Phytophthora Root and Collar Rot of Paulownia, a New Disease for Europe

Paulownia species are fast growing trees native to China, which are being grown in managed plantings in several European countries for the production of wood and biomasses. In 2018, wilting, stunting, leaf yellowing, and collapse, as a consequence of root and crown rot, were observed in around 40% of trees of a 2-year-old planting of Paulownia elongata × P. fortunei in Calabria (Southern Italy). Two species of Phytophthora were consistently recovered from roots, basal stem bark, and rhizosphere soil of symptomatic trees and were identified as Ph. nicotianae and Ph. palmivora on the basis of both morphological characteristics and phylogenetic analysis of rDNA ITS sequences. Koch’s postulates were fulfilled by reproducing the symptoms on potted paulownia saplings transplanted into infested soil or stem-inoculated by wounding. Both Phytophthora species were pathogenic and caused root rot and stem cankers. Even though P. palmivora was the only species recovered from roots of naturally infected plants, in pathogenicity tests through infested soil P. nicotianae was more virulent. This is the first report of Phytophthora root and crown rot of a Paulownia species in Europe. Strategies to prevent this emerging disease include the use of healthy nursery plants, choice of well-drained soils for new plantations, and proper irrigation management.

Pathogenicity, anastomosis groups, host range and genetic diversity of Rhizoctonia species isolated from soybean, pea and other crops in Alberta and Manitoba, Canada

Root rot is a common disease in soybean (<i>Glycine max</i>) and field pea (<i>Pisum sativum</i>), which restrain increased production in Canada. Sixty-seven isolates of <i>Rhizoctonia</i> were recovered from various diseased plants in Alberta, Canada along with three isolates from diseased soybean plants in Manitoba, Canada. According to their anastomosis behavior, 23 (32.9%) of the isolates were identified as anastomosis group (AG) 4 (AG4), 7 (10.0%) were AG2-1, 10 (14.3%) were AG2-2, 7 (10.0%) were AG5, 3 (4.3%) were AG-E and the AGs of the remaining 20 (28.6%) isolates could not be determined. Isolates belonging to AG4 produced typical symptoms of stem rot and root rot on seedlings of soybean and pea and were more aggressive than the AG2-1, AG2-2, AG5 and AG-E isolates. Selected isolates of AG4, AG2-1, AG2-2, AG5 and AG-E were to some degree able to infect common crops in Alberta, which included barley, canola, corn, faba bean, flax, lupin, lentil, pea, potato, soybean and wheat. The genetic variability among these isolates was evaluated using phylogenetic analysis based on the rDNA ITS sequences and inter-simple sequence repeat (ISSR) markers. For the ITS sequence analysis, a neighbour-joining tree was constructed using the PAUP program, which clustered the <i>Rhizoctonia</i> isolates into five groups (Groups I to V). However, no correlation was observed between AGs, locations, aggressiveness or host origins. For the ISSR analysis, 54 polymorphic ISSR patterns were identified, indicating a high level of diversity among the isolates.

Identification endophytic fungi of Nutgrass (Cyperus rotundus L.) as solubilizing phosphate and indole-3-acetic acid producers

Low phosphate content in the soil can cause insufficient plant needs. Besides, the endophytic fungi of nutgrass have the potential as a phosphate solvent and can produce IAA (Indole-3-Acetic Acid). This study aimed to determine the levels of solubilizing phosphate and production of IAA (Indole-3-Acetic Acid) by the endophytic fungi of nutgrass and to identify the isolates based on rDNA-ITS sequences. The methods used were the isolation of endophytic fungi, analysis of solubilizing levels of phosphate and IAA production, and molecular analysis with rDNA-ITS sequences. Results of isolation and purification, found five isolates coded URT1, URT2, URT3, URT4, and URT5. The endophytic fungi of nutgrass were able to solubilizing phosphate levels around 54.03 - 87.83 ppm, with the highest levels produced by URT4 isolate. IAA levels around 5.58 - 45.50 ppm, with the highest levels produced by URT1 isolate. Based on molecular analysis with rDNA-ITS sequences, it showed that URT4 had 97.42% similarity to Aspergillus tereus species, while UTR1 had 100% similarity to Fusarium oxyporum species. To conclude, the endophytic fungi of nutgrass from A. tereus and F. oxyporum species have high levels of solubilizing phosphate and IAA production so that they are potential candidates for biofertilizer.

Fungal species associated with apple Valsa canker in East Asia

Since its discovery more than 110 years ago, Valsa canker has emerged as a devastating disease of apple in East Asia. However, our understanding of this disease, particularly the identity of the causative agents, has been in a state of confusion. Here we provide a synopsis for the current understanding of Valsa canker and the taxonomy of its causal agents. We highlight the major changes concerning the identity of pathogens and the conflicting viewpoints in moving to “One Fungus = One Name” system for this group of fungal species. We compiled a list of 21 Cytospora species associated with Malus hosts worldwide and curated 12 of them with rDNA-ITS sequences. The inadequacy of rDNA-ITS in discriminating Cytospora species suggests that additional molecular markers, more intraspecific samples and robust methods are required to achieve reliable species recognition.

