Inquiries into Wheat Streak Mosaic Virus and Other WSM Associated Viruses

Wheat Streak Mosaic WSM) is a complex disease found to cause severe impact on wheat yield. Wheat streak mosaic virus (WSMV Triticum Mosaic Virus (TMV) and Wheat Mosaic Virus (WMOV) are all transmitted by Aceria tosichella, the wheat cun mite, and have been reported as the viruses associated with WSM. There is a research project on the genetic composition of the associated viruses as well as determining any novel viruses that may be involved in the disease. The process has begun with the virus assessment of neid samples by RT-PCR and sanger Sequencing in a different study, the potential of a common Insect in wheat fields. Rhopalosiphum padi, the Bird cherry oat aphid, to be a vector for WSMV was Investigated. R. Daar was found to be not a vector of WSMV through RT-PCR. The other proiect screened some wid-relative wheat plants for WSMV resistance Various lines of Aeglos tauschii, a landrace wheat, were tested for viral resistance by assessing the viral copy number by RT-PCR. The Initial result has demonstrated that one of the four selected lines may have promising tolerance The preliminary tests performed for each Inquiry provides Insight to Improving the respective experiment design for further understanding of how concerned parties such as farmers may better combat the disease

Metagenomics Analysis of the Wheat Virome Identifies Novel Plant and Fungal-Associated Viral Sequences

Wheat viruses including wheat streak mosaic virus, Triticum mosaic virus, and barley yellow dwarf virus cost substantial losses in crop yields every year. Although there have been extensive studies conducted on these known wheat viruses, currently, there is limited knowledge about all components of the wheat (Triticum aestivum L.) virome. Here, we determined the composition of the wheat virome through total RNA deep sequencing of field-collected leaf samples. Sequences were de novo assembled after removing the host reads, and BLASTx searches were conducted. In addition to the documented wheat viruses, novel plant and fungal-associated viral sequences were identified. We obtained the full genome sequence of the first umbra-like associated RNA virus tentatively named wheat umbra-like virus in cereals. Moreover, a novel bi-segmented putative virus tentatively named wheat-associated vipovirus sharing low but significant similarity with both plant and fungal-associated viruses was identified. Additionally, a new putative fungal-associated tobamo-like virus and novel putative Mitovirus were discovered in wheat samples. The discovery and characterization of novel viral sequences associated with wheat is important to determine if these putative viruses may pose a threat to the wheat industry or have the potential to be used as new biological control agents for wheat pathogens either as wild-type or recombinant viruses

Evolutionary studies of wheat streak mosaic-associated viruses and characterization of the wheat virome

Master of ScienceDepartment of Plant PathologyShahideh NouriWheat viruses including Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV), High Plains wheat mosaic emaravirus (HPWMoV), and Barley yellow dwarf virus (BYDV) cost substantial losses in crop yields annually. Although there have been extensive studies conducted on known wheat viruses, currently, there is limited knowledge about all viral components associated with wheat (Triticum aestivum L.) including potential novel viruses. Wheat streak mosaic (WSM), a disease of cereals and grasses, costs Kansas farmers millions in yield losses. Although WSMV is considered as the main causal agent of WSM, TriMV and HPWMoV have also been reported in mixed infections. While resistant varieties are utilized to minimize the effects of the disease, genetic variation in associated viruses increases the emergence of potential resistance-breaking isolates. Currently, little is known about the genetic composition of populations of WSM-associated viruses in the field. This study first aims to analyze the genetic variation and characterize the evolutionary mechanism(s) applied by WSM-associated viruses in the field using complete genomes sequences, and also to determine and characterize all viral populations associated with wheat. Field collections of 24 WSM-like symptomatic and asymptomatic wheat samples were used for total RNA deep sequencing, along with 5 historic WSMV samples for the evolutionary studies. Through bioinformatics analysis, sequences were mapped to available reference genomes and de novo assembled to identify new viruses. Results of the 2019 field survey showed WSMV as the predominant virus followed by mixed infections of WSMV+TriMV. Recombination was observed to be a major evolutionary force for WSMV but not for TriMV isolates. Phylogenetic analyses based on the obtained full genome sequences demonstrated that, unlike other isolates from the United States, Kansas isolates are widely distributed in sub-clades. Moreover, the phylogenetic studies suggested that TriMV field isolates may be under selection pressure to introduce genetic variations due to the use of resistant varieties in the fields. The full genome sequence of a new Kansas HPWMoV isolate was reported here. In addition to known wheat viruses, viral sequences sharing significantly low (<40%) similarity with potyviruses and recently discovered virga-like viruses were identified. Our analysis showed that these viral sequences belong to a novel putative virus tentatively named Wheat-associated vipovirus (WaVPV). Additionally, fungal-associated viruses, such as Mitovirus, were also identified. The findings of this study provide a better understanding of the current status of the genetic structure of WSM-associated viruses in Kansas fields. This, in turn, can aid in developing efficient and durable disease control strategies. The discovery and characterization of novel viruses potentially associated with wheat is important to determine if they may pose a threat to the wheat industry or have the potential to be used as new biological control agents for wheat pathogens

