Preliminary analysis of amplicon high-throughput sequencing as a method for the assessment of fungal diversity in discolored wood

Holzforschung ◽  
2017 ◽  
Vol 71 (10) ◽  
pp. 793-800 ◽  
Author(s):  
Xingxia Ma ◽  
Mingliang Jiang ◽  
Junliang Liu ◽  
Hao Deng ◽  
Shuangyong Wang

AbstractThe diversity of stain fungi is important if wood is inhabited with various fungi, and the discoloration mechanism will be better understood. MiSeq amplicon high-throughput sequencing (Illumina®) is able to detect species richness (the number of species within a community) and species evenness (the sizes of species populations within a community). This study detected fungal diversity in discolored Mongolian pine for the first time by the MiSeq approach, focusing on the nuclear ribosomal internal transcribed spacer-1 (ITS1). The results show that the discolored wood was inhabited by a combination of microorganisms, more than 90% of which belong toAscomycotafungi at the phylum level. The MiSeq method revealed not only all the inhabited fungal species but also their quantitative relation to each other. The dominant fungal species in sample A areHelotiales(34.1%) andHypocreales(20.7%). The dominant fungal species in sample B isNectriaceae(67.9%), whileHypocrea(34.7%) andSporothrix(27.6%) are the dominant fungal species in sample C. It was confirmed via core microbiome analysis that the following fungi were common stain fungi in the three discolored samples:Fusariumspp.,Aspergillusspp.,Sporothrixspp.,Penicilliumspp.,Trichodermaspp.,Alternariaspp. andCladophialophoraspp.

2017 ◽  
Vol 83 (17) ◽  
Author(s):  
Francesca De Filippis ◽  
Manolo Laiola ◽  
Giuseppe Blaiotta ◽  
Danilo Ercolini

ABSTRACT Target-gene amplicon sequencing is the most exploited high-throughput sequencing application in microbial ecology. The targets are taxonomically relevant genes, with 16S rRNA being the gold standard for bacteria. As for fungi, the most commonly used target is the internal transcribed spacer (ITS). However, the uneven ITS length among species may promote preferential amplification and sequencing and incorrect estimation of their abundance. Therefore, the use of different targets is desirable. We evaluated the use of three different target amplicons for the characterization of fungal diversity. After an in silico primer evaluation, we compared three amplicons (the ITS1-ITS2 region [ITS1-2], 18S ribosomal small subunit RNA, and the D1/D2 domain of the 26S ribosomal large subunit RNA), using biological samples and a mock community of common fungal species. All three targets allowed for accurate identification of the species present. Nevertheless, high heterogeneity in ITS1-2 length was found, and this caused an overestimation of the abundance of species with a shorter ITS, while both 18S and 26S amplicons allowed for more reliable quantification. We demonstrated that ITS1-2 amplicon sequencing, although widely used, may lead to an incorrect evaluation of fungal communities, and efforts should be made to promote the use of different targets in sequencing-based microbial ecology studies. IMPORTANCE Amplicon-sequencing approaches for fungi may rely on different targets affecting the diversity and abundance of the fungal species. An increasing number of studies will address fungal diversity by high-throughput amplicon sequencing. The description of the communities must be accurate and reliable in order to draw useful insights and to address both ecological and biological questions. By analyzing a mock community and several biological samples, we demonstrate that using different amplicon targets may change the results of fungal microbiota analysis, and we highlight how a careful choice of the target is fundamental for a thorough description of the fungal communities.


2020 ◽  
Vol 134 ◽  
pp. 349-358
Author(s):  
W.-H. Chen ◽  
S.-J. Wu ◽  
X.-L. Sun ◽  
K.-M. Feng ◽  
K. Rahman ◽  
...  

Plant Disease ◽  
2020 ◽  
Vol 104 (2) ◽  
pp. 330-339 ◽  
Author(s):  
Yi Ming Guan ◽  
Jin Chao Deng ◽  
Ying Ying Ma ◽  
Yu Li ◽  
Ya Yu Zhang

