Lipid Mobilization and Acid Phosphatase Activity in Lytic Compartments during Conidium Dormancy and Appressorium Formation of Colletotrichum graminicola.

Schadeck, Ruth Janice Guse; Leite, Brenda Chaves Coelho; Buchi, Dorly de Freitas

doi:10.1247/csf.23.333

Cited by 21 publications

(18 citation statements)

References 32 publications

(24 reference statements)

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“…According Barbosa et al, (2006) the dark bodies observed inside the ungerminated spore (Figure 2c) is related to the lipid reserves that represent a crucial role in energy storage, indispensable for spores' germination under suitable conditions. The lipid bodies in ungerminated spores have been reported in C. graminicola (Schadeck et al, 1998), C. lagenarium (Kimura et al, 2001), and C. gloeosporioides (Kuo, 1999). The anthracnose resistance observed in C. acutatum-moderately ('Cobrançosa') and C. acutatum-resistant ('Picual') fruits can have close analogies with the pathogen dormant phase until fruit ripening.…”

Section: Discussionmentioning

confidence: 91%

Infection Process of Olive Fruits by Colletotrichum acutatum and the Protective Role of the Cuticle and Epidermis

Gomes¹,

Bacelar²,

Martins-Lopes³

et al. 2012

JAS

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Colletotrichum acutatum is a serious concern for the Portuguese oliviculture and food industry, due to both olive oil yield and quality decrease. While the organism's phytopathogenic potential has been well documented, the pathogen adhesion and colonization process in olives remain poorly understood. This paper reports experiments conducted on C. acutatum-susceptible, C. acutatum-moderately resistant and C. acutatum-resistant olive fruits during infection process, in two consecutively years, to identify the physical differences related to the host cuticle promoting resistance and susceptibility to C. acutatum. Cuticle thickness, perimeter and area of epidermal cells of 'Galega' (susceptible), 'Cobrançosa' (moderate-resistant) and 'Picual' (resistant) fruits were measured. Here, we also describe the colonization process of olive fruits by C. acutatum. To achieve this goal olive fruits 102 from 'Galega', 'Cobrançosa' and 'Picual' were inoculated in a field trial with an aqueous suspension of C. acutatum (1x10 6 spores ml -1 ) under suitable humidity and temperature conditions. Light, fluorescent and scanning electron microscopy were used to view olive fruit sections. Significant differences were observed among the parameters studied: cuticle thickness, perimeter and area of olive fruit epidermal cells. The C. acutatum-resistant ('Picual') fruits showed highest mean values for each parameter in both years. Pathogen ultrastructures, such as spores, germ tube, and appressoria were clearly observed using different microscopy techniques. Acervuli sporulation was observed only 192 hours after inoculation in C. acutatum-susceptible ('Galega') fruits.

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Section: Discussionmentioning

confidence: 91%

Infection Process of Olive Fruits by Colletotrichum acutatum and the Protective Role of the Cuticle and Epidermis

Gomes¹,

Bacelar²,

Martins-Lopes³

et al. 2012

JAS

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“…We think it likely, therefore, that lipolysis occurs within the central appressorial vacuole, which is prominent in mature appressoria that have elaborated penetration pegs (Bourett and Howard, 1990). Transport of lipid reserves and their vacuolar degradation have been reported in the maize pathogen Colletotrichum graminicola during conidial germination (Schadeck et al, 1998a(Schadeck et al, , 1998b. Because C. graminicola uses a mechanical infection mechanism similar to that of M. grisea (Bechinger et al, 1999), perhaps the considerable invasive forces generated by appressoria of C. graminicola are also produced by a glycerol-dependent mechanism.…”

Section: Discussionmentioning

confidence: 96%

MAP Kinase and Protein Kinase A–Dependent Mobilization of Triacylglycerol and Glycogen during Appressorium Turgor Generation by Magnaporthe grisea

