Confocal ratio imaging of cytoplasmic pH during germ tube growth and appressorium induction by <i>Magnaporthe grisea</i>

Jelitto, Till C.

doi:10.1046/j.1469-8137.1999.00535.x

Cited by 4 publications

(2 citation statements)

References 35 publications

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“…The new germ tubes have higher pH in (>7.2) than macroconidia. The Wgures observed for these cells are comparable to the cytoplasmic pH found in hyphae of Neurospora crassa (pH 7.57) with dextran-conjugated dye (Parton et al, 1997), and in germ tubes of M. grisea (pH 7.4 § 0.1; Jelitto, 1999). The pH in of germinated compartments of the macroconidia of F. culmorum was lowered to pH in 6.8 after outgrowth.…”

Section: Diverentiation Of Macroconidial Compartmentssupporting

confidence: 76%

Differentiation inside multicelled macroconidia of Fusarium culmorum during early germination

Chitarra

Breeuwer

Rombouts

et al. 2005

Fungal Genetics and Biology

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Section: Diverentiation Of Macroconidial Compartmentssupporting

confidence: 76%

Differentiation inside multicelled macroconidia of Fusarium culmorum during early germination

Chitarra

Breeuwer

Rombouts

et al. 2005

Fungal Genetics and Biology

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“…So, CarO activity could generate external and internal changes in pH, predictably affecting hyphal development. Proton-gradients were reported to be involved in cell polarity and tip growth of fungi 47 48 49 , although more recent communications contradict the pH-gradient based cell polarity 46 50 51 . However, the prevalence of CarO in the conidia suggests that it might play a role in germination, possibly through the generation of a local proton gradient.…”

Section: Discussionmentioning

confidence: 99%

The CarO rhodopsin of the fungus Fusarium fujikuroi is a light-driven proton pump that retards spore germination

García-Martínez

Brunk

Ávalos

et al. 2015

Sci Rep

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Rhodopsins are membrane-embedded photoreceptors found in all major taxonomic kingdoms using retinal as their chromophore. They play well-known functions in different biological systems, but their roles in fungi remain unknown. The filamentous fungus Fusarium fujikuroi contains two putative rhodopsins, CarO and OpsA. The gene carO is light-regulated, and the predicted polypeptide contains all conserved residues required for proton pumping. We aimed to elucidate the expression and cellular location of the fungal rhodopsin CarO, its presumed proton-pumping activity and the possible effect of such function on F. fujikuroi growth. In electrophysiology experiments we confirmed that CarO is a green-light driven proton pump. Visualization of fluorescent CarO-YFP expressed in F. fujikuroi under control of its native promoter revealed higher accumulation in spores (conidia) produced by light-exposed mycelia. Germination analyses of conidia from carO− mutant and carO+ control strains showed a faster development of light-exposed carO− germlings. In conclusion, CarO is an active proton pump, abundant in light-formed conidia, whose activity slows down early hyphal development under light. Interestingly, CarO-related rhodopsins are typically found in plant-associated fungi, where green light dominates the phyllosphere. Our data provide the first reliable clue on a possible biological role of a fungal rhodopsin.

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Visualization of Localized Pathogen-Induced pH Modulation in Almond Tissues Infected byColletotrichum acutatumUsing Confocal Scanning Laser Microscopy

Diéguez-Uribeondo¹,

Förster²,

Adaskaveg³

2008

Phytopathology®

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Modulation of pH within the host during infection of almond by the anthracnose pathogen Colletotrichum acutatum was studied using confocal scanning laser microscopy and the dual emission fluorescence indicator SNARF-1. This highly sensitive method allowed visualization of the spatial distribution of localized pathogen-induced pH modulation within and in proximity to fungal infection structures in host tissue at the cellular level. Ratiometric measurement of fluorescence at two emission wavelengths and in situ calibration allowed the quantification of pH ranges. After incubation of leaf epidermal tissue with SNARF-1, distinct alkaline (pH 8 to > or =9), red-spectrum (650 nm wave length) fluorescent zones developed as partial or complete halos around many fungal appressoria and in infection vesicles at 24 to 36 h after inoculation. In samples taken after 48 to 72 h, colonizing hyphae in the biotrophic phase and subsequently in the necrotrophic phase were also emitting the red fluorescence that extended into the surrounding host tissue, as also verified by depth analyses. Host epidermal cells were intact and apparently alive during the fungal alkalization process, with no visible disruption of cell structure. Generally, the pH of epidermal cells in noninoculated samples or in areas away from the infection in inoculated samples was lower than pH 7 with green (i.e., 500 to 550 nm wave length) fluorescence detected. Using standard electrodes, a significant increase in pH and ammonia concentration in leaf and fruit tissue was also measured but only at advanced stages of disease. In contrast, hyphae of the pathogen Alternaria alternata were mostly acidic and no change in fluorescence was found inside invaded host cells. The sequence of events in the C. acutatum-almond interaction includes penetration, production of ammonia by C. acutatum, and subsequent pH modulation within almond epidermal tissue to an alkaline environment that leads to further colonization of the host.

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Confocal ratio imaging of cytoplasmic pH during germ tube growth and appressorium induction by Magnaporthe grisea

Cited by 4 publications

References 35 publications

Differentiation inside multicelled macroconidia of Fusarium culmorum during early germination

Differentiation inside multicelled macroconidia of Fusarium culmorum during early germination

The CarO rhodopsin of the fungus Fusarium fujikuroi is a light-driven proton pump that retards spore germination

Visualization of Localized Pathogen-Induced pH Modulation in Almond Tissues Infected byColletotrichum acutatumUsing Confocal Scanning Laser Microscopy

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