Steve Wylie

In March 2025, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote, newly proposed taxa were added to those under the mandate of the Plant Viruses Subcommittee. In brief, 1 new order, 3 new families, 6 new genera, 2 new subgenera and 206 new species were created. Some taxa were reorganized. Genus Cytorhabdovirus in the family Rhabdoviridae was abolished and its taxa were redistributed into three new genera Alphacytorhabdovirus , Betacytorhabdovirus and Gammacytorhabdovirus . Genus Waikavirus in the family Secoviridae was reorganized into two subgenera ( Actinidivirus and Ritunrivirus ). One family and four previously unaffiliated genera were moved to the newly established order Tombendovirales . Twelve species not assigned to a genus were abolished. To comply with the ICTV mandate of a binomial format for virus species, eight species were renamed. Demarcation criteria in the absence of biological information were defined in the genus Ilarvirus (family Bromoviridae ). This article presents the updated taxonomy put forth by the Plant Viruses Subcommittee and ratified by the ICTV.

The plant-infecting virus family Potyviridae was previously formed by 12 genera, consisting of 249 virus species, with the majority of these classified in the largest genus, Potyvirus. Potyvirids are viruses with a ssRNA genome packaged in long filamentous particles. While members of the genus Bymovirus have bipartite genomes, members of the remaining genera have monopartite genomes. All viruses in the family have a genome-linked protein (VPg) present at the 5' terminus of the genome, and all but celery latent virus (genus Celavirus) have a polyadenylated tail at the 3' end. The members of the 12 genera are differentiated by genomic sequence identity, various functional motifs, and biological factors such as the type of the transmission vector and host range. Demarcation criteria for a new genus include < 46% nucleotide sequence identity to potyvirids of other genera. Here, we report the new genus Phragmivirus within the family Potyviridae, which has been accepted by the International Committee on Taxonomy of Viruses, becoming the 13th genus in the family. The genus Phragmivirus is represented by two virus species (Phragmivirus phragmii and Phragmivirus spartinae). Complete genome sequences are available for both members, namely, common reed chlorotic stripe virus (CRCSV) and Spartina mottle virus (SpMV), respectively. The new genus name is derived from the botanical name of the host of CRCSV, Phragmites australis. The genome sequences of CRCSV and SpMV isolates resemble those of members of the genus Potyvirus but lack typical conserved aphid-transmission motifs.

Heat stress hampers plant growth and development, reduces yield and productivity, and thus threatens food security across the globe. Rice, one of the most widely consumed food crops in the world, is extremely sensitive to high-temperature stress: growth, yield, and production of rice are adversely affected. The development of thermotolerant rice varieties capable of adapting to a wide range of temperatures is an urgent need to feed the increasing population worldwide. CRISPR/Cas9 system has great potential to study gene function and generate crop varieties tolerant to multiple stresses. It has been used in a variety of crops to understand mechanisms underlying tolerance against abiotic stresses including heat stress. Here, we review applications of the CRISPR/Cas9 system aimed at exploring function of genes under heat stress in rice.

Cryptostylis ovata is a terrestrial orchid endemic to southwestern Australia. The virus status of C. ovata has not been studied. Eighty-three C. ovata samples from 16 populations were collected, and sequencing was used to identify RNA viruses from them. In one population, all tested plants were co-infected with isolates of the exotic-to-Australia viruses Ornithogalum mosaic virus (OrMV) and bean yellow mosaic virus (BYMV). In another population, one plant was infected with BYMV. No viruses were detected in the remaining populations. The OrMV isolate shared 98–99% nucleotide identity with isolates identified from wild indigenous Lachenalia (Iridaceae) plants in South Africa. This suggests that the source of OrMV in C. ovata may be one or more bulbous iridaceous flowering plants of southern African origin that were introduced to Western Australia as ornamentals and that have since become invasive weeds. One BYMV isolate from C. ovata also exhibited 99% nucleotide identity with strains isolated from the exotic leguminous crop Lupinus angustifolius in Western Australia, suggesting possible spillover to indigenous species from this source. This study with C. ovata highlights the probable role of invasive weeds and exotic crops as sources of exotic virus spillovers to indigenous plants.

