Planted forest health: The need for a global strategy Wingfield, M. J.; Brockerhoff, E. G.; Wingfield, B. D. ...
Science (American Association for the Advancement of Science),
08/2015, Letnik:
349, Številka:
6250
Journal Article
Recenzirano
Several key tree genera are used in planted forests worldwide, and these represent valuable global resources. Planted forests are increasingly threatened by insects and microbial pathogens, which are ...introduced accidentally and/or have adapted to new host trees. Globalization has hastened tree pest emergence, despite a growing awareness of the problem, improved understanding of the costs, and an increased focus on the importance of quarantine. To protect the value and potential of planted forests, innovative solutions and a better-coordinated global approach are needed. Mitigation strategies that are effective only in wealthy countries fail to contain invasions elsewhere in the world, ultimately leading to global impacts. Solutions to forest pest problems in the future should mainly focus on integrating management approaches globally, rather than single-country strategies. A global strategy to manage pest issues is vitally important and urgently needed.
The genus Ceratocystis was established in 1890 and accommodates many important fungi. These include serious plant pathogens, significant insect symbionts and agents of timber degradation that result ...in substantial economic losses. Virtually since its type was described from sweet potatoes, the taxonomy of Ceratocystis has been confused and vigorously debated. In recent years, particulary during the last two decades, it has become very obvious that this genus includes a wide diversity of very different fungi. These have been roughly lumped together due to their similar morphological structures that have clearly evolved through convergent evolution linked to an insect-associated ecology. As has been true for many other groups of fungi, the emergence of DNA-based sequence data and associated phylogenetic inferences, have made it possible to robustly support very distinct boundaries defined by morphological characters and ecological differences. In this study, DNA-sequence data for three carefully selected gene regions (60S, LSU, MCM7) were generated for 79 species residing in the aggregate genus Ceratocystis sensu lato and these data were subjected to rigorous phylogenetic analyses. The results made it possible to distinguish seven major groups for which generic names have been chosen and descriptions either provided or emended. The emended genera included Ceratocystis sensu stricto, Chalaropsis, Endoconidiophora, Thielaviopsis, and Ambrosiella, while two new genera, Davidsoniella and Huntiella, were described. In total, 30 new combinations have been made. This major revision of the generic boundaries in the Ceratocystidaceae will simplify future treatments and work with an important group of fungi including distantly related species illogically aggregated under a single name.
Genera of phytopathogenic fungi: GOPHY 2 Marin-Felix, Y.; Hernández-Restrepo, M.; Wingfield, M.J. ...
Studies in mycology,
03/2019, Letnik:
92, Številka:
1
Journal Article
Recenzirano
Odprti dostop
This paper represents the second contribution in the Genera of Phytopathogenic Fungi (GOPHY) series. The series provides morphological descriptions and information regarding the pathology, ...distribution, hosts and disease symptoms for the treated genera. In addition, primary and secondary DNA barcodes for the currently accepted species are included. This second paper in the GOPHY series treats 20 genera of phytopathogenic fungi and their relatives including: Allantophomopsiella, Apoharknessia, Cylindrocladiella, Diaporthe, Dichotomophthora, Gaeumannomyces, Harknessia, Huntiella, Macgarvieomyces, Metulocladosporiella, Microdochium, Oculimacula, Paraphoma, Phaeoacremonium, Phyllosticta, Proxypiricularia, Pyricularia, Stenocarpella, Utrechtiana and Wojnowiciella. This study includes the new genus Pyriculariomyces, 20 new species, five new combinations, and six typifications for older names.