Full Genome Evolutionary Studies of Wheat Streak Mosaic-Associated Viruses Using High-Throughput Sequencing

&lt;jats:p&gt;Wheat streak mosaic (WSM), a viral disease affecting cereals and grasses, causes substantial losses in crop yields. Wheat streak mosaic virus (WSMV) is the main causal agent of the complex, but mixed infections with Triticum mosaic virus (TriMV) and High plains wheat mosaic emaravirus (HPWMoV) were reported as well. Although resistant varieties are effective for the disease control, a WSMV resistance-breaking isolate and several potential resistance-breaking isolates have been reported, suggesting that viral populations are genetically diverse. Previous phylogenetic studies of WSMV were conducted by focusing only on the virus coat protein (CP) sequence, while there is no such study for either TriMV or HPWMoV. Here, we studied the genetic variation and evolutionary mechanisms of natural populations of WSM-associated viruses mainly in Kansas fields and fields in some other parts of the Great Plains using high-throughput RNA sequencing. In total, 28 historic and field samples were used for total RNA sequencing to obtain full genome sequences of WSM-associated viruses. Field survey results showed WSMV as the predominant virus followed by mixed infections of WSMV + TriMV. Phylogenetic analyses of the full genome sequences demonstrated that WSMV Kansas isolates are widely distributed in sub-clades. In contrast, phylogenetic analyses for TriMV isolates showed no significant diversity. Recombination was identified as the major evolutionary force of WSMV and TriMV variation in KS fields, and positive selection was detected in some encoding genomic regions in the genome of both viruses. Furthermore, the full genome sequence of a second Kansas HPWMoV isolate was reported. Here, we also identified previously unknown WSMV isolates in the Great Plains sharing clades and high nucleotide sequence similarities with Central Europe isolates. The findings of this study will provide more insights into the genetic structure of WSM-associated viruses and, in turn, help in improving strategies for disease management.&lt;/jats:p&gt

Metagenomics Analysis of the Wheat Virome Identifies Novel Plant and Fungal-Associated Viral Sequences

Wheat viruses including wheat streak mosaic virus, Triticum mosaic virus, and barley yellow dwarf virus cost substantial losses in crop yields every year. Although there have been extensive studies conducted on these known wheat viruses, currently, there is limited knowledge about all components of the wheat (Triticum aestivum L.) virome. Here, we determined the composition of the wheat virome through total RNA deep sequencing of field-collected leaf samples. Sequences were de novo assembled after removing the host reads, and BLASTx searches were conducted. In addition to the documented wheat viruses, novel plant and fungal-associated viral sequences were identified. We obtained the full genome sequence of the first umbra-like associated RNA virus tentatively named wheat umbra-like virus in cereals. Moreover, a novel bi-segmented putative virus tentatively named wheat-associated vipovirus sharing low but significant similarity with both plant and fungal-associated viruses was identified. Additionally, a new putative fungal-associated tobamo-like virus and novel putative Mitovirus were discovered in wheat samples. The discovery and characterization of novel viral sequences associated with wheat is important to determine if these putative viruses may pose a threat to the wheat industry or have the potential to be used as new biological control agents for wheat pathogens either as wild-type or recombinant viruses