Advanced Search. Search Menu. Article Navigation. Close mobile search navigation Article Navigation. Volume The role of soil-borne fungi in driving the coexistence of Pinus massoniana and Lithocarpus glaber in a subtropical forest via plant—soil feedback. Yumei Pan , Yumei Pan. College of Forestry, Beijing Forestry University.
Oxford Academic. Google Scholar. Zhongyuan Yao. Naili Zhang. Corresponding author. E-mail: zhangnaili bjfu. G F Veen Ciska. Revision requested:.
Corrected and typeset:. Select Format Select format. Permissions Icon Permissions. The results of fungal cultures compared by severity between fingernails and toenails in psoriatic nail patients. The association of onychomycosis and nail psoriasis remains unclear and sometimes contradictory, as observed from studies outlined in Table 3.
The clinical differentiation of psoriatic nails with onychomycosis can be challenging sometimes. Few of the previous studies reported that the prevalence of onychomycosis in patients with nail psoriasis did not differ significantly from the rate observed in the control group, whereas some other studies showed higher prevalence in the study group.
In the present study, NDMs were frequently discovered in more severely involved psoriatic toenails. These finding may be suggestive of contamination rather than true pathogens given the fact that the NDM species are widely distributed in the environment.
Yeasts were likely to be found more often in more severely involved psoriatic fingernails than in toenails probably owing to the fact that fingernails are more oftenly exposed to water than toenails. Bunyaratavej et al. Even though dermatophytes are a common cause of onychomycosis worldwide, this study did not find any dermatophyte-related onychomycosis.
Rapid growth of psoriatic nails may decrease the probability of fungal invasion of the nail plate. Increased expression of cytokine interleukin ILA may also play a significant role in defense mechanisms against extracellular bacterial and fungal infections, especially in psoriasis. There are a few limitations of this study.
First, this was not a case-control study as no healthy controls were recruited. Second, dermoscopic examinations for supportive evidence of clinical findings to distinguish onychomycosis from nail psoriasiswere not performed.
Third, this study also enrolled older cases of nail psoriasis who were previously treated with systemic immunosuppressive therapy, which may have increased the risk of overgrowth of organisms, especially yeasts.
A high rate of concomitant fungal infection, especially yeasts and NDMs, was found in patients with psoriatic nails. These organisms may be true pathogens that cause onychomycosis or their presence may reflect colonization, contamination, or concurrent infection in patients with nail psoriasis.
Interestingly, although N. Further prospective controlled studies are encouraged to confirm these findings and further elucidate the relationship between nail psoriasis and fungal infection. The authors gratefully acknowledge the patients who generously agreed to participate in this study.
National Center for Biotechnology Information , U. Indian Dermatol Online J. Author information Article notes Copyright and License information Disclaimer. Address for correspondence: Dr.
E-mail: moc. Received Jul; Accepted Feb. This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4. This article has been cited by other articles in PMC. Abstract Background: Nail involvement in psoriasis is often complicated by concomitant fungal infections. Results: Sixty-two patients 33 males, 29 females fulfilling the inclusion criteria were included in the study.
Conclusion: A high rate of concomitant fungal infections, especially yeasts and NDMs, was found in psoriatic nail patients. Keywords: Fingernails , fungal infection , nail psoriasis , prevalence , severity , Thailand , toenails. Introduction Psoriasis is one of the most common chronic inflammatory skin disease.
Materials and Methods Patients This retrospective study included patients with nail psoriasis aged 18 years or older with at least one fingernail and one toenail involvement who were treated at the Department of Dermatology, Siriraj Hospital from September to January Clinical examination Demographic data, including age, gender, occupation, underlying diseases, types of psoriasis, disease duration, and treatments, were recorded.
Mycological examinations The least and the most affected toenails and fingernails based on the minimum and maximum NAPSI score, respectively, were selected. Results Sixty-two patients 33 males, 29 females with a mean age of Open in a separate window. Out of the remaining 77 genes specifically upregulated in the coinoculation treatment compared with single-inoculation treatments, in host genotype COL, 15 of these were genes with a known function in different stages of mating in other fungal species Fig.
These genes were homologs of genes involved in: 1 pheromone perception; 2 encoded in MAT-loci HMG-box and RNA helicases ; 3 involved in MAPK pathways STE20 and Mkk2 ; 4 cell survival to pheromones; 5 formation of mating tubes; 6 meiosis; 7 sexual sporulation; and 8 mating regulators see Supplementary Note 6 for a detailed description of the 15 upregulated genes.
