Konya İli Marul Ekim Alanlarında Sorun Olan Virüs Hastalıklarının Belirlenmesi

Lettuce (Lactuca sativa L.) is a member of the family Compositae (Asteraceae). This plant, which is grown for its leaves, is grown in open field and greenhouse conditions almost everywhere in the world and in Turkey. With the present study virus diseases of lettuce and their prevalence in Konya province was revealed for the first time. For this purpose, leaf samples were taken from lettuce plants showing virus diseases symptoms with surveys carried out in Konya province lettuce planting areas from May to August in 2020. Then the collected lettuce leaf samples were tested in laboratory conditions by Double Antibody Sandwich Enzyme-linked Immunosorbent Assay (DAS-ELISA) method to reveal infections of Cucumber mosaic virus (CMV), Miraflori lettuce big vein virus (MiLBVV), Lettuce mosaic virus (LMV), and Tomato spotted wilt virus (TSWV). According to the information obtained from the results of the study, it was determined that 40 out of 97 (41.23%) lettuce plant samples and all (6) weed samples were infected with at least one of the viruses. In lettuce leaf samples; TSWV (27.83%), LMV (12.37%), CMV (10.31%) and MiLBVV (5.15%) infections have been detected. In weed samples; infections of CMV (83.33%), LMV (66.66%), and TSWV (50%) have been revealed. The infections of TSWV, LMV, CMV, and MiLBVV on lettuce plants in Konya province were reported firstly with the study.

Role of Sw5 gene cluster in the fight against plant viruses

The Sw5 gene cluster furnishes robust resistance to Tomato spotted wilt virus in tomato, which has led to its widespread applicability in agriculture. Among the five orthologs, Sw5b functions as a resistance gene against a broad-spectrum Tospovirus and is linked with Tospovirus resistance. However, its paralog, Sw5a, has been recently implicated in providing resistance against Tomato leaf curl New Delhi virus , broadening the relevance of the Sw5 gene cluster in promoting defense against plant viruses. We propose that plants have established modifications within the homologs of R genes that permit identification of different effector proteins and provide broad and robust resistance against different pathogens through activation of hypersensitive response and cell death.

Mining the Genome of Bacillus velezensis VB7 (CP047587) for MAMP Genes and Non-Ribosomal Peptide Synthetase Gene Clusters Conferring Antiviral and Antifungal Activity

Chemical pesticides have an immense role in curbing the infection of plant viruses and soil-borne pathogens of high valued crops. However, the usage of chemical pesticides also contributes to the development of resistance among pathogens. Hence, attempts were made in this study to identify a suitable bacterial antagonist for managing viral and fungal pathogens infecting crop plants. Based on our earlier investigations, we identified Bacillus amyloliquefaciens VB7 as a potential antagonist for managing Sclerotinia sclerotiorum infecting carnation, tobacco streak virus infecting cotton and groundnut bud necrosis infecting tomato. Considering the multifaceted action of B. amyloliquefaciens VB7, attempts were made for whole-genome sequencing to assess the antiviral activity against tomato spotted wilt virus infecting chrysanthemum and antifungal action against Fusarium oxysporum f. sp. cubense (Foc). Genome annotation of the isolate B. amyloliquefaciens VB7 was confirmed as B. velezensis VB7 with accession number CP047587. Genome analysis revealed the presence of 9,231,928 reads with an average read length of 149 bp. Assembled genome had 1 contig, with a total length of 3,021,183 bp and an average G+C content of 46.79%. The protein-coding sequences (CDS) in the genome was 3090, transfer RNA (tRNA) genes were 85 with 29 ribosomal RNA (rRNA) genes and 21 repeat regions. The genome of B. velezensis VB7 had 506 hypothetical proteins and 2584 proteins with functional assignments. VB7 genome had the presence of flagellin protein FlaA with 987 nucleotides and translation elongation factor TU (Ef-Tu) with 1191 nucleotides. The identified ORFs were 3911 with 47.22% GC content. Non ribosomal pepide synthetase cluster (NRPS) gene clusters in the genome of VB7, coded for the anti-microbial peptides surfactin, butirosin A/butirosin B, fengycin, difficidin, bacillibactin, bacilysin, and mersacidin the Ripp lanthipeptide. Antiviral action of VB7 was confirmed by suppression of local lesion formation of TSWV in the local lesion host cowpea (Co-7). Moreover, combined application of B. velezensis VB7 with phyto-antiviral principles M. Jalapa and H. cupanioides increased shoot length, shoot diameter, number of flower buds per plant, flower diameter, and fresh weight of chrysanthemum. Further, screening for antifungal action of VB7 expressed antifungal action against Foc in vitro by producing VOC/NVOC compounds, including hexadecanoic acid, linoelaidic acid, octadecanoic acid, clindamycin, formic acid, succinamide, furanone, 4H-pyran, nonanol and oleic acid, contributing to the total suppression of Foc apart from the presence of NRPS gene clusters. Thus, our study confirmed the scope for exploring B. velezensis VB7 on a commercial scale to manage tomato spotted wilt virus, groundnut bud necrosis virus, tobacco streak virus, S. sclerotiorum, and Foc causing panama wilt of banana.

