Development of Nested PCR, Multiplex PCR, and Loop-Mediated Isothermal Amplification Assays for Rapid Detection of Cylindrocladium scoparium on Eucalyptus

Advanced rDNA-Based Detection of Wheat Pathogens in Grain Samples Using Next-Generation Sequencing (NGS)

High-throughput sequencing (HTS) has revolutionized phytopathology by overcoming many limitations of traditional diagnostic methods, as it permits precise pathogen monitoring, identification, and control, with ribosomal DNA (rDNA) regions serving as reliable markers for fungal classification. In this study, next-generation sequencing (NGS) was used, targeting the ITS1 and ITS2 regions to explore fungal diversity and pathogen presence in winter wheat grain samples and identifying 183 OTU sequences across 115 taxa. The ITS1 analysis yielded 249,743 reads, with Fusarium sp. (61%) as the dominant pathogenic taxon, followed by Sporobolomyces sp. (14%), Cladosporium sp. (3%), and other yeast-like or saprotrophic fungi, such as Cryptoccocus spp., F. wieringae, and B. alba. Sequencing of ITS1 also permitted the detection of F. acuminatum and the quarantine-regulated pathogens T. caries and T. triticoides. The ITS2 analysis produced 179,675 reads, with F. culmorum (47%) as the most abundant taxon, confirming significant grain contamination with this pathogen. Other frequently detected taxa included yeast-like fungi such as C. tephrensis (21%) and V. victoriae (13%), along with saprotrophic species like S. roseus and Davidella sp. ITS2 provided better resolution for the identification of Fusarium species by the detection of more pathogenic taxa associated with cereal diseases, including F. culmorum, as well as F. cerealis, F. poae, and F. tricinctum. The analysis revealed a diverse fungal community, including other pathogens such as A. porri, B. cinerea, and C. herbarum, as well as various non-pathogenic and saprotrophic fungal taxa. These findings underscore the complementary utility of ITS1 and ITS2 in profiling fungal diversity and detecting critical pathogens using HTS, highlighting the potential of these DNA regions for monitoring and managing cereal crop health.

Two new species of Scolecobasidium (Venturiales, Sympoventuriaceae) associated with true mangrove plants and S.terrestre comb. nov

Scolecobasidium is cosmopolitan and includes species that inhabit a wide range of ecosystems including soil, water, air, plant and cold-blooded vertebrates. During a fungal survey from mangrove, strains of Scolecobasidium occurring on leaf spots of true mangrove plants, Aegicerascorniculatum and Acanthusebracteatus, were isolated from Futian Mangrove in Shenzhen and the Qi'ao-Dangan Island Mangrove in Zhuhai, China. Unlike most species in Scolecobasidium that produce dark conidia, our strains are characterized by hyaline to pale brown conidia and inconspicuous thread-like sterigmata. Further detailed morphological comparison and multi-locus (LSU, ITS, tub2, tef1-α) phylogenetic analyses revealed these collections as two new taxa, namely S.acanthisp. nov. and S.aegiceratissp. nov. We further emend the generic description of Scolecobasidium, propose one new combination, S.terrestre comb. nov., and clarify the taxonomic status of S.constrictum.

Recent Advances in Molecular Diagnostics of Fungal Plant Pathogens: A Mini Review

Phytopathogenic fungal species can cause enormous losses in quantity and quality of crop yields and this is a major economic issue in the global agricultural sector. Precise and rapid detection and identification of plant infecting fungi are essential to facilitate effective management of disease. DNA-based methods have become popular methods for accurate plant disease diagnostics. Recent developments in standard and variant polymerase chain reaction (PCR) assays including nested, multiplex, quantitative, bio and magnetic-capture hybridization PCR techniques, post and isothermal amplification methods, DNA and RNA based probe development, and next-generation sequencing provide novel tools in molecular diagnostics in fungal detection and differentiation fields. These molecular based detection techniques are effective in detecting symptomatic and asymptomatic diseases of both culturable and unculturable fungal pathogens in sole and co-infections. Even though the molecular diagnostic approaches have expanded substantially in the recent past, there is a long way to go in the development and application of molecular diagnostics in plant diseases. Molecular techniques used in plant disease diagnostics need to be more reliable, faster, and easier than conventional methods. Now the challenges are with scientists to develop practical techniques to be used for molecular diagnostics of plant diseases. Recent advancement in the improvement and application of molecular methods for diagnosing the widespread and emerging plant pathogenic fungi are discussed in this review.

Venturiales

Members of Venturiales (Dothideomycetes) are widely distributed, and comprise saprobes, as well as plant, human and animal pathogens. In spite of their economic importance, the general lack of cultures and DNA data has resulted in taxa being poorly resolved. In the present study five loci, ITS, LSU rDNA, tef1, tub2 and rpb2 are used for analysing 115 venturialean taxa representing 30 genera in three families in the current classification of Venturiales. Based on the multigene phylogenetic analysis, morphological and ecological characteristics, one new family, Cylindrosympodiaceae, and eight new genera are described, namely Bellamyces, Fagicola, Fraxinicola, Fuscohilum,Neofusicladium, Parafusicladium, Pinaceicola and Sterila. In addition, 12 species are described as new to science, and 41 new combinations are proposed. The taxonomic status of 153 species have been re-evaluated with 20 species excluded from Venturiales. Based on this revision of Venturiales, morphological characteristics such as conidial arrangement (solitary or in chains) or conidiogenesis (blastic-solitary, sympodial or annellidic), proved to be significant at generic level. Venturia as currently defined represents a generic complex. Furthermore, plant pathogens appear more terminal in phylogenetic analyses within Venturiaceae and Sympoventuriaceae, suggesting that the ancestral state of Venturiales is most likely saprobic.