The graphs show normalized counts of transcripts that displayed significantly higher gene transcription in the coinoculation treatment with isolates B1 and DAOM together compared with the two single-inoculation treatments B1 or DAOM The number of genes reflects the genes that were found in common between 1 isolate DAOM vs.
Together, these results suggest that different stages of a putative mating response were elicited when two genetically different R. A previous study identified a putative MAT-locus in R.
However, no evidence has ever been presented demonstrating that HD transcription factors are only transcribed in the presence of two genetically different R. We did not find any reads mapping to HD2 Supplementary Fig. We identified different upregulated genes in the coinoculation treatment compared with both single-inoculation treatments among the three plant genotypes COL 79 genes, CM 26 genes, and BRA 13 genes; Fig.
We observed that compared with host genotype COL, fewer genes were specifically upregulated in the coinoculation treatments in host genotypes CM and BRA Each number reflects the genes that were found in common between 1 isolate DAOM vs. We observed that 26 genes were specifically upregulated in the coinoculation treatment with host genotype CM Supplementary File 8. Of these, 18 genes were differentially transcribed in the coinoculation treatment in both host genotypes CM and COL These genes included several that are known to be involved in mating and sexual reproduction in other fungi: the GBC The interaction between the two isolates in symbiosis with host genotype BRA resulted in the upregulation of 13 genes that were differentially transcribed between the coinoculation treatment compared with the two single-inoculations Supplementary File 9.
In summary, all the genes related to a putative fungal mating responses identified in host genotypes CM and BRA were detected in host genotype COL The results from the three host genotypes taken together represent the first demonstration of genes involved in several steps of a putative mating response in AMF Fig.
We identified homologs of genes involved in 1 pheromone reception, 2 survival to pheromones, 3 different pheromone response MAPK cascades, 4 encoded in MAT-locus, 5 mating regulation, 6 meiosis, 7 formation of the mating tube, and 8 sexual sporulation. We did not observe upregulation of homeodomains proposed on a putative R. We did not find upregulation of genes encoding the mating pheromones or those involved in plasmogamy, karyogamy, and recombination.
Genes in red were observed in the three host plant genotypes in the coinoculation treatment specifically. Few studies have evaluated genome-wide gene transcription during the mating response in Mucoromycota species. In order to understand if the list and number of activated genes obtained in this study was representative of the genes expected to be identified in coinoculation studies compared with single-inoculations, we compared the results found in this study to an experiment that compared gene transcription in a coinoculation treatment to a single-inoculation treatment in the Mucoromycotina species Rhizopus microsporus [ 54 ].
In that experiment, the authors identified a set of genes transcribed during confirmed mating in R. We evaluated the homology of the coinoculation-specific differentially transcribed genes in R. Some of these genes were common to both organisms but a number of genes were either activated in R. We analyzed SNPs in the R. We identified positions with no missing data across the samples, where isolate DAOM displayed the reference allele previously samples had been mapped to isolate DAOM and where isolate B1 displayed an alternative allele.
In total, we kept positions from transcripts found in plant genotype COL, positions in plant genotype BRA, and positions in plant genotype CM Supplementary File We observed for almost all the positions, independently of the host plant genotype, that isolate DAOM displayed the reference allele, isolate B1 displayed an alternative allele and the coinoculation samples displayed a combination of both reference and alternative alleles see Supplementary Fig.
We then combined all the positions together to make allele frequency distributions of each sample. We observed that the majority of positions in isolate DAOM displayed an allele frequency of 1, meaning that the majority of positions displayed the reference allele.
In contrast, the majority of positions in isolate B1 displayed an allele frequency of 0, meaning that the majority of positions displayed the alternative allele. Finally, we observed that the coinoculation samples displayed intermediate levels of allele frequency confirming that both isolates indeed coexisted in the coinoculation treatment Fig.
In contrast, in plant genotype CM, isolate B1 predominantly colonized the plant roots in the ratio in one sample and in the second sample of isolate DAOM to B1, respectively Fig. Thus, we observed a more even coexistence in host genotype COL, where the greatest number of specifically upregulated genes where detected.
We plotted the allele frequency distribution of the reference and alternative allele in the single-inoculation and the coinoculation samples.
