CgSCD1 Is Essential for Melanin Biosynthesis and Pathogenicity of Colletotrichum gloeosporioides

Colletotrichum gloeosporioides, an important phytopathogenic fungus, mainly infects tropical fruits and results in serious anthracnose. Previous studies have shown that melanin biosynthesis inhibitor can inhibit the melanization of the appressoria of Magnaporthe grisea and Colletotrichum orbiculare, resulting in limited infection of the hosts. In this study, we identified and characterized a scytalone dehydratase gene (CgSCD1) from C. gloeosporioides which is involved in melanin synthesis. The CgSCD1 gene deletion mutant ΔCgscd1 was obtained using homologous recombination. The ΔCgscd1 mutant showed no melanin accumulation on appressoria formation and vegetative hyphae. Furthermore, the virulence of ΔCgscd1 was significantly reduced in comparison with the wild-type (WT) strain. Further investigations showed that the growth rate as well as germination and appressorium formation of ΔCgscd1 displayed no difference compared to the wild-type and complemented transformant Cgscd1com strains. Furthermore, we found that the appressorial turgor pressure in the ΔCgscd1 mutant showed no difference compared to that in the WT and Cgscd1com strains in the incipient cytorrhysis experiment. However, fewer infectious hyphae of ΔCgscd1 were observed in the penetration experiments, suggesting that the penetration ability of nonpigmented appressoria was partially impaired. In conclusion, we identified the CgSCD1 gene, which is involved in melanin synthesis and pathogenicity, and found that the melanization defect did not affect appressorial turgor pressure in C. gloeosporioides.

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Differential Activation of Ammonium Transporters During the Accumulation of Ammonia by Colletotrichum gloeosporioides and Its Effect on Appressoria Formation and Pathogenicity

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-07-12-0170-r ◽

2013 ◽

Vol 26 (3) ◽

pp. 345-355 ◽

Cited By ~ 31

Author(s):

Chen Shnaiderman ◽

Itay Miyara ◽

Ilana Kobiler ◽

Amir Sherman ◽

Dov Prusky

Keyword(s):

Gene Disruption ◽

Colletotrichum Gloeosporioides ◽

Ammonium Transporter ◽

Ammonium Transport ◽

Wild Type ◽

Ammonia Accumulation ◽

Ammonium Transporters ◽

Avocado Fruit ◽

Appressoria Formation ◽

Encoding Genes

Ammonium secreted by the post-harvest pathogen Colletotrichum gloeosporioides during host colonization accumulates in the host environment due to enhanced fungal nitrogen metabolism. Two types of ammonium transporter-encoding genes, AMET and MEP, are expressed during pathogenicity. Gene disruption of AMET, a gene modulating ammonia secretion, showed twofold reduced ammonia secretion and 45% less colonization on avocado fruit, suggesting a contribution to pathogenicity. MEPB, a gene modulating ammonium transport, is expressed by C. gloeosporioides during pathogenicity and starvation conditions in culture. Gene disruption of MEPB, the most highly expressed gene of the MEP family, resulted in twofold overexpression of MEPA and MEPC but reduced colonization, suggesting MEPB expression's contribution to pathogenicity. Analysis of internal and external ammonia accumulation by ΔmepB strains in mycelia and germinated spores showed rapid uptake and accumulation, and reduced secretion of ammonia in the mutant versus wild-type (WT) strains. Ammonia uptake by the WT germinating spores but not by the ΔmepB strain with compromised ammonium transport activated cAMP and transcription of PKA subunits PKAR and PKA2. ΔmepB mutants showed 75% less appressorium formation and colonization than the WT, which was partially restored by 10 mM exogenous ammonia. Thus, whereas both AMET and MEPB genes modulate ammonia secretion, only MEPB contributes to ammonia accumulation by mycelia and germinating spores that activate the cAMP pathways, inducing the morphogenetic processes contributing to C. gloeosporioides pathogenicity.

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GcSTUA, an APSES Transcription Factor, Is Required for Generation of Appressorial Turgor Pressure and Full Pathogenicity of Glomerella cingulata

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-9-1102 ◽

2007 ◽

Vol 20 (9) ◽

pp. 1102-1111 ◽

Cited By ~ 28

Author(s):

XingZhang Tong ◽

Xiuwen Zhang ◽

Kim M. Plummer ◽

Kathryn M. Stowell ◽

Patrick A. Sullivan ◽

...