Calonectria represents a genus of phytopathogenic ascomycetous fungi with a worldwide distribution. In recent years, there has been an increase in the number of taxonomic studies on these fungi. ...Currently, there are 169 described species of Calonectria based on comparisons of DNA sequence data, combined with morphological characteristics. However, for some of these species, the sequence data utilised at the time of their description were relatively limited. This has justified an urgent need to reconsider the species boundaries for Calonectria based on robust genus-wide phylogenetic analyses. In this study, we utilised 240 available isolates including the ex-types of 128 Calonectria species, and re-sequenced eight gene regions (act, cmdA, his3, ITS, LSU, rpb2, tef1 and tub2) for them. Sequences for 44 Calonectria species, for which cultures could not be obtained, were downloaded from GenBank. DNA sequence data of all the 169 Calonectria species were then used to determine their phylogenetic relationships. As a consequence, 51 species were reduced to synonymy, two new species were identified, and the name Ca. lauri was validated. This resulted in the acceptance of 120 clearly defined Calonectria spp. The overall data revealed that the genus includes 11 species complexes, distributed across the Prolate and Sphaero-Naviculate Groups known to divide Calonectria. The results also made it possible to develop a robust set of DNA barcodes for Calonectria spp. To accomplish this goal, we evaluated the outcomes of each of the eight candidate DNA barcodes for the genus, as well as for each of the 11 species complexes. No single gene region provided a clear identity for all Calonectria species. Sequences of the tef1 and tub2 genes were the most reliable markers; those for the cmdA, his3, rpb2 and act gene regions also provided a relatively effective resolution for Calonectria spp., while the ITS and LSU failed to produce useful barcodes for species discrimination. At the species complex level, results showed that the most informative barcodes were inconsistent, but that a combination of six candidate barcodes (tef1, tub2, cmdA, his3, rpb2 and act) provided stable and reliable resolution for all 11 species complexes. A six-gene combined phylogeny resolved all 120 Calonectria species, and revealed that tef1, tub2, cmdA, his3, rpb2 and act gene regions are effective DNA barcodes for Calonectria.
This paper is the fourth contribution in the Genera of Phytopathogenic Fungi (GOPHY) series. The series provides morphological descriptions and information about the pathology, distribution, hosts ...and disease symptoms, as well as DNA barcodes for the taxa covered. Moreover, 12 whole-genome sequences for the type or new species in the treated genera are provided. The fourth paper in the GOPHY series covers 19 genera of phytopathogenic fungi and their relatives, including Ascochyta , Cadophora , Celoporthe , Cercospora , Coleophoma , Cytospora , Dendrostoma , Didymella , Endothia , Heterophaeomoniella , Leptosphaerulina , Melampsora , Nigrospora , Pezicula , Phaeomoniella , Pseudocercospora , Pteridopassalora , Zymoseptoria , and one genus of oomycetes, Phytophthora . This study includes two new genera, 30 new species, five new combinations, and 43 typifications of older names.
The plant pathogenic asexual fungus Thielaviopsis basicola (Ascomycota) causes black root rot on many important agricultural and ornamental plant species. Since its first description in 1850, this ...species has had a tumultuous taxonomic history, being classified in many different genera. Thus far, DNA‐based techniques have not played a significant role in identification of T. basicola and have been used only to confirm its placement in the Microascales. This investigation reconsidered the phylogenetic placement of T. basicola, using DNA sequence data for six different gene regions. It included 41 isolates identified as T. basicola from 13 geographical locations worldwide. Phylogenetic analyses showed that these isolates grouped in a well‐supported lineage distinct from other genera in the Ceratocystidaceae, here described as Berkeleyomyces gen. nov. The data also provided robust evidence that isolates of T. basicola include a cryptic sister species. As a result, this report provides a new combination as B. basicola comb. nov. and introduces a new species as B. rouxiae sp. nov.