2000

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Magnaporthe grisea produces an infection structure called an appressorium, which is used to breach the plant cuticle by mechanical force. Appressoria generate hydrostatic turgor by accumulating molar concentrations of glycerol. To investigate the genetic control and biochemical mechanism for turgor generation, we assayed glycerol biosynthetic enzymes during appressorium development, and the movement of storage reserves was monitored in developmental mutants. Enzymatic activities for glycerol generation from carbohydrate sources were present in appressoria but did not increase during development. In contrast, triacylglycerol lipase activity increased during appressorium maturation. Rapid glycogen degradation occurred during conidial germination, followed by accumulation in incipient appressoria and dissolution before turgor generation. Lipid droplets also moved to the incipient appressorium and coalesced into a central vacuole before degrading at the onset of turgor generation. Glycogen and lipid mobilization did not occur in a ⌬ pmk1 mutant, which lacked the mitogen-activated protein kinase (MAPK) required for appressorium differentiation, and was retarded markedly in a ⌬ cpkA mutant, which lacks the catalytic subunit of cAMP-dependent protein kinase A (PKA). Glycogen and lipid degradation were very rapid in a ⌬ mac1 sum1-99 mutant, which carries a mutation in the regulatory subunit of PKA, occurring before appressorium morphogenesis was complete. Mass transfer of storage carbohydrate and lipid reserves to the appressorium therefore occurs under control of the PMK1 MAPK pathway. Turgor generation then proceeds by compartmentalization and rapid degradation of lipid and glycogen reserves under control of the CPKA/SUM1 -encoded PKA holoenzyme.

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“…As with acid phosphatases produced by S. cerevisiae and Colletotrichum graminicola (53, 54), Aph1 is transported to vacuoles. In plants, phosphate starvation triggers de novo biosynthesis of secreted and intracellular acid phosphatases (55).…”

Section: Discussionmentioning

confidence: 99%

Identification of Aph1, a Phosphate-Regulated, Secreted, and Vacuolar Acid Phosphatase in Cryptococcus neoformans

Lev

Crossett

Young

et al. 2014

mBio

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Cryptococcus neoformans strains isolated from patients with AIDS secrete acid phosphatase, but the identity and role of the enzyme(s) responsible have not been elucidated. By combining a one-dimensional electrophoresis step with mass spectrometry, a canonically secreted acid phosphatase, CNAG_02944 (Aph1), was identified in the secretome of the highly virulent serotype A strain H99. We created an APH1 deletion mutant (Δaph1) and showed that Δaph1-infected Galleria mellonella and mice survived longer than those infected with the wild type (WT), demonstrating that Aph1 contributes to cryptococcal virulence. Phosphate starvation induced APH1 expression and secretion of catalytically active acid phosphatase in the WT, but not in the Δaph1 mutant, indicating that Aph1 is the major extracellular acid phosphatase in C. neoformans and that it is phosphate repressible. DsRed-tagged Aph1 was transported to the fungal cell periphery and vacuoles via endosome-like structures and was enriched in bud necks. A similar pattern of Aph1 localization was observed in cryptococci cocultured with THP-1 monocytes, suggesting that Aph1 is produced during host infection. In contrast to Aph1, but consistent with our previous biochemical data, green fluorescent protein (GFP)-tagged phospholipase B1 (Plb1) was predominantly localized at the cell periphery, with no evidence of endosome-mediated export. Despite use of different intracellular transport routes by Plb1 and Aph1, secretion of both proteins was compromised in a Δsec14-1 mutant. Secretions from the WT, but not from Δaph1, hydrolyzed a range of physiological substrates, including phosphotyrosine, glucose-1-phosphate, β-glycerol phosphate, AMP, and mannose-6-phosphate, suggesting that the role of Aph1 is to recycle phosphate from macromolecules in cryptococcal vacuoles and to scavenge phosphate from the extracellular environment.

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Lipid Mobilization and Acid Phosphatase Activity in Lytic Compartments during Conidium Dormancy and Appressorium Formation of Colletotrichum graminicola.

Cited by 21 publications

References 32 publications

Infection Process of Olive Fruits by Colletotrichum acutatum and the Protective Role of the Cuticle and Epidermis

Infection Process of Olive Fruits by Colletotrichum acutatum and the Protective Role of the Cuticle and Epidermis

MAP Kinase and Protein Kinase A–Dependent Mobilization of Triacylglycerol and Glycogen during Appressorium Turgor Generation by Magnaporthe grisea

Identification of Aph1, a Phosphate-Regulated, Secreted, and Vacuolar Acid Phosphatase in Cryptococcus neoformans

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