The utility of traditional methods for detecting seed-borne fungi is limited by the fact some fungi are unculturable or difficult to isolate. The seed-borne pathogens affecting Panax ginseng cultivation have not been fully characterized. Seed-borne fungi can be identified based on the high-throughput sequencing of internal transcribed spacer (ITS) amplicons. A hierarchical clustering tree diagram analysis based on operational taxonomic units revealed a relationship between the seed-borne fungi and the region from which the seeds were collected. This study analyzed the fungal diversity on 30 ginseng seed samples from the main ginseng-producing areas of China. The 50 most abundant genera were identified including those responsible for ginseng diseases, Fusarium, Alternaria, Nectria, Coniothyrium, Verticillium, Phoma, and Rhizoctonia. Fusarium species, which are the primary causes of root rot, were detected in all seed samples. The results of a phylogenetic analysis indicated that the seed-borne fungal species originating from the same region were closely related. Fungi on ginseng seeds from eight different regions were divided into eight clades, suggesting they were correlated with the local storage medium. A total of 518 Fusarium isolates were obtained and 10 species identified, all of which can be detrimental to ginseng production. Pathogenicity tests proved that seed-borne Fusarium species can infect ginseng seedlings and 2-year-old ginseng root, with potentially adverse effects on ginseng yield and quality.


Viruses ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 385 ◽  
Author(s):  
Asimina Katsiani ◽  
Varvara Maliogka ◽  
Nikolaos Katis ◽  
Laurence Svanella-Dumas ◽  
Antonio Olmos ◽  
...  

Little cherry virus 1 (LChV1, Velarivirus, Closteroviridae) is a widespread pathogen of sweet or sour cherry and other Prunus species, which exhibits high genetic diversity and lacks a putative efficient transmission vector. Thus far, four distinct phylogenetic clusters of LChV1 have been described, including isolates from different Prunus species. The recent application of high throughput sequencing (HTS) technologies in fruit tree virology has facilitated the acquisition of new viral genomes and the study of virus diversity. In the present work, several new LChV1 isolates from different countries were fully sequenced using different HTS approaches. Our results reveal the presence of further genetic diversity within the LChV1 species. Interestingly, mixed infections of the same sweet cherry tree with different LChV1 variants were identified for the first time. Taken together, the high intra-host and intra-species diversities of LChV1 might affect its pathogenicity and have clear implications for its accurate diagnostics.


2017 ◽  
Vol 92 (1) ◽  
Author(s):  
Xiaojuan Liu ◽  
Jing Jin ◽  
Ping Qiu ◽  
Fangluan Gao ◽  
Wenzhong Lin ◽  
...  

ABSTRACTMost segmented negative-sense RNA viruses employ a process termed cap snatching, during which they snatch capped RNA leaders from host cellular mRNAs and use the snatched leaders as primers for transcription, leading to the synthesis of viral mRNAs with 5′ heterogeneous sequences (HSs). With traditional methods, only a few HSs can be determined, and identification of their donors is difficult. Here, the mRNA 5′ ends ofRice stripe tenuivirus(RSV) andRice grassy stunt tenuivirus(RGSV) and those of their host rice were determined by high-throughput sequencing. Millions of tenuiviral HSs were obtained, and a large number of them mapped to the 5′ ends of corresponding host cellular mRNAs. Repeats of the dinucleotide AC, which are complementary to the U1G2of the tenuiviral template 3′-U1G2U3G4UUUCG, were found to be prevalent at the 3′ termini of tenuiviral HSs. Most of these ACs did not match host cellular mRNAs, supporting the idea that tenuiviruses use the prime-and-realign mechanism during cap snatching. We previously reported a greater tendency of RSV than RGSV to use the prime-and-realign mechanism in transcription with leaders cap snatched from a coinfecting reovirus. Besides confirming this observation in natural tenuiviral infections, the data here additionally reveal that RSV has a greater tendency to use this mechanism in transcribing genomic than in transcribing antigenomic templates. The data also suggest that tenuiviruses cap snatch host cellular mRNAs from translation- and photosynthesis-related genes, and capped RNA leaders snatched by tenuiviruses base pair with U1/U3or G2/G4of viral templates. These results provide unprecedented insights into the cap-snatching process of tenuiviruses.IMPORTANCEMany segmented negative-sense RNA viruses (segmented NSVs) are medically or agriculturally important pathogens. The cap-snatching process is a promising target for the development of antiviral strategies against this group of viruses. However, many details of this process remain poorly characterized. Tenuiviruses constitute a genus of agriculturally important segmented NSVs, several members of which are major viral pathogens of rice. Here, we for the first time adopted a high-throughput sequencing strategy to determine the 5′ heterogeneous sequences (HSs) of tenuiviruses and mapped them to host cellular mRNAs. Besides providing deep insights into the cap snatching of tenuiviruses, the data obtained provide clear evidence to support several previously proposed models regarding cap snatching. Curiously and importantly, the data here reveal that not only different tenuiviruses but also the same tenuivirus synthesizing different mRNAs use the prime-and-realign mechanism with different tendencies during their cap snatching.