In contrast, the coinoculation samples display different proportions of each isolate represented by the peak of the distribution. We used an experimental approach to identify AM fungal genes that were exclusively transcribed in planta when two genetically different R. We did not observe any concordant plant growth response to the coinoculation treatments. However, we observed several fungal genes that were differentially transcribed in the coinoculation treatments compared with the single-inoculations.
Some of these genes specifically upregulated on the coinoculation treatments were known to be involved in different steps of mating or sexual reproduction in other fungi organisms. This represents the only known AMF genes that are specifically upregulated when two genetically different isolates of the same AMF species coexist in planta.
Second, we observed specific upregulation of several genes involved in different steps of the fungal mating response pheromone receptors, MAPK cascades, formation of conjugation tube, meiosis, and sexual sporulation.
Third, we observed that differences in the number of upregulated genes found among different host plant genotypes could be explained by the coexistence of the two fungi inside roots. The upregulation of these genes in the coinoculation treatment compared with the single-inoculations suggests that different parts of the molecular machinery of a putative mating response could be elicited by AMF.
A limitation of this study is that the functions of the upregulated genes were obtained based on homology and sequence comparison to other fungal model species. An appropriate approach to identify gene function in AMF would be to use reverse genetics methods such as host-induced gene silencing [ 55 ]. However, because of the heavy amount of work to develop these reverse genetics approaches, homology comparison is a good compromise to predict the function of a large number of genes.
The genes induced in coexistence in this study are homologs of genes involved in sexual reproduction in different fungal taxa. The comparison of this gene set to R. However, a similar number of genes of this gene set were expressed in R.
However, differences in the activation of genes involved in sexual reproduction between species of different taxa are common, as different taxon groups can share and have different genes related to sexual reproduction [ 54 ]. In consequence, it is not surprising that few genes induced in coexistence were shared between these two species from different phyla. The results observed in the three host plant genotypes suggest that the mating response was further developed in host genotype COL compared with the two other host plant genotypes.
In addition, it highlights a high conservation of the activation of five genes that were upregulated in the coinoculation treatment compared with the single-inoculation treatment in all three hosts: the HMG-box GBC These latter five genes could be used as genetic markers of a putative mating response between AMF isolates. In this experiment, we were interested in the gene transcription response of nonself-interactions between two isolates of the same species coexisting inside the plant, without specifically looking for mating.
Remarkably, we were able to identify genes involved in different steps of a putative mating comprising pheromone reception, MAPK kinases, encoded on an MAT-locus, mating regulators, involved in formation of the mating tube, meiosis, and in sexual sporulation.
Although, the discoveries in this experiment suggest that different steps of a putative mating response were activated when two different isolates coexist, the experimental design used in this experiment is not suited to demonstrate that sexual reproduction is happening.
A final demonstration of sexual reproduction in AMF should include the identification of recombinant progeny after coexistence of two different isolates of the same AMF species. We identified two upregulated HMG-box genes in the coinoculation treatment compared with the single-inoculations that were homologs of the HMG-box encoded in the MAT-locus of Mucoromycotina species but we did not observe upregulation of HD genes encoded in the putative MAT-locus previously identified.
This is in contrast to species from the Mucoromycotina subphylum, where sex-determination is regulated by HMG-box transcription factors [ 29 ]. The existence of an HD as a sex-determination transcription factor in R. Two hypotheses could emerge from the results concerning sex-determination genes. First, it could be possible that the HD genes are not involved in mating and that HMG-box genes are involved in the mating when two genetically different individuals encounter each other.
An alternative hypothesis is that HD genes and HMG-box genes are both required for mating, but their induction occurs at different times following the meeting of two fungi. The lack of any evidence concerning transcription of HD genes located in the putative MAT-locus described by Ropars et al.
A unique feature of this study, compared with other studies on transcription of AM fungal genes involved in mating and sexual reproduction, is that we successfully detected the upregulation of genes that only occurred when two genetically different R. Most notably, we identified the activation of genes when the fungi coexist in planta.
Previous published studies focussed on transcriptional responses occurring when extra-radical hyphae of the two fungal individuals met in an in vitro culture system growing on a sterile artificial medium [ 36 ]. Although we did not test whether the activation of a putative mating response is only present in planta , it is possible that this mechanism also occurs in extra-radical mycelia. Anastomosis between different isolates of the same species has been shown to be rare, but more likely when the isolates are genetically similar than when they are genetically distant [ 11 ].