Keyword(s):

Magnaporthe Grisea ◽

Turgor Pressure ◽

Apple Fruit ◽

Wild Type ◽

Glomerella Cingulata ◽

Reproductive Structures ◽

Aerial Hyphae ◽

Genes Encoding ◽

Visible Lesion ◽

Onion Epidermal Cells

Glomerella cingulata, which infects a number of different hosts, gains entry to the plant tissue by means of an appressorium. Turgor pressure generated within the appressorium forces a penetration peg through the plant cuticle. A visible lesion forms as the fungus continues to grow within the host. A G. cingulata homolog (GcSTUA) of the genes encoding Asm1, Phd1, Sok2, Efg1, and StuA transcription factors in Magnaporthe grisea and other fungi was cloned and shown to be required for infection of intact apple fruit and penetration of onion epidermal cells. Mobilization of glycogen and triacylglycerol during formation of appressoria by the GcSTUA deletion mutant appeared normal and melanization of the maturing appressoria was also indistinguishable from that of the wild type. However, GcSTUA was essential for the generation of normal turgor pressure within the appressorium. As is the case for its homologs in other fungi, GcSTUA also was required for the formation of aerial hyphae, efficient conidiation, and the formation of perithecia (sexual reproductive structures).

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CgEnd3 Regulates Endocytosis, Appressorium Formation, and Virulence in the Poplar Anthracnose Fungus Colletotrichum gloeosporioides

International Journal of Molecular Sciences ◽

10.3390/ijms22084029 ◽

2021 ◽

Vol 22 (8) ◽

pp. 4029

Author(s):

Xiaolian Wang ◽

Dongxiao Lu ◽

Chengming Tian

Keyword(s):

Cell Wall ◽

Calcium Signaling ◽

Colletotrichum Gloeosporioides ◽

Early Stage ◽

Turgor Pressure ◽

Cell Wall Integrity ◽

Economic Losses ◽

Appressorium Formation ◽

Independent Manner ◽

Penetration Ability

The hemibiotrophic ascomycete fungus Colletotrichum gloeosporioides is the causal agent of anthracnose on numerous plants, and it causes considerable economic losses worldwide. Endocytosis is an essential cellular process in eukaryotic cells, but its roles in C. gloeosporioides remain unknown. In our study, we identified an endocytosis-related protein, CgEnd3, and knocked it out via polyethylene glycol (PEG)-mediated protoplast transformation. The lack of CgEnd3 resulted in severe defects in endocytosis. C. gloeosporioides infects its host through a specialized structure called appressorium, and ΔCgEnd3 showed deficient appressorium formation, melanization, turgor pressure accumulation, penetration ability of appressorium, cellophane membrane penetration, and pathogenicity. CgEnd3 also affected oxidant adaptation and the expression of core effectors during the early stage of infection. CgEnd3 contains one EF hand domain and four calcium ion-binding sites, and it is involved in calcium signaling. A lack of CgEnd3 changed the responses to cell-wall integrity agents and fungicide fludioxonil. However, CgEnd3 regulated appressorium formation and endocytosis in a calcium signaling-independent manner. Taken together, these results demonstrate that CgEnd3 plays pleiotropic roles in endocytosis, calcium signaling, cell-wall integrity, appressorium formation, penetration, and pathogenicity in C. gloeosporioides, and it suggests that CgEnd3 or endocytosis-related genes function as promising antifungal targets.

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The Melanin Biosynthesis Genes of Alternaria alternata Can Restore Pathogenicity of the Melanin-Deficient Mutants of Magnaporthe grisea

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1997.10.4.446 ◽

1997 ◽

Vol 10 (4) ◽

pp. 446-453 ◽

Cited By ~ 64

Author(s):

Chie Kawamura ◽

Jouji Moriwaki ◽

Norio Kimura ◽

Yasunari Fujita ◽

Shin-ichi Fuji ◽

...