The pitch canker pathogen Fusarium circinatum has caused devastation to Pinus spp. in natural forests and non-natives in commercially managed plantations. This has drawn attention to the potential ...importance of Fusarium species as pathogens of forest trees. In this study, we explored the diversity of Fusarium species associated with diseased Pinus patula, P. tecunumanii, P. kesiya and P. maximinoi in Colombian plantations and nurseries. Plants displaying symptoms associated with a F. circinatum-like infection (i.e., stem cankers and branch die-back on trees in plantations and root or collar rot of seedlings) were sampled. A total of 57 isolates were collected and characterised based on DNA sequence data for the translation elongation factor 1-α and β-tubulin gene regions. Phylogenetic analyses of these data allowed for the identification of more than 10 Fusarium species. These included F. circinatum, F. oxysporum, species within the Fusarium solani species complex and seven novel species in the Fusarium fujikuroi species complex (formerly the Gibberella fujikuroi species complex), five of which are described here as new. Selected isolates of the new species were tested for their pathogenicity on Pinus patula and compared with that of F. circinatum. Of these, F. marasasianum, F. parvisorum and F. sororula displayed levels of pathogenicity to P. patula that were comparable with that of F. circinatum. These apparently emerging pathogens thus pose a significant risk to forestry in Colombia and other parts of the world.
Species of Calonectria are important plant pathogens, several of which have a worldwide distribution. Contemporary taxonomic studies on these fungi have chiefly relied on DNA sequence comparisons of ...the β-tubulin gene region. Despite many new species being described, there has been no phylogenetic synthesis for the group since the last monographic study almost a decade ago. In the present study, the identity of a large collection of Calonectria isolates from various geographic regions was determined using morphological and DNA sequence comparisons. This resulted in the discovery of seven new species; Ca. densa, Ca. eucalypti, Ca. humicola, Ca. orientalis, Ca. pini, Ca. pseudoscoparia and Ca. sulawesiensis, bringing the total number of currently accepted Calonectria species to 68. A multigene phylogeny was subsequently constructed for all available Calonectria spp., employing seven gene regions, namely actin, β-tubulin, calmodulin, histone H3, the internal transcribed spacer regions 1 and 2 and the 5.8S gene of the ribosomal RNA, 28S large subunit RNA gene and translation elongation 1-alpha. Based on these data 13 phylogenetic groups could be distinguished within the genus Calonectria that correlated with morphological features. Dichotomous and synoptic keys to all Calonectria spp. currently recognised are also provided.
Taxonomic novelties: New combinations -Calonectria angustata (Crous & El-Gholl) L. Lombard, M.J. Wingf. & Crous, Ca. australiensis (Crous & H.D. Hyde) L. Lombard, M.J. Wingf.& Crous, Ca. canadensis (J.C. Kang, Crous & C.L. Schoch) L. Lombard, M.J. Wingf. & Crous, Ca. chinensis (Crous) L. Lombard, M.J. Wingf. & Crous, Ca. citri (H.S. Fawc. & Klotz) L. Lombard, M.J. Wingf. & Crous, Ca. curvata (Boedijn & Reitsma) L. Lombard, M.J. Wingf. & Crous, Ca. curvispora (Crous & D. Victor) L. Lombard, M.J. Wingf. & Crous, Ca. ecuadoriae (Crous& M.J. Wingf.) L. Lombard, M.J. Wingf. & Crous, Ca. gordoniae (Leahy, T.S. Schub. & El-Gholl) L. Lombard, M.J. Wingf. & Crous, Calonectria hawksworthii (Peerally) L. Lombard, M.J. Wingf. & Crous, Calonectria hurae (Crous) L. Lombard, M.J. Wingf. & Crous, Calonectria indonesiae (Crous) L. Lombard, M.J. Wingf. & Crous, Ca. leucothoës (El-Gholl, Leahy & T.S. Schub.) L. Lombard, M.J. Wingf. & Crous, Ca. malesiana (Crous) L. Lombard, M.J. Wingf. & Crous, Ca. multiphialidica (Crous, Simoneau & Risède) L. Lombard, M.J. Wingf. & Crous, Ca. pacifica (J.C. Kang, Crous & C.L. Schoch) L. Lombard, M.J. Wingf. & Crous, Ca. penicilloides (Tubaki) L. Lombard, M.J. Wingf. & Crous, Ca. pseudonaviculata (Crous, J.Z. Groenew. & C.F. Hill) L. Lombard, M.J. Wingf. & Crous, Ca. sumatrensis (Crous) L. Lombard, M.J. Wingf. & Crous. New species -Ca. densa L. Lombard, M.J. Wingf. & Crous, Ca. eucalypti L. Lombard, M.J. Wingf. & Crous, Ca. humicola L. Lombard, M.J. Wingf. & Crous, Ca. orientalis L. Lombard, M.J. Wingf. & Crous, Ca. pini L. Lombard, M.J. Wingf. & Crous, Ca. pseudoscoparia L. Lombard, M.J. Wingf. & Crous, Ca. sulawesiensis L. Lombard, M.J. Wingf. & Crous.