Characterization and Establishment of a Recombinase Polymerase Amplification Assay for Rapid Detection of Tomato Spotted Wilt Virus in Pepper

Tomato spotted wilt virus (TSWV) is one of the most economically destructive and scientifically challenging plant viruses, which has seriously affected the production of commercial crops. At present, there is no effective strategy to control this virus. Therefore, there is an urgent need for a rapid and simple method to detect TSWV, which is of great significance to prevent its spread. In this study, an isolate of TSWV (TSWV-LNTL) infecting pepper from Liaoning Province of northeast China was obtained. A phylogenetic tree based on neighbor-joining using coat protein (CP) gene was established. A rapid method for detecting TSWV by recombinase polymerase amplification (RPA) was established. The phylogenetic tree based on the nucleotide sequences of coat protein (CP) genes of different TSWV isolates showed that the genetic relationship of TSWV-LNTL was most closely related to that of TSWV-LX-Lettuce-12 (Yunnan) and TSWV-TSHL (Shandong) isolates in China. It can be finished at 39 °C for 20 min and then purified by heating at 65 °C for 10 min. The RPA primers were highly specific and no cross-reactivity was detected with other selected viruses infecting pepper. The results of sensitivity test revealed that the detection limit of RPA is 1.0 × 103 copies/μL, which was tenfold lower than that of PCR method. In addition, the RPA method was successfully applied to detect TSWV in field samples. These results reported the occurrence of TSWV on crop in Liaoning Province of northeast China and demonstrated that the established RPA assay provided an effective molecular diagnostic tool for the accurate and rapid detection of TSWV to prevent its spread.

Integration of transcriptomics and network analysis reveals co-expressed genes in Frankliniella occidentalis larval guts that respond to tomato spotted wilt virus infection

Background The gut is the first barrier to infection by viruses that are internally borne and transmitted persistently by arthropod vectors to plant and animal hosts. Tomato spotted wilt virus (TSWV), a plant-pathogenic virus, is transmitted exclusively by thrips vectors in a circulative-propagative manner. Frankliniella occidentalis (western flower thrips), the principal thrips vector of TSWV, is transmission-competent only if the virus is acquired by young larvae. To begin to understand the larval gut response to TSWV infection and accumulation, a genome-assisted, transcriptomic analysis of F. occidentalis gut tissues of first (early L1) and second (early L2 and late L2) instar larvae was conducted using RNA-Seq to identify differentially-expressed transcripts (DETs) in response to TSWV compared to non-exposed cohorts. Results The larval gut responded in a developmental stage-dependent manner, with the majority of DETs (71%) associated with the early L1 stage at a time when virus infection is limited to the midgut epithelium. Provisional annotations of these DETs inferred roles in digestion and absorption, insect innate immunity, and detoxification. Weighted gene co-expression network analysis using all assembled transcripts of the gut transcriptome revealed eight gene modules that distinguish larval development. Intra-module interaction network analysis of the three most DET-enriched modules revealed ten central hub genes. Droplet digital PCR-expression analyses of select network hub and connecting genes revealed temporal changes in gut expression during and post exposure to TSWV. Conclusions These findings expand our understanding of the developmentally-mediated interaction between thrips vectors and orthotospoviruses, and provide opportunities for probing pathways for biomarkers of thrips vector competence.