Characterisation of the mating-type loci in species of Elsinoe causing scab diseases.

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.

Complete genome sequence of a novel lytic phage of Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice.

Bacteriophage L522, which infects Xanthomonas oryzae pv. oryzae, was isolated from a paddy leaf sample collected in Long An province, Vietnam. The phage shows myovirus morphology based on transmission electron microscopy. It displays a latent period and burst size of approximately 3 h and 63 new virions per infected cell (PFU/infected cell), respectively. The genome of L522 is 44,497 bp in length, with 52% GC content. Of the 63 genes identified, functions were predicted for 26. No virulence or antibiotic-resistance genes were detected. The results of a BLASTn search showed similarity to a previously reported Xanthomonas phage, with 85% average nucleotide sequence identity and 87.15% query coverage. Thus, this L522 is a representative of a new species in the genus Xipdecavirus.

A novel species of Microsphaeropsis causing cankers on Rafnia amplexicaulis in South Africa.

Cankers leading to branch, stem and plant death were observed on the South African endemic Rafnia amplexicaulis (Fabaceae) in the Cederberg Wilderness Area, South Africa, during September 2021. Conidiomatal pycnidia were found developing on the cankers, and isolations consistently yielded a Microsphaeropsis species. Phylogenetic analysis based on partial nucleotide sequences of the internal transcribed spacers (ITS), the nuclear large subunit (LSU) and RNA polymerase II second largest subunit (RPB2) regions showed that the fungus represented an undescribed species. Based on the multigene phylogeny and morphological characteristics, we describe the species here as M. rafniae sp. nov. Pathogenicity tests and the fulfilment of Koch's postulates confirmed that M. rafniae sp. nov. is the cause of the cankers of R. amplexicaulis. Presently, this disease is known from a single location in South Africa, and further surveys are required to determine its distribution and relative importance. Citation: Paap T, Marincowitz S, Pham NQ, Roets F, Basson RJ, Wingfield BD, Oberlander K, Wingfield MJ (2023). A novel species of Microsphaeropsis causing cankers on Rafnia amplexicaulis in South Africa. Fungal Systematics and Evolution 12: 73-80. doi: 10.3114/fuse.2023.12.05.

Microfungi associated with dying Euphorbia mauritanica in South Africa and their relative pathogenicity.

Euphorbia mauritanica is a succulent shrub that is indigenous to South Africa and widely distributed throughout the country. Dying plants have been observed in their natural habitat in the Northern and Western Cape Provinces of South Africa in recent years. Stems displaying lesions were collected and the emerging cultures were identified based on ITS, LSU, ACT, RPB2, TEF1 and/or TUB2 sequence data. Four filamentous fungi were consistently observed and isolated. One was identified as Alanphillipsia (Ala.) aloes, and the other three were new to science and are described here as Cytospora euphorbiicola sp. nov., Nothomicrosphaeropsis namakwaensis sp. nov. and Austrophoma (Aus.) euphorbiae gen. et sp. nov. These new species and Ala. aloes were the most commonly encountered, and their pathogenicity was tested on E. mauritanica plants in a greenhouse trial. All four species gave rise to lesions that were significantly larger than those associated with the controls, but they were not significantly different to each other. Although the lesions associated with the inoculations were well-developed, they did not give rise to plant death, suggesting that they are not responsible for the large-scale die-off of E. mauritanica in the field. The primary cause of the death of E. mauritanica in the studied area remains unknown and could be due to environmental factors such as has been found with the die-off of Euphorbia ingens in South Africa. Citation: Marincowitz S, Pham NQ, Wingfield BD, Roets F, Wingfield MJ (2023). Microfungi associated with dying Euphorbia mauritanica in South Africa and their relative pathogenicity. Fungal Systematics and Evolution 12: 59-71. doi: 10.3114/fuse.2023.12.04.

Phytophthora acaciivora sp. nov. associated with dying Acacia mangium in Vietnam.

Acacia mangium plantations account for more than 50 % of the exotic plantations in Vietnam. A new black butt symptom was discovered in 2012, followed by the wilting sign in Acacia seedlings in Tuyen Quang Province. Isolations recovered two Phytophthora species, the well-known Acacia pathogen P. cinnamomi, and an unknown species. The new species is described here as Phytophthora acaciivora sp. nov. Phylogenetically this species resides in clade 2d and is most closely related to P. frigida. Phytophthora acaciivora is a heterothallic species, oospores are aplerotic and antheridia are amphigynous. It produces predominantly elongated ovoid, semi papillate, persistent sporangia, no hyphal swellings and no chlamydospores. Optimum temperature for the growth is 25-30 °C and the maximum temperature is over 37.5 °C. Studies are underway to determine the impact of this new species on Acacia plantations in Vietnam.

Interferon and ribavirin for patients with chronic hepatitis C who did not respond to previous interferon therapy: a meta-analysis of controlled and uncontrolled trials.

The efficacy of interferon (IFN) combined with ribavirin for the treatment of patients with hepatitis C who failed to respond to initial IFN therapy is not well established. The primary goal of this study was to perform a systematic review of the literature evaluating the efficacy of combination therapy in nonresponders. Studies were retrieved from MEDLINE, abstracts of scientific meetings, and review of the bibliographies of retrieved studies. Controlled trials were included in the primary analysis whereas uncontrolled trials and trials reported as abstracts were included for sensitivity analysis. The primary endpoints were biochemical and virologic response. A combined estimate of the odds ratio (OR) for each endpoint was obtained by using the random effects model. The number needed to treat (NNT) was calculated by taking the inverse of the pooled risk difference. Nine controlled trials (789 patients) were identified. Six months after treatment, the overall sustained biochemical and virologic responses to 24 weeks of combination therapy were 15.2% and 13.2% with a common OR of 3.8 (95% confidence interval [CI] 2.2-6.7) and 4.9 (95% CI 2.1-11.2) compared with patients treated with IFN monotherapy. The pooled risk difference for the sustained virologic response (SVR) to combination therapy was 7% (95% CI 2-13). The NNT was 14 (95% CI 8-50), suggesting that approximately 14 patients would need to be treated with 6 months of combination therapy for 1 patient to have a SVR. A number of variables were associated with a high response rate in individual studies. Sensitivity analysis of preliminary trials suggest a higher response rate with longer duration of therapy and non-type 1 genotypes.