The genus Elsinoe includes many aggressive plant pathogens that infect various economically important agricultural, horticultural and forestry plants. Significant diseases include citrus scab caused ...by E. fawcettii and E. australis, grapevine spot anthracnose by E. ampelina, and the emerging Eucalyptus scab and shoot malformation disease caused by the recently described E. necatrix. Despite their importance as plant pathogens, little is known regarding the biology of many Elsinoe spp. To gain insights into the reproductive biology of these fungi, we characterized the mating-type loci of seven species using whole genome sequence data. Results showed that the MAT1 locus organization and its flanking genes is relatively conserved in most cases. All seven species manifested a typical heterothallic mating system characterized by having either the MAT1-1 or MAT1-2 idiomorph present in an isolate. These idiomorphs were defined by the MAT1-1-1 or the MAT1-2-1 gene, respectively. A unique MAT1-1 idiomorph containing a truncated MAT1-2-1 gene, and a MAT1-1-1 gene, was identified in E. necatrix and E. fawcettii genomes. Additionally, two idiomorph-specific proteins were found in the MAT1-1 and MAT1-2 idiomorphs of E. australis. Universal mating-type markers confirmed heterothallism across 21 Elsinoe spp., are poised to advance future studies regarding the biology of these fungi.
The
and
genes are thought to be the master regulators of sexual development in most ascomycete fungi, and they are often essential for this process. In contrast, it has been suggested that the ...secondary mating-type genes act to calibrate the sexual cycle and can be dispensable. Recent functional characterization of genes such as Aspergillus fumigatus
Huntiella omanensis
, and Botrytis cinerea
has, however, shown that these secondary genes may play more central roles in the sexual pathway and are essential for the production of mature fruiting structures. We used a comparative transcriptome sequencing (RNA-seq) experiment to show that the truncation of
in the wood inhabiting
residing in the Ceratocystidaceae is associated with the differential expression of approximately 25% of all the genes present in the genome, including the transcriptional regulators
,
,
,
,
, and
. This suggests that MAT1-2-7 may act as a transcription factor and that Δ
mutant sterility is the result of layered deregulation of a variety of signaling and developmental pathways. This study is one of only a few that details the functional characterization of a secondary
gene in a nonmodel species. Given that this gene is present in other Ceratocystidaceae species and that there are diverse secondary
genes present throughout the Pezizomycotina, further investigation into this gene and others like it will provide a clearer understanding of sexual development in these eukaryotes.
Secondary mating-type genes are being described almost as quickly as new fungal genomes are being sequenced. Understanding the functions of these genes has lagged behind their description, in part due to limited taxonomic distribution, lack of conserved functional domains, and difficulties with regard to genetic manipulation protocols. This study aimed to address this by investigating a novel mating-type gene,
, for which two independent mutant strains were generated in a previous study. We characterized the molecular response to the truncation of this gene in a nonmodel, wood-infecting fungus and showed that it resulted in widespread differential expression throughout the transcriptome of this fungus. This suggests that secondary
genes may play a more important role than previously thought. This study also emphasizes the need for further research into the life cycles of nonmodel fungi, which often exhibit unique features that are very different from the systems understood from model species.
PDF