Keyword(s):

Alternaria Alternata ◽

Magnaporthe Grisea ◽

Phytopathogenic Fungi ◽

The Other ◽

Melanin Synthesis ◽

Melanin Biosynthesis ◽

Polyketide Biosynthesis ◽

Host Penetration ◽

Appressorium Development

The phytopathogenic fungi Magnaporthe grisea and Alternaria alternata produce melanin via the polyketide biosynthesis, and both fungi form melanized colonies. However, the site of melanin deposition and the role of melanin in pathogenicity differ between these two fungi. M. grisea accumulates melanin in appressoria, and their melanization is essential for host penetration. On the other hand, A. alternata produces colorless appressoria, and melanin is not relevant to host penetration. We examined whether the melanin biosynthesis genes of A. alternata could complement the melanin-deficient mutations of M. grisea. Melanin-deficient, nonpathogenic mutants of M. grisea, albino (Alb¯), rosy (Rsy¯), and buff (Buf¯), were successfully transformed with a cosmid clone pMBR1 that carries melanin biosynthesis genes ALM, BRM1, and BRM2 of A. alternata. This transformation restored the melanin synthesis of the Alb¯ and Buf¯ mutants, but not that of the Rsy¯ mutant. The melanin-restored transformants regained mycelial melanization, appressorium melanization, and pathogenicity to rice. Further, transformation of Alb¯ and Buf¯ mutants with subcloned ALM and BRM2 genes, respectively, also produced melanin-restored transformants. These results indicate that the Alternaria genes ALM and BRM2 can restore pathogenicity to the mutants Alb¯ and Buf¯, respectively, due to their function during appressorium development in M. grisea.

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Genetic Relationships in the Toxin-Producing Fungal Endophyte, Alternaria oxytropis Using Polyketide Synthase and Non-Ribosomal Peptide Synthase Genes

Journal of Fungi ◽

10.3390/jof7070538 ◽

2021 ◽

Vol 7 (7) ◽

pp. 538

Author(s):

Rebecca Creamer ◽

Deana Baucom Hille ◽

Marwa Neyaz ◽

Tesneem Nusayr ◽

Christopher L. Schardl ◽

...

Keyword(s):

Amino Acid ◽

Polyketide Synthase ◽

Genetic Relationships ◽

Protein Sequences ◽

Fungal Endophyte ◽

Melanin Synthesis ◽

Melanin Biosynthesis ◽

Protein Levels ◽

Oxytropis Sericea ◽

And Function

The legume Oxytropis sericea hosts a fungal endophyte, Alternaria oxytropis, which produces secondary metabolites (SM), including the toxin swainsonine. Polyketide synthase (PKS) and non-ribosomal peptide synthase (NRPS) enzymes are associated with biosynthesis of fungal SM. To better understand the origins of the SM, an unannotated genome of A. oxytropis was assessed for protein sequences similar to known PKS and NRPS enzymes of fungi. Contigs exhibiting identity with known genes were analyzed at nucleotide and protein levels using available databases. Software were used to identify PKS and NRPS domains and predict identity and function. Confirmation of sequence for selected gene sequences was accomplished using PCR. Thirteen PKS, 5 NRPS, and 4 PKS-NRPS hybrids were identified and characterized with functions including swainsonine and melanin biosynthesis. Phylogenetic relationships among closest amino acid matches with Alternaria spp. were identified for seven highly conserved PKS and NRPS, including melanin synthesis. Three PKS and NRPS were most closely related to other fungi within the Pleosporaceae family, while five PKS and PKS-NRPS were closely related to fungi in the Pleosporales order. However, seven PKS and PKS-NRPS showed no identity with fungi in the Pleosporales or the class Dothideomycetes, suggesting a different evolutionary origin for those genes.

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Behavior of a Wild-Type and Two Mutant Strains of Colletotrichum gloeosporioides f. sp. aeschynomene on Northern Jointvetch in the Field

Plant Disease ◽

10.1094/pdis.1998.82.4.374 ◽

1998 ◽

Vol 82 (4) ◽

pp. 374-379 ◽

Cited By ~ 4

Author(s):

Y. Luo ◽

D. O. TeBeest

Keyword(s):