2021 ◽  
Author(s):  
Alba Pérez-Cataluña ◽  
Álvaro Chiner-Oms ◽  
Enric Cuevas-Ferrando ◽  
Azahara Díaz-Reolid ◽  
Irene Falcó ◽  
...  

The use of SARS-CoV-2 metagenomics in wastewater can allow the detection of variants circulating at community level. After comparing with clinical databases, we identified three novel variants in the spike gene, and six new variants in the spike detected for the first time in Spain. We finally support the hypothesis that this approach allows the identification of unknown SARS-CoV-2 variants or detected at only low frequencies in clinical genomes.Abstract Figure


Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 666
Author(s):  
Phongeun Sysouphanthong ◽  
Naritsada Thongklang ◽  
Jian-Kui Liu ◽  
Else C. Vellinga

In our ongoing research on lepiotaceous taxa (Agaricaceae s.l.) in Laos and northern Thailand, we focus here on Chlorophyllum, Clarkeinda, Macrolepiota, Pseudolepiota, and Xanthagaricus. Collections were obtained from various habitats, including agricultural habitats, grasslands, and rainforests. A total of 12 taxa were examined and investigated. Of these 12, two are new for science; viz. Xanthagaricus purpureosquamulosus with brownish-grey to violet-brown squamules on a pale-violet to violet background; it shares the pileus color with X. caeruleus and X. ianthinus, but differs in other characters; and Macrolepiota excelsa, rather similar to M. procera but related toM. detersa. Two species, Pseudolepiota zangmui and Xanthagaricus necopinatus are recorded for the first time in Thailand. Four species of Chlorophyllum and a total of four species of Macrolepiota were found, viz., C. demangei and C. hortense with white basidiospores, C. molybdites and C. globosum with green basidiospores, M. detersa, M. dolichaula, the new M. excelsa, and M. velosa. Another rather common striking species is Clarkeinda trachodes, with yellow-green basidiospores. Each species is described in detail, with color photographs and line drawings. Phylogenetic analyses based on internal transcribed spacer (nrITS) region, the large subunit nuclear ribosomal (nrLSU) DNA and RNA polymerase II second largest subunit (rpb2) genes provide evidence for the placement of the species covered.


2021 ◽  
Vol 13 (13) ◽  
pp. 20118-20123
Author(s):  
Skarma Nonzom ◽  
Geeta Sumbali

A filamentous fungus Paecilomyces formosus (Eurotiales, Ascomycota) was detected for the first time from the region while surveying fungal diversity of a cold arid high-altitude pass (4,000 msl) located in Kargil district (Ladakh), India. The fungal isolate was characterized morphologically with camera lucida drawings and microphotographs, and identified using internal transcribed spacer (ITS) ribosomal DNA sequences. P. formosus has not been reported from India, or from arid/semi-arid/cold regions before, thus this represents a new record of Indian hot/cold desert mycoflora that is psychrotrophic in contrast to the more common thermophilic fungi.


2013 ◽  
Vol 79 (8) ◽  
pp. 2519-2526 ◽  
Author(s):  
Nicholas A. Bokulich ◽  
David A. Mills

ABSTRACTUltra-high-throughput sequencing (HTS) of fungal communities has been restricted by short read lengths and primer amplification bias, slowing the adoption of newer sequencing technologies to fungal community profiling. To address these issues, we evaluated the performance of several common internal transcribed spacer (ITS) primers and designed a novel primer set and work flow for simultaneous quantification and species-level interrogation of fungal consortia. Primer comparison and validation were predictedin silicoand by sequencing a “mock community” of mixed yeast species to explore the challenges of amplicon length and amplification bias for reconstructing defined yeast community structures. The amplicon size and distribution of this primer set are smaller than for all preexisting ITS primer sets, maximizing sequencing coverage of hypervariable ITS domains by very-short-amplicon, high-throughput sequencing platforms. This feature also enables the optional integration of quantitative PCR (qPCR) directly into the HTS preparatory work flow by substituting qPCR with these primers for standard PCR, yielding quantification of individual community members. The complete work flow described here, utilizing any of the qualified primer sets evaluated, can rapidly profile mixed fungal communities and capably reconstructed well-characterized beer and wine fermentation fungal communities.


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