Inhibition by 2-deoxy-D-glucose of callose formation, papilla deposition, and resistance to powdery mildew in an ml-o barley mutant

Bayles, Carol J.; Ghemawat, M. S.; Aist, James R.

doi:10.1016/0885-5765(90)90092-c

Cited by 72 publications

(39 citation statements)

References 36 publications

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“…In incompatible interactions, results have generally indicated that callose is important for penetration resistance. The susceptibility of Arabidopsis to nonadapted fungal pathogens increased because of the inhibition or absence of callose deposition (Bayles et al, 1990;Zeyen et al, 2002;Jacobs et al, 2003). Hence, we anticipated an improved resistance to the avirulent powdery mildew Bgh in Arabidopsis lines showing increased pathogen-induced callose deposition.…”

Section: Discussionmentioning

confidence: 99%

“…An active role of callose in resistance to powdery mildew was further questioned in recent studies of mildew resistance locus O (mlo) mutants of barley (Hordeum vulgare). While Consonni et al (2010) showed that PMR4-dependent callose deposition was not required for the observed mlo2-conditioned penetration resistance in Arabidopsis, this appeared not to be the case in barley, where treatment of mlo-resistant coleoptiles with a callose inhibitor resulted in reduced formation of callose-containing papillae and decreased penetration resistance to powdery mildew (Bayles et al, 1990). Callose inhibition studies with several Gramineae, including barley, wheat (Triticum aestivum), and oat (Avena sativa), revealed that penetration resistance to powdery mildew was especially suppressed in incompatible plant-fungus interactions (Zeyen et al, 2002).…”

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confidence: 99%

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Elevated Early Callose Deposition Results in Complete Penetration Resistance to Powdery Mildew in Arabidopsis

et al. 2013

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A common response by plants to fungal attack is deposition of callose, a (1,3)-b-glucan polymer, in the form of cell wall thickenings called papillae, at site of wall penetration. While it has been generally believed that the papillae provide a structural barrier to slow fungal penetration, this idea has been challenged in recent studies of Arabidopsis (Arabidopsis thaliana), where fungal resistance was found to be independent of callose deposition. To the contrary, we show that callose can strongly support penetration resistance when deposited in elevated amounts at early time points of infection. We generated transgenic Arabidopsis lines that express POWDERY MILDEW RESISTANT4 (PMR4), which encodes a stress-induced callose synthase, under the control of the constitutive 35S promoter. In these lines, we detected callose synthase activity that was four times higher than that in wild-type plants 6 h post inoculation with the virulent powdery mildew Golovinomyces cichoracearum. The callose synthase activity was correlated with enlarged callose deposits and the focal accumulation of green fluorescent protein-tagged PMR4 at sites of attempted fungal penetration. We observed similar results from infection studies with the nonadapted powdery mildew Blumeria graminis f. sp. hordei. Haustoria formation was prevented in resistant transgenic lines during both types of powdery mildew infection, and neither the salicylic acid-dependent nor jasmonate-dependent pathways were induced. We present a schematic model that highlights the differences in callose deposition between the resistant transgenic lines and the susceptible wild-type plants during compatible and incompatible interactions between Arabidopsis and powdery mildew.Land plants are exposed to a wide range of potential pathogens and, accordingly, have evolved a variety of strategies that facilitate an early and rapid recognition of pathogens and the mobilization of biochemical and structural defenses. As a result, successful infection of plants by pathogens is the exception rather than the rule (

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Elevated Early Callose Deposition Results in Complete Penetration Resistance to Powdery Mildew in Arabidopsis

et al. 2013

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“…Papillae often form immediately beneath the penetration peg and are heterogeneous in composition (Heath, 1980); they are thought to physically blockfungal penetration of host cells (Bayles et al, 1990). However, it is also possible that their formation is required to provide adequate support for subsequent haustorium development, in which case they may be essentia1 for pathogenesis (Heath, 1980).…”

Section: Cell Wall Fortificationmentioning

confidence: 99%

Resistance gene-dependent plant defense responses.

1996

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“…2A). As a positive control, we added the known callose synthase inhibitor 2-deoxy-Dglucose (2-DDG; Bayles et al, 1990) to the activity assay. Compared with the unsaturated FFAs, the inhibitory effect of 2-DDG was even stronger: an 80% reduction of activity was already observed at a concentration of 7 mM and complete inhibition at 17.5 mM ( Fig.…”

Section: Inhibition Of Callose Synthase Activity By Ffasmentioning

confidence: 99%

Secreted Fungal Effector Lipase Releases Free Fatty Acids to Inhibit Innate Immunity-Related Callose Formation during Wheat Head Infection

Blümke

Falter

Herrfurth³

et al. 2014

Plant Physiology

110

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The deposition of the (1,3)-b-glucan cell wall polymer callose at sites of attempted penetration is a common plant defense response to intruding pathogens and part of the plant's innate immunity. Infection of the Fusarium graminearum disruption mutant Dfgl1, which lacks the effector lipase FGL1, is restricted to inoculated wheat (Triticum aestivum) spikelets, whereas the wild-type strain colonized the whole wheat spike. Our studies here were aimed at analyzing the role of FGL1 in establishing full F. graminearum virulence. Confocal laser-scanning microscopy revealed that the Dfgl1 mutant strongly induced the deposition of spot-like callose patches in vascular bundles of directly inoculated spikelets, while these callose deposits were not observed in infections by the wild type. Elevated concentrations of the polyunsaturated free fatty acids (FFAs) linoleic and a-linolenic acid, which we detected in F. graminearum wild type-infected wheat spike tissue compared with Dfgl1-infected tissue, provided clear evidence for a suggested function of FGL1 in suppressing callose biosynthesis. These FFAs not only inhibited plant callose biosynthesis in vitro and in planta but also partially restored virulence to the Dfgl1 mutant when applied during infection of wheat spikelets. Additional FFA analysis confirmed that the purified effector lipase FGL1 was sufficient to release linoleic and a-linolenic acids from wheat spike tissue. We concluded that these two FFAs have a major function in the suppression of the innate immunity-related callose biosynthesis and, hence, the progress of F. graminearum wheat infection.

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Inhibition by 2-deoxy-D-glucose of callose formation, papilla deposition, and resistance to powdery mildew in an ml-o barley mutant

Cited by 72 publications

References 36 publications

Elevated Early Callose Deposition Results in Complete Penetration Resistance to Powdery Mildew in Arabidopsis

Elevated Early Callose Deposition Results in Complete Penetration Resistance to Powdery Mildew in Arabidopsis

Resistance gene-dependent plant defense responses.

Secreted Fungal Effector Lipase Releases Free Fatty Acids to Inhibit Innate Immunity-Related Callose Formation during Wheat Head Infection

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