Population Density ◽

Wild Type Strain ◽

Colletotrichum Gloeosporioides ◽

Biological Control Agent ◽

Field Tests ◽

The United States ◽

Control Agent ◽

Sampling Time ◽

Wild Type ◽

Mutant Strains

The fungus Colletotrichum gloeosporioides f. sp. aeschynomene causes an anthracnose on Aeschynomene virginica and has been used as a biological control agent to control this weed in the United States. The population dynamics of a wild-type strain (3-1-3) and two mutant strains of 3-1-3 of C. gloeosporioides f. sp. aeschynomene, a benomyl-resistant strain (B21) and nitrate-nonutilizing strain (Nit A), were studied in field tests on northern jointvetch in 1994 and 1995 to determine how the strains interacted on infected plants under field conditions. Plants were co-inoculated with strains 3-1-3 and B21, strains 3-1-3 and Nit A, and strains 3-1-3, B21, and Nit A at equal and unequal initial proportions. Plants were grown and maintained under flooded conditions in small wading pools. In co-inoculation of plants with 3-1-3 and B21 from equal initial proportions, the population of 3-1-3 increased slightly until it reached a proportion of 60 to 70%, whereas the population density of B21 reached 30 to 40% at the end of growing season. From unequal initial proportions, the population density of B21 decreased from 90 to about 50%, whereas the 3-1-3 increased from 10 to 50%. The population density of 3-1-3 increased from an equal initial proportion and was significantly greater than that of Nit A on every sampling time. From unequal initial proportions, the population density of 3-1-3 increased from 10 to 90%, whereas that of Nit A declined. In co-inoculation of plants with the three strains, the population density of 3-1-3 was significantly greater than those of the mutant strains at every sampling time. The proportions of mutant strains within the total population of C. gloeosporioides f. sp. aeschynomene on plants varied according to the test conditions and the number and types of strains co-inoculated.

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Royal Jelly Reduces Melanin Synthesis Through Down-Regulation of Tyrosinase Expression

The American Journal of Chinese Medicine ◽

10.1142/s0192415x11009536 ◽

2011 ◽

Vol 39 (06) ◽

pp. 1253-1260 ◽

Cited By ~ 9

Author(s):

Sang Mi Han ◽

Joo Hong Yeo ◽

Yoon Hee Cho ◽

Sok Cheon Pak

Keyword(s):

Royal Jelly ◽

Mrna Levels ◽

Dependent Manner ◽

Melanin Synthesis ◽

Mrna Transcription ◽

Down Regulation ◽

Melanin Biosynthesis ◽

Skin Whitening ◽

Key Enzyme ◽

Dose Dependent

For cosmetic reasons, the demand for effective and safe skin-whitening agents is high. Since the key enzyme in the melanin synthetic pathway is tyrosinase, many depigmenting agents in the treatment of hyperpigmentation act as tyrosinase inhibitors. In this study, we have investigated the hypo-pigmentary mechanism of royal jelly in a mouse melanocyte cell line, B16F1. Treatment of B16F1 cells with royal jelly markedly inhibited melanin biosynthesis in a dose-dependent manner. Decreased melanin content occurred through the decrease of tyrosinase activity. The mRNA levels of tyrosinase were also reduced by royal jelly. These results suggest that royal jelly reduces melanin synthesis by down-regulation of tyrosinase mRNA transcription and serves as a new candidate in the design of new skin-whitening or therapeutic agents.

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Histopathology of Colletotrichum gloeosporioides on guava fruits (Psidium guajava L.)

Revista Brasileira de Fruticultura ◽

10.1590/s0100-29452013000200039 ◽

2013 ◽

Vol 35 (2) ◽

pp. 657-664 ◽

Cited By ~ 14

Author(s):

Sylvia Raquel Gomes Moraes ◽

Francisco André Osama Tanaka ◽

Nelson Sidnei Massola Júnior

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Colletotrichum Gloeosporioides ◽

Psidium Guajava ◽

Mature Stage ◽

Guava Fruit ◽

Transmission Electron ◽

Colonization Process ◽

Parenchymal Cells ◽

Appressoria Formation

Anthracnose, caused by Colletotrichum gloeosporioides, produces brown lesions on guava fruits, causing severe losses on postharvest. In this study, the infection and colonization of guava fruits by C. gloeosporioides has been examined using scanning and transmission electron microscopy. Fruits at the physiologically mature stage were inoculated with a 10(5) conidia/mL spore suspension. Afterward, fruits were incubated at 25 °C in a wet chamber for periods of 6, 12, 24, 48, 96 and 120 h to allow examination of the infection and colonization process. Conidia germination and appressoria formation occurred six hours after inoculation (h.a.i). Penetration occurred directly via penetration pegs from appressoria, which penetrated the host cuticle 48 h.a.i. Notably, the appressoria did not produce an appressorial cone surrounding the penetration pore. Infection vesicles were found in epidermal cells 96 h.a.i. The same fungal structures were found in epidermal and parenchymal cells of the host 120 h.a.i. Colonization strategy of C. gloeosporioides on guava fruit was intracellular hemibiotrophic.

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