The Taxon Hypothesis Paradigm—On the Unambiguous Detection and Communication of Taxa

Here, we describe the taxon hypothesis (TH) paradigm, which covers the construction, identification, and communication of taxa as datasets. Defining taxa as datasets of individuals and their traits will make taxon identification and most importantly communication of taxa precise and reproducible. This will allow datasets with standardized and atomized traits to be used digitally in identification pipelines and communicated through persistent identifiers. Such datasets are particularly useful in the context of formally undescribed or even physically undiscovered species if data such as sequences from samples of environmental DNA (eDNA) are available. Implementing the TH paradigm will to some extent remove the impediment to hastily discover and formally describe all extant species in that the TH paradigm allows discovery and communication of new species and other taxa also in the absence of formal descriptions. The TH datasets can be connected to a taxonomic backbone providing access to the vast information associated with the tree of life. In parallel to the description of the TH paradigm, we demonstrate how it is implemented in the UNITE digital taxon communication system. UNITE TH datasets include rich data on individuals and their rDNA ITS sequences. These datasets are equipped with digital object identifiers (DOI) that serve to fix their identity in our communication. All datasets are also connected to a GBIF taxonomic backbone. Researchers processing their eDNA samples using UNITE datasets will, thus, be able to publish their findings as taxon occurrences in the GBIF data portal. UNITE species hypothesis (species level THs) datasets are increasingly utilized in taxon identification pipelines and even formally undescribed species can be identified and communicated by using UNITE. The TH paradigm seeks to achieve unambiguous, unique, and traceable communication of taxa and their properties at any level of the tree of life. It offers a rapid way to discover and communicate undescribed species in identification pipelines and data portals before they are lost to the sixth mass extinction.

Biodiversity of Entomopathogenic Fungi in the Soils of South China

The southern part of China, located in tropical and south subtropical areas has unique natural environments, but the distributions of entomopathogenic fungi (EFs) in the soil are not clear. In this research, 198 soil samples were collected from the four Provinces (Autonomous Region) of South China. The results indicated that a total of 292 fungal isolates were obtained from 176 soil samples. Then, based on the morphological and rDNA-ITS sequences analysis, 213 EFs isolates of 19 species in 12 genera were identified. Furthermore, Purpureocillium lilacinum with 75 isolates was recognized as the absolutely dominant EF species, while Isaria javanica, Metarhizium anisopliae, and Beauveria bassiana (respectively with 29, 26, and 26 isolates) were the richer species. The data also indicated that Guangxi Province has the best EFs diversity with the Shannon–Wiener index (SWI) of 2.29, the soils covered with grass had the best EFs diversity with the 2.14 SWI, while the orchard and fallow land had the lowest SWI of 1.52, which suggested that the diversity of plants and insects on ground, as well as the massive application of broad-spectrum fungicides, affect the EFs diversity in the soil. Finally, the rare species, Nectria mauritiicola and Scopulariopsis brumptii were first reported about their entomopathogenic activities against Bemisia tabaci. Our experiment will give new insights to the understanding of EFs distribution characteristics and their biodiversity conservation.

Hydnaceous fungi of China 7. Morphological and molecular characterization of Phellodon subconfluens sp. nov. from temperate, deciduous forests

A new hydnaceous fungus, Phellodon subconfluens, from northeast China, is described and illustrated based on morphological characteristics and rDNA ITS sequences. The new species is characterized by circular to flabelliform basidiocarps, a greyish buff, brownish orange to reddish brown and obscurely zonate pileal surface with white, incurved margins, a monomitic hyphal system with simple-septate, generative hyphae, and broadly ellipsoid to subglobose, thin-walled basidiospores with echinulate ornamentation. Molecular analysis confirms the phylogenetic position of the new species in Phellodon. The discriminating characters of the new species and closely related species are discussed.

Morphological and molecular evidence for the occurrence of Itajahya galericulata (Basidiomycota, Phallales) in India

Itajahya galericulata (Phallales, Phallaceae) was previously reported from several countries in South America and Africa. Recently we found I. galericulata in the city of Vadodara, Gujarat State, India. To verify its identity we studied its morphology and performed molecular phylogenetic analyses using nuclear rDNA LSU and mitochondrial ATP6 loci. Here we also provide nuclear rDNA ITS sequences for the Indian collection, since up to now no sequences of this region have been available for I. galericulata in GenBank. This study furnishes the first evidence for the occurrence of I. galericulata in India and in Asia as a whole.