presence of Si, the necrotic lesions on the leaves of PA-sprayed plants were less in number and of reduced size. The necrosis of leaf tissues caused by PA spray was accompanied by lower values of net CO 2 assimilation rate and transpiration rate and high internal CO 2 concentration values indicating the occurrence of biochemical limitations in photosynthesis regardless of Si supply. For plants non-sprayed with PA, there was no change in the activities of the enzymes involved in host defense (chitinases (CHI), β-1,3-glucanases (GLU), polyphenoloxidases (PPO), and phenylalanine ammonia-lyases (PAL)) and on the antioxidative system (superoxide dismutases (SOD), catalases (CAT), peroxidases (POX), ascorbate peroxidases (APX), and glutathione reductases (GR)). The activities of CHI, GLU, PAL, GR, POX, and SOD were greater on the leaves of PA-sprayed plants in the absence of Si than on its presence. Silicion did not alleviate the physiological and biochemical aspects of PAmediated stress on rice leaf blades. We hypothesize that Si forms a physical barrier. Such physical impediment makes the diffusion of PA into the leaf blades more difficult rather than actively affecting the physiology and biochemistry of the plant.

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Induction of Chlorosis, ROS Generation and Cell Death by a Toxin Isolated fromPyricularia oryzae

Cited by 5 publications

References 35 publications

Picolinic acid spray stimulates the antioxidative metabolism and minimizes impairments on photosynthesis on wheat leaves infected by Pyricularia oryzae

Picolinic acid spray stimulates the antioxidative metabolism and minimizes impairments on photosynthesis on wheat leaves infected by Pyricularia oryzae

Unravelling the biosynthesis of pyriculol in the rice blast fungus Magnaporthe oryzae

Picolinic acid stress imposed on rice leaves is not alleviated by silicon

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