The two R. These isolates have never been tested for extra-radical mycelia anastomosis, so it is possible that anastomosis could occur between these two isolates. Studies of coexistence between extra-radical mycelia of different AMF genotypes are still needed to better understand the nature of the putative mating response in R. In this experiment, we observed that the number of differentially transcribed genes in the coinoculation treatment was altered by host plant genotype.
When we looked at the presence of each isolate in the coinoculation treatment, we observed that coexistence was more even in host genotype COL In contrast, coexistence between the isolates was less evenly distributed towards dominance by one isolate in host genotypes CM and BRA It is likely that the activation of genes involved in a putative mating response could be influenced by the proportion of both coexisting fungi, where a more even distribution would maximize the signal and a less even distribution would decrease the signal.
Thus, we suspect that the small number of genes detected in host genotype CM and BRA were the result of an uneven colonization of both isolates. Several hypotheses could explain uneven colonization of the different isolates in the coinoculation samples.
First, it is possible that direct fungal competition or plant mediated competition could be responsible of the proportion of each isolate in the coinoculations [ 6 ]. It was previously experimentally demonstrated that both AM fungal and plant genetic re-programming in the symbiosis is strongly affected by the plant genotype [ 37 ]. Thus, the host genotype could influence faster growth of one of the fungal isolates, thus, giving rise to more uneven colonization of the two fungi than in other host genotypes.
An alternative hypothesis to explain the differences regarding which fungal genes were specifically upregulated in coinoculation treatments among host genotypes is that the host plant influences the recognition and subsequent mating between two isolates by providing the required conditions for the fungus. Evidence of a role of host plant derivatives on fungal traits was recently observed in R.
Population genetics studies of R. This study experimentally demonstrates that two different isolates of R. In consequence, this study represents an important step in the identification of the molecular mechanisms of recognition and mating in AMF. Our discovery of in planta activation of genes related to different stages of mating in R.
AMF are enormously important for plant growth and comprehending sex in these fungi is key for generating genetically diverse isolates having differential effects on plant growth that could lead to their more directed use in agriculture [ 59 ]. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability and productivity. Google Scholar. Mycorrhizal ecology and evolution: the past, the present, and the future.
N Phytol. A phylum-level phylogenetic classification of zygomycete fungi based on genome-scale data. Four hundred-million-year-old vesicular arbuscular mycorrhizae. Genetic variability in a population of arbuscular mycorrhizal fungi causes variation in plant growth. Ecol Lett. PubMed Google Scholar. Relatedness among arbuscular mycorrhizal fungi drives plant growth and intraspecific fungal coexistence.
ISME J. Sanders IR. Sex, plasticity, and biologically significant variation in one Glomeromycotina species. Evidence for the sexual origin of heterokaryosis in arbuscular mycorrhizal fungi.
Nat Microbiol. Ancient asexual scandals. Trends Ecol Evol. Anastomosis formation and nuclear and protoplasmic exchange in arbuscular mycorrhizal fungi. Appl Environ Microbiol. Nonself vegetative fusion and genetic exchange in the arbuscular mycorrhizal fungus Glomus intraradices. CAS Google Scholar. Patterns of below-ground plant interconnections established by means of arbuscular mycorrhizal networks. Different levels of hyphal self-incompatibility modulate interconnectedness of mycorrhizal networks in three arbuscular mycorrhizal fungi within the Glomeraceae.
Evidence for the evolution of multiple genomes in arbuscular mycorrhizal fungi. Bever JD, Morton J. Heritable variation and mechanism of inheritance of spore shape within a population of Scutellosporea pellucida , an arbuscular mycorrhi.
Am J Bot. A population genomics approach shows widespread geographical distribution of cryptic genomic forms of the symbiotic fungus Rhizophagus irregularis. Conserved meiotic machinery in Glomus spp. Genome Biol Evol. Genome of an arbuscular mycorrhizal fungus provides insight into the oldest plant symbiosis.
Proc Natl Acad Sci. Comparative genomics of Rhizophagus irregularis, R. Croll D, Sanders IR. Recombination in Glomus intraradices , a supposed ancient asexual arbuscular mycorrhizal fungus. BMC Evol Biol. Single nucleus sequencing reveals evidence of inter-nucleus recombination in arbuscular mycorrhizal fungi. Auxier B, Bazzicalupo A.
0コメント