The aim of this review is to summarize current advancements in the application of CRISPR to ameliorate allergenicity in plant-based foods. The literature on food allergens highlights the negative impacts on quality of life for many sufferers. Efforts to select low-allergenicity crop varieties through conventional means have had limited success. Here we review the literature describing gene editing to eliminate allergenicity genes and measure subsequent allergen expression. Gene editing is a means of inserting or deleting nucleotides at precise locations/genes in the genome, and the most widely used technology is CRISPR (clustered regularly interspaced short palindromic repeats) along with an endonuclease such as Cas9 (CRISPR/Cas9). An example are the α-amylase/trypsin inhibitors (ATIs) in wheat that are responsible for bakers' asthma. CRISPR was utilized to simultaneously knock down two ATI subunits, resulting in reduced expression of both subunits. Between 1.4 % and 4.5 % of children suffer from peanut allergy. Progress toward knock down of expression of genes encoding known allergens in peanuts is reviewed. Other allergenic plant species of interest in this review are soy and mustard. Gene editing has the potential to manipulate expression of allergen genes to reduce allergenicity, but as some allergens play important roles in physiological processes such as biotic and abiotic stress amelioration, simply targeting their genes with CRISPR to abolish expression is not always feasible.

Temperature stress is a factor limiting agricultural production in many regions. High and low temperatures can cause irreversible damage to plants, affecting the development and profitability of crops, and are a threat to national and global food security. Raising agricultural outputs by developing elite crop cultivars capable of coping with damaging environmental temperatures is a primary objective of plant breeders. Gene editing systems offer opportunities to rapidly develop improved cultivars. Gene editing has already been applied to several species to improve valuable traits, including yield, quality, nutritional values and tolerance to abiotic and biotic stresses. This review focuses on the recent progress and future potential of gene editing in developing new cultivars with greater heat and cold stress tolerance.

The diversity of mycoflora associated with grass and sedges belonging to 24 species of eight plant families inhabiting three regions of the Hyrcanian Forest in Iran was surveyed. Fungal isolates were recovered from the roots, stems and leaves of plants, and ITS sequences of ribosomal DNA were determined. The 113 fungal isolates were categorized into the lowest taxonomic rank possible. Surprisingly, pathogen-like fungi encompassed 34% of the endophytic isolates. Colletorichum, Fusarium, and Alternaria, all genera containing important pathogenic species, were abundant. Occurrence of Fusarium was highest in root tissues, while Colletotrichum appeared more dominant in leaves and stems. Wheat seedlings were exposed to inocula of 25 of these endophytic isolates. Eleven isolates inhibited growth of the seedlings, whereas 14 isolates promoted growth compared to uninoculated controls. Further, wheat seedlings treated with isolates reported as etiological agents such as Parastagonospora nodorum and Fusarium sp., promoted growth. We report first-time isolation of Darksidea sp., a genus of root-colonizing dark septate endophytes (DSE), from herbaceous vegetation of Hyrcanian forests of Iran.

Aconitum carmichaelii is a herbaceous herb indigenous to China that has been cultivated for traditional medicine for centuries. Virus-like symptoms of A. carmichaelii plants were observed on leaves in some A. carmichaelii plantations in Zhanyi and Wuding Counties, Yunnan Province, southwest China. High-throughput sequencing (HTS) was performed on 28 symptomatic plants, and the results revealed infection with 11 viruses, including 2 novel viruses and 9 previously described viruses: Aconitum amalgavirus 1 (AcoAV-1), aconite virus A (AcVA), cucumber mosaic virus (CMV), currant latent virus (CuLV), apple stem grooving virus (ASGV), chilli veinal mottle virus (ChiVMV), tomato spotted wilt orthotospovirus (TSWV), tobacco vein distorting virus (TVDV), and potato leafroll virus (PLRV). Two novel viruses tentatively named Aconitum potyvirus 1 and Aconitum betapartitivirus 1, were supported by sequence and phylogenetic analysis results of their genomes. We proposed the names Potyvirus aconiti and Betapartitivirus aconiti. RT-PCR assays of 142 plants revealed the predominance and widespread distribution of CMV, AcVA, and AcoPV-1 in plantations. The detection of isolates of CuLV, ASGV, ChiVMV, TSWV, TVDV, and PLRV infections for the first time in A. carmichaelii expands their known host ranges.